Re: Collett Focuser Clamp and Cold Weather


Feb 28 8:13 AM

 


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#14068 Feb 28 8:13 AM

From an earlier post I learned that the standard collett focuser clamp

might loosen a bit in cold weather. I plan to use my scope for imaging

with cameras that weigh 2-3 pounds. The coldest weather we get where I

live is around -10F.



What are some of your experiences with the standard collett, and

should I consider getting the optional brass ring focuser clamp instead?



----------------------------

#14071 Feb 28 9:33 AM

Get the compression ring adapter! While I really can't say enough about the performance of my 200ED, Ilost a binoviewer, two TV Click-stop zoom EPs AND a Maxbright diagonal when theyfell out of that collet holder (concrete patio :-(.  That was a $2,000 lossso I feel qualified to comment.  Also, if you say, well, I'll just threadthe collet real tight such that NOTHING can fall out?  Good luck trying toloosen that thing :-(.  I had to buy an oil-filter loosening gadget toloosen the collet after I tried that in response to the binoviewerfiasco.  The compression ring adapter is less than $100 and WELL worththe investment I assure you! Mark



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14072 Feb 28 9:53 AM

Hey mark,  Not to good, I lost a set of Naglers to my concrete patio, so I knowthe feeling, thanks for the heads up on the compression ring.  From:tec-scopes@yahoogroups.com [mailto:tec-scopes@yahoogroups.com] On Behalf Of pandrolmb@...

Sent: Thursday, February 28, 2008 10:33 AM

To: tec-scopes@yahoogroups.com

Subject: Re: [tec-scopes] Collett Focuser Clamp and Cold Weather



----------------------------

#14073 Feb 28 10:02 AM

Am I understanding this correct.....using stock TEC equipment,when it's cold outside there is a chance my camera is going to fall out the backof the focuser tube when tightened firmly by hand pressure alone?Gedas Gallery gedas.ccWeb Page www.w8bya.com

----- Original Message -----From:Roy RamdeenTo: tec-scopes@yahoogroups.comSent: Thursday, February 28, 2008 12:53PMSubject: RE: [tec-scopes] Collett FocuserClamp and Cold Weather

Heymark,  Notto good, I lost a set of Naglers to my concrete patio, so I know the feeling,thanks for the heads up on the compression ring.  From: tec-scopes@yahoogroups.com[mailto:tec-scopes@yahoogroups.com] On Behalf Of pandrolmb@...Sent:Thursday, February 28, 2008 10:33 AMTo: tec-scopes@yahoogroups.comSubject:Re: [tec-scopes] Collett Focuser Clamp and ColdWeather



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#14074 Feb 28 10:16 AM

Gedas, Probably not as YOU are aware of the danger in advance.  I was not sofortunate.  Still, the compression ring adapter is, IMHO, much easier touse and there is less chance of disaster, again, IMO. Mark



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14075 Feb 28 10:35 AM

Would the type of barrel on the diagonal make a difference here? If

the "nose" has the typical undercut - I can see where the collet

might lose grip in cold weather. Less contact area, as the metal

shrinks? Does this sound right?



The tapered "nose" diagonals should allow a better lock by the

collet? More material on the nose without the undercut - therefore

less compression of the "nose"?



I'm trying to wrap my head around this. A rotating collet - assuming

that the barrel of the diagonal or bino-viewers are not slightly

undersized - should be able to put a death grip on any barrel that is

of the correct diameter. Machining lathes use locking collets if I

remember correctly, electric drills, etc, etc.



So, were you guys using undercut diagnoals, or tapered?



Igor









In tec-scopes@yahoogroups.com, pandrolmb@... wrote: >

> Gedas,

>

> Probably not as YOU are aware of the danger in advance. I was not

so > fortunate. Still, the compression ring adapter is, IMHO, much

easier to use and > there is less chance of disaster, again, IMO.

>

> Mark

>

>

>

> **************Ideas to please picky eaters. Watch video on AOL

Living. > (living.aol.com/video/how-to-please-your-picky-eater/rachel-

campos-duffy/ > 2050827?NCID=aolcmp00300000002598)

>



----------------------------

#14076 Feb 28 11:29 AM

Igor, Wrapping you head around it won't bring the camera back, butconsider this.  The collet employs a ring material that isseveral times thicker than the brass compression ring used in the alternateadapter.  It is MOST likely that the thickness of that ring is theculprit when dealing with cold weather contractionproblems.  Depending upon how tight the collet is to begin with, evena 1% thermal contraction loss would make a significant difference in theactual sustained force (grip) that holds your camera in place. Since the brass ring in the alternate adapter is only a fractionof the collet ring's thickness, it will be effected in somewhatlinear fashion suffering only a fraction of the compressionloss due to thermal contraction.  That's MY take anyway;-)   Mark   



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14077 Feb 28 12:11 PM

Mark, I'm with you now that you describe the collet ring. I'm at a

disadvantage here, never having seen the 3545 focuser.



Perhaps this ring material will compress slighly over time given the

number of clamping operations. A tiny bit of compression, combined

with the cold shrinking the diagonal nose and other aluminium parts

producing the "oops" effect.



Also, I'm still wondering about the safely undercut. Some of these

undercuts are very wide. Where would the collet ring be located in

relation to the undercut? If this ring is only grasping part of the

diagonal due to the undercut - this could contribute to the issue?



I'm just speculating here. Have you "miked" the "nose" of the insert

to see if it was undersized slightly? A simple slip of paper wrapped

once around the "nose" should take out any tolerance - and would make

an interesting test. Good paper is very uniform in thickness, and

also offers a "grip" due to it's fibres. A ring pressing uniformely

around it will not cause the paper to compress by much. Paper makes

a great shim. I'm not suggesting the paper over the inserter - but

only for a test.



Two wraps of paper should provide enough thickness, assuming that

the "nose" fits into the collet, that the collet will put a "death

grip" on it.



I've asked Sergei to comment on this, but perhaps this question

should be put to Starlight? Afer all, they make the focuser.



Igor

--- In tec-scopes@yahoogroups.com, pandrolmb@... wrote:

>

> Igor,

>

> Wrapping you head around it won't bring the camera back, but

consider this.

> The collet employs a ring material that is several times thicker

than the

> brass compression ring used in the alternate adapter. It is MOST

likely that

> the thickness of that ring is the culprit when dealing with cold

weather

> contraction problems. Depending upon how tight the collet is to

begin with, even

> a 1% thermal contraction loss would make a significant difference

in the

> actual sustained force (grip) that holds your camera in place.

Since the brass

> ring in the alternate adapter is only a fraction of the collet

ring's

> thickness, it will be effected in somewhat linear fashion

suffering only a fraction

> of the compression loss due to thermal contraction. That's MY

take anyway

> ;-)

>

> Mark

>

>

>

> **************Ideas to please picky eaters. Watch video on AOL

Living.

> (living.aol.com/video/how-to-please-your-picky-eater/rachel-

campos-duffy/

> 2050827?NCID=aolcmp00300000002598)

>







----------------------------

#14078 Feb 28 1:00 PM

Igor, I have not measured any of the aforementioned components, but I can giveyou one more important observation related to the (other) portion of youroriginal concerns.  Unfortunately, there is no apparent standard employedby the different manufacturers of hardware components other than (I believe) EPbarrels and focuser tube diameters.  Different manufacturers use differentundercut designs on the (male) barrels of  EPs and other (male)hardware in an effort to increase integrity of the connections.  As aresult of the missing standards, some "undercuts" channels, grooves, or tapers,on the barrels are located at different distances from the business end of theirproducts.  So there is no guarantee that a compression ring will eventouch such features rendering them useless.  Worse yet, forexample, I've encountered 1-1/4" Tak barrels, that, if used with a common(non-Tak) 1-1/4" compression ring adapter, will result in the brasscompression ring becoming stuck in the groove on the malebarrel.  The two become inseparable :-O?  When that occurs, theONLY way out is by force and the compression ring (spring) typically ends upgetting bent, or kinked, and must be replaced :-(.  IMO though,the AP/Baader tapered barrel design is the most effective if such a featureis really required at all.  Even the tapered barrel is going to distort thecompression ring to some extent though.  I personally would prefer it ifthey would standardize, redesign, or simply eliminate the use ofgrooves and tapers all together.  But that's just me ;-) STEADY skies! Mark   



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14079 Feb 28 1:17 PM

Icompletely agree with you regarding standards.  Why engineers anddesigners decide to come up with these non typical or standard parts is beyondme.  This is not rocket science.  It’s a tube, or part, that isused throughout the industry.  Inoticed that Starlight even has a “short” or custom compressionring set up for use with tapered barrels.  This makes sense to me. The tapered barrel makes sense as well, with the compression rings holding atthe tapered end.  If the ring loosens slightly, the increasing taper keepsit from falling out.  I have had this happen, with no “oops”. 

