What conditions/actions will cause the Absolute Encoders to go into the "Set" condition? I have a GTO1600AE/CP4 and when I ran the APAE utility it showed the status of the encoders as "Set". I changed

That is great news. Still have not had a clear night yet to try 3 arc lines, weather forecast is showing early next week .. I think the night of the full moon (typical). When using 3 arc lines, what w

Hi Dean, Thanks for sharing your tracking results using DEC arc modeling, this is very useful information for others looking to try it. Looks like 3 arcs works very well, do you know if 2 arcs works?

I will give that a try on my next clear night. First, I will create a new model with two DEC arcs, with the target DEC arc sitting between the two sample arcs. That way the model straddles equally eit

Thanks Ray. Here is the pnt file. It consists of 22 samples along a DEC arc of -15 degrees from HA -3 to the meridian. With refraction correction turned off the Offset error in HA is -170.12. With ref

That is what I said in my first post to this thread, that others are using this temporarily, but it would be useful to summarize the process for others who are not familiar with the technique to try i

Dean, Actually, you can try DEC ARC modelling now. It is very simple, fast and easy to setup. Here is what you do: 1. Run APCC (I am running latest version (v1.8.2.1) 2. Click Pointing Model tab 3. Cl

Call it what you want Ray, the fact is it does work, as long as you do not use the Offset Error terms with refraction. And it is a lot easier to say than "Building an APPM model by sampling only point

Can anyone, who is using APPM to build DEC ARC models, confirm that enabling refraction correction changes the model terms significantly. You can easily run this test during the day by slewing to any

The problem appears to be related to the Offset Error - Hour Angle term in the model. If this term is checked AND refraction correction unchecked then the model term value in the box is -170.12. If I

Recently I read here on the forum of others using APPM to create DEC arc models and getting good results when doing unguided images so I thought I would give it a try since previous attempts using a w

Roland, I ran the clock test for 12 hours and there was no drift in the time. That would indicate the crystal oscillator is well within the accuracy required since a 0.1% drift would be 43 seconds in

Roland, two tests were requested. The first one I think was to put tape on the mount to measure the RA drift after 24 hours. I believe this was done to check the sidereal rate. Assuming the sidereal r

Thanks Roland, that is a big help. So by checking the time we can check the crystal oscillator. And given the clock is not maintained during the power down state I will run the test with the mount alw

I am not absolutely certain the RA drift is due to an offset in the clock frequency, it is only a possibility among others. But I do like the idea of measuring the clock using the method you described

Hi Christopher, Take a look at the DONUTS article I posted above, ATrack, a software program I developed, follows closely what they did. In other words, to maintain the very high tracking accuracy, AT

The graph shows clearly that a small change in servo sidereal rate will result in a significant drift in RA, 10 arcsec over 700 seconds. Last night ATrack showed an average drift in RA of -0.01500 arc

The ATrack design is very similar to DONUTS, introduced in 2013: https://www.jstor.org/stable/10.1086/670940?seq=1#metadata_info_tab_contents For high precision photometry it is very important that th

Ray, So if I understand correctly, using your scope, unguided, and with APCC corrective tracking, you can plate solve your first image, three hours later plate solve your last image and the difference

Ray, No problem, let me know if you want to discuss further offline. But as I said above, it is not really necessary because ATrack provides excellent tracking with whatever condition the scope/mount