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Galaxy and imaging season finale - M51


wimvb
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Astro darkness ended thursday night up here, but it's still reasonably dark för an hour or two each night. With the moon out of the way, I could catch a few hours on the Whirlpool galaxy, M51. I had to reshoot the blue channel because of high cloud which made the combined image look like it came straight out of a low quality refractor, with a lot of blue bloat around the stars. In total I captured about 6 hours worth of data, equally divided between L, Ha and RGB.

As always, captured with my 190MN and ASI294MM.

To blend the Ha with the red and luminance, I used Vicent Peris' red continuum subtraction technique.

M51_LHaRGB_crop.thumb.jpg.3c935ef8685dbedc44eb26779737579d.jpg

One thing that occurred to me when processing this image is that there is more Ha in the arm nearest M51B (the smaller galaxy above the large spiral) than on the opposite side of the galaxy's centre. This makes sense, because the gravitational interaction causes Ha clouds to concentrate and stars to form.

M51_Ha_R.jpg.7e84ce1fc4cc4b3ea6fdb401f345cfa6.jpg

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Great M51 Wim, another fine result from your MN190/ASI 294 combination. 
My Astro darkness is dwindling fast but will keep going into June.
I like your observation on the Ha channel, I think there is science to be found as well as beauty in the images we capture.

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Grand finale indeed Wim! Lovely colour and details. Darkness is gone for us up here so time to prepare for late August. I assume isolating your obsy is first on the list.

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5 minutes ago, gorann said:

Darkness is gone for us up here

Thanks Göran. If the weather plays nice sometime during the coming two weeks, I can probably squeeze in a cluster or two. But after that I’ll pack away the scope and roll in the insulation.

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14 hours ago, alan potts said:

That is lovely, now what better reason for me to mount up my M/N 190.

Alan

Thanks, Alan. I thought this might convince you. Go for it!

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8 hours ago, GalaxyGael said:

Very nice, clear and no oversaturation. Nice way to end the imaging year. At least, with the guide camera and the Mak-Newt, there is some nice sun spot activity...

Thanks. I don’t have filters for solar imaging, but very likely I will have opportunity to catch noctilucent clouds. Just not with the MakNewt.

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On 27/04/2022 at 08:39, wimvb said:

Thanks, Alan. I thought this might convince you. Go for it!

Be nice to see some clear sky at the moment, this time of year we often get sunny days and stormy evenings, as well as up and down weather in general, 27c yesterday 12c today

Alan

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Posted (edited)

An updated version with more Ha: a total of 117 4 minutes subs of Ha

Total integrationtime is now 14 hours and 52 minutes, most of this shot after astro darkness ended up here.

(also posted in the competition section)

M51_new_LHaRGB.thumb.jpg.cd7f9338eed48491a7dcf7652c256a3c.jpg

Edited by wimvb
information added
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That's a very attractive rendition, subtly processed.  Good point about the star forming regions on the companion side.

I really think the MN190 should receive more attention than it does.

Olly

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55 minutes ago, ollypenrice said:

I really think the MN190 should receive more attention than it does.

Thanks, Olly. I agree. It's a great scope, especially when kept on a pier

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 I used Vicent Peris' red continuum subtraction technique.

I have never heard of this. Is it possible to send some links for me to investigate.

 

 

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1 hour ago, m.tweedy said:

 I used Vicent Peris' red continuum subtraction technique.

I have never heard of this. Is it possible to send some links for me to investigate.

 

 

In essence you create two new images, Ha-R which is the original Ha image with all the background red subtracted, and a new combined red image, where the true Ha signal is added to red.

Ha-R = Ha - x*(R - median(R))
where x<1

HaR = R + y*(Ha-R - median(Ha-R))

where y>1

https://pixinsight.com/examples/M31-Ha/index.html

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The first one is very nice for me.  The “more Ha version” can be called the “ much, much more Ha version”.  A good Ha study, but the delicate balance achieved in the first has been tipped.  I think the MN 190 has impressed me more than any other scope.  

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I really like the soft yet very detailed processing in the first version, beautiful image. I also find that the Ha stands out a bit too much in the new version.

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