8 replies to this topic

[Bgopalak]

Dear All,

 

I have a peculiar problem and I am sure it has been addressed before.  Not sure what to search for in the board.  Pardon me for starting a new thread if this has been addressed.

 

I use NINA with AP Mach2.  My routine is this

 

1. Set AP Mount to face north.  I dont have a polaris visibility, so do this using daytime alignment app

2. Slew to a visible area of sky and plate solve and sync the location to AP Mach2

3. Then search for a target from NINA and hit slew and center

 

 

Invariably everytime, the mount moves the telescope in opposite direction.  A couple of problems I have noticed are

 

1. AP asks you to set the site lat/long in a certain way

2. Nina things the latitude is exactly opposite of where the site says it is.

3. But I thought syncing after platesolving should take care of this. 

 

Any help will hugely be appreciated.

 

Thanks & regards

 

Balaji

[rgsalinger]

I would polar align the mount using one of the techniques that do not require Polaris after the stars are out. I use NINA with my AP Mach2 which can't see Polaris in my observatory. So, I use the NINA TPPA at about DEC 60. I assume that you have the date/time/location correct and saved in the mount.

 

If you are setting up each night de novo then you need to get the mount as close as possible to the one of the park positions. I use Park 5. Then loosen the clutches and tell the mount to park there. Now tighten the clutches. The mount will now know where it is ACTUALLY parked - ALT and AZ. If you're in an observatory you just need to do this once. 

 

Now slew the mount and solve and center and sync and your done. Now run a small APPM model while waiting for full darkness. 

 

This is all in the APCC Pro Manual that you should have. Read it. Also get onto the AP forums and ask questions there. 

Edited by rgsalinger, 02 November 2024 - 11:22 PM.

[Bgopalak]

Thank you so much for the quick reply.  Will look up the AP forum.  I thought I read through the Manual and followed to the tee. Will try again tomorrow and post here when successful.

[bbasiaga]

With the mach 2, you should not need to do the clutch thing. Just open apcc. Connect, unpark,then park in whatever position. This mount can't get lost the way an 1100 can.

If you're going off the map, it's either an initialization error, or wrong date/time/location.

If you have a hand controller and PC, make sure that hand controller is set to slave mode (or whatever its called). In Nina I think you can choose to sync the location from the mount, or from nina to the mount. So make sure which is correct and choose appropriately.

Brian

[rgsalinger]

Well, we agree that the first step is polar alignment. After that, once you do a single plate solve (recal) and then the mount is good to go until you set it up again. It the mount is not polar aligned then it cannot know where it is pointing by reading the encoders. Since there are no homing sensors, there has to be some assumption made at the factory when the encoders were calibrated. So, when I got mine, I leveled it and put it in Park5. Then I polar aligned it. Since then I just start it up (PC clock is good) and it points just fine. If you know better, please explain.  

[bbasiaga]

I was just saying that to get to park 5, it can be done without loosening the clutches.

With a good PA, mine is always within a few minutes of pointing accuracy with no cal points. I always use slew and center via NINA, so I've never really given it a major look. But the errors are small and it only takes two tries to perfectly center.

When I got mine, I just did PA. If I move the mount ma ually, even with the power off, it can still accurately get back to any of the park positions. I assume the absolute position of the encoders are noted and applied in the firmware at the factory.



Brian.

[rj144]

You need to enter in the coordinates.  Plate solving just tells the mount where it is pointing, but it also needs to know your time and coordinates to slew correctly.

[bbasiaga]

Yes of course.   I think I said that in my first reply.   Gross pointing errors (asuming decent PA) are commonly incorrect time/location or incorrect initilization of those parameters in the mount .

 

Maybe the confusion is when I said 'get lost'.   I meant - the mount not knowing where the scope was related to its own axies.  It knows, and won't point the scope West when it thinks its pointing the scope East, for example.   It can however get bad pointing information and get 'lost' in the sky.  With the date off, or the location set to East instead of West longitude, it could point to strange places.   

 

Brian

[rgsalinger]

All mounts need to know initially what the correct date/time/location are. That's a given until the first time you do a plate solve and sync the mount. After that, time/location just don't matter since the mount now knows where it is actually pointing and how to get anywhere else. There's an edge case, here, where you have high resolution encoders and the mount might be checking the actual time to modify its tracking. That can be really useful if you are going unguided.