ZWO AM5 Polar alignment

[pmrid (Peter)]

I’m finding that my AM5 does not hold PA at all well. Between last night and tonight, it is out by 17 ‘ in RA and 6’ in Dec. Same scope, camera etc. Just 24 hours between the 2 sessions. Does anyone else have similar experience?

[ronson]

Hi Peter,
I don’t have AM5, but do you remove and reinstall the equipment in-between nights and do you use a tripod or a pier? These could affect the PA.

Also have you tried to run the PA procedure two times one after another to confirm the last tightening of the bolts in PA1 hasn’t messed up the PA which PA2 will confirm?

[pmrid (Peter)]

Originally Posted by ronson

Hi Peter,
I don’t have AM5, but do you remove and reinstall the equipment in-between nights and do you use a tripod or a pier? These could affect the PA.

Also have you tried to run the PA procedure two times one after another to confirm the last tightening of the bolts in PA1 hasn’t messed up the PA which PA2 will confirm?

Tripod - no movement or other changes. And yes. I’m familiar with the double PA trick. The scope being used is a short FL (275mm with the reducer) so perhaps that is a fsctor in the accuracy pf the PA routine. But that’s a guess.

[joshman (Josh)]

what kind of ground are you setup on? there might be some slight settling of the setup?

[AdamJL]

Hi Peter. Might be obvious, but are you sure the latches on the side are engaged? They have to be sticking out to be locked in. If the paddles are against the body, you don't have a good lock. Also make sure the azimuth bolts are up against the azimuth knob. And make sure the altitude locks are tightened.

The reason I'm saying this is because I made these mistakes previously and noticed my PA drift.

Lastly, what tripod are you using? Depending on how you've got it connected (e.g. single 3/8 bolt only) it can rotate as the scope slews about. My solution to this was to create (via Josh Bunn) an adapter that prevents rotation.

[pmrid (Peter)]

G’day Adam. Good points but covered. I’m on the ASI carbon fibre tripod with their 200mm riser. This tripod comes with interchangeable sets of feet - both s/steel pointy feet ones and rubber pads. I’ve been using the metal feet since I have it set up on a concrete base and I figured that these would transmit less ground tremors etc.

I’ve noticed that AA+ does something interesting when it returns to the Home Position. It does a little shimmy as if it overshoots the mark and has to go back a bit. So there must be some kind of built-in indexed position it returns to but even so, to my eye, the head is still “off” a bit. I’ll have to try to measure this somehow.

[AdamJL]

Originally Posted by pmrid

G’day Adam. Good points but covered. I’m on the ASI carbon fibre tripod with their 200mm riser. This tripod comes with interchangeable sets of feet - both s/steel pointy feet ones and rubber pads. I’ve been using the metal feet since I have it set up on a concrete base and I figured that these would transmit less ground tremors etc.

I’ve noticed that AA+ does something interesting when it returns to the Home Position. It does a little shimmy as if it overshoots the mark and has to go back a bit. So there must be some kind of built-in indexed position it returns to but even so, to my eye, the head is still “off” a bit. I’ll have to try to measure this somehow.

Hi Peter. The "shimmy" does happen and is normal. If you want to calibrate the home position more accurately, you'll need to use the ASI Mount app on your phone/tablet. The ASCOM driver doesn't allow calibration of the home position, only the ASI Mount app does. I did it with mine and it now returns to a correct level position.