M13 from early this morning + PHD2 query

[Aramcheck]

24 x 3min subs from quarter past midnight 'till 2am this morning. Skywatcher 200dps+EQ6, Canon 600d (astromodified) with IDAS D2 light pollution filter & Baader MKIII coma corrector. Bortle 6 sky.

Had problems with guiding. I got the usual warning error during calibration (*), but then some of the dithering moves inbetween subs timed out. At the moment I'm using a modified SW finderscope & ZWO ASI 120MM.

Any guidance (sic) on how to improve matters would be much appreciated!

Cheers
Ivor
(*) "Calibration alert: Advisory: Calibration successful but little south movement was measured, so guiding may be impaired.  This is usually caused by very large Dec backlash or other problems with the mount mechanics. Read the online help for how to deal with this type of problem (Declination backlash)."

PHD2_GuideLog_2020-06-25_000858.txt

[daemon]

Sorry, no real suggestions on the guiding issue, but it doesn't seem to have hurt the result much! Really nice....and Sharp!!

[Aramcheck]

Re-processed the data a bit more carefully this morning...

 

[daemon]

Even better! That's a great M13! I like the star colours and the way NGC6207 stands out even more.

[MarkAR]

That's a great improvement, well done.

[Jiggy 67]

Nice improvement on the 2nd, lovely contrast and sharpness 

[Aramcheck]

Thanks folks - much appreciated... I tried applying Pixinsight's HDRMT (High Dynamic Range Compression Tool) & LocalHistogramEqualisation to the core & then recombined using PixelMath to try to bring out a bit more detail... here's the result.
I probably should go through these iterations before initially posting, but it's such a buzz being able to finally 'see' this stuff given the light pollution, so it's difficult not to post the 1st (& 2nd) results...
Cheers
Ivor

[rockinrome]

Hi there Ivor!
Depends what exactly the issues are with your guiding, but one thing that helped me enourmously is setting the focal length of the guide scope properly in PHD2.
Brain icon > Guiding Tab > Calibration section > Focal length (mm)

(Of course it goes without saying - so I'll say it!! - you need to have your polar alignment spot-on. It looks like your stars are a little dragged to the right?)

All the best and clear skies
Matthew

 

[rockinrome]

1 minute ago, rockinrome said:

Hi there Ivor!
Depends what exactly the issues are with your guiding, but one thing that helped me enourmously is setting the focal length of the guide scope properly in PHD2.
Brain icon > Guiding Tab > Calibration section > Focal length (mm)

(Of course it goes without saying - so I'll say it!! - you need to have your polar alignment spot-on. It looks like your stars are a little dragged to the right?)

All the best and clear skies
Matthew

 

Ooo also ....
I did find my guiding much smoother using ASCOM Pulse guiding rather than ST4.

Matthew

[Aramcheck]

@rockinrome Thanks Matthew.
I'm using an iPolar for alignment. PHD2 log gave the PA error as 7.9' - I saw something online that recommended checking the PA again once the scope has slewed to target, so I might try that.

I'm using ASCOM Pulse guiding rather than the ST4. I probably should have let the guiding settle for longer rather than starting the image run right away, as the guiding did settle down after ten  or so minutes. Then again, as I'm using Pixinisght's SubFrameSelector to discard the worst subs, there's nothing lost in starting earlier.

Cheers
Ivor

[Paul M]

Can't help with the guiding but that's a stunning image. Very nice indeed!