5 replies to this topic

[bersonic]

So I just got a new Atlas Pro, and I'm getting really odd guiding results. I have a good polar alignment, no dragging cables, balanced slightly east heavy and camera heavy. In phd2 I seem to be able to guide reasonably well-ish for short stretches, then I get a spike in ra in both directions of about 3", then the star goes back to normal. I've attached the logs, I'd really appreciate some help, I'm tearing my hair out on this one. I did a long run with the guide output disabled to look at the PE, and the spikes seem to show up there as well. (Included in the .zip)

 

Here's the RA drift:

 

And here's the harmonics:

Edited by bersonic, 26 June 2019 - 03:08 PM.

[ChrisWhite]

I'm on my phone, but are you using hystersis? If so, try setting the value to 0. I found that any hystersis value with my atlas gave worse results. Worked with the non pro,might help with yours

[calypsob]

well the atmosphere is going to be different each night, Id recommend you try again 2 or 3 more times, you may get completely different results

[jd200]

Look at the time between successive spikes... if it is in the 7 to 8 minute range, then I suspect that there is a problem with the worm gear.  I had a brand new Atlas Pro that exhibited a spike in RA every 7 to 8 minutes.  Looking at the PHD2 logs, I determined that the spike occurred at the exact interval of the period of the worm gear.  After a couple of nights with the same behavior, I sent my PHD2 logs to the company where I bought the mount, and they sent me a new mount head.  The new mount head did not have that problem.  So I think it was a manufacturing or assembly defect.  

 

If it is a new mount I would contact the place where you bought the mount immediately and establish that you are having a problem, so that if it continues - you have built the case for a replacement.

[jd200]

I'm curious if you ever resolved anything with respect to your problem... 

[betelgeuse91]

Judging from the first two screenshots, it looks like that the spikes occur periodically. Try RA guiding with PPEC and see if it helps. I don't know if this applies to your situation, but I had non-periodic DEC spikes and re-greasing the DEC worm gears seem to help. (I need to monitor this more)

 

I further notice that your mount has full cycle of 500s. The 4th harmonic of that is 125s and that seems like it. So try the PPEC from PHD2. Remember that the PPEC effect comes effectively in after one or two full cycles. 

 

However, this much of spikes could be from non-negligible defect in the worm gears, so contact where you bought the mount with the PHD2 log and see if they recognize this as a defect of the mount. 

Edited by betelgeuse91, 09 August 2019 - 10:39 AM.