First image post on SGL - Fireworks Galaxy and the Ghost Bush Cluster

[GalaxyGael]

I thought I'd share my first image content post on SGL with the most recent one.

Fireworks Galaxy (NGC 6946) and the Ghost Bush cluster (NGC 6939), medium field image.

Captured using my beloved and 'ancient' Intes MN56 Maksutov-Newtonian, at 760 mm focal length f/6.

This is 10 hrs of exposure using 240s subs (-10C) with the  ASI2600MC Pro .

~1"/pixel scale, no darks, masterflat used. Guided with 240 mm f/4 scope (asi290mm mini) on iOptron GEM45G on tri-pier.

EDIT: I used Gain 100 on the 2600MC, no filters except the UV-IR cut on the camera. At f/6, I'll keep gain 100 but reduce exposure to 180 s from now on to reduce a bit of star clipping just a little.

CS, Colm

Edited August 12, 2021 by GalaxyGael

[russ]

That's an absolutely stunning image. Love the star colours, details in the galaxy. And doesn't look over processed, really nice.

[GalaxyGael]

Thanks Russ. To be honest, the ASI2600MC is just amazing, after years of slit spectroscopy measurements using huge CCDs. These backlit CMOS chips are quite the thing, with 16bit native depth. I have a version with processing pushed more, but it affected galaxy detail but did bring out the dust in this region and there a lot of it. I'm glad to see someone appreciate holding back on the processing and letting the stack do the talking. I used only some noise reduction (colormancer plugin) and color saturation using match color (matching image to itself). I decided to avoid almost every other image processing (sharpening, screen mask inverts, selective color etc.) and I like the minimalist approach when I'm lucky to get a decent set of data.

 I'm still surprised what the Intes can do, even after I butchered it by sticking a 46mm short axis secondary (originally has a 30 mm one) on it without any measurements (position, offset etc.), just stuck it on there and it collimated OK!

CS, Colm

[russ]

Which Intes do you have?  One of the MN models. 

[GalaxyGael]

Yes, the 127 mm aperture MN56. 

[russ]

19 minutes ago, GalaxyGael said:

Yes, the 127 mm aperture MN56. 

Great scope. I would have the guts to tinker with one. I took my M603 apart once as the focuser was playing up. Then put it straight back together and posted it off for repair....

[CraigT82]

Wonderful image, full of life and sparkle! 

[GalaxyGael]

This one owes me nothing at this stage, and the vignetting form the visual-type small secondary was just too much even for micro 4/3 sensors. The 2600MC pro was black all around the frame. Luckily, the three glue-type dots on the secondary holder remained so I made a pretty good estimate where it should be and fixed the focuser position to check the offset, and I got a bit lucky.  the main mirror cell is so well constructed. My current issue is the helical focuser. Manual focusing only, but it holds very well all night. No screw adaption for the camera so if I see tilt issue I tap the camera to the side and go from there! The compression ring is not what they are nowadays, so I'll either upgrade the focuser or get a new imaging scope at slightly bigger aperture at around 1"/pixel scale.

 

[GalaxyGael]

12 minutes ago, CraigT82 said:

Wonderful image, full of life and sparkle! 

Thanks @CraigT82

[peter shah]

super shot, lovely colour balance

[GalaxyGael]

Thanks peter, appreciate that. 

[Padraic M]

Hi Colm, that's a fine image! Great detail and lovely star colour, you obviously know your stuff. You must have good skies in your part of Cork.

[GalaxyGael]

Thanks Padraic, I've been imaging for years but never for the sake of photos but always measurements (RCs, mono, astrometry/spectroscopy), mostly from my darkish location in Limerick where I'm from originally. As a researcher, that hobby was a busman's holiday. I'm still picking my jaw off the floor looking at what has been going on from imagers over the last few years.

The color balance worked nicely if I am careful with it, but Astropixel processor is very good for these camera, and has a lot of powerful features inside, a lot of which remind me of programs I used to use for other reasons (plating, photometry, color-colour diagram analysis...). Given my previous hobby was all about stars, HFR and their magnitude, I don't do any star reduction on any image. And star cluster next to galaxies are my favourite objects, although I can can nebula (if my first go at them works), could be a lot of fun.

I'm in Ballincollig, so it is Bortle 5 on a good night. Although, here is what I shoot through  - 3 LED streetlamps that I have taken a serious dislike to whose position changes wrt scope during a session . I used to live in Macroom, and took milky way view for granted, ignored the skies in the yeas I was not doing anything astro-related. Need to get to Kerry for some astro-glamping if such exists. 

[Padraic M]

Great stuff Colm, you'll enjoy that camera from all I've heard about it.

Kerry skies can be spectacular but as I'm sure you know the weather can be a problem!!! I've been here for the last four weeks; one great week, and three completely cloudy ones. So you can be lucky or unlucky if you book a trip - best plan is to be agile and watch the forecasts. Not sure about glamping, but there are plenty of guesthouses around here (Waterville/Portmagee etc) that won't mind you staying up all night. We should get a discount!

I'm back to Dublin tomorrow so I'll have more imaging opportunities but badly polluted skies. Ah well!