Plate Solving issues: exposures with DSLRs

aye330

Hi,
I've been giving my ASIAir Pro a good workout recently with a Nikon D5500. I've had some issues with plate solving that I want to report.

In my experience, there are two times when the software dictates the exposure length for plate solving:

during Polar Alignment after rotating 60 degrees
after a GOTO for centering purposes

(A two-second exposure seems to be used and I cannot find a setting that will change this. If it exists, I apologize.)

PA:
During polar alignment, "the second plate solve" always fails. Frequently the focal length resets to "0" and/or thousands of "stars" are found. In rare cases I've been able to advance to the display which is used to adjust the mount, but no data is provided. Just a bunch of "dashes."

As a test, I mounted my 290 mini camera in the telescope and used that for PA instead of the Nikon. The image plate solved almost instantaneously.

GOTO:
Similar failures.

SOLUTION??:
It would seem that the plate-solving routines are optimized for sensitive astro cameras that can deliver a cleaner image in much less time than a DSLR. I think it might be very helpful to allow the user to specify the length of exposure in the two cases I have mentioned. I am glad that DSLR support was added the software and once I'm onto my target, things work well.

Regards,

Paul

w7ay

during Polar Alignment after rotating 60 degrees

With a ZWO camera, there is an EXP button below the large round button on the right of the Polar Alignment window. The current exposure value is displayed below the EXP button. Click on EXP and a set of other exposure values can be selected (just as in the Preview window). I have changed that exposure setting even in the middle of doing Polar Alignment.

If your camera does not have that, you can always use your guide scope to perform Polar Alignment. I just checked and the EXP button in the Polar Alignment window is available with a ASI290-mini guide camera selected as the Main Camera (make sure the focal length of the Main Camera is switched to your guide scope's focal length).

after a GOTO for centering purposes

The Telescope Settings window has "Center EXP Time" selection when you turn on "GoTo Auto-Center."

Chen

aye330

Thanks for replying, Chen.

I have also used the exposure setting during Polar Alignment as you suggest. That setting does not seem to carry through to the next exposure made after rotating in RA by 60 degrees.

I will check the Telescope Settings window more closely. I might have missed that one.

Thanks again,

Paul