M106 (LHaRGB) - 12 April 2021

[geoflewis]

After weeks of crap weather or clear skies only when the Moon was up, I finally managed to finish my first image since January. It is an LHaRGB image of the intermediate spiral galaxy M106 in Canes Venatici. I started the project in March in the run up to 1st Qtr Moon, but the ~8 hours of LRGB data that I captured proved unusable, so I shot all that again over the past week, or so. The Ha data captured in March seemed to survive ok despite the bright Moon, so I've used that. Total integration is just over 15.5 hours, comprising L=31x10m, Ha=19x15m, R=24x5m, G+B=22x5m each.

Processing was all done in ImagesPlus, with Registar used to accuratrely align the 5 stacked channel images, before building the final colour image which also done in ImagesPlus.

This was a very tricky image to process, with countless iterations at various stages of the process for both the luminance and colour images, before combining them, with 4 completed versions of which the above is V4. I really struggled to reveal the galaxy's outer halo whilst trying to control the noise in the background sky. I had both more crunchy and much softer versions, but have settled on this one - at least for now. I think I've just been able to reveal a couple of the Ha flares in the galaxy outer core (at about the 5 o'clock position), but clearly would need much more than 5 hours Ha data, also not captured during a bright Moon phase, to show these better.

Thanks for looking.

[AbsolutelyN]

I really like the smooth background of version B on astrobin which has nice softer background. Personally I'd try layering them up and allow the smooth dark background of B to blend into your final image? What focal length are you working at? 

[geoflewis]

8 minutes ago, AbsolutelyN said:

I really like the smooth background of version B on astrobin which has nice softer background. Personally I'd try layering them up and allow the smooth dark background of B to blend into your final image? What focal length are you working at? 

Thanks Tristan,

I know what you mean and I did wonder about doing that, or something similar, so maybe I'll give that a try. This is a C14 with native FL of 3910mm (F11), with an approximately x0.63 Optec telecompressor, so allowing for the moving mirror, then net FL will be ~2500mm.

 

[AbsolutelyN]

4 minutes ago, geoflewis said:

Thanks Tristan,

I know what you mean and I did wonder about doing that, or something similar, so maybe I'll give that a try. This is a C14 with native FL of 3910mm (F11), with an approximately x0.63 Optec telecompressor, so allowing for the moving mirror, then net FL will be ~2500mm.

 

Wow. You must have some seriously good guiding at that focal length for 15min exposures!  I can only manage 1 min at less than half the focal length 🙂 

[geoflewis]

23 minutes ago, AbsolutelyN said:

Wow. You must have some seriously good guiding at that focal length for 15min exposures!  I can only manage 1 min at less than half the focal length 🙂 

The AP1200 mount is a monster. It's a 2007 model which hasn't been upgraded and I'm not even running any PEC. It barely knows that it has a C14 + 4" APO riding on it. I'm guiding through the OAG of my QSI583 and typically get ~0.5" total RMS, though some nights sub 0.4". Imaging scale is 0.43", so I'm around 1px.

[AbsolutelyN]

13 minutes ago, geoflewis said:

The AP1200 mount is a monster. It's a 2007 model which hasn't been upgraded and I'm not even running any PEC. It barely knows that it has a C14 + 4" APO riding on it. I'm guiding through the OAG of my QSI583 and typically get ~0.5" total RMS, though some nights sub 0.4". Imaging scale is 0.43", so I'm around 1px.

That's insane. I managed 0.8" the other night with AZEQ6 but the 10" is too heavy and even dithering can make it lose it somewhat. I thought I'd invested in a mount that would handle anything I needed when I bought it 5 years ago but I think I need to consider something a bit more robust soon.   

[geoflewis]

58 minutes ago, AbsolutelyN said:

Personally I'd try layering them up and allow the smooth dark background of B to blend into your final image

Hi Tristan,

I layered B and D together with B at 100% lighten blend mode on top of D knocked back just a tad to 97% Normal mode. I also applied a gradient removal as I think there was one running broadly left to right.

What do you think of this version?

[geoflewis]

2 minutes ago, AbsolutelyN said:

That's insane. I managed 0.8" the other night with AZEQ6 but the 10" is too heavy and even dithering can make it lose it somewhat. I thought I'd invested in a mount that would handle anything I needed when I bought it 5 years ago but I think I need to consider something a bit more robust soon.   

I paid £6.5k for my preowned mount 5 years ago. I am least the 4th owner....!! I won't be letting go of it anytime soon if I can help it.....

[AbsolutelyN]

37 minutes ago, geoflewis said:

I paid £6.5k for my preowned mount 5 years ago. I am least the 4th owner....!! I won't be letting go of it anytime soon if I can help it.....

That's way out of my budget, I'm thinking more reasonably priced CEM70 or similar.  

[AbsolutelyN]

42 minutes ago, geoflewis said:

Hi Tristan,

I layered B and D together with B at 100% lighten blend mode on top of D knocked back just a tad to 97% Normal mode. I also applied a gradient removal as I think there was one running broadly left to right.

What do you think of this version?

Looks great, best of both. Definitely an improvement to me. 

[geoflewis]

16 minutes ago, AbsolutelyN said:

That's way out of my budget, I'm thinking more reasonably priced CEM70 or similar.  

I have a very understanding wife. It was something of a retirement present, along with the observatory, the C14 and the QSI camera. We became mortgage free when we moved from Surrey to Norfolk, so some of the released equity and retirement lump sum went on my hobby.....🙂