M52 and Bubble Bobble Widefield

[jase (Jason)]

Hi All,

Well, not really related to the legendary arcade game by Taito, but a glorious bubble it is! Actually, I should not avert from the centre showpiece, the magnificent open cluster M52 in all its glory...

So without further ado, I’m pleased to present “M52 environs”.

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The open cluster M52 appears lost within the rich Milky Way star fields of the constellation Cassiopeia. This cluster consists of approximately 200 stars that are at varying stages of their lives, though most are still in main sequence. The cluster resides 3,000 light years away. To the upper-right of M52, the diffused nebula NGC7635 glows brilliantly. This nebula is commonly known as the Bubble Nebula due to its sphere-like figure. The nebula surrounds a hot star approximately 20 times larger than our Sun, which is visible on the left edge of the bubble. Ultraviolet light from the star causes the gas to glow through a process known as fluorescence. Winds of material are blown from the star which gives the nebula its characteristic outline. The Bubble Nebula is approximately 11,000 light years distant. At the very top of the image is the lesser-known bright emission nebula NGC7538 which is located in the adjacent constellation of Cepheus. This nebula houses the largest known protostar which is approximately 300 times the size of our Solar System! NGC7538 is 9,100 light years away.
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About the image;
I took a minimalist approach to acquiring this image. Total exposure time of only 1.5 hours (R:30mins:G:30mins:B:30mins). I opted to not acquire any luminance data for this image. Instead I used the red channel, thus an RRGB composition. I think the image screams for more data, but appears to hold its own reasonably well. I feel certain greater nebulosity would have been captured with longer exposures or the use of a luminance/Ha filter to bring out some intricate knots of dust/gas etc. Having object pairings in a single FOV adds a pleasant dimension to this wide field image. This is a crop of a much larger frame.

Image processing;
This was one of the simpler processing workflows considering there was no luminance involved, though I did add a few twists to the flow to try new things (experimenting and potentially making things more complex for no apparent reason – such as life). All subs calibrated (dark/flat/bias/hot&dead pixel removal) in MaximDL. Registered in Registar and Sigma Reject combined back in MaximDL. Red channel, pushed through 1 iteration of deconvolution using CCDSharp. I created two RGB balanced images with 1:1:1.1 colour ratios. The first I stretch with DDP (no sharpening). The stretch was rather crude – wasn’t worried about loosing too much data as this was going to be purely used for colour information. The second image was manually stretched (levels/curves) in PS. The second layer (DDP stretched version) was then introduced in PS using a softlight blend, thus providing richer hues/saturation. I used the colour range tool to selectively process the stars and ran the minimum filter. This gave smoother feel to the stars and provided the opportunity to really focus on the individual star colours – rather important for wide field aesthetics. I made adjustments to saturation and normalised the selection. Red channel added as luminance and stretched manually. Minor noise reduction performed, though think I could have been a little harder in the dim areas. Flattened image before finalising.

Thanks for looking, hope you enjoy it.

Cheers

[Garyh]

I certainly enjoyed this widefield Jase!
Always very fond of these sort of widefield shots with so many different and varied objects all in the same field!
It sounds like a very unusual way that you have processed the image but it has certainly brought out the star and neb colors nicely...
Another fine image!
cheers Gary

[little col]

amazing detail and i love this widefield image , looking around the cass constellation myself at the moment but i am finding it hard to locate the bubble neb to one of the constellations stars so this gives me a great idea and perspective of where it is.
love the resolution to and pin point stars

[ballaratdragons (Ken)]

Amazing result, Jase.

The clarity and detail is superb!!!

Yes the cluster looks great, but it's the Bubble Nebula that catches my attention more. Sorry about that, but I find the Bubble Nebula drawing me in.

Great work, and again nicely presented and helpful information.

[Lee]

Awesome image - geez there are a few stars in there!
What length subs did you use???

[glenc (Glen)]

Jase where did you take the M52 image from? It is a great shot.

[iceman (Mike)]

Beautiful image Jase, I really love widefield images with star clusters.

Thanks for all the info on your capture and processing. At some stage this will all sink in and become useful in my own exploits

[Ric]

Wonderful image Jase, so clean crisp and detailed. There is so much to see in the whole image.

Ken is right, the Bubble really does draw you in.

Top stuff.

[jase (Jason)]

Originally Posted by Garyh

I certainly enjoyed this widefield Jase!
Always very fond of these sort of widefield shots with so many different and varied objects all in the same field!
It sounds like a very unusual way that you have processed the image but it has certainly brought out the star and neb colors nicely...
Another fine image!
cheers Gary

Thanks Gary. Its a rather busy scene making it visually congested (in my opinion). Still fun to image though. The original frame appears more pleasing (compared to this crop) as there is more "blank" areas that give a better sense of object/spacial distance. Not sure if I'm onto something with the new processing flow - time will tell. Thanks again.

Originally Posted by little col

amazing detail and i love this widefield image , looking around the cass constellation myself at the moment but i am finding it hard to locate the bubble neb to one of the constellations stars so this gives me a great idea and perspective of where it is.
love the resolution to and pin point stars

Hey Col. Haven't seen you around here for a while. Pleased you like this image considering its at your "neck of the wood" in the Northern Hemisphere. I've read reports that visually detecting the Bubble is quite difficult and is likely to require filters. I hope you get to track it down mate. Though those winter nights are approaching.

Originally Posted by ballaratdragons

Amazing result, Jase.
The clarity and detail is superb!!!

Yes the cluster looks great, but it's the Bubble Nebula that catches my attention more. Sorry about that, but I find the Bubble Nebula drawing me in.

