Re: ATM film

[Brian Nestel <blast@aloha.net>]

Tony Dunlap wrote:
> 
> Well, the weather forecast is looking good, the sky dark, and I took two
> days off of work so I can sit up the nights of the 11th and 12th looking for
> Perseids (I guess I'll drag the scope out too). I am also taking the
> opportunity to try my hand at some piggyback astrophotography. I am brand
> new at this (I'm even borrowing the camera) and wanted to ask for those in
> the know what film I should use (B&W) and what kind of exposure time I
> should use for a fair chance at success. The camera will be piggybacked on
> the scope, and it will be hand guided. Sorry for off topic but I knew
> someone here would know.
Hi:
You didn't say what kind of scope you were going to use, unless you have
a eyepiece with a illuminated reticle or some way of keeping a guide point
centered you may have some problems like elongated stars, etc.
If you are going to be using a dob or a az/el, you will also get some field 
rotation after a few minutes, if you are going to use a equatorial fork or 
gem, this wouldn't be a problem, but you should have something to guide with, 
just trying to keep an object centered in a eyepiece field without a motor
drive or something to reference like a reticle  for a long period can be 
frustrating and may not give you the results you seek.

One thing to do if you don't have the proper accessories for guided
astrophotography is to build a "barn door tracker/Scotch mount", 

http://www98.pair.com/rfields/cgi-bin/DIY/barndoor/index.html
http://www.jlab.org/services/pced/tracker/

Here is a astrophotography link:
http://www2.astronomy.com/astro/hobby/backyard/Imaging/ConstPhoto.html


As far as film goes Kodak has a few color films that have 
good reciprocity failure rates, Pro 400/800 has almost the reciprocity rate of
hypered film, For stuff like meteors I use Royal Gold 1000, I usually do
5 minute exposures , For regular astro-photography I've done 15/20 minute 
exposures with royal gold, and 45 minutes
with Pro 400/800 and have seen no problems. Unless you want to process your 
own film there is not much of a reason to use b/w film any more except for 
cost, If you do want to do B/W, try T-Max for short exposures.
Have fun.
-- 
Aloha   159 30 W, 21 55 N
Brian   Middle of the Pacific,
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