On Fri, Jul 23, 2021 at 08:57 AM, Edward Plumer wrote:
Fascinating!? From this video, I am also hard pressed to see how this is not an issue in the Gemini firmware itself since the discontinuity clearly occurs in the HC. When I get back home to my scope, I will try to reproduce as well.
(1)? I lost track of your configurations ... did you see this on both the released and beta version of Gemini firmware??
(2)? To echo an earlier question, can you confirm this only occurs during a slew operation, not during normal sidereal tracking?
(3)? Are you only seeing this around the Meridian, which John relayed is likely to have trickier math?
(4)? If so, do you have any sense of how close you have to be to the meridian during a slew to see the anomaly?
(5)? I gather from your last comment that this does not happen everywhere along the meridian?
As you continue to document this, it might be good to note your lat/lon, time-of-day, rough RA/DEC, etc before the slews to see if there is any pattern that might be useful to someone who knows the code. Also allow others to reproduce the issue by resetting their clock and location in the HC to match your documented occurances.
In the meantime, as a work-around in your automation it might be good to set BOTH "Pause Before Meridian" and "Minutes after Meridian" in NINA to a minute or two, based on what you report for question #4 above. Leave "Max Minutes after Meridian" to the larger value based on WSL. Use the spreadsheet to get consistent values for the other parameters. This should ensure that NINA is not pushing the slew buttons or grabbing bogus coordinates during the window around the meridian.?
I would like to hear whether those settings sufficiently "hide" the occurrence of the anomaly.
By the way, I uploaded a newer version of the spreadsheet with some added round-off error checks.
Edward,?
This issue I do think does lurks at the route of other issues. I experienced it for my self about 6 months ago during galaxy season, but attributed to a configuration problem on my end. I learned to work around the problem buy imaging up to an hour past the meridian.? ?I reported numerous times that I could not get the meridian flip to work correctly. I now realize that the flip did take place, although thank you for your spread sheet. The scope ended up staying on the west side pointing at the ground. I now know the reason for this which I will explain.
I've set a lot of info over to Rene, but this is what I think is happening:
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1. Gemini responds correctly to the coordinates provided by the planetary software to the area of the sky where the bullseye vanishes. This is close to the meridian, but the invisible zone is cone shaped with the tip at the poll star.?
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2. When the bullseye disappears, the scope still responds correctly to co-ordinates given in that general area, even though the bullseye has now appeared in the southern hemisphere. That appearance in the southern hemisphere of the bullseyes and its associated coordinates is why the scope ends up pointing at the ground after a flip attempt for me.?
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I think there must be a translation problem from the internal co-ordinate system to the co-ordinates sent back to the planetary software.? ?I'm sure Rene will get to the bottom of this.?
Peter
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