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vdb14 15, Sh 202, Soul mosaic, around 70 hours.

ollypenrice

By ollypenrice
in Imaging - Deep Sky

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ollypenrice

ollypenrice

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Tom came up with the idea of hitting the vdb 14 and 15 objects. Since they don't emit any light they were right up his street! (He hates the idea of an easy image.) So we banged away for 31 hours and cracked them to our satisfation. Then, fool that I am, I noticed that we weren't too far from the Soul nebula... I already had 16 hours of Soul data so most of late August into September has seen the tandem Tak rig filling in the rest, with Yves' SXVH36 strutting it's stuff on one side. 6 panel, though I found I coud squeeze the top down to two instead of three once we had the framing finalized.

This is my processing and I'm still unable to send Tom and Yves the final raw data because the net is not playing with Dropbox. You'll have to make do with my version till these gentlemen get onto the job.

So, two FSQ106Ns with full frame mono CCDs on a Mesu 200 with about 70 hours all in, in Ha O111 LRGB. The O111 and L are only present in parts of the image which needed them.

The image covers about 7 x 3 degrees and lies in both Cassiopeia and Camelopardarlis.

Olly and collaborators, Tom and Yves.

Bigger, though the full size TIFF is about 230 meg;  http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-J6hBf6k/0/X3/VDB14%2015%20TO%20SOUL%20Web-X3.jpg

VDB14%2015%20TO%20SOUL%20Web-XL.jpg

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Knight of Clear Skies

Knight of Clear Skies

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That's very nice.

Glad you made it over to the Soul as it gives me a point of reference I can understand. The Heart & Soul are bright enough for me to pick up in framing shots, but in my 30 minute stack I haven't got even a hint of Sh 202 next to it. From context, I guess vdb 14 & 15 are fainter again. That's another nice thing about doing a bit of imaging myself, it gives me a better understanding and appreciation of other people's images. There is faint and then there is faint.

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Tom OD

Tom OD

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Yes Excellent shot Olly. I didn't even know that you took O3 data. What is the purple object at the top left of center. Is that another VdB object?

I too like the dark ribbons of dust in the Ha regions.

That's very nice.

Glad you made it over to the Soul as it gives me a point of reference I can understand. The Heart & Soul are bright enough for me to pick up in framing shots, but in my 30 minute stack I haven't got even a hint of Sh 202 next to it. From context, I guess vdb 14 & 15 are fainter again. That's another nice thing about doing a bit of imaging myself, it gives me a better understanding and appreciation of other people's images. There is faint and then there is faint.

The VdB is faintish, but 202 is very dim. We had to get a lot of data to get a good signal on that one.

Tom.

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ollypenrice

ollypenrice

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That's very nice.

Glad you made it over to the Soul as it gives me a point of reference I can understand. The Heart & Soul are bright enough for me to pick up in framing shots, but in my 30 minute stack I haven't got even a hint of Sh 202 next to it. From context, I guess vdb 14 & 15 are fainter again. That's another nice thing about doing a bit of imaging myself, it gives me a better understanding and appreciation of other people's images. There is faint and then there is faint.

Yes, and the thing is, in preparing an image, to decide on the relative brighntesses across the target. This image is not remotely photometric. You can say the same of any stretched image, of course, but in a normal single-frame, single object image you do at least respect the order of brightnesses within the frame. As long as you never put a negative bend into the Curve you will never invert the brightnesses. I guess this is a good thing!

In this image there is a falsehood in that the vdb reflection nebulae are probably shown in a brightness out of synch with the emission nebulae. They are brighter than they should be relative to the rest. We used masses of luminance on the lower left panel in order to pull them out. There is no luminance in the rest. Then again, we shot masses of Ha to lift the emission nebulae and in this version I was careful not to apply the Ha in luminance because I didn't want to subdue the work of the L layer on the vdb parts. (I could have got round this by applying Ha in blend mode lighten, I suppose, but I didn't.) However, in the only other version of this that I've so far found on the net the imager lifted Sh202 to the brightness of the SOul. Even if we'd had enough signal to do that I doubt that any of us would have wanted to do so.

Olly

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Knight of Clear Skies

Knight of Clear Skies

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Thanks for the info Tom & Olly. So if I'm understanding correctly the VdBs and Sh202 are both very faint, but we aren't quite sure which is fainter?

Just been searching online and came across this handy site. By scrolling over to the Heart & Soul and switching to the Ha view I can see how bright they are compared to the surrounding nebulosity (I'm assuming their data is calibrated). Should be useful for working out which nebulae I can image by comparing with my previous images.

I find myself wondering why Sh202 is so much fainter than the Soul. Is it less completely ionised, more diffuse or both? Does it represent a later stage of evolution, having been dispersed more by radiation pressure from the stars at its core? Is it further away and obscured by dust? I'm struggling to find much information on the Sharpless catalogue objects online.

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ollypenrice

ollypenrice

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Thanks for the info Tom & Olly. So if I'm understanding correctly the VdBs and Sh202 are both very faint, but we aren't quite sure which is fainter?

That's about it!  :grin:

The Sharpless nebulae are often huge, diffuse and not easily pinned down to any one obvious ionizing source. Homework time!

Good link on the wavelengths. Thanks. My favourite text book, Kauffmann's Universe, religiously specifies the wavelength of every image. This cavalier mixing of filters makes me feel guilty...

Olly

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dave_galera

dave_galera

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That's about it!  :grin:

The Sharpless nebulae are often huge, diffuse and not easily pinned down to any one obvious ionizing source. Homework time!

Good link on the wavelengths. Thanks. My favourite text book, Kauffmann's Universe, religiously specifies the wavelength of every image. This cavalier mixing of filters makes me feel guilty...

Olly

Yes but Olly, we don't do it for scientific reasons but aesthetics, so I can see no reason for doing what you have done with the filters, providing you don't change the basic science. :laugh:

Dave

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