Question about the values ​​in the fits header (Mount offset) and batch processing (SQM) after solve

[Jean-Pierre NICOLAS]

Hello
I would like to perform some analyzes and graphs on data calculated by ASTAP, in particular offset mount and SQM values.
1 - After astrometric solving, a new line is added in the fits header: COMMENT 7 ' Solved in 0.4 sec. Offset 0.0". Mount offset RA=-1.4", DEC=1.0"'
Regarding the Mount offset values, is it actually the difference between the pointing value of the mount and the astrometric resolution of the image?
In my case, the pointing error of my mount (10Micron GM2000HPS), I have an error of 1.4" in RA and 1.0" in DEC. That's right ?
And what is the first Offset 0.0" value which is always 0.0"?

2 - When I use the "Tools/SQM report based on an image" menu, I get the SQM value.
To calculate the SQM value on all of my images, I select the "Batch processing/Batch solve images FITTS & TIFF" menu. Beforehand, I select the "Add limiting magnitude and SQM" option.
After batch processing, when I look at the fits header of the images, the limit magnitude value is present. But no SQM value!
Am I doing something wrong?

Thank you for your reply.

Jean-Pierre

[han.k]

Hello Jean-Pierre,

The first value is the search offset. There is something wrong there. It should produce something like:
COMMENT 7 ' Solved in 0.2 sec. Offset 2.9'. Mount offset RA=1.5', DEC=2.4''

If you specify a different start point the offset should increase.

The SQM value is not added if a pedestal value is missing. It is reported in the log as:

20:28:24 Can not measure SQM. Add fixed pedestal value in SQM menu. De pedestal value is the median dark or bias value

That is probably confusing. I will add a simular message to the FITS header. I will do that tomorrow.
Add the pedestal value in the SQM menu, shortcut CTRL+Q. Then you get something like:

SQM = 1.794828562868E+001 / Sky background [magn/arcsec^2]
COMMENT SQM , used 100 as pedestal value

Cheers, Han

[han.k]

It is fixed in the code but I'm busy with an improvement of the solver which takes maybe two more days. So the release to fix this will come after that.

Han

[Jean-Pierre NICOLAS]

Hi Han
No problem, I can still wait :-)

[han.k]

Development version with a fix released for Windows:

http://www.hnsky.org/astap_setup.exe

Linux will follow later in the day. Mac maybe tomorrow.