ASI 1600mmc plate solve problem

I just received an ASi 1600 and all went well with the imaging session the first night. Last night, the centering action and plate solves seem to result in a large shift in the image location. When I went to calibrate and register all of the subs, a rather large portion of the image was cropped out. There were no changes in any of the settings from the night before. I don’t have access to the logs right now, just curious as to whether any one else has experienced something similar to this with the 1600. Previously, I have been using an STT 8300m with no problems.

Thanks for any help…Gunny

I have an ASI 1600mmc. I can’t say the plate solve issues are directly attributed to the camera. However I can say the inconsident and not centering of SGP and plate solveing continues for me for weeks now. I thought switching to Astrometry from PS2 fixed the problem, but then it began not centering targets or being far off target as I’ve experience before. I’ve been up and down the settings, confirming everything but problem still persists. On July 5th I plate solved using Astrometry for M27 and it was dead center in two attempts. Tonight, it plate solves on M27 placing it in the lower left corner of the frame and says successful. Which is it clearly not. No settings have changed. On July 5th I also plate solved to CED214 and it made 4 attempts, used blind solve even, and failed. Yet CED 214 was in the FOV! My other thread on this issue has yet to have any serious responses and suggestions for fix. So I continue to try and understand the plate solving problems myself.

Hi Shawn,

See my response to the folowing: ASI1600 image download hangs (frame and focus routine).

Really odd behavior with the rotation from one night to the next and with meridian flip…Gunny

I wanted to update this. I had every plate solve and center successful last night. Many of them in just two attempts. One thing I did different, was I took a 10 sec 2x2 image from my park poition, pointing at Polaris. Plate solved it, didn’t apply it to anything just used it so SGP knew where it was pointing. Then I proceeded to plate solve and center Vega which previously was way off. Last night, dead center. Did the same for M57 and the Eastern Veil. Later successfully plate solved CED 214 and M31. Not a single problem. And I used PS2 again which previous was giving me problems. I’m going to test this out again on the weekend when its supposed to be clear here again. Hopefully this is the answer to the plate solve problems I have been having.

I have excellent plate solving (knock on wood SO FAR). ASI1600MM-c. I like that idea - shooting polaris at the start. Are you clearing your sync list in eqmod/ascom?
There is a check box to clear - or append.

I actually don’t have it set to build a sync list. I did previous but disabled that during troubleshooting and never enabled it again.

This is a good idea all the time. It is considered a best practice to run a solve and sync or blind solve and sync at the start of every new (non-permanent) session. In this way you can ensure that SGPro is able to deliver reliable location hint data to the solver for future, in-sequence solves.

Final update on this. We had a marathon three nights of clear here and I continue to have success with plate solving using PS2. Shoot and blind solve from home position of Polaris region, and then off it goes no trouble at all. Quite nice to have this working again properly.

I would recommend NOT using polaris or anything that near the pole if you’re using a GEM, it can cause pretty crazy errors during the sync. Slew off 10 or more degrees and then do your initial solve and sync.


thanks - I found that last night. Since the mount doesn’t really see polaris as home position. It wants to slew a lot to point at it (well to get into a tracking position it would seem).

You say do a blind solve “near pole position”. Is there a way to buy pass the normal solve and go straight to blind? (mine only falls back on blind).

Dunno why but I use to solve in 10 seconds. It now takes minutes. I’m puzzled on that one.

Regardless, the blind solve from home position to start with (which the scope isn’t pointing directly at Polaris anyhow) does work and has continued to work perfectly for me each and every time. Doing anything else, resulted in the exact problem of crazy errors you mention. I spent weeks trying to figure out why plate solving was erratic, centering one object but not another just few degrees away. Made no sense. Then I went against all the nay sayers after reading another user’s posts on this same problem and who suggested the blind solve pointing at Polaris. Worked like a charm.