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Old 29-05-2021, 04:38 PM
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Sunfish (Ray)
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MPCC iii test

Just tried a quick test while the moon is up of the MPCC on an 8 inch f5 newt.
Not quite the correct spacing and over by a few mm. The best I can do without customisation of the OAG.

Acceptable?
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Old 29-05-2021, 04:52 PM
Saturnine (Jeff)
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Seems acceptable enough, very slightly oval stars if you want to be pedantic. Could be more of a slight tilt issue than spacing a the oval shape seems to all point in the one direction rather than radiating out from the centre.
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Old 29-05-2021, 05:17 PM
Startrek (Martin)
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Ray,
What was your sub length and guiding error ?
It doesn’t look like coma , more tilt or tracking
I had to add a 1mm spacer to my MPCC Mk3 to eliminate coma in the corners ( 8”f5 GSO newt and 6”f6 GSO newt with a 2600MC camera )
So the distance from camera sensor face to CC was 56mm instead of the standard 55mm
Martin
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Old 29-05-2021, 06:35 PM
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multiweb (Marc)
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TBH I can't see it. Pretty bloody good IMHO.
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Old 29-05-2021, 09:26 PM
Alchemy (Clive)
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Not seeing a spacing issue, if I had to guess, I would say it’s a minor guiding issue, you might have to dig into the guiding program to investigate. Sometimes changing guide exposure, or reselecting guide stars can fix such issues if that’s what it is.
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Old 29-05-2021, 09:41 PM
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Sunfish (Ray)
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Thanks for the helpful comments.

The sub length was 3 minutes and there are four stacked. Not sure about the guiding . Probably about 1 but need to work out how to read the the log.
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Old 30-05-2021, 08:20 AM
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Sunfish (Ray)
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. Managed to access the PHD2 log. Guiding total RMS 1.1. Seems to burble along under 2sec except for the occasional lost star blip . Here is a single sub and a log.

The tilt in one direction does seem to be an issue although all threaded together. Could be gravity on the side mounting.
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Old 30-05-2021, 08:38 AM
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multiweb (Marc)
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On closer inspection there is some very minimal tilt. TBH that would average out during stacking.
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Old 30-05-2021, 09:39 AM
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Sunfish (Ray)
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Thanks Marc. I will give a run and see now the train is set up.
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Old 30-05-2021, 11:01 AM
Startrek (Martin)
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Ray,
Just looking at your guide log I noticed the following things that stand out and “may” contribute to your guiding operation and performance
1/ Your guide camera is the same as mine and has a pixel size of 3.75uM your guide log shows 3.8uM ??
2/ Your guide log shows no dark library or bad pixel map create or used ( Dsrks and BPM are recommended by PHD2 to eliminate lost guide stars or saturated stars or hot pixels )
3/ Min mov should match seeing conditions , your guide log shows 0.35 which seems a tad high , I’m usually around 0.18 min to 0.25 max for both Ra and Dec
4/ Guide camera is set to 1.5 sec ( maybe try default 2.0 sec as it may be a bit more forgiving )
5/ Generally your guide error looks ok

6/ What mount is your 8” f5 newt sitting on ?

****This latest image your stars look good to me !!

I’ll attached a few PHD2 docs I put together last year, they may be of some assistance ??

Cheers
Martin
Attached Files
File Type: pdf PHD2 Guiding Information.pdf (23.8 KB, 32 views)
File Type: pdf PHD2 Multi Star Guiding.pdf (22.4 KB, 21 views)
File Type: pdf PHD2 Guiding Procedures.pdf (67.1 KB, 50 views)
File Type: pdf PHD2 Settings in EQMOD.pdf (304.8 KB, 78 views)
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Old 30-05-2021, 05:06 PM
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Sunfish (Ray)
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Thanks Martin. The mount is a HEQ5 with Rowan belt mod.

I will check out those PHD details and perhaps it will help. My darks keep getting lost although I have taken plenty. Perhaps it is the pixel size anomaly causing the problem.
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