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Set-up issues

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The issue is at the end of this post - but I'll go through set-up etc. 

Despite buying my HEQ5 PRO at the beginning of June, it took until 1st week of September for the Esprit 100 APO to arrive. Its arrival didn't add cloud, merely continued what had been going on since the end of the long fine spell at the end of May.

I know I have more work to do to improve PA for example e.g. I haven't confirmed that the reticle is correctly aligned, but it does seem to be 'OK'. With a camera an a 200mm lens a 200s exposure has little/no evidence of trailing. I had a successful first session with the Esprit about 3 weeks ago and my first image was M31. Not enough subs, but I was impressed with the results considering only about 12m of data.

Now to last night.

I had an orchestra rehearsal last night (yay - been shut down for 7 months) so it was about 22.30 when I got home. Miraculously it was clear. Got scope out, PA was quick. Problem with no prior set-up is getting finder aligned. Mount alignment took a while as until work on garden is completed, I've basically got a 'slot' that runs N - S: Vega was too low, as was Altair, Aldebaran was blocked by house etc. So, took a while to get through alignment process. Used Deneb to focus the Z6 with a Bahtinov mask (the Z6 has focus peaking which helps too).

Headed for NGC 7000. Schoolboy error as ISO was left at 12,800.... so second image... by now clouds coming in from the north. Switched to M31...

Anyway, I had about 15 minutes' of observing time before it clouded over.

Examining the images on the Mac, there's a problem. On all of the images, it looks like it starts then moves. It must then 'settle' as the end point is brighter.

I've attached one of the images - this is a JPEG generated from the RAW file - no processing whatsoever other than re-sizing to post here.

I'm guessing I rushed part of the set-up process and perhaps cable was dragging or similar? I will be adding an RPi with Astroberry and a guidecam shortly.

Would appreciate thoughts.



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Certainly does look like a backlash issue. Might be caused by balance not being quite right.

Depending on which side of the meridian you are imaging, you ideally want to be either weight biassed or scope biassed. 

You really want the gears to be pushing on the load rather than the load falling onto the gear. Hope that makes sense.

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@MarkAR Thanks - yes it does. I suspect the alignment set-up may have been the issue as there were two 90 deg+ shifts from star 1 - 2 then 2 - 3.

The Losmandy bar is too short - it's only about 8 inches long so no scope for using is to adjust balance and it was definitely 'tail heavy'.

To be fair... it was all a bit rushed and I was setting up in the dark, so I might have missed something obvious. Previous runs I haven't had this issue but I did initial set-up and balance in daylight.

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There are a few of us here that use the Raspberry Pi with EKOS for data acquisition so I'm also happy to help when that arrives.

Is the mount a "normal" one or is it the Rowan belt modded one?

I had an issue with my HEQ5 Rowan in something had come loose and it developed a slight clunk in the RA - the whole of the RA assembly could be moved a bit with slight pressure on the counterweight shaft. On investigation I then found a couple of the allen screws on the underside of the mount RA needed tightening and it fixed it. So it may be something as simple as that.

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It's a standard HEQ5 at the moment.

My patio is still being built (that's a long story) there is one loose slab which needs resetting. I don't the tripod was on it, but could be wrong.

I need to a do a daylight set-up and eliminate a few things.  

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