Can I Get SGP to do Meridian Flip an hour before?

I have an issue with my NexDome rotation while tracking past vertical (zenith):

Lately I’ve been imaging NGC 2841 (Tigers Eye Galaxy). My telescope and dome slit are perfectly aligned and they follow each other as expected throughout the night. However, the tracking of this object goes from W to E as the night progresses and will pass pretty much through the zenith.

The issue I am having is that, with this path, eventually the scope - while still centered in the dome slit - starts to point into the top of the shutter as it tracks beyond the zenith. This starts to occur about 1 hr before SGP wants to do a meridian flip.

So, do I have an issue with my dome setup - even though the telescope and dome slit remain aligned - should the dome be able to recognize this and adjust or does it have no way of knowing that it is pointing into the shutter?

Or is there some way to get the dome and mount to do the meridian flip together an hour early in SGP?

Anyone else experience this? Is this expected behaviour when up near the zenith?

This depends on your mount. If you can enter a negative value in the Pier flip area then your mount can likely do it. If SGP doesn’t allow you to enter a negative value then we don’t have what we need to flip your mount prior to the meridian.


Hi Jared,

The mount is an AP100GTO and I was able to set the time to -60 min. So will see if that does the trick.


General, did setting the time to a negative number work for the meridian flip issue you reported?