[Aavso-photometry] Beginner CCD Questions..

[Wolfgang Renz]

Derek

Its no question that it can be and is already done.
Worst what happens with slight field rotation is that you
loose limiting magnitude, your SNRs are a bit lower than
without it and that you might not be able to resolve two
stars in crowded fields or if one has a close companion. 

Just stay away from the zenith and use shorter exposures to
minimize field rotation.

E.g. Mira can derotate and stack images using the nearest-
neighbour algorithm which preservs the SNR.
Its apertures and annuli can be made elliptically to avoid
having to include to much unnecessary sky.

You can submit your obs right from the beginning.
If you don't feel confident, choose a target that others
observe too. Then you can compare the results and
gain confidence.

Did you contact Roland ?

Clear skies
 Wolfgang

-- 
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV = WRe.vsnet = RWG.AAVSO



----- Original Message ----- 
From: "Derek C Breit" <breit_ideas at hotmail.com>
To: "'Wolfgang Renz'" <w_renz at onlinehome.de>
Sent: Friday, August 03, 2007 2:18 AM
Subject: RE: [Aavso-photometry] Beginner CCD Questions..


There is no mention of success..

And I know people are doing Alt Az Photometry..

So I will just do my own thing for awhile.. And when I learn enough, maybe I
will submit some CCD Observations..

Derek



-----Original Message-----
From: Wolfgang Renz [mailto:w_renz at onlinehome.de] 
Sent: Thursday, August 02, 2007 4:41 PM
To: Derek C Breit
Subject: Re: [Aavso-photometry] Beginner CCD Questions..

There was an Alt/Az discussing in April:
http://www.aavso.org/pipermail/aavso-photometry/2007-April/date.html

Clear skies
 Wolfgang

-- 
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV = WRe.vsnet = RWG.AAVSO



----- Original Message ----- 
From: "Derek C Breit" <breit_ideas at hotmail.com>
To: <aavso-photometry at mira.aavso.org>
Sent: Thursday, August 02, 2007 11:37 PM
Subject: [Aavso-photometry] Beginner CCD Questions..

> Can some one answer a question or two..
> 
> I will be using a 12" LX200 in alt az mode, and an ST7 ABG camera..
> 
> Any rough ideas of a general rule for my maximum useable exposure 
> time, what mag I can reach, what would be the minimum exposure time 
> recommended to be useful in regards to noise overwhelming the data, 
> how do I concentrate on areas of the sky with the least rotation from 
> 38 degrees N Latitude?
> 
> Any ideas as to what magnitudes an ST7 can reach in 10,15,20,30,45, 
> 60s . or more?
> 
> I intend on doing NGC 7990 standards in V for starters.
> 
> I am very used to video when it comes to finding targets. My primary 
> question is what exposure time should I start out with to display mag 
> 12 stars in an Auto Dark subtracted image, or a raw image,  with 
> enough signal to see the star above the noise, but not go too much 
> deeper than that so as to not be overwhelmed by field stars when I am 
> still locating the target?
> 
> Also, if anyone would like suggest any other targets to try (as a 
> beginner) feel free.. I already know I can put any star down to mag 
> 12.5 on a CCD Chip..
> 
> Anywhere in the Eastern sky is good..
> 
> TIA..
> 
> Derek