Observation by Ron Morley: M101 Pinwheel Galaxy
Uploaded by
Ron Morley
Observer
Ron Morley
Observed
2020 Apr 14 - 22:30
Uploaded
2020 Apr 21 - 14:22
Objects
The Triangulum Galaxy (M33)
The Coma Pinwheel Galaxy (M99)
M101
Equipment
- Takahashi 60mm refractor FS60C
- SX Ultrastar Mono camera
- Baader RGB absorptive filters with UV/IR block
- Piggy-backed on Meade LX200 10"
- Exposures taken using Starlight Live. Pre and post processing using Astroart 7
Exposure
Two sets of 5 minute exposures for Luminance and RGB plus corresponding flats and darks
Location
Perth and Kinross
Target name
Pinwheel Galaxy M101
Title
M101 Pinwheel Galaxy
About this image
This was my first attempt at RGB imaging. The exposures were unguided. Considerable time had been spent over the preceding weeks in refining the polar alignment (PTFE washers on wedge and SharpCap 3.3 method), worm training and tube balancing. Flats were taken using 315mm Aurora flatfield panel mounted on an extendable (3m high) camera tripod. Panel held in position using an articulated iPad clamp. A layer of thin card was inserted to reduce the luminosity of the panel. M101 was around altitude 75 degrees. Minor unsharp mask applied to luminance. Combined LRGB colour image used unadjusted Astroart settings. The Takahashi optics are excellent, the Ultrastar is a very good high-end guide camera but the Meade wedge/tracking system is modest. Satellite trails caused 30% of images to be discarded which suggests 5 minutes is about the longest you can economically manage these days.
Files associated with this observation
Like this image
Jeremy Shears,
Peter Mulligan,
David Basey,
Nick Hewitt,
Dr Paul Leyland,
Andy Wilson,
Clive Nanson,
Mike Foylan,
Lyn Smith,
Mr John William Hughes,
Andrew Dumbleton,
Ron Arbour
Comments
Thats a great first image Ron and impressive at 5 minutes unguided. All that prep work before hand certainly played its part.
Thank you for sharing your image here.
John
In my experience, median stacking allows frames with minor pollution from satellites and cosmic ray hits to be used without serious effects on either aesthetics or scientific value.
Did you use median stacking or something else, such as average stacking?
Sigma clipping can also work well, I'm told,but median stacking is what I use.
Hi John, Thank you for your kind words. Imaging can be a bit of a slog so your encouragement is appreciated. Ron
Hi Paul, Thank you for your helpful comments. I used 'average' stacking for the image. I carried out a rapid re-processing today using 'median'. It did help. One of the thick satellite streaks unfortunately went right across the centre of M101 but the fainter ones further away from the object could be dimmed to acceptable levels. Thank you for your kind advice. Ron
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