Great work, and again nicely presented and helpful information.

Thanks Ken. I do agree, the bubble is quite a show piece, but I feel Messier 52 holds its own. I like that its a wash in other Milky Way stars, subtly resolved and defined. Thanks for taking the time to check it out.

Originally Posted by Lee

Awesome image - geez there are a few stars in there!
What length subs did you use???

Cheers Lee. Subs were short in this image - only 5 min. There is reasoning behind this. Longer subs can cause issues with star bloat if not managed correctly. It can be processed this out later, but at the expensive of star colours. To circumvent this in the past, after taking 10 or 15min subs for nebulosity details I take a few shorter subs through individual colour filters which I use as a star only layer in PS. I then combine the two to achieve an aesthetic image. A lot of work, but the results speak for them selves. No one said imaging was easy right? Thanks again for your comments.

Originally Posted by glenc

Jase where did you take the M52 image from? It is a great shot.

Hi Glen, the image was acquired from a robotic internet telescope under the pristine dark skies of New Mexico. At 2,225 meters above see level, seeing conditions regularly reach a FWHM of ~1 arcsecond.http://www.global-rent-a-scope.com
There is something special about remote imaging. Technically, I can image 24x7 as the sky is dark somewhere in the world. You still need to plan your targets carefully and determine composition, exposure times etc. The image processing components are no different to using your own telescope - its still very challenging. In fact, my own observatory is also remotely controlled so I merely see this as an extension to my imaging goals. Thanks for checking out the image.

Originally Posted by iceman

Beautiful image Jase, I really love widefield images with star clusters.

Thanks for all the info on your capture and processing. At some stage this will all sink in and become useful in my own exploits

Cheers Mike. I concur, the M52 open cluster gives an interesting focal point, but like the others indicate, its hard not to focus on the bubble. Re: processing - give it time and more importantly take your time. I spend hours processing a single image until I'm happy I've maximised the most from the acquired data. Don't be afraid to experiment and read/glean as much information on image processing as you can. Being methodical can assist. Thanks again.

Originally Posted by Ric

Wonderful image Jase, so clean crisp and detailed. There is so much to see in the whole image.

Ken is right, the Bubble really does draw you in.

Top stuff.

Thanks Ric. Indeed the stars are pin point sources of light, but they weren't that way originally. Required some work to get them looking cleaner, but not crunchy. Can't say much more about the bubble, its great. May target it with a longer focal length sometime. Pleased you liked it!

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Thanks again for all your comments.

[Ric]

Hi Jase, I was just just having a look at the GRAS site. I must say that it's a fantastic setup that they have and the prices are very reasonable for what you are getting.

I may have a go one day and get that Andromeda Galaxy image, but it's a bit out of my league for the moment.

Cheers

[Alchemy (Clive)]

Certainly an incredibly detailed image, a look at the largest image size on your site was well worth it.

as always...a quality image to enjoy .....post some more

[jase (Jason)]

Hi Ric,
It really does depend on what your imaging goals are. Remote imaging isn't for everyone. It will certain expand your horizon (literally). There are also other telescope networks that are privately owned - these are harder to tap into.

The GRAS guys are good value with great customer service. They'll certainly help you get started. My only issue which I mentioned in another post (here) is pricing. I think they could revise this to better accommodate the imager. The remote internet controlled telescope market is only going to increase. You'll start to see more private operators providing telescope time resulting in a competitive market. Here is another for example - a RCOS 20" with STL11k - http://rc20.stonehenge-obs.com/
To clarify - using someone else's telescope does not change the ownership of the data. You still have full rights over the data you acquire. Be careful before you jump into remote imaging however. In some cases, you'll require software to assist in planning your imaging session. Some remote telescopes use Software Bisque's suite, CCDAutoPilot or ACP. You should be reasonably familiar with this software before you sign up. There are a few tricks to know i.e image up to a point you know the mount needs to meridian flip etc.

From my perspective, I enjoy both realms - remote and local imaging. The strange thing is, when I'm out there in my own observatory, I don't actually do anything. I've got everything automated - telescope pointing, focusing, guiding, acquiring data etc. The telescope does what its told via a script and smart software. So in a lot of ways, it's almost a remote/unattended operation anyway - just the like robotic internet controlled telescopes. I enjoy the efficiencies of automation as it bring improved accuracy and most importantly productivity. It allows me to focus on the more technical side such as image processing.

As you're interested in narrowband work. I'd recommend trying out Fred's (Bassnut) GRAS-15. He's good some nice narrowband filters attached to an RCOS 10" + ST8. Haven't used it yet, but planning on doing so soon - still planning targets.

Hope this helps.

[jase (Jason)]

Originally Posted by Alchemy

Certainly an incredibly detailed image, a look at the largest image size on your site was well worth it.

as always...a quality image to enjoy .....post some more

Thanks Alchemy. Quality over quantity mate. Thanks for taking the time to check out the image and comment.

[little col]

Originally Posted by jase

Hey Col. Haven't seen you around here for a while. Pleased you like this image considering its at your "neck of the wood" in the Northern Hemisphere. I've read reports that visually detecting the Bubble is quite difficult and is likely to require filters. I hope you get to track it down mate. Though those winter nights are approaching.

hmm may be an impossibilty hunting the bubble down with my light pollution but if i can get the area bagged on the chip then i can progress from there , cass is in a nice position at the moment so i wouldn't mind having a go. been busy at work with some new staff so i havn't had time to post much in the forum. i am just going to upload my first attempt at m27

[Ric]

Thanks for the insights Jase, it is certainly a fascinating area of imaging.

I definitely have a lot more to learn first before I attempt anything on this scale.

Cheers