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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

ASTAP astrometry integration

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Replied by han on topic ASTAP astrometry integration

Hello Schwim,

Probably the best thing is to update the focal ratio & sensor size in Ekos. What you could do is open an unsolved image in the ASTAP viewer. Look to the status bar and you will see the dimensions. Then solve the image in ASTAP or Nova.Astrometry.net and see if the dimensions match with the unsolved image. If they change more then 5% then adapt the focal ratio or sensor size in Ekos. This will be only effective for any new image. To test it with the image in the ASTAP viewer you could overwrite it as shown below.

ASTAP can handle differences up to maybe 30% but solving will be more unreliable. So better correct this.

Han



4 years 4 months ago #45756
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I had some success using ASTAP in Kstars on my Rpi4 running stellarmate last night. Using my primary scope and camera it solved very quickly and every time. However using my guide scope and camera (190 x 50mm and asi290mm) it would not solve at all. A small rectangular window would pop up in the top left of the screen and count up in degrees (e.g. 5(30) then 6(30)...) but then eventually say solver failed. The image size was also displayed in the window and that was the correct image size.
RPi 4B (4gb) running Stellarmate OS
Skywatcher Quattro 250 with f4 coma corrector
Skywatcher Evostar 80ED with 0.85 reducer/flattener
Skywatcher AZ-EQ6,
ASI1600MM Pro with ZWO 8x1.25" EFW,
Guide scope 50x190mm, Guide camera ASI290MM
ZWO EAF focuser
4 years 4 months ago #45779

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Replied by han on topic ASTAP astrometry integration

Carneb,

Can you share an image made by the setup you try to solve?

Han
4 years 4 months ago #45783

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I didn't save any of the images, but I will try to get some tonight and share them here.
RPi 4B (4gb) running Stellarmate OS
Skywatcher Quattro 250 with f4 coma corrector
Skywatcher Evostar 80ED with 0.85 reducer/flattener
Skywatcher AZ-EQ6,
ASI1600MM Pro with ZWO 8x1.25" EFW,
Guide scope 50x190mm, Guide camera ASI290MM
ZWO EAF focuser
4 years 4 months ago #45789

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Replied by han on topic ASTAP astrometry integration

I didn't save any of the images, but I will try to get some tonight and share them here.[/quote]

Yes that will be interesting for me. Focal length of 190 mm hasn't been tested. Try to save a series and drop it somewhere in the web so I can have a look.

To avoid saturation, short or very short exposure times will be beneficial for solving.

Han
4 years 4 months ago #45799

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I've attached 2 images. They are actually fits files but the forum software does not allow fits files for some reason.

File Attachment:

File Name: Light_L_1_...1-14.txt
File Size:4,151 KB

File Attachment:

File Name: NGC7293_Li..._001.txt
File Size:4,151 KB
RPi 4B (4gb) running Stellarmate OS
Skywatcher Quattro 250 with f4 coma corrector
Skywatcher Evostar 80ED with 0.85 reducer/flattener
Skywatcher AZ-EQ6,
ASI1600MM Pro with ZWO 8x1.25" EFW,
Guide scope 50x190mm, Guide camera ASI290MM
ZWO EAF focuser
Last edit: 4 years 4 months ago by Barry Carney. Reason: fix format
4 years 4 months ago #45803
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Replied by han on topic ASTAP astrometry integration

They solve without problems if you overwrite the image height in degrees from 0.37 degrees to 0.97 degrees (in the ASTAP program, stack menu, tab alignment).

The FITS header reports 190 mm focal length. That's is correct.
Pixel size is in the header PIXSIZE1 is 2.9 microns.
The CDELT1, CDELT2 are already specified at 3.258E-4 degrees per pixel . After solving they are 8.8118E-4 degrees per pixel. The CDELT1,2 values overwrite the result from focal length and pixel size.

So the CDELT1, CDELT2 values are wrong in the header. At the moment I don't know where you can correct a value to get CDELT1, CDELT2 corrected.

Han
Last edit: 4 years 4 months ago by han.
4 years 4 months ago #45804

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Replied by S on topic ASTAP astrometry integration

I have had some problems (not with ASTAP) that related to wrong information on the fits header. Maybe a small sanity check and a warning if the values are wrong would help identify these kinds of problems. It was at least not the first thing to my mind when I had trouble, which turned out not to be trouble after all but a bad fits header ;-)
4 years 4 months ago #45805

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Replied by han on topic ASTAP astrometry integration

I have a similar problem with image from a Mac user. The CDELT1,CDELT2 values in the header are also wrong.

Focal length 560 mm
Pixel size 3.8 micrometer. Pixel size 1.4 arcsec/pixel equals 0.000391 degrees/pixel
Dimensions 4656 x 3520 => Image size is 1.82 x 1.37 degrees
CDELT1,2 in header 0.000777 degrees/pixel but should be 0.000391 degrees/pixel

Why are CDELT1,2 wrong ?


image link
dl.free.fr/getfile.pl?file=/gAfdJ7sV
4 years 4 months ago #45813

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I believe I found the issue. INDI::CCD was always using the primary focal length when calculating CDELT1,2. It's now fixed in GIT.
4 years 4 months ago #45822

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Replied by han on topic ASTAP astrometry integration

Does that mean users can also fix it by setting values correct in the ccd driver?
4 years 4 months ago #45823

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It's not set in the driver, it's calculated. So they need to use INDI Nightly or update from GIT. Since this is a major bug, I will also publish it to the stable channel.
4 years 4 months ago #45824

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