[Aavso-photometry] Fw: Need Advice, CCD photometry;

[Michael Newberry]

> Hi Mike K., Justin P., Michael N., and Tom K.,  thanks gentlemen for your 
> advice and I've written something below to each of you!
>
>  ---
>  Mike K. and Justin P.:
>
>  After you guys mentioned sigma clip processing, I went on a search to 
> find 'better' algorithims and I'm quite satisfied with what I've found. 
> Infact, I have chosen an alogorithm entitled SD mask, which incorporates 
> the best of sigma clip, median, and average.  If you guys have any 
> suggestions on the prefferred settings for these algorithms, I'd love to 
> here them.
>
>  I've also discovered that when combining there's another cool algorithm 
> to use entitled bicubic resampling, do you guys have any experience with 
> this?  Do you also use SD mask or sigma clip when combining your images or 
> just for calibration frames?
>
>  ----
>  Michael N.:
>
>  Most individuals who continue to do photometry in Win32 environment and 
> have been able to resist the IRAF group have mentioned both AIP4WIN and 
> Mira as the top programs to use.  Our University has copies of 
> MaximDL--which we're very content with--but this are our first trials 
> pushing the program to a photometry precision beyond the basic 'input a 
> known standard and deduce the magnitudes for all the other stars in the 
> images' method.   I won't discuss the issues at hand, but I'd love to try 
> Mira AL which I must confess is a bargain: do you guys offer a demo of the 
> program?
>
>  ----
>  Tom K.:
>
>  I wish I would have talked to you before I went out and bought a bunch of 
> books which amazon reviewers claimed had detailed CCD photometry 
> techniques--perhaps I shall now stick to AAVSO referrals!   The 
> combination of AIP4WIN + Berry's book is a very attractive offer and I'm 
> seriously considering trying demos of it along with Mira AL.  Had this 
> been two weeks ago I would of just bought it!
>
>  I'd like to thank you for your suggestions on testing linearity, this has 
> inspired all sorts of other tests that one can think of and I'm VERY 
> excited to try them all.   Unfortunately, these epiphany moments come when 
> you're about to fall asleep and obviously you then can't!   This has 
> certainly answered my question with regards to exposure times and has 
> upgraded me to a more technical testing approach.
>
>  I have three additional questions for you ... =)  :
>  - You mentioned you take 1:1 darks to images, what is your take on the 
> biases?
>  - I'd assume it's better to scale down dark images rather than scale up?
>  - I didn't quite follow the advice on aperature circles.   However, I 
> just noticed an e-mail from you hidden amongst my inbox so I'll rethink 
> the issue and get back to you.
>
>
>  Many thanks to all!
>
>
>
>
>
>
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