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Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Roberto on Jun 24, 2020, 08:54:10

Title: Cepheus in perspective from Petts Wood
Post by: Roberto on Jun 24, 2020, 08:54:10
Hello All

I trust you are all well and enjoying the sunshine.

Below is a mosaic (my first!) composed of two panels along RA. Taken during nautical twilight, I was gladly surprised the colours were not completely off. L taken with Moravian G4 - 152mm refractor at 1300mm - and RGB with ASI2600 - 92mm refractor at 490mm. Great field to ponder about the distance of objects along our line of sight: Barnard 150, the Seahorse Nebula is at roughly 1200ly; the cluster NGC6939 at 3860ly and NGC6946, the fireworks galaxy, at 22.5 million ly...

Cepheus in Perspective - B148, B149, B150, NGC6939 and NGC6946 - Mosaic - LRGB
https://www.astrobin.com/padq19/D/?nc=all (https://www.astrobin.com/padq19/D/?nc=all)

See the link for RGB only version and annotated image.  Large mosaic is 9K x 4K resolution.

Roberto

(https://cdn.astrobin.com/thumbs/Tnm6j9QDtHrW_16536x16536_BhGLtlq6.jpg)
Title: Re: Cepheus in perspective from Petts Wood
Post by: Carole on Jun 24, 2020, 09:52:58
Great Mosaic Roberto.  I still don't know what Nautical Twilight is, must look it up.

Carole
Title: Re: Cepheus in perspective from Petts Wood
Post by: Roberto on Jun 24, 2020, 13:29:08
Thank you Carole.

This charts clarifies the issue; degrees are Sun below horizon.

(https://c.tadst.com/gfx/600x337/twiligh-phases.png?1)
Title: Re: Cepheus in perspective from Petts Wood
Post by: Carole on Jun 24, 2020, 13:58:34
Thanks for that Roberto, very clear:

Carole
Title: Re: Cepheus in perspective from Petts Wood
Post by: RobertM on Jun 24, 2020, 17:43:20
Great image and framing Roberto.  The gradients must have been interesting to process  ;)

Will have a better look on my big screen a bit later.

Robert
Title: Re: Cepheus in perspective from Petts Wood
Post by: Roberto on Jun 24, 2020, 17:47:54
Thank you Robert.  Surprisingly the gradients were not an issue  There were definitely gradients towards London from LP but they were well behaved and cleared from each panel easily using ABE in PixInsight.  When I formed the Mosaic, I did one more pass of ABE and nothing after.  These objects were at AZ40-50/ALT 40 when I started imaging so there was definitely an LP dome visible when by the side of the scope.

Roberto
Title: Re: Cepheus in perspective from Petts Wood
Post by: MarkS on Jun 27, 2020, 09:26:29
As usual, another great image from you!

I love the way the dark nebulae have come out.

Mark
Title: Re: Cepheus in perspective from Petts Wood
Post by: Roberto on Jun 27, 2020, 12:20:59
Thank you Mark! It's a very dark one; it was clearly visible in the 5 min colour subframes even in less than total darkness. It must be fantastic seeing it with a wide field piece at a dark location.
Roberto
Title: Re: Cepheus in perspective from Petts Wood
Post by: The Thing on Jun 29, 2020, 10:04:56
You really are a bit good at this lark Roberto, very nice.
Title: Re: Cepheus in perspective from Petts Wood
Post by: Roberto on Jul 02, 2020, 13:08:51
Apologies for the late reply...and thank you!
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