NEQ6 issue

LewisM · #1 10-01-2013, 08:01 PM

Imaging last night, decided to try NGC 1365 for the supernova. It was not far from zenith.

My NEQ6 couldn't track it. Watching the guiding through PHD, you could sit and watch the stars moving - quite rapidly. PHD could not hack keeping up with an obviously slipping mount.

The mount is lightly loaded, well under max. The balance is precise. I know zenith can be a cow for some mounts, but this seemed excessive to me, and I have tracked zenith/near zenith successfully before.

Do I need to pull this mount apart and "tighten up the specs"?I note that the dec scale wheel won't stay put any longer either, even if the thumb screws are locked.

Tracking low to medium alt targets was no problem whatsoever - tracked and guided flawlessly.

Thoughts appreciated.

gbeal · #2 10-01-2013, 08:25 PM

Maybe your balance is too precise Lewis? Perhaps try it so the motor has something to push against.
Gary

LewisM · #3 10-01-2013, 08:32 PM

Yeah, I've heard of that.

I had a friend make me up a small stainless steel counterweight so I could even refine it further, but may use it to give some counter-rotational weight.

Astro_Bot · #4 10-01-2013, 08:38 PM

I'll ask the obvious question: how was unguided tracking against the same target? Any "slippage"?

Where was the Meridian at the time?

I've tracked targets (unguided) at/near zenith and don't have issues. At/near the SCP is a different matter, though.

LewisM · #5 10-01-2013, 08:42 PM

Same. PHD couldn't correct for the slipping.

naskies (Dave) · #6 13-01-2013, 01:30 AM

Was it a polar alignment issue? Problems tracking near zenith - but fine at low altitudes - suggest that you might be misaligned in azimuth but not altitude.

Also, if your mount is slipping - how did you go about calibrating PHD at zenith? (Sorry if this is obvious... but long story short - it's easiest to re-calibrate PHD whenever you point at a different part of the sky.) If PHD's calibration is off, then it'll never be able to fix the drift...

Merlin66 (Ken) · #7 13-01-2013, 05:31 PM

9 times out of 10 it's a result of the changing OTA position and the balancing.....
been there - done that!

LewisM · #8 13-01-2013, 06:21 PM

Quote:

Originally Posted by naskies

Was it a polar alignment issue? Problems tracking near zenith - but fine at low altitudes - suggest that you might be misaligned in azimuth but not altitude.

The alt was 6 secs off. The Az was 2 minutes out initially, and I got that down to 55 secs. Did 3 x 3 star alignments that night after checking and rechecking

Quote:

Originally Posted by naskies

Also, if your mount is slipping - how did you go about calibrating PHD at zenith? (Sorry if this is obvious... but long story short - it's easiest to re-calibrate PHD whenever you point at a different part of the sky.) If PHD's calibration is off, then it'll never be able to fix the drift...

I couldn't calibrate PHD at zenith - I tried, and failed. So, I tried calibrating on Achernar, and then slewing.Still didn't cut the mustard obviously.