 Personally,undercuts drive me nuts.  Having a situation develop such as your Takexperience is beyond me.  The fact that this requires the purchaser todetermine what fits with what dimensions or product is another sore spot.  Isend an email to Starlight asking them to comment on the collet.  I seethe 2 compression ring end cap listed as an option.  At least they offer asolution to a problem, which may partly be a design flaw of their own doing.  Also,to  order the part with the compression rings made to fit tapered barrels.   Igor



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#14080 Feb 28 2:52 PM

 ----- Original Message -----From:IVMTo: tec-scopes@yahoogroups.comSent: Thursday, February 28, 2008 9:17PMSubject: RE: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather

Icompletely agree with you regarding standards.  Why engineers anddesigners decide to come up with these non typical or standard parts is beyondme.  This is not rocket science.  It.s a tube, or part, that is usedthroughout the industry.  Inoticed that Starlight even has a .short. or custom compression ring set upfor use with tapered barrels.  This makes sense to me.  The taperedbarrel makes sense as well, with the compression rings holding at the taperedend.  If the ring loosens slightly, the increasing taper keeps it fromfalling out.  I have had this happen, with no .oops.. 

 Personally,undercuts drive me nuts.  Having a situation develop such as your Takexperience is beyond me.  The fact that this requires the purchaser todetermine what fits with what dimensions or product is another sorespot.  Isend an email to Starlight asking them to comment on the collet.  I seethe 2 compression ring end cap listed as an option.  At least they offera solution to a problem, which may partly be a design flaw of their own doing. Also, to  order the part with the compression rings made to fittapered barrels.    Igor



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#14082 Feb 28 7:29 PM

What is the brass ring focuser clamp, and who makes it?

--- In tec-scopes@yahoogroups.com, "Jim McSheehy" trimil@...> wrote:

>

> From an earlier post I learned that the standard collett focuser clamp

> might loosen a bit in cold weather. I plan to use my scope for imaging

> with cameras that weigh 2-3 pounds. The coldest weather we get where I

> live is around -10F.

>

> What are some of your experiences with the standard collett, and

> should I consider getting the optional brass ring focuser clamp

instead?

>



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#14084 Feb 28 9:35 PM

As I understand it, the type of clamp can be selected when a scope is

ordered. TEC buys focusers from Starlight Instruments, and Starlight

makes both types of clamps. Either one can be installed on their focusers.





--- In tec-scopes@yahoogroups.com, "stardoctor5" stardoctor5@...> wrote:

>

> What is the brass ring focuser clamp, and who makes it?

>

> --- In tec-scopes@yahoogroups.com, "Jim McSheehy" trimil@> wrote:

> >

> > From an earlier post I learned that the standard collett focuser clamp

> > might loosen a bit in cold weather. I plan to use my scope for imaging

> > with cameras that weigh 2-3 pounds. The coldest weather we get where I

> > live is around -10F.

> >

> > What are some of your experiences with the standard collett, and

> > should I consider getting the optional brass ring focuser clamp

> instead?

> >

>



----------------------------

#14085 Feb 28 10:24 PM

Or there seems to be an AP 2.7" compatible back? Where doesthat come from? I want that one so I can use the AP rigid extensions and APclampring back. 



From: tec-scopes@yahoogroups.com[mailto:tec-scopes@yahoogroups.com] On Behalf Of JimMcSheehySent: Thursday, February 28, 2008 8:35 PMTo:tec-scopes@yahoogroups.comSubject: [tec-scopes] Re: Collett FocuserClamp and Cold Weather



As I understand it, the type of clamp can be selected when a scopeisordered. TEC buys focusers from Starlight Instruments, andStarlightmakes both types of clamps. Either one can be installed on theirfocusers.

--- In tec-scopes@yahoogro ups.com,"stardoctor5" stardoctor5@ ...> wrote:

>> What is the

brass ring focuser clamp, and who makes it? > > --- In href="mailto:tec-scopes%40yahoogroups.comtec-scopes@yahoogro ups.com,"Jim McSheehy" trimil@> wrote: > >> > From an earlier

post I learned that the standard collett focuser clamp > > might loosen

a bit in cold weather. I plan to use my scope for imaging > > with

cameras that weigh 2-3 pounds. The coldest weather we get where I > >

live is around -10F. > > > > What are some of your

experiences with the standard collett, and > > should I consider

getting the optional brass ring focuser clamp > instead?>>>







----------------------------

#14086 Feb 28 10:52 PM

 ----- Original Message -----From:Dave BaileyTo: tec-scopes@yahoogroups.comSent: Thursday, February 28, 2008 5:24PMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather

Is there a drawing or a description of the twoclamping devices you have been discussing in this thread?ThanksDave Bailey    ----- Original Message -----From:pandrolmb@...To: tec-scopes@yahoogroups.comSent: Thursday, February 28, 2008 12:29PMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather



Igor, Wrapping you head around it won't bring the cameraback, but consider this.  The collet employs a ring materialthat is several times thicker than the brass compression ring usedin the alternate adapter.  It is MOST likely that the thickness of thatring is the culprit when dealing with cold weather contractionproblems.  Depending upon how tight the collet is to begin with,even a 1% thermal contraction loss would make a significant differencein the actual sustained force (grip) that holds your camera inplace.  Since the brass ring in the alternate adapteris only a fraction of the collet ring's thickness,it will be effected in somewhat linear fashion sufferingonly a fraction of the compression loss due to thermalcontraction.  That's MY take anyway ;-)   Mark   





Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14088 Feb 29 5:59 AM

I have the 2.7" compression ring and I got it from Starlight. Mark



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14090 Feb 29 7:20 AM

Mark,



I'm not familiar with the various extensions and adapters - my scope

won't arrive until April. Does the 2.7" adapter allow use of the TEC

field flattener? I thought it was ~3" aperture.



--- In tec-scopes@yahoogroups.com, pandrolmb@... wrote:

>

> I have the 2.7" compression ring and I got it from Starlight.

>

> Mark

>

>

>

> **************Ideas to please picky eaters. Watch video on AOL

Living.

>

(living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/

> 2050827?NCID=aolcmp00300000002598)

>



----------------------------

#14091 Feb 29 7:43 AM

Mark,



Here is a pic of the 2.7" clamp ring adapter from the SI web site:



www.starlightinstruments.com/images/3545-CR-End-Cap.jpg



It looks like it screws or clamps on to the back of the 3.5" focuser

draw tube. If anyone is using this setup with the field flattener and

a camera, I'd like to hear your opinions of it.





> --- In tec-scopes@yahoogroups.com, pandrolmb@ wrote:

> >

> > I have the 2.7" compression ring and I got it from Starlight.

> >

> > Mark

> >

> >

> >

> > **************Ideas to please picky eaters. Watch video on AOL

> Living.

> >

>

(living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/ > > 2050827?NCID=aolcmp00300000002598)

> >

>



----------------------------

#14092 Feb 29 7:53 AM

I also have the compression ring screw clamp from Starlight. Just wanted to add that it provides a shorter light path and I was able to reach focus with my Maxbright binoviewer using the Baader T2 prism diagonal and no glaspath. This was an unexpected and delightful surprise. Paul





-----Original Message-----

From: Jim McSheehy trimil@...>

To: tec-scopes@yahoogroups.com

Sent: Fri, 29 Feb 2008 10:43 am

Subject: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather



Mark,



Here is a pic of the 2.7" clamp ring adapter from the SI web site:



www.starligh tinstruments. com/images/ 3545-CR-End- Cap.jpg



It looks like it screws or clamps on to the back of the 3.5" focuser

draw tube. If anyone is using this setup with the field flattener and

a camera, I'd like to hear your opinions of it.

> --- In tec-scopes@yahoogro ups.com, pandrolmb@ wrote:

> >

> > I have the 2.7" compression ring and I got it from Starlight.

> >

> > Mark

> >

> >

> >

> > ************ **Ideas to please picky eaters. Watch video on AOL

> Living.

