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LDN1235 The Shark in Cepheus - the RASA way

gorann

By gorann
in Imaging - Deep Sky

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gorann

gorann

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This fantasy provoking object, a mix between reflection and dark nebulosity, probably needs no presentation. It is very faint so f/2 and my dark (Bortle 2-3) site helped. This is a merger of two datasets collected 13 - 17 September in 2020. I used Star Exterminator to bring out as much nebulosity as possible and then brought the stars back at a controlled level, since the starfield is quite rich and can overhelm the weak nebulosity. Again, the combination of RASA and ASI2600MC is really good at going deep and bringing out colours in the nebulosity.

So, RASA 8 and ASI2600MC without filter. 146 x 4 min (Gain 100, offset 30, -15°C), so nearly 10 hours. Put together in PI and processed in PS and PI.

Cheers, Göran

20200912-13 LDN1235 RASA PS33smallSign.jpg

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gorann

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9 hours ago, Tom OD said:

That's the most aggressive looking shark I ve seen yet. A little bit over processed for my tastes, but I like how the "head" is showing more shape and features than most pics.

Tom

 

9 hours ago, Sunshine said:

That is an awesome capture of what seems to be a challenging target from your description, amazing!

 

4 hours ago, Roy Foreman said:

Impressive capture, well done.

 

2 hours ago, tomato said:

Found it, PGC67671, awesome!👍

Thank you all!

Not sure Tom I would agree that it is over-processed, but I agree that it is brighter and shows more colour and structure in the dust than in most shark images. Nearly 10 hours with a RASA 8 brings out much more structure and colour, especially in dark nebulosity, than I ever have seen with my refractors. I think it has to do with the large aperture combined with f/2 (and the high dynamic range of the ASI2600). I have not done any sharpening routines like deconvolution that often introduce artifacts. So I am rather sure that what is seen in the image are for real. I also took care in avoiding the often seen dark ringed (panda eye) stars when I brought back the stars after having stretched the starless image.

Cool that you spotted the spiral galaxy Steve!

Cheers, Göran

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Tom OD

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3 hours ago, gorann said:

 

 

 

Thank you all!

Not sure Tom I would agree that it is over-processed, but I agree that it is brighter and shows more colour and structure in the dust than in most shark images. Nearly 10 hours with a RASA 8 brings out much more structure and colour, especially in dark nebulosity, than I ever have seen with my refractors. I think it has to do with the large aperture combined with f/2 (and the high dynamic range of the ASI2600). I have not done any sharpening routines like deconvolution that often introduce artifacts. So I am rather sure that what is seen in the image are for real. I also took care in avoiding the often seen dark ringed (panda eye) stars when I brought back the stars after having stretched the starless image.

Cool that you spotted the spiral galaxy Steve!

Cheers, Göran

There is lots of colour data in there, as you say 8 inch light gathering with high QE camera, makes for a great system.

Maybe I m just not used to seeing the new style of photos with all the deeper details, and signal from higher QE cameras, and Star Xt processing (I dont have Win 10 so I m not using it yet) so it seemed pushed to me.

The cropped inserts you have do show good smooth data, so I guess I was a bit quick to judge.

Tom

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gorann

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4 hours ago, carastro said:

A great result Goran, you have really been churning them out since the dark skies returned to Sweden.

Carole 

Thanks a lot Carole! The UK has lately been sending the bad weather our way but now it looks like two clear nights may be comming up😉

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2 hours ago, ollypenrice said:

I don't see any artifacts arising from the hard process so I think the look of the image is down to the extremely strong signal. 

This is not a shark I'd want in my swimming pool!!!

Olly

(Not that I have a swimming pool.... :D)

 

1 hour ago, Tom OD said:

There is lots of colour data in there, as you say 8 inch light gathering with high QE camera, makes for a great system.

Maybe I m just not used to seeing the new style of photos with all the deeper details, and signal from higher QE cameras, and Star Xt processing (I dont have Win 10 so I m not using it yet) so it seemed pushed to me.

The cropped inserts you have do show good smooth data, so I guess I was a bit quick to judge.

Tom

Thanks Olly & Tom,

yes, for me the RASA 8 and the ASI2600MC has been a game changer. A lot of signal and very little fight against noise. The fight is against the fast focal ratio allowing decent star shapes over a 18x24 mm image. Celestron's camera attachment system with a rather flimsy retention ring, and the lack of a good (accessible) tilt adjustment can be a bit frustrating.

CS, Göran

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21 minutes ago, gorann said:

 

Thanks Olly & Tom,

yes, for me the RASA 8 and the ASI2600MC has been a game changer. A lot of signal and very little fight against noise. The fight is against the fast focal ratio allowing decent star shapes over a 18x24 mm image. Celestron's camera attachment system with a rather flimsy retention ring, and the lack of a good (accessible) tilt adjustment can be a bit frustrating.

CS, Göran

Is a tilt adjustable camera a good thing or a pain? I m looking at the Apex atik CMOS but its not out yet. It has that feature, but I'll be imaging at F/5 at the shortest, so it may not affect me as much as F/2

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gorann

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2 hours ago, Tom OD said:

Is a tilt adjustable camera a good thing or a pain? I m looking at the Apex atik CMOS but its not out yet. It has that feature, but I'll be imaging at F/5 at the shortest, so it may not affect me as much as F/2

I think it is a very good idea to have a tilt adjustible camera, even with an f/5 scope (and how knows what scopes you may have in the future). The ASI2600 has a built in adjustible tilt plate but it can only be adjusted from the front end so it cannot be reached when it is sitting on a RASA and it will be very cumbersome to adjust it as you will have to remove the camera back and fourth. I do not know how the adjustment works on the ATIK but if it is adjustable from the side that would be great. I think QHY has some model where that can be done.

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gorann

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9 minutes ago, carastro said:

Lol, well we didn't want it to we were happy to send it on it's way, sorry it landed on you.

Carole 

Sorry that you did not want to keep it but it seems it is heading for Russia now 😉

 

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