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Polar alignment (was: Which G-11 should I get?- Bill)


Jun 14, 2005

 


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

#26011 Jun 14, 2005

Bill,



I hope I'm wrong, but you appear a little close-minded about this

whole topic.



Drift alignment does work and is an excellent, low-tech way of

achieving polar alignment. There are now many hi-tech ways of doing

it. Some are faster, some are more precise, and some are both.



Citing works published years ago accomplishes very little, as many

of the newer methods have been developed in the past couple of years.



PAC is one of them, as is PoleAlignMax. Takahashi mounts have a

computer controlled polar finder that's extremely precise. T-Point

is an excellent way to do it, and most professional observatories

use it or a similar method -- they don't drift align. By the way,

PAC works on the same principle as T-Point, just fewer modeling

terms.



I'd have to say that drift alignment is only one of many excellent

methods available to us today.



I would not recommend making such categorical statements about other

alignment methods until you try them yourself.



Just my $0.02.



Regards,





-Paul



--- In Losmandy_users@yahoogroups.com, "William R. Mattil"

wrmattil@i...> wrote: > Chris Appleton wrote:

>

> >

> >Hi Teri and Bill

> >

> >The PAC works excellent and is much easier and faster then doing

a > >drift align.

> >

>

> But not better ... and that is exactly my point.

>

> > I can image for up to 3 min unguided and 15 min guided

> >(have not tried any longer due to seeing no benefits in my area)

> >with my G11/Gemini.

> >

> >

>

> Again irrelevant. Unless of course one is going to limit

themselves to > 15 minute exposures :)

>

> >Bill, I'm just curious where you live that would permit one hour

of > >a single exposure (no planes, satelites or light pollution)??

> >

>

> Chris, I'm confused by your apparent naivete here. You do realise

that > there are many, many astrophotographers that bundle up the mount

and > gear and travel regularly to nice dark environs ? There are

precious > few people that live under mag 6-7 skies. So what do you think

the rest > of us actually do ? Why is it that you think that this PAC (or

whatever > it's called) is simply magical and instantly allivates the need

to > carefully align to the pole ? I would recommend that you take a

few > minutes and research this. I highly recomend

>

> A Manual of Advanced Celestial Photography by Wallis and Provin

> Widefield Astrophotgraphy by Robert Reeves

>

> And then take the time to observe what other pioneers in this

pastime > have done and how they practice it. You will find that every one

of them > drift align. I am amazed that my taking the time to pass along

wisdom > passed down to me by others would be met with such resistance.

You can > practice your photography any way that you like. But do not waste

> bandwidth here by suggesting that drift aligning a mount is

*wrong*. > Drift aligning a mount will *always* work. Period. PAC might, and

might > not work. Have you ever actually drift aligned a mount ? I am not

trying > to be pendantic here .... seriously. A lot of people are somehow

afraid > of doing it. Probably because thay don't understand it. Most of us

are > drift aligned and ready to take exposures of up to two hours

before it's > actually dark enough to open a shutter anyway. So there isn't any

real > time lost in doing so. Hopefully you aren't so into instant

> gratification that you can't see that this is part of the process

and as > such it is to be enjoyed.

>

> > Are

> >you doing film?

> >

> I do film and CCD and I will not change my proceedure based upon

the > medium with which I am capturing photons.

>

> > With today's ccd camera's sensitivity, you do not

> >have to go beyond 10 to 15 min sub-exposures and then stack them.

> >

> >

>

> Ahh I see you are an expert in CCD then ? :) are you a published

author > and might we read your rationale behind this statement ? laughs>

>

> You have undoubtedly missed the entire point .......... but I'll

try > again ..... you align your mount however you want and place a 35mm

> camera at the prime focus and open the shutter for a one hour

exposure > and then inspect the results. You might be surprised by your

results.... > I won't though because my (and thousands of others) process works

100% > of the time. And that sir is exactly my point.

>

> >Teri, go for the Gemini you will not regret it.

> >

> >

>

> Somehow my statement has been interpreted as "Don't get the

Gemini" ???? > Not hardly. I have a Gemini and it performs well. And after drift

> aligning can handle in excess of one hour exposures on film .....

And I > have plenty of photographic evidence to support my claims.

>

> And another point .... stacking images while extremely useful in

> increasing S/N is not a cure-all for everything. Technique however

is. > Stacking is a useful techique once the other issues are solved.

>

> We now return to our regularly scheduled programming :)

>

> Bill

>

> --

>

> William R. Mattil.:.www.celestial-images.com







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