> >

>

(living. aol.com/video/ how-to-please- your-picky- eater/rachel- campos-duffy/ > > 2050827?NCID= aolcmp0030000000 2598)

> >

>



----------------------------

#14093 Feb 29 8:05 AM

Mark, You've raised an excellent question/observation.  I don't have the 3"flattener yet, but I'm planning on getting one as well.  I think yourquestion will have to be fielded by Yuri.  Yuri?  BTW:  for anyone who hasn't used one yet, the 3545 FT focuser isa real work-of-art.  In fact, ALL of the Starlight stuff is trulyimpressive!  I bought their power package for the 3545 (recommended forimaging) plus a motor for a second FT that I have on alarge SCT.  The same control set works for both scopes now. A testament to component workmanship and finish is the fact that Ican't seem to keep myself from removing even tiny specs of dust,or very light fingerprint smudges, because the anodized surfacesappear to be flawless, as if they were glass :-).  I'm NOT a"clean freak" either.  It just looks THAT good, and functionality iseasily equal to, or maybe even better.  IMO, the 3545 is nothing shortof a GRAND-SLAM. STEADY skies to all! Mark      



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.







----------------------------

#14094 Feb 29 8:24 AM

Maybe its a problem caused by differential contraction. The PBS collet

will have a higher coefficient of expansion than either aluminium or

steel, but the rate of change maybe such that in a rapidly falling

temperature (or where you have a room temperature 'scope taken into a

frigid outdoor environment) the collett doesn't keep up with the

metal's contraction.



Collet chucks have the opposite problem. The workpiece typically warms

up, and can jam in the collet. The secret is to only just nip it up, so

it easier to release afterwards.



The moral of the tale is put your 'scope on grass (or a piece of

astroturf if you've concretized your back yard) that way there's

something to cushion the fall. Grass gives far better local seeing than

concrete in case.



Chris Lord

On 28 Feb 2008, at 18:35, imoirn wrote:



> Would the type of barrel on the diagonal make a difference here? If

> the "nose" has the typical undercut - I can see where the collet

> might lose grip in cold weather. Less contact area, as the metal

> shrinks? Does this sound right?

>

> The tapered "nose" diagonals should allow a better lock by the

> collet? More material on the nose without the undercut - therefore

> less compression of the "nose"?

>

> I'm trying to wrap my head around this. A rotating collet - assuming

> that the barrel of the diagonal or bino-viewers are not slightly

> undersized - should be able to put a death grip on any barrel that is

> of the correct diameter. Machining lathes use locking collets if I

> remember correctly, electric drills, etc, etc.

>

> So, were you guys using undercut diagnoals, or tapered?

>

> Igor



----------------------------

#14095 Feb 29 8:33 AM

That has been my experience with the TMB SuperMono's fitted to my TEC 5

port turret. I dislike undercut eyepiece sleeves, and I dislike lock

screws (plastic or metal) I prefer locking rings or collets. With

either you do not need an undercut sleevepiece.



Just bear in mind you do not have to stick with the PBS collet, there

are beryllium-copper alloy or dural collets too. I have a pair of backs

for my focuser, one with the PBS collet and one with a dural collet. It

is a triflinf matter to swap them over.



Chris Lord

On 28 Feb 2008, at 21:00, pandrolmb@... wrote:



> Worse yet, for example, I've encountered 1-1/4" Tak barrels, that, if

> used with a.common (non-Tak) 1-1/4" compression ring adapter,.will

> result in the brass compression ring becoming.stuck in the groove on

> the male barrel...The two become inseparable :-O?. When that occurs,

> the ONLY way out is by force and the compression ring (spring)

> typically ends up getting bent, or kinked,.and must be replaced.:-(..

> IMO though, the AP/Baader tapered.barrel design is the most effective

> if such a feature is really required at all.. Even the tapered barrel

> is going to distort the compression ring to some extent though.. I

> personally would prefer it if they would.standardize, redesign,.or

> simply eliminate the use of grooves and tapers all together.. But

> that's just me ;-)



----------------------------

#14097 Feb 29 9:03 AM

Well ... If for some reason one can't make the switch to compression ringadapter, then there is always tether insurance to avoid catastropheanyway.  After my $2000 loss, I not only switchedto the 2.7" compression ring adapter, but I tether the diagonalas well ;-). Mark



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.



----------------------------

#14098 Feb 29 9:21 AM

In tec-scopes@yahoogroups.com, Mark wrote:

> BTW: for anyone who hasn't used one yet, the 3545 FT focuser is a

> real work-of-art. In fact, ALL of the Starlight stuff is truly

> impressive!

> IMO, the 3545 is nothing short of a GRAND-SLAM.



Hi Mark (and group),



With all the Collet vs. Compression ring discussion, and since my new

TEC 140 is scheduled to be shipped to me next week (Yeah!) I took the

opportunity to call Yuri and Sergei yesterday and ordered the

compression ring fitting in addition to the standard collet. Hey, for

$90 it's worth the peace of mind to use whatever I decide is the one

for me. I also called Werner at Starlight Instruments who mentioned

he saw the discussion here recently. Werner told me he personally

prefers the collet since it guarantees perfect centering and absolute

on-axis alignment of the diagonal or camera. He also stated Yuri,

being the design perfectionist he is, insists on the collet for these

very reasons. Werner also said he's re-visiting the hard plastic

material used to grip the nose of the diagonal/camera and come up with

a different material that won't allow the slippage experienced by some

in adverse cold conditions.



Dark Clear Steady Skies,

Dave Jessie (Stow, OH)



----------------------------

#14099 Feb 29 10:29 AM

Along with a seating adjustment to accommodate the thinnercollet ring, a thinner ring is really all that is needed.  No need tore-write the book here, Starlight can use the same spring-brass employed byAP, TV and everyone else who makes compression ring adapters.  Thiswas never a perplexing issue, but I'm sure that the original colletring design had its' advantages too.  BTW, one can get excellentcentering for imaging using the 3-point version of the compressionring adapter.  AP/Baader offer 3-point compression ringhardware in a variety of configurations for this very reason. Mark       



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.







----------------------------

#14101 Feb 29 12:23 PM

Paul,That's an exciting thought!Has anyone measured how much the light path isshortened by replacing the collett clamp with the compression ring?ThanksDave Bailey    ----- Original Message -----From:mcp37@...To: tec-scopes@yahoogroups.comSent: Friday, February 29, 2008 8:53AMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather



I also have the compression ring screw clamp from Starlight. Just wantedto add that it provides a shorter light path and I was able to reach focuswith my Maxbright binoviewer using the Baader T2 prism diagonal and noglaspath. This was an unexpected and delightful surprise. Paul

-----Original Message-----From: Jim McSheehytrimil@...>To: tec-scopes@yahoogro ups.comSent: Fri, 29Feb 2008 10:43 amSubject: [tec-scopes] Re: Collett Focuser Clamp and ColdWeather

Mark,

Here is a pic of the 2.7" clamp ring adapter from the SI website:

www.starligh tinstruments. com/images/ 3545-CR-End- Cap.jpg

Itlooks like it screws or clamps on to the back of the 3.5" focuserdrawtube. If anyone is using this setup with the field flattener anda camera,I'd like to hear your opinions of it.

> --- In tec-scopes@yahoogro ups.com,pandrolmb@ wrote:> >> > I have the 2.7" compression ringand I got it from Starlight.> > > > Mark> >

> > > > > > ************ **Ideas to pleasepicky eaters. Watch video on AOL> Living. > >>(living. aol.com/video/ how-to-please- your-picky- eater/rachel- campos-duffy/>> 2050827?NCID= aolcmp0030000000 2598)>>>



----------------------------

#14102 Feb 29 1:29 PM

Intrigued by this discussion about the looseness/tightness ofthe stock collet in cool weather it forced me to run out to the observatory totry it out first hand.  I slipped in two different WO 2" diagonals and gavethe collet ring a pretty good twist with both.  Surprisingly, it was not atall difficult to twist the diagonal right out of the focuser. I then proceededto twist the ring tighter and tighter, but each time still able to twist thediagonal loose and out. I find this very disturbing since my normal load will bean expensive camera. I guess my question is can I apply an extremely firmtwist to the ring without damaging anything inside the assembly? I suspect withmore torque than what I was applying things might solidify but I was afraid toproceed.  Any thoughts on this?Gedas Gallery gedas.ccWeb Page www.w8bya.com



----------------------------

#14103 Feb 29 1:42 PM

Perhaps Yuri could make that measurement and post it. It was a pleasant surprise for me at the Winter Star Party to be able to binoview without the extra magnification. Paul





-----Original Message-----

From: Dave Bailey davealta@...>

To: tec-scopes@yahoogroups.com

Sent: Fri, 29 Feb 2008 3:23 pm

Subject: Re: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather



Paul,That's an exciting thought!Has anyone measured how much the light path is shortened by replacing the collett clamp with the compression ring?ThanksDave Bailey    ----- Original Message -----From: mcp37@...To: tec-scopes@yahoogro ups.comSent: Friday, February 29, 2008 8:53 AMSubject: Re: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather

I also have the compression ring screw clamp from Starlight. Just wanted to add that it provides a shorter light path and I was able to reach focus with my Maxbright binoviewer using the Baader T2 prism diagonal and no glaspath. This was an unexpected and delightful surprise. Paul





-----Original Message-----

From: Jim McSheehy trimil@...>

To: tec-scopes@yahoogro ups.com

Sent: Fri, 29 Feb 2008 10:43 am

Subject: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather



Mark,



Here is a pic of the 2.7" clamp ring adapter from the SI web site:



www.starligh tinstruments. com/images/ 3545-CR-End- Cap.jpg



It looks like it screws or clamps on to the back of the 3.5" focuser

draw tube. If anyone is using this setup with the field flattener and

a camera, I'd like to hear your opinions of it.



