Asiair sync and sync to mount question

[LaurenceT]

Although I've been using an Asiair for some time I still confused about these two commands.

The sync option is offered once the the target has been acquired and position validated and the sync to mount option is elsewhere in the menus.

It's the usage and difference between these two that confuses me. I'd be grateful for any comments.

[Tomatobro]

Given that plate solving is used to locate the object I also am confused. According to HPS its something to do with using the phones geo location data to tell the mount where it is but I think it tells the asiair software where the mount is geo wise. Would have been better to use the term sync location rather than the mount?

[LaurenceT]

1 hour ago, Tomatobro said:

Given that plate solving is used to locate the object I also am confused. According to HPS its something to do with using the phones geo location data to tell the mount where it is but I think it tells the asiair software where the mount is geo wise. Would have been better to use the term sync location rather than the mount?

I also saw that YT video from HPS and it didn't help me at all.

[Tomatobro]

I found this on the ASIAIR forum 

When you click on "sync" after a plate solve, you are instructing the telescope mount where it is really pointed at (i.e., the true RA and Declination coordinates), not where the mount thinks the telescope is pointed at before you synced it.

 

If you had previously performed a goto to a star or DSO object in ASIAIR's telescope window, then a "sync and goto" will (1) first do the above, and (2) then move the mount to center that star or DSO object on your sensor.

 

So, before you do a "sync and goto," you *must* have already done a previous goto in the ASIAIR telescope window. Otherwise, it will go to wherever the target was set to when the ASIAIR boots up.

 

If you are using SkySafari, notice that ASIAIR's target object is *not* the same as SkySafari's target object. If you prefer using SkySafari to move the telescope around, what you need to do is (1) perform a goto in SkySafari, (2) switch app to ASIAIR and plate solve, (3) perform a plain Sync (do not use "sync and goto") in ASIAIR, and then (4) switch back to SkySafari and perform a goto in SkySafari to center the object. (You may have to repeat steps 1,2,3,4 once again to get close if you had not previously done a multi-star alignement on the mount; see below).

 

If a star or DSO object is in the ASIAIR catalog, the easiest thing to do is just use the ASIAIR to do everything... select a target object, then click goto, plate solve, and click "sync and goto" in the plate solve window; there is no need to switch apps. There is really no need to use SkySafari anymore, once you have an ASIAIR.

 

If the plate center is already quite close to the target object, the target should then be pretty darn close to the center of the camera sensor after you perform a "sync and goto."

 

You can always do a second plate solve followed by a second "sync and goto," and that should get you really, really close (unless the polar alignment is off by a lot; like many minutes of arc off). You can even do a third pass, but you will find that it is pretty much never needed.

 

[LaurenceT]

Many thanks for that