There is no hard limit just a recommendation. A resolution of 1280x 960 should work. If you could provide a download link to some image(s) made with the 120mm-s camera, i could have a look and investigate. You could also upload them to nova.astrometry.net and give me the link(s) to the result.
I just checked ASTAP on two images 1280x960, I found on the internet and they solve without problems. It helps if you set the tolerance from 0.005 to 0.007. To find the correct image dimensions in degrees, you could load the image in ASTAP and try "auto" image height and ASTAP will try all all sizes. If it founds a solution watch the change in image height and if it change more then 5%, correct the focal length in INDI/EKOS accordingly:
Just to report results of my testing - I used ASTAP couple of nights and so far no issues, except if I try to go to an image, taken from previous session which has long exposure of 1200s. Looks like ASTAP is finding too many stars and gets lost.
My work around is - if I plan to shoot same object multiple nights (which I normally do), I save a "go to" Lum image with bin 2 and 5s exposure and then use it for targeting during subsequent sessions.
Many thanks to Han and Jasem for integrating ASTAP! So far it seems more reliable and much faster at solving, as long as you dont ask it to do blind solving.
Good. Auto is only intended to find the image scale. It will just go trough all image scales. Once you know the image height, adapt focal length accordingly.
There was a problem with image scale of the guide scope focal length which was fixed two weeks ago. I don't know which version this is:
>> knro wrote:
>>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.
>>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.
Normally you don't have to worry about the values once they are set correctly. If you load an image in ASTAP, you can read the image dimensions in degrees in the viewer statusbar or in the alignment tab the image height as calculated from the header info. So below as indicated 1.32 degrees. You can overwrite this value (fro solving) by entering a manual value there. This is also handy if you try to solve a jpeg or raw file. This value is stored (save settings or by a solve) until new info is read from the header or command line overrides.
If you select in ASTAP temporary the external local Astrometry.net solver, there is a small calculator included intended for Astrometry.net commandline but could be used to check the values. In the example below, I typed a focal length of 580 mm and pixel size of 5 micrometer resulting in an pixel scale of 1.78" and image dimensions 1.15 x0.869 degrees. The correct pixel size should have been 7.8 micrometer and then the image height will match with the header value above of 1.32 degrees. The calculator values or only used for Astrometry.net command line not for the internal solver.
The image scale should be correct within 5% for best performance but offsets of 30 or 40% could still produce a valid solution.
I'm trying by clicking on load and solve from ekos, but it always fails. I see that when I do this, the image vertical dimension is always 1 degree, even if my FOV is different. It seems all my settings, like focal lenght and CCD data, are not taken into account when using load and solve. Is this the expected behaviour?
Go to the mount tab (tripod icon) on ekos and make sure your focal length is correctly set up there. Try saving the config , move back to align tab switch between the camera's and confirm the FOV is correct in Ekos before you hit solve.
If the suggestion of tkottary doesn't work, then you should install the latest nightly build INDI. What I understand is that there was a bug in the pixel scale reporting (keywords CDELT1, 2). Unfortunately there is no way to add an additional command line command in EKOS to override the FOV
There is a simple way to override the FOV setting (my previous remark was incorrect) . You can just enter it in the command line as show below. Just add something like :
This will override and other FOV (focal length, sensor size) setting. So once you found out the image height in degrees just add this value in the command line. Note that -fov auto doesn't work. This only works in the viewer. If the solver is more then 2 degrees from the start position the
will show the FOV used.