> --- In tec-scopes@yahoogro ups.com, pandrolmb@ wrote:

> >

> > I have the 2.7" compression ring and I got it from Starlight.

> >

> > Mark

> >

> >

> >

> > ************ **Ideas to please picky eaters. Watch video on AOL

> Living.

> >

>

(living. aol.com/video/ how-to-please- your-picky- eater/rachel- campos-duffy/

> > 2050827?NCID= aolcmp0030000000 2598)

> >

>



----------------------------

#14106 Feb 29 2:43 PM

Dave,



I have both the collet type and compression type backs for the

focuser. Measuring the overall length of the back, the compression

ring back is 1.5 inches deep and the collet type back is 2.0 inches

deep, so it looks like you would get an additional 0.5 inches of

in-focus with the compression ring back.



Steve Dashiell

--- In tec-scopes@yahoogroups.com, "Dave Bailey" davealta@...> wrote:

>

> Paul,

> That's an exciting thought!

> Has anyone measured how much the light path is shortened by

replacing the collett clamp with the compression ring?

> Thanks

> Dave Bailey

>

>

>

>

> ----- Original Message -----

> From: mcp37@...

> To: tec-scopes@yahoogroups.com

> Sent: Friday, February 29, 2008 8:53 AM

> Subject: Re: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather

>

>

>

> I also have the compression ring screw clamp from Starlight. Just

wanted to add that it provides a shorter light path and I was able to

reach focus with my Maxbright binoviewer using the Baader T2 prism

diagonal and no glaspath. This was an unexpected and delightful surprise.

>

> Paul

>

>

> -----Original Message-----

> From: Jim McSheehy trimil@...>

> To: tec-scopes@yahoogroups.com

> Sent: Fri, 29 Feb 2008 10:43 am

> Subject: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather

>

>

> Mark,

>

> Here is a pic of the 2.7" clamp ring adapter from the SI web site:

>

> www.starlightinstruments.com/images/3545-CR-End-Cap.jpg

>

> It looks like it screws or clamps on to the back of the 3.5" focuser

> draw tube. If anyone is using this setup with the field flattener and

> a camera, I'd like to hear your opinions of it.

>

> > --- In tec-scopes@yahoogroups.com, pandrolmb@ wrote:

> > >

> > > I have the 2.7" compression ring and I got it from Starlight.

> > >

> > > Mark

> > >

> > >

> > >

> > > **************Ideas to please picky eaters. Watch video on AOL

> > Living.

> > >

> >

>

(living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/

> > > 2050827?NCID=aolcmp00300000002598)

> > >

> >

>

>

>

>

---------------

> Supercharge your AIM. Get the AIM toolbar for your browser.

>







----------------------------

#14109 Feb 29 4:10 PM

Thanks Steve,I'm now anxious to try and determine  if1/2 inch might do it.Thanks for doing the measurement!Dave Bailey ----- Original Message -----From:steve_dashiellTo: tec-scopes@yahoogroups.comSent: Friday, February 29, 2008 3:43PMSubject: [tec-scopes] Re: Collett FocuserClamp and Cold Weather

Dave,

I have both the collet type and compression type backs forthefocuser. Measuring the overall length of the back, thecompressionring back is 1.5 inches deep and the collet type back is 2.0inchesdeep, so it looks like you would get an additional 0.5 inchesofin-focus with the compression ring back.

SteveDashiell

--- In tec-scopes@yahoogro ups.com,"Dave Bailey" davealta@.. .> wrote:>> Paul,>That's an exciting thought!> Has anyone measured how much the lightpath is shortened byreplacing the collett clamp with the compressionring?> Thanks> Dave Bailey> > > >

> ----- Original Message ----- > From: mcp37@... > To: tec-scopes@yahoogro ups.com

> Sent: Friday, February 29, 2008 8:53 AM> Subject: Re:[tec-scopes] Re: Collett Focuser Clamp and Cold Weather> >

> > I also have the compression ring screw clamp from Starlight.Justwanted to add that it provides a shorter light path and I was abletoreach focus with my Maxbright binoviewer using the Baader T2prismdiagonal and no glaspath. This was an unexpected and delightfulsurprise.> > Paul> > > -----OriginalMessage-----> From: Jim McSheehy trimil@...>> To: tec-scopes@yahoogro ups.com>Sent: Fri, 29 Feb 2008 10:43 am> Subject: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather> > > Mark,>

> Here is a pic of the 2.7" clamp ring adapter from the SI website:> > www.starligh tinstruments. com/images/ 3545-CR-End- Cap.jpg>

> It looks like it screws or clamps on to the back of the 3.5"focuser> draw tube. If anyone is using this setup with the fieldflattener and> a camera, I'd like to hear your opinions of it.>

> > --- In tec-scopes@yahoogro ups.com,pandrolmb@ wrote:> > >> > > I have the 2.7"compression ring and I got it from Starlight.> > > > >> Mark> > > > > > > > > >> > ************ **Ideas to please picky eaters. Watch video onAOL> > Living. > > >> >> (living. aol.com/video/ how-to-please- your-picky- eater/rachel- campos-duffy/>> > 2050827?NCID= aolcmp0030000000 2598)> >>> >> > >

>------------ --------- --------- --------- --------- --------- ->Supercharge your AIM. Get the AIM toolbar for yourbrowser.>



----------------------------

#14110 Feb 29 3:24 PM

Yuri,I have an Optec Filter Wheel, an Optec Pyxisrotator and an SBIG ST-10XME in the imaging train behind TEC140 #90. With a .63 reducer lens in the nosepiece of the Pyxis (Ted Agos) Ican almost get close to focus.  The comment that the compression ring is shorterthan the collett suggests that it might allow the .63 reducer to beused.What do you think?Dave Bailey   ----- Original Message -----From:mcp37@...To: tec-scopes@yahoogroups.comSent: Friday, February 29, 2008 2:42PMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather



Perhaps Yuri could make that measurement and post it. It was a pleasantsurprise for me at the Winter Star Party to be able to binoview without theextra magnification. Paul

-----Original Message-----From: Dave Bailey davealta@gmail. com>To: tec-scopes@yahoogro ups.comSent:Fri, 29 Feb 2008 3:23 pmSubject: Re: [tec-scopes] Re: Collett FocuserClamp and Cold Weather

Paul,That's an exciting thought!Has anyone measured how much the light path isshortened by replacing the collett clamp with the compressionring?ThanksDave Bailey    ----- Original Message -----From: mcp37@...To: tec-scopes@yahoogro ups.comSent: Friday, February 29, 2008 8:53AMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather

I also have the compression ring screw clamp from Starlight. Justwanted to add that it provides a shorter light path and I was able to reachfocus with my Maxbright binoviewer using the Baader T2 prism diagonal and noglaspath. This was an unexpected and delightful surprise. Paul

-----Original Message-----From: Jim McSheehy trimil@...>To:tec-scopes@yahoogro ups.comSent: Fri, 29 Feb 2008 10:43amSubject: [tec-scopes] Re: Collett Focuser Clamp and ColdWeather

Mark,

Here is a pic of the 2.7" clamp ring adapter from the SIweb site:

www.starligh tinstruments. com/images/ 3545-CR-End- Cap.jpg

Itlooks like it screws or clamps on to the back of the 3.5" focuserdrawtube. If anyone is using this setup with the field flattener andacamera, I'd like to hear your opinions of it.

