GSS (Green Swamp Server) alternative to EQMOD

[david_taurus83]

On 27/03/2022 at 11:01, Stuart1971 said:

So how does it know the worm period for the attached mount…? And have you tried running this alongside the GSS PPEC, or,is that not possible, I thought I read somewhere this can be done…🤔

No idea how it knows but that 477s looks correct. Perhaps an index encoded somewhere? My guiding got worse as the night went on after the above screenshot..

Anyway, I had a look at things again last night. Left PHD looping frames at Dec 0° and there was a noticeable drift. Checked polar alignment, azimuth was spot on still but altitude was 4 minutes off. Should have realised it would need checking after mounting the Esprit. Set PHD back to hysteresis, redone calibration and PEC trained again. All seemed well for the couple of hours I was imaging last night. 

 

[Stuart1971]

4 minutes ago, david_taurus83 said:

No idea how it knows but that 477s looks correct. Perhaps an index encoded somewhere? My guiding got worse as the night went on after the above screenshot..

Anyway, I had a look at things again last night. Left PHD looping frames at Dec 0° and there was a noticeable drift. Checked polar alignment, azimuth was spot on still but altitude was 4 minutes off. Should have realised it would need checking after mounting the Esprit. Set PHD back to hysteresis, redone calibration and PEC trained again. All seemed well for the couple of hours I was imaging last night. 

 

Lovely graph, you seem to have it dialled in there….

I have come to the conclusion that, guiding is never going to be the same all night, mine seems to go from anywhere between 0.4 to 0.8 rms depending on where the scope is pointing, and on which side of the pier it is, so I am guessing this all must make a bigger difference than I thought it would, not sure if it’s balance, or just down to where it’s pointing. But at the end of the day I image at 1.74”/pixel, so as long as my guiding rms, is al least half of that (0.8 ish) then the stars will be good…otherwise I am worrying too much about the guiding and not enjoying the imaging…

[david_taurus83]

Hmm...had issues again the other night. Had a look at things again today. This might explain a lot! No idea how or when this happened. I've took out the OAG now and installed my mini guide scope. Hope there's no flexure issues like I had last time I used one.

 

[scotty38]

On 10/04/2022 at 19:05, david_taurus83 said:

Hmm...had issues again the other night. Had a look at things again today. This might explain a lot! No idea how or when this happened. I've took out the OAG now and installed my mini guide scope. Hope there's no flexure issues like I had last time I used one.

 

Blimey, only just saw this. I assume because you went back to the guide scope it couldn't be tightened up and something had broken?

[david_taurus83]

2 hours ago, scotty38 said:

Blimey, only just saw this. I assume because you went back to the guide scope it couldn't be tightened up and something had broken?

No nothing broken. The OAG gets close to the pier plate near zenith but I've not had any meridian flips fail but I suppose it's possible there was contact somewhere and possibly loosened it? Or maybe putting on or taking off the TG cover as it's quite heavy? However it's happened, I don't know when so I've been scratching my head for weeks as to why I need to keep doing new PHD calibrations! 

Before I found out it had loosened I had already decided to try a guide scope again as I prefer to use them if possible as can get better guide stars. I don't think I'll image longer than 10 minute subs with the Esprit so hope there's no issues with flexure like I had a year ago or so on another scope. I've drilled and tapped a couple of extra threads into the Esprit finder shoe for better security as it only comes with one. Hoping for a clear night this weekend to test things again.

[david_taurus83]

Well ita all gone Pete Tong with Green Swamp Server for me. Tried my mini guide scope a few nights ago and wasn't happy with it. At 120mm FL it's too coarse for my liking at over 6"/pp. I went back to an OAG but fitted my as yet unused Starlight Xpress OAG unit. Those of you who are familiar with these will know how solid they are as they are bolted directly to the filter wheel so no thumbscrews to tighten and the prism is nice and big. The issue I found out is the stalk is too long to work with 55mm reducer backpacking as you can't physically get your guide sensor close enough. The remedy? A hacksaw and 10mm shorter! I can now focus my ASI120MM mini at infinity. Happy days! So despite the full moon on Friday night I tried some problem solving. GSS works fine initially with very accurate pointing as usual. Pointed to a star near the equater before the meridian and started a new calibration in PHD. The first 3 attempts below are with GSS.

 

 

 

 

For whatever reason it just wouldnt calibrate in North/South. Was taking over 20 steps to move North and sometimes wouldn't move at all. At this point I was convinced the mount had some mechanical issues and prob needed backlash or something adjusting out. Fair enough, it's been on the pier for over 6 months so maybe the temperature changes in that time have loosened something. As a sanity check first though, I switched back to EQMod to see if I can replicate the issue.

 

 

Spot on first time. What's odd is that the North/South step in EQMod went in the opposite direction to GSS so I don't know what GSS thought it was doing? Yes, I had reverse Dec output after meridian tick in PHD which is required for GSS.

Left the mount guiding in EQMod with PHD's own PPEC algorithm and it returned expected figures for an EQ6 type mount. Took about 15 minutes or so but after a couple of worm cycles it settles down.

 

 

I'm a bit disappointed tbh. After working so well out of the box, so to speak, with stock settings, I don't understand why GSS has started to play up? It's almost like even though I had PEC turned off each night, it was still replaying it through the mount as guiding was very erratic. Don't know if I can trust it again unattended? Perhaps keep with EQMod...