On Mount Guding and Meridian Flips


#1

Hi,

I’m getting ready to do a widefield run and as I will be imaging at around 12 arc seconds/pixel, I don’t need to guide, but want to use the on mount guiding option for dithering. I tried this last week with my T3 piggybacked as a test and SGPro gave me a message when I started a sequence that I could not use the meridian flip option with on mount guiding. Why is this? I would like to set up full night runs which will require flips, but I also have work arounds with slews to the west side then a short wait until my target crosses the meridian to slew back to it. The flips would be better as I don’t have to worry about timing the sequence from night to night.

Also, even at extreme dither, it was quite weak at the 12 arc seconds/pixel scale. Is there a way to bump this up (or a feature request for a future update)? I’m using a Gemini 1 ver 4 1.05 on a Titan.

Thanks,

Frank Z…


Meridian Flip not possible without Platesolving & PHD?
#2

Frank,
I think I know what’s up with the guider. We can fix this fairly easily. You should be allowed to flip and use that guider.

As for the scaling you can try changing your guide rate in the gemini controller. We just send a guide pulse for a certain amount of time. Maybe if you can give us an idea of how long you actually need to get an acceptable dither we can think about scaling the times up.

Thanks,
Jared


#3

Thanks Jared,

I have my Gemini set to 0.5x sidereal and I get good results with that. Even at extreme dither, it didn’t seem to last more than a second or so. For this particular setup, maybe 5 seconds max would give me about a 3 pixel walk. As an feature request, you could allow one to enter the maximum dither time for the on mount guider, equivalent to the dither scale in PHD2.

Thanks,
Frank Z…


#4

Try bumping it up to 0.8x and see if that actually moves it a little more.

Thanks,
Jared


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