> --- In tec-scopes@yahoogro ups.com,pandrolmb@ wrote:> >> > I have the 2.7" compression ringand I got it from Starlight.> > > > Mark> >

> > > > > > ************ **Ideas to pleasepicky eaters. Watch video on AOL> Living. >>>(living. aol.com/video/ how-to-please- your-picky- eater/rachel- campos-duffy/>> 2050827?NCID= aolcmp0030000000 2598)>>>



----------------------------

#14111 Feb 29 9:01 PM

--- In tec-scopes@yahoogroups.com, "Dave Bailey" davealta@...> wrote: >

> Yuri,

> I have an Optec Filter Wheel, an Optec Pyxis rotator and an SBIG

ST-10XME in the imaging train behind TEC140 #90. With a .63 reducer

lens in the nosepiece of the Pyxis (Ted Agos) I can almost get close

to focus. > The comment that the compression ring is shorter than the collett

suggests that it might allow the .63 reducer to be used. > What do you think?

> Dave Bailey



Dave, it is appr. 10mm shorter. Yuri



----------------------------

#14112 Mar 1, 2008

Gedas,



You would not be able to do this with the metal collet. The PBS collet

is not designed to grip an eyepiece sleeve so tightly it cannot be

twisted round. The metal one is. The advantage of the PBS collet is

that it will not scratch or score your eyepiece sleeves.



Just take my advice and get two backs, one with each collet type.



Chris Lord

On 29 Feb 2008, at 21:29, Gedas wrote:



> Intrigued by this discussion about the looseness/tightness of the

> stock collet in cool weather it forced me to run out to the

> observatory to try it out first hand.. I slipped in two different WO

> 2" diagonals and gave the collet ring a pretty good twist with both..

> Surprisingly, it was not at all difficult to twist the diagonal right

> out of the focuser. I then proceeded to twist the ring tighter and

> tighter, but each time still able to twist the diagonal loose and out.

> I find this very disturbing since my normal load will be an expensive

> camera. I guess my.question is can I apply an extremely firm twist to

> the ring without damaging anything inside the assembly? I suspect with

> more torque than what I was applying things might solidify but I was

> afraid to proceed.. Any thoughts on this?

> Gedas







----------------------------

#14113 Mar 1, 2008

Thanks Chris.  I sure am glad this came up and saved mepicking up my camera up off the ground.Gedas Gallery gedas.ccWeb Page www.w8bya.com

----- Original Message -----From:Chris LordTo: tec-scopes@yahoogroups.comSent: Saturday, March 01, 2008 4:22AMSubject: Re: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather

Gedas,

You would not be able to do this with the metalcollet. The PBS collet is not designed to grip an eyepiece sleeve so tightlyit cannot be twisted round. The metal one is. The advantage of the PBS colletis that it will not scratch or score your eyepiece sleeves.

Just takemy advice and get two backs, one with each collet type.

Chris Lord

On 29 Feb 2008, at 21:29, Gedaswrote:

Intrigued by thisdiscussion about the looseness/tightness of the stock collet in cool weatherit forced me to run out to the observatory to try it out first hand.  Islipped in two different WO 2" diagonals and gave the collet ring a prettygood twist with both.  Surprisingly, it was not at all difficult totwist the diagonal right out of the focuser. I then proceeded to twist thering tighter and tighter, but each time still able to twist the diagonalloose and out. I find this very disturbing since my normal load will be anexpensive camera. I guess my question is can I apply an extremely firmtwist to the ring without damaging anything inside the assembly? I suspectwith more torque than what I was applying things might solidify but I wasafraid to proceed.  Any thoughts on this? Gedas



----------------------------

#14114 Mar 2, 2008

Group - I emailed Starlight Instruments regarding this problem and

this is Werner's reply.



Thank you for the email and the comments. When the 3545 was designed

we did not have 5 pound cameras and bin-viewers that are as prevalent

as now. The collet design was largely meant for visual and I still

use mine this way.

After havening dropped a Nagler myself, unrelated to the Collet end

cap, you learn to be more cautious. I think this can happen to any of

us. We are more than willing to look into this and will be sending

one of our customers a prototype to see if we can make an improvement

here. My advise to any of the users of the 3545 with the Collet style

end cap is that, if they are going to use expensive and very heavy

equipment, get the Compressing ring end cap and try not to set up on

concrete. You do have our commitment to improve this to meet the more

demanding uses of today.







-- In tec-scopes@yahoogroups.com, "Gedas" w8bya@...> wrote: >

> Thanks Chris. I sure am glad this came up and saved me picking up

my camera up off the ground. > Gedas

>

> Gallery gedas.cc

> Web Page www.w8bya.com

>

> ----- Original Message -----

> From: Chris Lord

> To: tec-scopes@yahoogroups.com

> Sent: Saturday, March 01, 2008 4:22 AM

> Subject: Re: [tec-scopes] Re: Collett Focuser Clamp and Cold

Weather >

>

> Gedas,

>

> You would not be able to do this with the metal collet. The PBS

collet is not designed to grip an eyepiece sleeve so tightly it

cannot be twisted round. The metal one is. The advantage of the PBS

collet is that it will not scratch or score your eyepiece sleeves. >

> Just take my advice and get two backs, one with each collet type.

>

> Chris Lord

>

> On 29 Feb 2008, at 21:29, Gedas wrote:

>

>

> Intrigued by this discussion about the looseness/tightness of

the stock collet in cool weather it forced me to run out to the

observatory to try it out first hand. I slipped in two different WO

2" diagonals and gave the collet ring a pretty good twist with both.

Surprisingly, it was not at all difficult to twist the diagonal right

out of the focuser. I then proceeded to twist the ring tighter and

tighter, but each time still able to twist the diagonal loose and

out. I find this very disturbing since my normal load will be an

expensive camera. I guess my question is can I apply an extremely

firm twist to the ring without damaging anything inside the assembly?

I suspect with more torque than what I was applying things might

solidify but I was afraid to proceed. Any thoughts on this? > Gedas

>



----------------------------

#14205 Mar 24, 2008

I thought I'd throw in some new info to this thread.



I recently installed an SBig ST-10XME+CFW9+AO8. Total of about

5lbs. The nose that I chose to install at first was a tapered nose,

like the one avalable from AstroPhysics. I have found that these are

quite good and better than the grooved safety gap kind. However, I

found that, with the collet, there is no amount of tightening of the

collet that will secure the nose piece in place. Slight amount of

pressure in any direction and the nose piece will easily wiggle out

of the collet. When I replaced the tapered nose piece with a grooved

kind, I experienced the same, but a little less. So, I recommend

with the collet, to only use straight nose pieces for your gear.



Upon closer examination, I discoveed something about the collet

adapter that seems to be refered to in the message that I'm replying

to here, but I didn't catch it at first. Inside the collet there is

an inner split-ring lining made of plastic. It kind of acts as a

compression ring... but it is made of plastic. I noticed on mine

that the two ends of the plastic actually touch together before the

collet is completely tightened. If that happens, the collet will

never get a good grip on the nose piece. I easily removed the

plastic split ring/inner lining and cut off about 1/8" from one end.

This will now allow me to clamp down with the collet all the way.

However, I can still easily wiggle the ST-10 out of the collet in

this configuration. I determined that it is because of the

properties of the plastic allowing it to slip and especially when

used with non-straight nosepieces.



Dave

TEC140 #367







--- In tec-scopes@yahoogroups.com, Chris Lord chrislord@...> wrote:

>

> Maybe its a problem caused by differential contraction. The PBS

collet

> will have a higher coefficient of expansion than either aluminium

or

> steel, but the rate of change maybe such that in a rapidly falling

> temperature (or where you have a room temperature 'scope taken into

a

> frigid outdoor environment) the collett doesn't keep up with the

> metal's contraction.

>

> Collet chucks have the opposite problem. The workpiece typically

warms

> up, and can jam in the collet. The secret is to only just nip it

up, so

> it easier to release afterwards.

>

> The moral of the tale is put your 'scope on grass (or a piece of

> astroturf if you've concretized your back yard) that way there's

> something to cushion the fall. Grass gives far better local seeing

than

> concrete in case.

>

> Chris Lord

>

> On 28 Feb 2008, at 18:35, imoirn wrote:

>

> > Would the type of barrel on the diagonal make a difference here?

If

> > the "nose" has the typical undercut - I can see where the collet

> > might lose grip in cold weather. Less contact area, as the metal

> > shrinks? Does this sound right?

> >

> > The tapered "nose" diagonals should allow a better lock by the

> > collet? More material on the nose without the undercut -

therefore

> > less compression of the "nose"?

