Author Topic: Andromeda Galaxy - Nov 2021  (Read 132 times)

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Andromeda Galaxy - Nov 2021
« on: Nov 24, 2021, 14:43:41 »

Taken from Bromley ( Bortle 7 or 8 ) on 22nd November 2021

Sharpstar 15028HNT
ASI1600MM Pro (Temp -15, Gain 139)
iOptron CEM25P mount.
ASIAir Pro (Imaging, guiding, focus and filter control)

Ha: 54 x 120sec
B: 53 x 24sec
G: 29 x 30sec
R: 26 x 48sec

Process: Pixinsight and Photoshop

Moon: 63% (seperation 49 degrees)

Excuses: Cloud was increasing during imaging. By the time I was imaging with in Red cloud was thick enough to stop the guiding.

I have removed the dew heater from the secondary mirror but there are still some odd stars.

I suspect that the sensor is not perpendicular. Some subs were taken pre Meridian Flip, they do not precisely mirror the post Meridian Flip subs. This is a (stretched) master Flat:

The vignetting is not symmetrical and I would presume that it should be. There are push me/pull you screws at the base of the focuser and so I am thinking of seeing if I can get the circle centred. Then I can attack collimation (bearing in mind this is an f2.8 telescope and is fussy).



ps: Unfortunately, my family has to self-isolate this week and so I will have to attend tonight's talk via Zoom. I was looking forward to being there.
« Last Edit: Nov 24, 2021, 16:26:49 by JohnH »


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Re: Andromeda Galaxy - Nov 2021
« Reply #1 on: Nov 24, 2021, 17:36:58 »
Hi John,

That's pretty good considering it was taken from Bromley, not a good area for Broadband, but HaRGB sometimes works for me.  But the main part of this image is indeed RGB so you have done well. 

Despite removing the dew heater from the secondary the star are still a peculiar shape, with 6 spikes,  I am pretty sure this is a Newtonian (a pretty good one too), so should only have 4 spikes.
Not sure what is going on there, I wonder whether something else is getting in the way of the light path. 

Colour is excellent. 

Sorry you are having to self isolate, presume you have been in contact with a CV case or one of you has it.



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Re: Andromeda Galaxy - Nov 2021
« Reply #2 on: Nov 26, 2021, 10:39:02 »
Nice Image.

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