NGC 300 with hydrogen enhancement

[Stephane]

Hi all,

I was hoping to wrap this one up with 10 hours of integration, only to realize that this galaxy is fainter than I thought. I went a little over 24 hours (plus 5h of L-Extreme data), making good use of 4 clear nights in a row in Melbourne. It could probably do with a little more still just to reduce the noise further on the outer edge of the galaxy without noise reduction making it look too soft. However, I think I'm done with this target now - 24h is a PB for me.

Captured with a OSC camera and no filter. However, I enhanced the galaxy with hydrogen using the red channel of an image I acquired with the L-Extreme filter. The method used was similar to the one used here (http://www.arciereceleste.it/tutorial-pixinsight/cat-tutorial-eng/85-enhance-galaxy-ha-eng).

Initially I wanted to frame the galaxy only, but there are so many smaller galaxies nearby that came out quite nicely. I hope you all enjoy. As usual, constructive criticism is most welcome.

Bigger version here (https://www.astrobin.com/9qmfjn/).

Clear skies,
Stéphane

[Addos]

outstanding result stephane, one of your best!

[Dave882]

That’s unbelievably good mate!! Wow, if you’d said that was taken with a cdk14 I’d believe you! Stunning detail, depth and colour. And those background galaxies too :eyepop:

[Startrek]

Stephane,
I know I’ve mentioned this previously but your Deep Sky imaging is of an extremely high standard now for someone just over a year into the hobby and imaging with a Mid sized Newt straight off the bat.
This image of NGC 300 is one of the best I’ve seen on this forum in recent times
You’ve got that f4 Newt well and truly tamed
Well done !!

Martin

PS: Just out of interest are you imaging from inner suburban Melbourne ( Bortle 6 to 9 ) , outer suburban Melbourne ( Bortle 5 to 7 ) or semi rural just outside Melbourne ( < Bortle 5 ) ?

[AdamJL]

Good work Stéphane. You should be very happy with that one.

[gregbradley]

A top shelf image. It looks fantastic.

One of my favourite galaxies to image.

Greg.

[AstroViking]

That is insanely great.

[SB]

Hi Stephanie
Thats a lovey image!
What method do you use to collimate your F4 Reflector? Are you using a stock focuser?

Chris

[oska]

Top shot Stephane. Watch out Dave, he's coming for you ;)

[Stephane]

Awesome comments everyone, thank you.

Dave, my wife might need a little convincing before purchasing a CDK14 :lol:

Chris, I just use a laser collimator (which itself is out of collimation). However, I have noticed that I get reasonably good collimation when the laser does not point back to the bull's eye, but rather slightly off at about 4pm. Not sure why, but it seems to be working...for now! The focuser is the standard Crayford that comes with GSOs, and I use a ZWO EAF secured with a 3D printed accessory.

[Stephane]

Martin, again, thank you for the kind words. Many on this forum have helped me tremendously.

I live in the inner suburbs of Melbourne and believe I'm in a Bortle 6 zone.

Light pollution is a pain to deal with as the gradients always leave artefacts once removed, but I have had some interesting results when stacking 150ish subs at a time, removing light gradients, and then combining stacks. The artefacts from the stacks appear in different locations and tend to smoothen out when combined. Then, once combined, I do another light gradient removal. I got the idea here (https://www.astrobin.com/7ez0pl/). I'm not sure if this is a recommended technique, but it seems to have worked well on this image. I might try it again on my next galaxy.

[alpal]

Excellent result Stephane.
I see you're using advanced processing skills in PixInsight.

Your image looks like it was an LRGBHa but it's from a color camera.
So - why is it so good?
You have 24 hours integration of 485 frames so
the square root of that is 22 so you have 1/22 of the single frame noise.
That's enabled you to pull those distant galaxies out of the noise
even in a light polluted suburb.
I'm impressed.


thanks
Allan

[Stephane]

Thank you Allan. I indeed used this formula to obtain an "Ha layer" that I added onto my main image using the red channel of my colour image and the red channel of my dual band image (Optolong L-Extreme). Performing quite a bit of noise reduction on the Ha layer also helped in not adding "red noise" into my main colour image. I will continue using this technique on galaxies as I find that being able to see those pink clusters of hydrogen really beautifies galaxies.

[Startrek]

Yes, light pollution is the bane of our existence in AP
Pushing those longish 3 min subs under that Bortle 6 Sky and no filter ( only the UV/ IR cut protective window) takes a lot of skill and patience in post processing.
Most folk limit broadband sub exposure lengths around 30sec to 90 sec under heavy light polluted skies ( Bortle 6 to 9) and still struggle to achieve good results with resolution and fine detail.
Your mammoth amount of data ( signal ) irrespective of heavy gradient, made all the difference with this wonderful image
Also your post processing techniques are working beautifully, keep going !!
I assume that your using Gain 100 on the 2600MC ( HCG mode , low read noise ) ?

Cheers
Martin

[Stephane]

Thanks Martin. Yes, gain is set at 100 and offset at 50 as per your recommendations and those of others who live in cities. I do realize though that if I want light gradients completely removed, I will need to travel to darker skies. At this stage, however, I’d be happy to get any clear skies at all! Sadly, nothing here for the foreseeable future.

[strongmanmike]

That's a very good 300 Stephane, it sits in a cool field, the background galaxies make it for me :thumbsup:

Mike