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Hot Summer nights with Andromeda


bdlbug

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So bit of a strange experience for a few nights last week, out in my SkyShedPOD, imaging at 1:30am in shorts, T-Shirt and Sandals, don't think it got below about 17degC any of the nights I was out -  hence even the font colour is hot ☀️ - ( Normally when I am out imaging it's B*l**ks cold and I'm encased in several layers of thermals and an Arctic standard down jacket)

I  imaged M31 as a secondary effect in that my main goal was to test and fine tune my change over from using a guide scope to an OAG setup. The good news is that I have got the spacings about right from my reducer/flattener and  imaging camera and guide camera in focus and achieving reasonable tracking,. My setup images at 1.51"/pixel and guiding at 3.3"/pixel - the calibration and guide graph show that I have a lot more work to do to get more accurate guiding, may also be that the transparency last week Thursday - Sunday night  worked against me. There was also high cloud that also reduced the quality of the sky and the Lum subs suffered as a consequence I think.

Anyway the stars are reasonably round and I captured 5.5hrs of LRGBHa over 5 sessions using 60s and 90s subs with ASI1600 unity gain.  I just threw everything into APP and processed the main image with APP and PS, its quite a 'warm' rendition of this target, I have probably overcooked the amount of Ha I mixed into the red channel.  As I said its a hot summer night rendering of M31 ?

I did mess around mixing my image from Nov 2016 from my samyang 135mm wide field setup , I've posted that as well just as a bit of fun with Registar and PS much lower res as it was a wide field around 6.6"/pixel

I'm hoping to head down to Exmoor in September and use my now ex-guide scope, AT72ED, which is in fact a decent doublet nearly APO with a Star Adventurer and possibly a new OSC camera. So hopefully some dark sky images to come,

Bryan

 

 

M31_Andromeda_LRGBHa(7nm) processed v2.png

M31_Andromeda_LRGBHa(7nm) plus 135mm Samyang colour v2.png

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@AndrewG, @newbie alert

thanks for your kind comments and everyone who has posted a like

Regards noise - the ASI1600 still managed to hit -20degC, i think its spec'd to be able to go -40 below ambient so in terms of noise, no I didn't  expect an increase in electrical noise from sensor data readout as I normally image with temp set at -20.  So the ambient temp at around 20degC enabled me to get to -20, any hotter and probably would not have been able to operate at such low sensor temp.

What I probably had was high clouds and looking at APP quality scores I probably should have removed most of the first night's Ha and Lum as the subs are all scored less than 100, which is bad. But then having 127 subs of 60s each gives the algorithms in APP  a lot of data to chew on and from the image it integrated I managed to process the first image.

Bryan

 

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