> >

> > I'm trying to wrap my head around this. A rotating collet -

assuming

> > that the barrel of the diagonal or bino-viewers are not slightly

> > undersized - should be able to put a death grip on any barrel

that is

> > of the correct diameter. Machining lathes use locking collets if

I

> > remember correctly, electric drills, etc, etc.

> >

> > So, were you guys using undercut diagnoals, or tapered?

> >

> > Igor

>







----------------------------

#14206 Mar 24, 2008

 I am finally replacing the collet with the Astro-Physicslocking adapter this week. It wasn't the never ending wiggle with heavyloads that did it,it was an event where I almost lost my binoviewer, FFC, andpair of25 aspherics to the floor due to the lack of goodtactile feedback with the collet. I have used the AP clamprings for years and theyare dead solid when they grip. I want it to firmly tighten and thenSTOP dead when its as tight as it can be made, that says it's ~locked~in place. The collet is just a  mushyexperience.   No clampring is perfect with every nosepiece (the FT 2"focuser clamp ring was probably the least cooperative) IMHO the AP comesclosest and should be the TEC standard issue ! Especially given theamount of attention that Astro-Physics does to their machining qualityand surface finishes. Then you figure the modularilty/expansion optionsthat AP has with their 2.7" threadedaccessories and it's a sure thing. Mike  



From: tec-scopes@yahoogroups.com[mailto:tec-scopes@yahoogroups.com] On Behalf Ofmogulskier_groupsSent: Monday, March 24, 2008 1:42PMTo: tec-scopes@yahoogroups.comSubject: [tec-scopes] Re:Collett Focuser Clamp and Cold Weather



I thought I'd throw in some new info to this thread.

I recentlyinstalled an SBig ST-10XME+CFW9+ AO8. Total of about 5lbs. The nose thatI chose to install at first was a tapered nose, like the one avalable fromAstroPhysics. I have found that these are quite good and better than thegrooved safety gap kind. However, I found that, with the collet, there is noamount of tightening of the collet that will secure the nose piece in place.Slight amount of pressure in any direction and the nose piece will easilywiggle out of the collet. When I replaced the tapered nose piece with agrooved kind, I experienced the same, but a little less. So, I recommend

with the collet, to only use straight nose pieces for your gear.

Upon closer examination, I discoveed something about the collet

adapter that seems to be refered to in the message that I'm replying tohere, but I didn't catch it at first. Inside the collet there is an innersplit-ring lining made of plastic. It kind of acts as a compression ring...but it is made of plastic. I noticed on mine that the two ends of theplastic actually touch together before the collet is completely tightened.If that happens, the collet will never get a good grip on the nose piece. Ieasily removed the plastic split ring/inner lining and cut off about 1/8"from one end. This will now allow me to clamp down with the collet all theway. However, I can still easily wiggle the ST-10 out of the collet in

this configuration. I determined that it is because of the properties ofthe plastic allowing it to slip and especially when used with non-straightnosepieces.

DaveTEC140 #367

--- In tec-scopes@yahoogro ups.com,Chris Lord chrislord@. ..> wrote:

>> Maybe its a problem

caused by differential contraction. The PBS collet > will have a

higher coefficient of expansion than either aluminium or > steel, but

the rate of change maybe such that in a rapidly falling > temperature (or

where you have a room temperature 'scope taken into a > frigid

outdoor environment) the collett doesn't keep up with the > metal's

contraction. > > Collet chucks have the opposite problem. The

workpiece typically warms > up, and can jam in the collet. The secret

is to only just nip it up, so > it easier to release

afterwards. > > The moral of the tale is put your 'scope on grass

(or a piece of > astroturf if you've concretized your back yard) that way

there's > something to cushion the fall. Grass gives far better local

seeing than > concrete in case.> > Chris Lord>

> On 28 Feb 2008, at 18:35, imoirn wrote:> > > Would the

type of barrel on the diagonal make a difference here? If > > the

"nose" has the typical undercut - I can see where the collet > > might

lose grip in cold weather. Less contact area, as the metal > > shrinks?

Does this sound right? > >> > The tapered "nose" diagonals

should allow a better lock by the > > collet? More material on the nose

without the undercut - therefore > > less compression of the

"nose"? > >> > I'm trying to wrap my head around this. A

rotating collet - assuming > > that the barrel of the diagonal or

bino-viewers are not slightly > > undersized - should be able to put a

death grip on any barrel that is > > of the correct diameter.

Machining lathes use locking collets if I > > remember correctly,

electric drills, etc, etc. > >> > So, were you guys using

undercut diagnoals, or tapered? > >> >

Igor >



----------------------------

#14207 Mar 24, 2008

Right. I spoke with Starlight today and order the "end cap". I

ordered the AP end cap upon recommendation from AP so that I could

use AP 2.7" accessories (part number is FTF3545-EC-AP $68.85).

However, this is just and end cap that you will screw an AP 2"

adapter with 3 lare thumbscrews (ADA2003 $50.00) into. Starlight has

an end cap for $68.85 that inclueds a built in 2" adapter that

includes the 3 large thumbscrews (I don't have part numbe, it is

probably something close to FTF3545-EC). So, for those of you who

aren't interested in switching to the AP accessories, or if you need

the extra 1/2 or so of back focus, you can save $50. Neither of

these are on Starlight's web site. You can order it by phone or

paypal.



--- In tec-scopes@yahoogroups.com, "Mike C" mike@...> wrote:

>

>

> I am finally replacing the collet with the Astro-Physics locking

adapter

> this week. It wasn't the never ending wiggle with heavy loads that

did it,

> it was an event where I almost lost my binoviewer, FFC, and pair of

> 25 aspherics to the floor due to the lack of good tactile feedback

with the

> collet. I have used the AP clamprings for years and they are dead

solid

> when they grip. I want it to firmly tighten and then STOP dead when

its

> as tight as it can be made, that says it's ~locked~ in place. The

collet

> is just a mushy experience.

>

> No clampring is perfect with every nosepiece (the FT 2" focuser

clamp ring

> was probably the least cooperative) IMHO the AP comes closest and

> should be the TEC standard issue ! Especially given the amount of

attention

> that Astro-Physics does to their machining quality and surface

finishes.

> Then you figure the modularilty/expansion options that AP has with

> their 2.7" threaded accessories and it's a sure thing.

>

> Mike

>

>

>

>

> _____

>

> From: tec-scopes@yahoogroups.com [mailto:tec-

scopes@yahoogroups.com] On

> Behalf Of mogulskier_groups

> Sent: Monday, March 24, 2008 1:42 PM

> To: tec-scopes@yahoogroups.com

> Subject: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather

>

>

>

> I thought I'd throw in some new info to this thread.

>

> I recently installed an SBig ST-10XME+CFW9+AO8. Total of about

> 5lbs. The nose that I chose to install at first was a tapered nose,

> like the one avalable from AstroPhysics. I have found that these

are

> quite good and better than the grooved safety gap kind. However, I

> found that, with the collet, there is no amount of tightening of

the

> collet that will secure the nose piece in place. Slight amount of

> pressure in any direction and the nose piece will easily wiggle out

> of the collet. When I replaced the tapered nose piece with a

grooved

> kind, I experienced the same, but a little less. So, I recommend

> with the collet, to only use straight nose pieces for your gear.

>

> Upon closer examination, I discoveed something about the collet

> adapter that seems to be refered to in the message that I'm

replying

> to here, but I didn't catch it at first. Inside the collet there is

> an inner split-ring lining made of plastic. It kind of acts as a

> compression ring... but it is made of plastic. I noticed on mine

> that the two ends of the plastic actually touch together before the

> collet is completely tightened. If that happens, the collet will

> never get a good grip on the nose piece. I easily removed the

> plastic split ring/inner lining and cut off about 1/8" from one

end.

> This will now allow me to clamp down with the collet all the way.

> However, I can still easily wiggle the ST-10 out of the collet in

> this configuration. I determined that it is because of the

> properties of the plastic allowing it to slip and especially when

> used with non-straight nosepieces.

>

> Dave

> TEC140 #367

>

> --- In tec-scopes@yahoogro mailto:tec-scopes%40yahoogroups.com>

ups.com,

> Chris Lord chrislord@> wrote:

> >

> > Maybe its a problem caused by differential contraction. The PBS

> collet

> > will have a higher coefficient of expansion than either aluminium

> or

> > steel, but the rate of change maybe such that in a rapidly

falling

> > temperature (or where you have a room temperature 'scope taken

into

> a

> > frigid outdoor environment) the collett doesn't keep up with the

> > metal's contraction.

