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Can someone review my guide logs?

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#1 FiveByEagle

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Posted 21 January 2021 - 11:30 AM

Hello

Pretty rough night out here. After spending nearly $400 getting the entire mount cable managed and cleaned up with zero snags and even weight distribution, I still had a rough go with the setup trying to get the Jellyfish nebula.

 

I set up a sequence for 72, 300s images tonight, and packed it away about 25 images in, as radar showed clouds coming in in ~ 20 mins but even before that  only 12-14 did not have trails and bad stars.

 

A weird behavior to report, when I ran unguided, I was able to pull off 60 second unguided sharp exposures, but with Guiding started the DEC axis spiked 200 arc seconds away..the graphs should show that. When I changed the DEC direction it fixed it but then within a minute or two it spiked again.

 

I do not know if that is a bug, but I tried everything to adjust and get it smoothed out, but it didnt really seem to make a difference. 

https://openphdguidi...2_logs_xEED.zip

 

 



#2 rgsalinger

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Posted 21 January 2021 - 12:18 PM

It's unclear what scope you were using but if you are using an SCT with a guide scope then mediocre results are probably what you are going to get. Do make sure that you lock down the mirror after focusing it. That's about the best you can do with that configuration. 

 

I can see that at the beginning of your run, the DEC guiding went "crazy" but after that the mount seems to have settled down. It would be useful to see what the system looks like and to post some images to see what problems they showed. 

 

The only thing that I noticed was that you've trying to guide that mount at .9 sidereal.  I think that's way to fast for this class of mounts. The faster speed means that the motors have to work harder and should be reserved for more expensive mounts that have more powerful motors. 

 

The EQ6R that I use occasionally (and I'm not a "real" expert) gets down to around .8 arc seconds of RMS guide error using in one case a similarly large telescope. I'm not sure what more you expected. Maybe I'm missing something obvious here. 

 

Rgrds-Ross



#3 FiveByEagle

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Posted 21 January 2021 - 12:56 PM

It's unclear what scope you were using but if you are using an SCT with a guide scope then mediocre results are probably what you are going to get. Do make sure that you lock down the mirror after focusing it. That's about the best you can do with that configuration. 

 

I can see that at the beginning of your run, the DEC guiding went "crazy" but after that the mount seems to have settled down. It would be useful to see what the system looks like and to post some images to see what problems they showed. 

 

The only thing that I noticed was that you've trying to guide that mount at .9 sidereal.  I think that's way to fast for this class of mounts. The faster speed means that the motors have to work harder and should be reserved for more expensive mounts that have more powerful motors. 

 

The EQ6R that I use occasionally (and I'm not a "real" expert) gets down to around .8 arc seconds of RMS guide error using in one case a similarly large telescope. I'm not sure what more you expected. Maybe I'm missing something obvious here. 

 

Rgrds-Ross

Hello!

 

I use an 81mm Refractor, the William Optics GT81-IV ~380mm

 

I will set it to .5 and give it a shot tonight. 



#4 michael8554

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Posted 21 January 2021 - 02:01 PM

The Log reports that you last Calibrated on 22nd Dec.

 

Unless you have a permanent setup, or you set up exactly as on 22nd Dec, you need to recalibrate.

 

A log with a good Calibration in it helps to judge guiding performance.

 

There were a lot of random changes to settings in the logs, running the Guide Assistant will offer best settings, including Backlash Correction.


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