Re: APPM Image Scale Question and Suggestions


Ray Gralak
 

Hi Marty,

1. With a color camera the appropriate x-scale and y-scale factors to enter are twice the individual pixel dimensions.
In my case I should enter 0.52 rather than 0.26 for each X and Y scale. Is that correct?
This assumes the information you provided is correct (that 2x2 binning results in 1 arc-sec/pixel image scale using the ASI294MC with a 300mm aperature F15 scope).

-Ray


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of mjb87 via groups.io
Sent: Sunday, April 18, 2021 4:26 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM Image Scale Question and Suggestions

[Edited Message Follows]

Thanks. I appreciate the assistance. Here is what I'm taking away so far

1. With a color camera the appropriate x-scale and y-scale factors to enter are twice the individual pixel dimensions.
In my case I should enter 0.52 rather than 0.26 for each X and Y scale. Is that correct? (Not sure I understand why
it would be.)

2. When you later attempt to redo a platesolve on a saved image, and when it reports its estimated actual image
scale, it is reporting the binned scale. In other words, the reason my reported scale was 1.04 is that the actual
unbinned image scale was 0.52 and I was using 2x2 binning. Is that correct? (If so, it might be helpful to modify that
window to emphasize that the reported scale is binned scale.)

3. I may just be asking too much to get good solutions using an f/15 telescope and a camera with small pixels, given
my Bortle 5 skies and with the moon out. One option is to use a camera with a larger pixel size. As evidence of this,
in using a similar camera on my 130mm GTX I still had to do 2x2 binning to get easy solutions. I use a Lodestar X2
as a guide camera on my other setup. It has 8.2x8.4 pixels. I can try that instead of the ASI1600MC-Cool.

4. Other things to try: more tolerance around image scale, less sigma above mean, longer exposures.

Make sense?

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