> >

> > Collet chucks have the opposite problem. The workpiece typically

> warms

> > up, and can jam in the collet. The secret is to only just nip it

> up, so

> > it easier to release afterwards.

> >

> > The moral of the tale is put your 'scope on grass (or a piece of

> > astroturf if you've concretized your back yard) that way there's

> > something to cushion the fall. Grass gives far better local

seeing

> than

> > concrete in case.

> >

> > Chris Lord

> >

> > On 28 Feb 2008, at 18:35, imoirn wrote:

> >

> > > Would the type of barrel on the diagonal make a difference

here?

> If

> > > the "nose" has the typical undercut - I can see where the collet

> > > might lose grip in cold weather. Less contact area, as the metal

> > > shrinks? Does this sound right?

> > >

> > > The tapered "nose" diagonals should allow a better lock by the

> > > collet? More material on the nose without the undercut -

> therefore

> > > less compression of the "nose"?

> > >

> > > I'm trying to wrap my head around this. A rotating collet -

> assuming

> > > that the barrel of the diagonal or bino-viewers are not slightly

> > > undersized - should be able to put a death grip on any barrel

> that is

> > > of the correct diameter. Machining lathes use locking collets

if

> I

> > > remember correctly, electric drills, etc, etc.

> > >

> > > So, were you guys using undercut diagnoals, or tapered?

> > >

> > > Igor

> >

>







----------------------------

#14208 Mar 24, 2008

> Especiallygiven the amount of attention > thatAstro-Physics does to their machiningquality and surface finishes.  I need a bit more tactdon't I? The collet on the TEC is gorgeously produced andprobably wholly adequate for typical single eyepiece viewing with a diagonal.

 I would think a large percentage of people buying thesescopes use them with heavy visual setups or ccd cameras, and themodular/threaded/tactile AP solution would be optimum. Mike  

From:tec-scopes@yahoogroups.com [mailto:tec-scopes@yahoogroups.com] On Behalf OfMike CSent: Monday, March 24, 2008 1:54 PMTo:tec-scopes@yahoogroups.comSubject: RE: [tec-scopes] Re: CollettFocuser Clamp and Cold Weather



 I am finally replacing the collet with the Astro-Physicslocking adapter this week. It wasn't the never ending wiggle with heavyloads that did it,it was an event where I almost lost my binoviewer, FFC, andpair of25 aspherics to the floor due to the lack of goodtactile feedback with the collet. I have used the AP clamprings for years and theyare dead solid when they grip. I want it to firmly tighten and thenSTOP dead when its as tight as it can be made, that says it's ~locked~in place. The collet is just a  mushyexperience.   No clampring is perfect with every nosepiece (the FT 2"focuser clamp ring was probably the least cooperative) IMHO the AP comesclosest and should be the TEC standard issue ! Especially given theamount of attention that Astro-Physics does to their machining qualityand surface finishes. Then you figure the modularilty/ expansionoptions that AP has with their 2.7" threadedaccessories and it's a sure thing. Mike  



From: tec-scopes@yahoogro ups.com[mailto:tec- scopes@yahoogrou ps.com] On Behalf Ofmogulskier_groupsSent: Monday, March 24, 2008 1:42PMTo: tec-scopes@yahoogro ups.comSubject: [tec-scopes]Re: Collett Focuser Clamp and Cold Weather



I thought I'd throw in some new info to this thread.

I recentlyinstalled an SBig ST-10XME+CFW9+ AO8. Total of about 5lbs. The nose thatI chose to install at first was a tapered nose, like the one avalable fromAstroPhysics. I have found that these are quite good and better than thegrooved safety gap kind. However, I found that, with the collet, there is noamount of tightening of the collet that will secure the nose piece in place.Slight amount of pressure in any direction and the nose piece will easilywiggle out of the collet. When I replaced the tapered nose piece with agrooved kind, I experienced the same, but a little less. So, I recommend

with the collet, to only use straight nose pieces for your gear.

Upon closer examination, I discoveed something about the collet

adapter that seems to be refered to in the message that I'm replying tohere, but I didn't catch it at first. Inside the collet there is an innersplit-ring lining made of plastic. It kind of acts as a compression ring...but it is made of plastic. I noticed on mine that the two ends of theplastic actually touch together before the collet is completely tightened.If that happens, the collet will never get a good grip on the nose piece. Ieasily removed the plastic split ring/inner lining and cut off about 1/8"from one end. This will now allow me to clamp down with the collet all theway. However, I can still easily wiggle the ST-10 out of the collet in

this configuration. I determined that it is because of the properties ofthe plastic allowing it to slip and especially when used with non-straightnosepieces.

DaveTEC140 #367

--- In tec-scopes@yahoogro ups.com,Chris Lord chrislord@. ..> wrote:

>> Maybe its a problem

caused by differential contraction. The PBS collet > will have a

higher coefficient of expansion than either aluminium or > steel, but

the rate of change maybe such that in a rapidly falling > temperature (or

where you have a room temperature 'scope taken into a > frigid

outdoor environment) the collett doesn't keep up with the > metal's

contraction. > > Collet chucks have the opposite problem. The

workpiece typically warms > up, and can jam in the collet. The secret

is to only just nip it up, so > it easier to release

afterwards. > > The moral of the tale is put your 'scope on grass

(or a piece of > astroturf if you've concretized your back yard) that way

there's > something to cushion the fall. Grass gives far better local

seeing than > concrete in case.> > Chris Lord>

> On 28 Feb 2008, at 18:35, imoirn wrote:> > > Would the

type of barrel on the diagonal make a difference here? If > > the

"nose" has the typical undercut - I can see where the collet > > might

lose grip in cold weather. Less contact area, as the metal > > shrinks?

Does this sound right? > >> > The tapered "nose" diagonals

should allow a better lock by the > > collet? More material on the nose

without the undercut - therefore > > less compression of the

"nose"? > >> > I'm trying to wrap my head around this. A

rotating collet - assuming > > that the barrel of the diagonal or

bino-viewers are not slightly > > undersized - should be able to put a

death grip on any barrel that is > > of the correct diameter.

Machining lathes use locking collets if I > > remember correctly,

electric drills, etc, etc. > >> > So, were you guys using

undercut diagnoals, or tapered? > >> >

Igor >



----------------------------

#14209 Mar 24, 2008

wouldn't it be nice if the scopes came with an attachment point to

attach a safety strap too? Does anyone have a recommendation for a

safety strap (ok, we call them "Oh Sh#t Straps"). Al heavy gear,

like binoviewers, cameras, etc, should come with attachment points

for these kinds of straps.



The mfgrs keeps saying that you should take precautions of your own,

etc. But they have to remember that we're fiddling around with this

stuff in the dark and we're mostly dilerious with little or no sleep

and not functioning at 100%. A little help here would go a long way.



Dave

--- In tec-scopes@yahoogroups.com, "Mike C" mike@...> wrote:

>

>

> I am finally replacing the collet with the Astro-Physics locking

adapter

> this week. It wasn't the never ending wiggle with heavy loads that

did it,

> it was an event where I almost lost my binoviewer, FFC, and pair of

> 25 aspherics to the floor due to the lack of good tactile feedback

with the

> collet. I have used the AP clamprings for years and they are dead

solid

> when they grip. I want it to firmly tighten and then STOP dead when

its

> as tight as it can be made, that says it's ~locked~ in place. The

collet

> is just a mushy experience.

>

> No clampring is perfect with every nosepiece (the FT 2" focuser

clamp ring

> was probably the least cooperative) IMHO the AP comes closest and

> should be the TEC standard issue ! Especially given the amount of

attention

> that Astro-Physics does to their machining quality and surface

finishes.

> Then you figure the modularilty/expansion options that AP has with

> their 2.7" threaded accessories and it's a sure thing.

>

> Mike

>

>

>

>

> _____

>

> From: tec-scopes@yahoogroups.com [mailto:tec-

scopes@yahoogroups.com] On

> Behalf Of mogulskier_groups

> Sent: Monday, March 24, 2008 1:42 PM

> To: tec-scopes@yahoogroups.com

> Subject: [tec-scopes] Re: Collett Focuser Clamp and Cold Weather

>

>

>

> I thought I'd throw in some new info to this thread.

