Feature request: user initiated meridian flip

darkmatter

I have a feature request: could somebody at ZWO please add a "do meridian flip now" function to the Asiar? Right now all I can do is set how long before reaching the meridian the mount will stop tracking, and that just wastes valuable time. My mount is of itself very simple (Avalon Linear) and doesn't have any "intelligence" of its own. Without an external device like a laptop or Asiair, all it can do is slew - no goto, no guiding, just basic tracking and slewing. So unlike what is said in this thread: https://bbs.astronomy-imaging-camera.com/d/12297-major-issues-with-meridian-flip-please-fix/16 , it's not the mount that decides whether to do a meridian flip. Asiair is in full control of goto's which means it should be possible to have the Asiair perform the flip at any given time.

Light pollution and obstructions often limit me to targets high up in the sky and my scope is fairly long (130mm f/7 refractor) so hitting the tripod is a very real concern, and the meridian flip should be done on time. However the point where tracking needs to stop varies considerably depending on filter wheel orientation. Clear nights are quite rare and often don't even last a whole night so the last thing I need is for my setup to be sitting idle, just waiting for the target to cross the meridian. Ideally what I'd like to see is, when you start an autorun and the target will cross the meridian in 30 minutes or so, Asiair will say "Target crosses meridian soon. Perform flip now?" Or perhaps just when you've done a goto and the scope is close to the mount, you can hit the "do flip now" button and have uninterrupted tracking. Like I said, the meridian flip functionality is already in the Asiair so it looks to me that all that needs to be added is a different triggering mechanism. Any possibility of seeing this anytime soon?

Jarno

w7ay

darkmatter all it can do is slew - no goto, no guiding, just basic tracking and slewing

Like the EQMOD (which is also just a dumb motor controller), any GOTO and meridian flip is done by the software driver, and not by ZWO's code in the ASIAIR.

If you want to pre-stage the flip (I do that all the time), simply tap on the RA field of the GOTO target and reduce it by 1 hour (assuming the actual target is within 1 hour of transiting). Then tap GOTO. The mount should now meridian flip to the temporary target.

You can even home in on the temporary target with plate solves and syncs, so that the next step is accurate right of the bat, and saving a lot of time.

Now chill out until the original target has transited past Meridian, then go back to the RA field and set the RA back to original. After changing the RA back, execute a GOTO.

Since the target is now on the correct side of the pier, the mount should go directly to it without performing yet another meridian flip -- if it is just 15 degrees off, this GOTO should be very fast too. And if you had earlier plate solved and corrected for mount leveling, may not even need to be plate solved and sync'ed again.

I do this (pre-staging meridian flips) all the time when I use ASIAIR because I don't use any of the "auto" functions (just did it for the Cygnus Loop last night, in fact).

Chen

darkmatter

Thanks for your reply Chen. I agree that your method will work, but isn't being able to do astrophotography unattended one of the main selling points of the Asiair? Doing the flip manually and then intervening again an hour later, or else having everything sit around idle for 15, 20, 30 minutes seem like very inefficient solutions to me. Your workaround doesn't seem too hard to execute automatically, and Avalons own StarGo software does have a "force meridian flip" feature so it's certainly possible. In fact, the Asiair seems one of the few mount controllers that doesn't offer this feature. It's a strange omission in my opinion.

Jarno

w7ay

darkmatter unattended one of the main selling points of the Asiair

You have a point, Jarno. ZWO could easily have programmed in the sequence that I just described, and save people a bunch of time waiting. Just automatically move to the temporary target N minutes before transit, do all the pre-work, wait for 30 seconds after transit, and go back to the target.

They could even do a guide recalibration at that temporary target location while waiting for the transit of the real target.

Chen