Just received a new-to-me AP Mach 1. One of the features advertised is avoiding meridian flips by using the meridian delay, positioning the OTA on the east side and letting it move through the meridian during the night. (It would be, I think, in counterweight up position until it passes the Meridian.
Questions: if I correctly program the Mach 1 for, say, 6 hour delay past the Meridian, have the OTA on the east side, have the sequence programmed for an object that is on the east side, will SGP attempt a meridian flip when I run the sequence to center the target? Or, will it center on the target while staying east of the meridian?
If this has been covered in another post, apologies, and a link to the post would be very useful.
It should work if you are not using APCC. I don’t have APCC but I have read that it’s tricky to do what you want it to do if you have APCC. But if you don’t have APCC and you set the Meridian Delay in ASCOM driver to an appropriate value, I don’t see why it wouldn’t work.
SGP does not have a “Meridian Flip” command. All it does is send the coordinates of your target object to the mount and the scope should slew to under the counterweight position (CW higher than the scope) if you want it to do what you said in OP.
If you have a keypad, Meridian Delay in ASCOM driver will override the keypad’s Meridian Delay setting. So it’s best not to use keypad in this situation or scope collision with the pier may happen.
I use Meridian Delay rather frequently. But my guard hairs rise when you mention a 6 hour delay!
How far you can SAFELY delay a flip is totally dependent on two things:
1/ The declination of the target, and
2/ The geometry of your hardware.
Example:
I can safely delay meridian passage only 14 minutes when using a long FL refractor at high declinations, i.e., with the OTA vertical at the meridian. Longer would be feasible at lower declinations without danger of pier contact but, I prefer just to not set M.D. with that particular OTA for safety reasons.
With my 14.5" iDK, I can comfortably use a one hour delay and often do if the target is within an hour east of the meridian at the start of acquisition as it avoids about five minutes of time that would be wasted on an otherwise “useless,” meaning, totally avoidable flip.
This is all transparent to SGP. Just set the flip parameters as usual just as if M.D. were not enabled at all. Or not set them at all for that matter. It matters not whether the flip box is checked or not. Obviously, the mount is not going to flip as it has already been flipped.
I emphasize though, that in setting M.D., it is entirely your responsibility to ensure that whatever delay you set will not result in a pier crash when the scope slews to that target!
I image only with a laptop. I can’t vouch for how adding the AP hand controller into the mix might change things.
Thanks for your thoughtful responses. Yes, I am well aware of the potential problems and will insure no crashes by (1) manually slewing to the target and (2) slewing through the shot to insure no pier crashes before starting the imaging run. Any MD would be a one-off for that target only. Normally I don’t use any MD and I never use the Keypad/HC. I shall be experimenting and promise to be careful.
Your concerns are well put and greatly appreciated.