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Garnet Star to Kemble's Cascade


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Taken during November and December on very cold but clear nights from a suburban back garden illuminated by street lights, 45 degrees of milky way.

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My target was the Cassiopeia constellation area.

The mosaic is made from 5 runs of the barn door, image 2 from the first night and images 1, 2, 3 and 4 (these two had been combined) from the second night.

stack 2 - 16 lights 10 flats 20 dark flats 33 bias ISO 800 Neodymium filter -total  32 minutes

stack 1  - 12 lights 28 flats 15 dark flats 30 bias ISO 400 - total 34 minutes

stack 2  - 9 lights 28 flats 15 dark flats 30 bias ISO 400 - total 23 minutes

stack 3  - 4 lights 28 flats 15 dark flats 30 bias ISO 400 - total 11 minutes 

stack 4  - 11 lights 28 flats 15 dark flats 30 bias ISO 400 - total 33 minutes

Manual barn door tracker, unmodded Canon 1100d 40mm pancake lens f4 and a plastic flower pot flocked dew shield for the lens.

I find that the 10 second window works well if I work the mount behind the clock I can reliably get 2-3 minute exposures, bad star shapes occur when I get ahead of the clock, so I work behind it with a 5 second float. (assuming 400/40 gives 10 seconds before trails evident on static mount)

Stacked in DSS, cropped and processed in StarTools saved as jpg (gave higher compression on file size). In StarTools I added refraction spikes to highlight the constellation, Garnet and Kemble's Cascade stars. DSS using kappa-sigma clipping (does a great job on star shape) on 4 stacks and median on the problematic stack with the blazing 4 engine jet landing lights, (no alignment of RGB and no hot pixel removal) and used autosaved fits file. Mosaic built using Microsoft Image Composition Editor (ICE) part way through the process as ICE couldn't stitch fully processed files.

Astrometry.net was used to plate solve the image, though I had to upload the star mask for the area to be recognised.

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This if my home made barn door tracker. It is designed to sit on a flat chair and with three adjustable feet can be set level, I sit next to it and work the turning cd disk (under the bottom board out of sight). The black circle is the button battery for a red led that shines unto the winding disk so i can can where the pointer is. The red dot finder enables the tracker hinge to be aligned with Polaris and the camera sits on the ball head with it's own red dot finder. The angle of the board's mount support for the actual barn door which is fixed to it is set for my latitude. This mount is rock steady. I use DSLR Controller on an android 7 inch tablet to control the camera, makes focusing so much easier.

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Personally, I preferred the one you posted in your thread on 6th January. Better colour balance and brighter too.

Ian

Edit. Sorry, I think that sounds a bit critical. Relatively easy final tweaking which I think would turn a great picture into an eye-catching one.

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There's some wonderful deep sky gems in there; Caroline's Rose is strikingly bright more like a globular cluster, the Pacman and Heart & Souls Neb easily visible, a tiny ET can be seen floating in space complete with eyes, arms and legs, and some lovely large open clusters with obsure names which don't often get mentioned (ASCC6, St2, etc - well, I've never heard of them! :smiley:). Lovely widefield image.

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