Ursa Major Triplet - LRGB

[wimvb]

A week of clear nights with the moon out of the way, and still a few hours of astro darkness each night. Enough to shoot a decent amount of data for my last project this season.

NGC 3613 is a small elliptical galaxy (3.9" x 1.9"), magnitude 11 - 12. It's at a distance of about 96 Mly.

NGC 3619 is a spiral galaxy that has an interesting shell structure. This is probably due to the merger of or mass transfer by several smaller galaxies. Magnitude 13, 2.7" x 2.3", 92 odd Mly from earth. (ref: http://adsabs.harvard.edu/full/1988ApJ...328...88S)

NGC 3625 is a barred spiral galaxy, magnitude 13, 2" x 0.6", 89 Mly away.

About 11 hours of data collected over four nights. I didn't plan to shoot luminance with the light pollution that I have, but in the end I added about 4.5 hours L (150 seconds subs) to 6.75 hours of RGB (5 minutes subs).

Equipment as per my signature.

 

(click on the image to get to the full size version)

More details on my astrobin page:

https://www.astrobin.com/342011/?nc=user

... and plate solved:

[toxic]

very nice image Wim and i am glad you have some clear skies 

[Petergoodhew]

great image Wim.

[Demonperformer]

I never cease to be amazed at the vast number of galaxies that are (i) in this part of the sky, and (ii) can be captured with easily attainable 'amateur' equipment.

Another great effort, Wim.

[wimvb]

9 hours ago, toxic said:

very nice image Wim and i am glad you have some clear skies 

 

8 hours ago, Petergoodhew said:

great image Wim.

Thanks guys. Those clear skies were probably the last for the next four months or so. At the moment astro darkness is down to two and a half hours, and shrinking fast.

[wimvb]

Just now, Demonperformer said:

I never cease to be amazed at the vast number of galaxies that are (i) in this part of the sky, and (ii) can be captured with easily attainable 'amateur' equipment.

Another great effort, Wim.

Thanks DP. Many of those "faint fuzzies" have interesting physics going on. That's what interests me most. Unfortunately, my LP conditions make it necessary to dedicate many hours to each target, in order to get the noise under control.

Of these galaxies, there's very little information on the internet. Most of it is burried in scientific articles.

[wimvb]

Now that I'm viewing this image from my mobile phone, it seems very dark, and the faint structures are burried in the background. This image is best viewed on a larger computer screen. I may publish a lighter version tonight. I also want to try a new processing technique anyway.

[lux eterna]

An interesting part of the sky and nicely processed. Based on my screen (Dell 2709W) the background is definitely not too dark - I may prefer even darker.

Ragnar

[wimvb]

36 minutes ago, lux eterna said:

An interesting part of the sky and nicely processed. Based on my screen (Dell 2709W) the background is definitely not too dark - I may prefer even darker.

Ragnar

Tack Ragnar. I first posted a slightly darker version, but the details were hard to see on my mobile phone. I replaced the image with one that has a slightly brighter background. Normally I prefer a darker background, but here the brighter one shows the faint details better, I think.

The annotated version still has the darker background.