M101 - LRGB-Ha (~12 Hrs)

[Xiga]

Since getting the new camera (Qhy268m) this time last year, i've only managed one proper image with it to date (Butterfly Nebula in NB), so i've been itching to have a go at shooting something in Broadband. I think this is my first full LRGB image so still getting to grips with it all. 

I have a pretty restrictive horizon all around (can't shoot anything that transits below 60 deg to the South) but M101 is well positioned so i opted for it during the clear spells we've been enjoying here recently in N.I. I captured the LRGB over 3 nights in Feb, but have been too busy to process it up to now. I'm glad i didn't, as it i gave me time to shoot some Ha this past weekend (during a full Moon and wind speeds approaching 20mph!). I was amazed to see so much detail in the Ha stack, and somehow pretty much all the subs ended up being keepers, despite the wind and subsequent dodgy-looking guide graph! 

I've been dabbling a bit with Pixinsight this past few weeks, but i'm not exactly loving it if i'm being honest. I still prefer to use APP for all the stacking and gradient reduction. I think i did use P.I to do deconvolution on the galaxy in the Master Lum stack, but apart from that i was struggling to have any joy with any other processes that i couldn't already do one way or another in PS. I'm not giving up on P.I just yet though, i'll persist with it and see if i start to come around to it as i get to spend more time with it. 

The processing in general i found to be quite challenging. Although i think this was mostly down to the limitations of the scope (the SW 80ED being only a doublet) and possibly because of the filters as well (cheap SVBony ones). I made a Synthetic Luminance from just the RGB subs, as well as a Master Lum from all the subs. Between the R,G,B and L, the star sizes differed by quite a lot (Blue and Lum were really quite bloated looking, but Green looked great). The Lum went nice and deep so i wanted to keep it for all the faint background stuff as well as the galaxy, but just not the stars, so in the end i used Starnet2 to remove the stars from the Master Lum, and then added back in just the stars from the Synthetic Lum stack. This made a big difference, but still some of the larger stars were a bit too big, so i used Starnet2 once more but this time i only replaced the handful of biggest stars with those from the Green channel. This gave me a decent base level Lum file to work from, and the processing became easier from here on. 

Full capture details:

SW 80ED; HEQ5-Pro, OAG with ZWO 290mm; Qhy268m; 2" SVBony LRGB filters; 2" Baader 3.5nm Ha. Mode 1, Gain 56, Offset 25, -10C. Bortle 5/6 skies. 

RGB - 30 x 180s each (4.5 Hrs)

Lum - 211 x 60s (3.5 Hrs)

Ha - 44 x 360s (4.4 Hrs) - Added to Red in Blend mode Lighten

Total - 12.4 Hrs

Stacked in APP, Processed mostly in PS. 

Thanks for looking and CS! 🙂

 

Full FOV:

 

Crop:

 

Edited March 23, 2022 by Xiga

[tooth_dr]

That’s a great M101 Ciarán. It’s looking clear tonight again so hoping to get our myself. 

[tomato]

Great image, lots of fainter regions visible and the Ha really complements it.👍

[teoria_del_big_bang]

Nice image, far better than any of my galaxy attempts.
Thanks for the great detail of the acquisition and processing 🙂 
How much detail does the Ha add ?

Steve

Edited March 22, 2022 by teoria_del_big_bang

[Xiga]

3 hours ago, tooth_dr said:

That’s a great M101 Ciarán. It’s looking clear tonight again so hoping to get our myself. 

Thanks Adam. Have you managed much imaging over these past few weeks? What's on the menu tonight? I'm going to struggle for NB targets now that i've finished this one. 

1 hour ago, tomato said:

Great image, lots of fainter regions visible and the Ha really complements it.👍

Thanks tomato. The Ha made a big difference once i added it in. 

1 hour ago, teoria_del_big_bang said:

Nice image, far better than any of my galaxy attempts.
Thanks for the great detail of the acquisition and processing 🙂 
How much detail does the Ha add ?

Steve

Thanks Steve. I did actually add a small percentage of the Ha as Luminance too, but was very careful to only apply it to certain areas in the core. It was subtle, but it definitely helped to boost the detail near the core. Then adding it to the Red channel in Lighten mode really made the Hii regions pop with colour. I thought the image was looking a bit anaemic before i added it, so i'm really glad i went to the bother of shooting it now. The conditions for the Ha were really not good at all, but the beauty of adding Ha to an LRGB image is that it doesn't need to be the best data ever, and you can even hit it with the proverbial processing hammer and it won't show through in the final image. I'm at work, but i'll post up an auto stretch of the Ha stack later on tonight when i get home. 

[Padraic M]

That's a super 101. It's not an easy target but the Ha makes a big difference. 

[tooth_dr]

1 hour ago, Xiga said:

Thanks Adam. Have you managed much imaging over these past few weeks? What's on the menu tonight? I'm going to struggle for NB targets now that i've finished this one. 

I've just been gathering data since before Christmas, havent got round to processing any of it yet.  Nine panel mosaic on Markarians, 12 panels on Orion, and a single panel on the Witch Head nebula.  I dont think I'll swap over to a longer focal length this year, so just continue adding to widefield galaxy data in Leo.

[Xiga]

3 hours ago, Padraic M said:

That's a super 101. It's not an easy target but the Ha makes a big difference. 

Thanks Padraic 👍

2 hours ago, tooth_dr said:

I've just been gathering data since before Christmas, havent got round to processing any of it yet.  Nine panel mosaic on Markarians, 12 panels on Orion, and a single panel on the Witch Head nebula.  I dont think I'll swap over to a longer focal length this year, so just continue adding to widefield galaxy data in Leo.

Wow Adam you have been busy, some big projects on the go there. Looking forward to seeing the finished articles! 

[Xiga]

For anyone interested, here is what the Ha stack looked like, with zero processing other than gradient reduction in APP and saved as .jpg. 

[GalaxyGael]

Nice one Ciarán. The Ha addition is nice, a little different punch compared to the red from an OSC capture.

[DrMike]

Lots of other faint galaxies in the Ha image. Nice touch. Amazing image overall . I’m envious.😊

[teoria_del_big_bang]

6 hours ago, Xiga said:

For anyone interested, here is what the Ha stack looked like, with zero processing other than gradient reduction in APP and saved as .jpg. 

Nice one, yes I can see how that adds detail now to the final image, well worth adding.

Steve

[Xiga]

Thanks Colm, Mike and Steve!  🙂