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RE: [Phishing] - RE: [Phishing] - Re: [Losmandy_users] Re: G11 for astrophotography?


Jul 1, 2007

 


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

#33457 Jul 1, 2007

Just 2 small things..







1- I've never seen PAC fail to no other reason then a user error.



2- Do you have enough sky to shoot 270 mins ???







Regards,







Jose Canela











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



From: Losmandy_users@yahoogroups.com

[mailto:Losmandy_users@yahoogroups.com] On Behalf Of Alan Voetsch

Sent: domingo, 1 de Julho de 2007 6:01

To: Losmandy_users@yahoogroups.com

Subject: [Phishing] - Re: [Losmandy_users] Re: G11 for astrophotography?







Hey Mike,



Well the PAC is supposed to fine tune the polar alignment. If you do a

decent job of

setup, leveling and balancing (all that stuff), get it close with the

PS, and run through

the normal alignment modeling and PAC routines, you should end up with a

pretty darn good

polar alignment. If the results show otherwise (and further PAC runs

don't help), then a

good long drift alignment is what you need to do.



I have never seen field rotation in my images from the FS-102 and G-11.

I do see a field

curvature problem that shows as elongation in the corners away from the

center of the

image. I usually crop that out. I am a 35mm film imager and I guide off

axis with a

Taurus Tracker III, so I won't have as many possible 'rotational' and

flexure issues as

those who use a guidescope. The PAC is far easier and faster than drift

aligning. I know.

When I first started we all drift aligned. I still drift align my LX200

when I need to,

although not since I finished the new observatory almost 2 years ago.



I will say that I specialize in pushing the limits of ALL my equipment

by asking for 270

minute single exposures, and almost always it all does what I ask. 10

years ago i could

barely manage 60 minute exposures. I swear it's a miracle. My biggest

problems now are

from field curvature and focus shifts during those long exposures. Some

may ask why shoot

that long? Well, I'm not usually interested in star clusters amd M42.

I've shot those and

now chase after ever fainter DSOs and I gotta have long shots to get the

faint stuff.

Galaxies are what i crave and other than a 'Rosette' and a 'Veil', all

I've shot in the

last several months are not members of the Milky Way.



Alan



--- Mike Siniscalchi helixgate@... mailto:helixgate%40yahoo.com> > wrote:

> I'm not familiar with PAC but how does that compensate for field

> rotation when imaging for long periods of time?

> With the Losmandy polar alignment scope, I am able to do field drift

> alignments in 30 minutes because the polar scope is that accurate.



Astrophotography: www.pbase.com/avoetsch12952

www.pbase.com/avoetsch12952>











[Non-text portions of this message have been removed]



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

#33461 Jul 1, 2007

Hey Jose,



--- jose canela jcanela@...> wrote:

> Just 2 small things..



> 1- I've never seen PAC fail to no other reason then a user error.



Apparently, I induce user error every once in awhile. 8-)



> 2- Do you have enough sky to shoot 270 mins ?



Yep, if I get an early start in the East (like where the 'Veil' is now) and tracking past

the meridian, it's no problem. Also, Northerly objects can allow even longer exposures.

Theoretically, my fork mounted LX could track from the Eastern horizon all the way to the

western horizon. Depending on declination, that could be 8-10 hours (of course the nights

are not nearly that long this time of year). My single longest was a 330 minute shot of

the 'Bubble' many years ago when I fell asleep for longer than I planned.



This conversation is putting the thought into my head that I ought to try to break that

record. M27 would be a good target for that. I shot it last year with exposures of 4 and

5 hours. I would love to see if that outer shell will show on film, no luck so far

though.



Alan















Astrophotography: www.pbase.com/avoetsch12952



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

#33463 Jul 1, 2007

I didn't explain myself right. What I meant with the 270 mins question

was... Doesn't the background affect you with those expositions ?

Perhaps you'll be better off exposing 50 or 60 min subframes... I have

an observatory at Europe's finest skies with no Light pollution

whatsoever and 270 mins sounds a bit too much on any filter.... Canyou

please explain why you expose that much ? I can't see the advantage you

might have...







Jose Canela











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



From: Losmandy_users@yahoogroups.com

[mailto:Losmandy_users@yahoogroups.com] On Behalf Of Alan Voetsch

Sent: domingo, 1 de Julho de 2007 19:00

To: Losmandy_users@yahoogroups.com

Subject: [Phishing] - RE: [Phishing] - Re: [Losmandy_users] Re: G11 for

astrophotography?







Hey Jose,



--- jose canela jcanela@... mailto:jcanela%40comstore.pt> >

wrote:

> Just 2 small things..



> 1- I've never seen PAC fail to no other reason then a user error.



Apparently, I induce user error every once in awhile. 8-)

> 2- Do you have enough sky to shoot 270 mins ?



Yep, if I get an early start in the East (like where the 'Veil' is now)

and tracking past

the meridian, it's no problem. Also, Northerly objects can allow even

longer exposures.

Theoretically, my fork mounted LX could track from the Eastern horizon

all the way to the

western horizon. Depending on declination, that could be 8-10 hours (of

course the nights

are not nearly that long this time of year). My single longest was a 330

minute shot of

the 'Bubble' many years ago when I fell asleep for longer than I

planned.



This conversation is putting the thought into my head that I ought to

try to break that

record. M27 would be a good target for that. I shot it last year with

exposures of 4 and

5 hours. I would love to see if that outer shell will show on film, no

luck so far

though.



Alan



Astrophotography: www.pbase.com/avoetsch12952

www.pbase.com/avoetsch12952>











[Non-text portions of this message have been removed]







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

#33464 Jul 1, 2007

Jose,



I want the dime stuff to show. The kind that won't show on 90 minute exposures. It

doesn't matter if you stack a thousand 60 minute shots, they only go so deep and can't

pickup the dim outer areas.



Alan



--- jose canela jcanela@...> wrote:

> I didn't explain myself right. What I meant with the 270 mins question

> was... Doesn't the background affect you with those expositions ?

> Perhaps you'll be better off exposing 50 or 60 min subframes... I have

> an observatory at Europe's finest skies with no Light pollution

> whatsoever and 270 mins sounds a bit too much on any filter.... Canyou

> please explain why you expose that much ? I can't see the advantage you

> might have...







Astrophotography: www.pbase.com/avoetsch12952



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