>

> I recently installed an SBig ST-10XME+CFW9+AO8. Total of about

> 5lbs. The nose that I chose to install at first was a tapered nose,

> like the one avalable from AstroPhysics. I have found that these

are

> quite good and better than the grooved safety gap kind. However, I

> found that, with the collet, there is no amount of tightening of

the

> collet that will secure the nose piece in place. Slight amount of

> pressure in any direction and the nose piece will easily wiggle out

> of the collet. When I replaced the tapered nose piece with a

grooved

> kind, I experienced the same, but a little less. So, I recommend

> with the collet, to only use straight nose pieces for your gear.

>

> Upon closer examination, I discoveed something about the collet

> adapter that seems to be refered to in the message that I'm

replying

> to here, but I didn't catch it at first. Inside the collet there is

> an inner split-ring lining made of plastic. It kind of acts as a

> compression ring... but it is made of plastic. I noticed on mine

> that the two ends of the plastic actually touch together before the

> collet is completely tightened. If that happens, the collet will

> never get a good grip on the nose piece. I easily removed the

> plastic split ring/inner lining and cut off about 1/8" from one

end.

> This will now allow me to clamp down with the collet all the way.

> However, I can still easily wiggle the ST-10 out of the collet in

> this configuration. I determined that it is because of the

> properties of the plastic allowing it to slip and especially when

> used with non-straight nosepieces.

>

> Dave

> TEC140 #367

>

> --- In tec-scopes@yahoogro mailto:tec-scopes%40yahoogroups.com>

ups.com,

> Chris Lord chrislord@> wrote:

> >

> > Maybe its a problem caused by differential contraction. The PBS

> collet

> > will have a higher coefficient of expansion than either aluminium

> or

> > steel, but the rate of change maybe such that in a rapidly

falling

> > temperature (or where you have a room temperature 'scope taken

into

> a

> > frigid outdoor environment) the collett doesn't keep up with the

> > metal's contraction.

> >

> > Collet chucks have the opposite problem. The workpiece typically

> warms

> > up, and can jam in the collet. The secret is to only just nip it

> up, so

> > it easier to release afterwards.

> >

> > The moral of the tale is put your 'scope on grass (or a piece of

> > astroturf if you've concretized your back yard) that way there's

> > something to cushion the fall. Grass gives far better local

seeing

> than

> > concrete in case.

> >

> > Chris Lord

> >

> > On 28 Feb 2008, at 18:35, imoirn wrote:

> >

> > > Would the type of barrel on the diagonal make a difference

here?

> If

> > > the "nose" has the typical undercut - I can see where the collet

> > > might lose grip in cold weather. Less contact area, as the metal

> > > shrinks? Does this sound right?

> > >

> > > The tapered "nose" diagonals should allow a better lock by the

> > > collet? More material on the nose without the undercut -

> therefore

> > > less compression of the "nose"?

> > >

> > > I'm trying to wrap my head around this. A rotating collet -

> assuming

> > > that the barrel of the diagonal or bino-viewers are not slightly

> > > undersized - should be able to put a death grip on any barrel

> that is

> > > of the correct diameter. Machining lathes use locking collets

if

> I

> > > remember correctly, electric drills, etc, etc.

> > >

> > > So, were you guys using undercut diagnoals, or tapered?

> > >

> > > Igor

> >

>







----------------------------

#14211 Mar 24, 2008

I switched to the AP 2.7" threaded backend - I had a surplus of

Astro-Physics extension tubes and 2.7" to 2" adapters available so it

was an easy option. Works very well for me.



Philip



----------------------------

#14215 Mar 25, 2008

Your conclusion is correct. The plastic collet will not grip a smooth

metal surface with the same tension that a metal collet can apply.



It is not difficult to remove the back of the focuser that houses the

collet, and swap it for another with a metal collet (either duralamin

or berylium-copper). Feathertouch will supply spare backplates with a

metal collet.



Also, if memory serves me well, Feathertouch were experimenting with a

different plastic with less resilient properties. It may be worth

asking them how they are progressing.



The advantage of the plastic collet is that there is little probability

of eyepiece sleeves becoming scored.



The disadvantage of a metal collet manifests itself if you take your

telescope from a warm room into freezing air. Insert an accessory into

the collet whilst it is still warm, tighten it securely, and later when

it has cooled to ambient you may well find you cannot remove your

accessory without one hell of a tussle.



Chris Lord

On 24 Mar 2008, at 21:42, mogulskier_groups wrote:



> I thought I'd throw in some new info to this thread.

>

> I recently installed an SBig ST-10XME+CFW9+AO8. Total of about

> 5lbs. The nose that I chose to install at first was a tapered nose,

> like the one avalable from AstroPhysics. I have found that these are

> quite good and better than the grooved safety gap kind. However, I

> found that, with the collet, there is no amount of tightening of the

> collet that will secure the nose piece in place. Slight amount of

> pressure in any direction and the nose piece will easily wiggle out

> of the collet. When I replaced the tapered nose piece with a grooved

> kind, I experienced the same, but a little less. So, I recommend

> with the collet, to only use straight nose pieces for your gear.

>

> Upon closer examination, I discoveed something about the collet

> adapter that seems to be refered to in the message that I'm replying

> to here, but I didn't catch it at first. Inside the collet there is

> an inner split-ring lining made of plastic. It kind of acts as a

> compression ring... but it is made of plastic. I noticed on mine

> that the two ends of the plastic actually touch together before the

> collet is completely tightened. If that happens, the collet will

> never get a good grip on the nose piece. I easily removed the

> plastic split ring/inner lining and cut off about 1/8" from one end.

> This will now allow me to clamp down with the collet all the way.

> However, I can still easily wiggle the ST-10 out of the collet in

> this configuration. I determined that it is because of the

> properties of the plastic allowing it to slip and especially when

> used with non-straight nosepieces.

>

> Dave

> TEC140 #367



----------------------------

#14219 Mar 25, 2008

I just e-mailed SI about those metal collets. My binoviewers have

fallen out TWICE now! :-( Fortunately, I have a timber floor in my

observatory with a lot of give in it, along with carpet. They have

survived the falls without any damage, but it's the last time it will

happen as far as I'm concerned. Time to get this collet business

sorted.

Regards,

Michael.



--- In tec-scopes@yahoogroups.com, Chris Lord chrislord@...> wrote:

>

> Your conclusion is correct. The plastic collet will not grip a

smooth

> metal surface with the same tension that a metal collet can apply.

>

> It is not difficult to remove the back of the focuser that houses

the

> collet, and swap it for another with a metal collet (either

duralamin

> or berylium-copper). Feathertouch will supply spare backplates with

a

> metal collet.

>

> Also, if memory serves me well, Feathertouch were experimenting

with a

> different plastic with less resilient properties. It may be worth

> asking them how they are progressing.

>

> The advantage of the plastic collet is that there is little

probability

> of eyepiece sleeves becoming scored.

>

> The disadvantage of a metal collet manifests itself if you take

your

> telescope from a warm room into freezing air. Insert an accessory

into

> the collet whilst it is still warm, tighten it securely, and later

when

> it has cooled to ambient you may well find you cannot remove your

> accessory without one hell of a tussle.

>

> Chris Lord

>

> On 24 Mar 2008, at 21:42, mogulskier_groups wrote:

>

> > I thought I'd throw in some new info to this thread.

> >

> > I recently installed an SBig ST-10XME+CFW9+AO8. Total of about

> > 5lbs. The nose that I chose to install at first was a tapered

nose,

> > like the one avalable from AstroPhysics. I have found that these

are

> > quite good and better than the grooved safety gap kind. However,

I

> > found that, with the collet, there is no amount of tightening of

the

> > collet that will secure the nose piece in place. Slight amount of

> > pressure in any direction and the nose piece will easily wiggle

out

> > of the collet. When I replaced the tapered nose piece with a

grooved

> > kind, I experienced the same, but a little less. So, I recommend

> > with the collet, to only use straight nose pieces for your gear.

> >

> > Upon closer examination, I discoveed something about the collet

> > adapter that seems to be refered to in the message that I'm

replying

> > to here, but I didn't catch it at first. Inside the collet there

is

> > an inner split-ring lining made of plastic. It kind of acts as a

> > compression ring... but it is made of plastic. I noticed on mine

> > that the two ends of the plastic actually touch together before

the

> > collet is completely tightened. If that happens, the collet will

> > never get a good grip on the nose piece. I easily removed the

> > plastic split ring/inner lining and cut off about 1/8" from one

end.

> > This will now allow me to clamp down with the collet all the way.

> > However, I can still easily wiggle the ST-10 out of the collet in

> > this configuration. I determined that it is because of the

> > properties of the plastic allowing it to slip and especially when

> > used with non-straight nosepieces.

> >

> > Dave

> > TEC140 #367

>






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