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Old 06-05-2021, 11:44 PM
Mickoid (Michael)
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Coal Sack to Carina

I took this over two nights this week between breaks in clouds from a Bortle 7 backyard. Tuesday night, 11 X 2mins @ 800iso with UVIR cut filter and Wednesday night, 20 X 2.5mins @ 3200iso 7nm Ha filter. Both with the modded Canon 550d and a 50mm lens mounted on a Sightron Nano Tracker. High cloud interfered with the Ha session on Wednesday night.

Processed in Deep Sky Stacker and blended in Photoshop.
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  #2  
Old 07-05-2021, 10:04 AM
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AlextheMartian (Alex)
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Great framing of coal sack plus the running chicken and eta carina too. Nice job
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Old 07-05-2021, 10:56 AM
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multiweb (Marc)
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Nice widefield. You've certainly picked up a lot of faint Ha neb between carina and the chook. Well done.
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Old 07-05-2021, 01:50 PM
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Merlin66 (Ken)
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Michael,
What f stop did you use on the 50mm lens?
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Old 07-05-2021, 05:20 PM
AdamJL
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that's great Lots of nice nebulosity there!
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Old 07-05-2021, 05:49 PM
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Merlin66 (Ken)
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On the .jpg image, when plate solved and compared with CdC catalogues the limiting mag seems around 11 mag.
The reason for the interest in the aperture of the lens is to compare these wide angle shots with similar taken with objective gratings, which are only 25mm diameter.
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Old 07-05-2021, 06:01 PM
Mickoid (Michael)
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Quote:
Originally Posted by AlextheMartian View Post
Great framing of coal sack plus the running chicken and eta carina too. Nice job
Thanks Alex, by using the 50mm on a crop sensor this was all I could get in the frame at the angle I had the camera.

Quote:
Originally Posted by multiweb View Post
Nice widefield. You've certainly picked up a lot of faint Ha neb between carina and the chook. Well done.
Thanks Marc, the UVIR cut filtered shots on their own looked a bit bland so it was nice to introduce a bit of Ha to spice it up!

Quote:
Originally Posted by Merlin66 View Post
Michael,
What f stop did you use on the 50mm lens?
Ken, I shot both filtered shots at f8.

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Originally Posted by AdamJL View Post
that's great Lots of nice nebulosity there!
Thanks Adam, it's always a struggle from light polluted skies to capture the nebulosity but the Ha filter really helped to show it up.
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Old 07-05-2021, 06:11 PM
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Michael,
Thanks for that.
That’s an effective aperture of around 6mm. I would like to think the 25mm grating could give useable spectrum of 6-7 mag target stars.
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Old 07-05-2021, 06:16 PM
Mickoid (Michael)
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Quote:
Originally Posted by Merlin66 View Post
On the .jpg image, when plate solved and compared with CdC catalogues the limiting mag seems around 11 mag.
The reason for the interest in the aperture of the lens is to compare these wide angle shots with similar taken with objective gratings, which are only 25mm diameter.
Correct me if I haven't understood what you're saying, is that my shot has picked up fainter stars at nearer to a 6mm grating than at the wider aperture of 25mm?
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Old 07-05-2021, 06:46 PM
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Merlin66 (Ken)
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Michael,
Basically yes, a 25mm aperture has the potential to record fainter stars than a 6mm aperture.
With the spectral spread with say a 100 l/mm being 4 or 5 times, meaning a reduction in limiting magnitude by that amount.
What it infers, is that a grating could (I say could) record useable Spectra from target stars down to 6-7 mag stars.
I ‘ve setup a scope/ camera set-up which will hopefully show this.
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Old 13-05-2021, 08:28 PM
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Anth10 (Anthony M)
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Very nice combination of data Mick, resulting in a pleasing wide field of the southern night sky. Really like the colour in this well done.
Anth
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