RE: [ap-gto] A Heart Stoppping Moment


Apr 18, 2001

 


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

#2288 Apr 18, 2001

Last night I found out how extremely important the end bolt on the 15"

slider bar is to the safety of my telescope(s).



I had just finished balancing my setup on the 900 GTO and was performing the

N-Polar alignment routine. As the scope started slewing towards Polaris, I

watched in horror as my 155 EDFS came sliding down the dovetail plate and I

heard this god awful "CLUNK". If I had anything in my hands at the time I do

not remember all I was thinking was OH SH#%T! I immediately grabbed the

scope(s) (more on that later) and felt a sense of sheer terror, then

embarrassment and then relief that the end bolt on the slider bar had just

saved my entire setup from the jaws of death.



Sitting atop the mount was my 155 w/MaxBright and 31mm Nagler 5. My TMB 105

w/FF and Pentax 67 attached riding piggyback on a DOVE08 and the STV on a

DOVE08 on top of that! What a sight that is! What a terrible thing it would

have been to have $10k+ worth of equipment sent immediately into the junk

pile! I was in my driveway that is paved with concrete.



I cannot thank Astro-Physics enough for having the forethought of designing

that end bolt into their dovetail system! Thank you, thank you, THANK YOU!



I am still shuddering at the though of what might have been.



USE THAT END BOLT! It may someday save your very life!



I was imaging with both scopes later on in the evening. Field Flatteners on

both with the Pentax 67 attached to the TMB and the Nikon F2 on the 155.

Imaged M66, M101 and M13. Light pollution and all I did not retire until

4:30 am.



I am thinking a Rib plate in in order for this heavy setup.



Dialing AP now...



--

Clear Skies!



Mark Jenkins

markj@...

www.pcsincnet.com/astronomy/



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

#2295 Apr 18, 2001

I forgot to mention in my report, that this incident was 100% my fault for

not double checking the tightness of the DOVE15's knobs. I proceeded to

crank down so hard with my "hand tightening" after the incident last night,

that I had to use a ViseGrip to loosen them this afternoon.



The DOVE15 is a wonderfully designed and very strong mounting plate. I did

visit AP today and while there, I picked up a 15" rib plate to accommodate

my momentary lapses of diligence.



Do not think for one moment that this little bolt will save your scope 100%

of the time. I was extremely lucky last night. There is no guarantee that it

will save your scope as it did mine. I know, I talked about this at length

with Marj today.



I inspected the bolt and the plate very closely today. I am discarding the

bolt so as not to use it again for that purpose as a small "ding" is now in

the head of the bolt and a very small "ding" is also present on the DOVE15.

I'm thinking that if this type of event happens repeatedly the "fail-safe"

nature of the bolt and plate will be compromised and will no longer provide

that extra margin of safety. But, if something like this happens repeatedly,

I will have to seek professional help! ;-)



Still not breathing quite right.



Thanks for listening.



Mark



p.s. M13 turned out pretty OK. The polar alignment was not perfect so the

stars are a tiny bit elongated. If you care to look it is on my web site

under New Images. www.pcsincnet.com/astronomy



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

#2296 Apr 18, 2001

Hi Mark, Good point you have made here.



Yes, I totally agree with what you have said. Any time a DOVELM, or a similar Doveplate arangement is used (AP or Losmandy) A safety stop bolt should definitely be used. I use a Stainless 1/4"-20 with my DOVELM placed within a 1/2" square Nylon block. In case it does slip, no cosmetic damage is likely to occur.



Surely the very best set-up is as you mention, a solid (Ribbed) Plate, in which your OTA's (And rings) are firmly attached.

Sure, it's a bit more work, but it's the safest way to go.



I've probably lost hours of sleep thinking about the very same thing that happened to you. I'm very glad you were lucky. Mark



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

#2297 Apr 18, 2001

I've actuually had that happen (my fault entirely) a few weeks back,

and the 8" SCT OTA (no CCD though) hit the ground. It had rained and

my backyard grass was very, very soft so OTA landed safely!

Re-collimation and a bottle of Valium later and I was back in

business. First OTA crash in 45 years of observing and I hope it will

be my very last. My heart certainly won't take anymore incidents like

that.



Glad you incident turned out okay.

--- In ap-gto@y..., Mark Jenkins markj@p...> wrote:

> I forgot to mention in my report, that this incident was 100% my

fault for

> not double checking the tightness of the DOVE15's knobs. I proceeded

to

> crank down so hard with my "hand tightening" after the incident last

night,

> that I had to use a ViseGrip to loosen them this afternoon.

>

> The DOVE15 is a wonderfully designed and very strong mounting plate.

I did

> visit AP today and while there, I picked up a 15" rib plate to

accommodate

> my momentary lapses of diligence.

>

> Do not think for one moment that this little bolt will save your

scope 100%

> of the time. I was extremely lucky last night. There is no guarantee

that it

> will save your scope as it did mine. I know, I talked about this at

length

> with Marj today.

>

> I inspected the bolt and the plate very closely today. I am

discarding the

> bolt so as not to use it again for that purpose as a small "ding" is

now in

> the head of the bolt and a very small "ding" is also present on the

DOVE15.

> I'm thinking that if this type of event happens repeatedly the

"fail-safe"

> nature of the bolt and plate will be compromised and will no longer

provide

> that extra margin of safety. But, if something like this happens

repeatedly,

> I will have to seek professional help! ;-)

>

> Still not breathing quite right.

>

> Thanks for listening.

>

> Mark

>

> p.s. M13 turned out pretty OK. The polar alignment was not perfect

so the

> stars are a tiny bit elongated. If you care to look it is on my web

site

> under New Images. www.pcsincnet.com/astronomy







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

#2298 Apr 18, 2001

Sounds more like a pants-filling moment!



Gus



Contact Us
This Site's Privacy Policy
Google's privacy policies

S
e
n
i
o
r
T
u
b
e
.
o
r
g