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Astro Pixel Processor – Learning about LRGB processing

March 30, 2020 Leave a comment

I have been used to imaging in the past with RGB colour cameras, but now that the iTelescope remote telescope network has switched completely to cameras fitted with the more sensitive mono sensors and RGB filters I am forced to learn a new method of processing to combine RGB exposures with the luminance exposures. This is a good skill to learn as the images will potentially be more detailed with less noise and this is how the vast majority of astro imaging is done.

I saw the recommendation for the Astro Pixel Processor software on the iTelescope website and it seems to be well respected with good results so I thought I would give it a go on the free trial offer. Astro Pixel Processor can be found here https://www.astropixelprocessor.com/ There is an excellent video tutorial taking you through all steps to process an LRGB image of the Small Magellanic Cloud NGC292 here LRGB Tutorial The data was kindly made available by Christian Sasse,

The tutorial is in 9 parts and easy to follow although some of the menu items have changed in the latest update to those visible in the tutorial and there are additional options when loading files that are different too like the panel asking you about which session you want to use. I just went with the defaults and dropped all files into Session 1 every time and everything worked out fine.

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The staged workflow is easy to follow and the software is actually very good at auto processing many of the early stages with minimal input. The fun really starts in the Tools section after you have combined the RGB image following calibration, registration and integration. Here you can calibrate star colours, remove light pollution and crop the image to suit. Then you can switch to the Preview section on the right and follow through the comprehensive Digital Development Process (DDP) including adjustment of the black/white point, saturation, sharpness, contrast, select the correct histogram stretch and much more. The changes are visible in real-time on the screen and when you get to a result you are happy with just save the stretched image as a Tiff or Jpeg.

I was pretty pleased with the results for a first ever process of LRGB data and look forward to using the software for comet and supernova imagery.

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Small Magellanic Cloud processed in Astro Pixel Processor using data by Christian Sasse. Star Spikes added with Starspikes Pro in Photoshop Elements.

Supernova PSN J07174570 in galaxy NGC 2357

Supernova PSN J07174570 was discovered by T. Noguchi on 2/5/15 in spiral galaxy NGC 2357 in the constellation Gemini. It is a Type Ia supernova and is currently at magnitude 14.2 brightening from the discovery magnitude of 15.7

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Image taken 7/5/15 9.21pm New Mexico time (UTC -6) on iTelescope T11 20″ Planewave CDK 508mm and FLI ProLine PL11002M camera. RA: 07h 17m 42.0s DEC: 23° 21′ 00″ (J2000). 5 x 180 sec luminance. Processed in Maxim DL5, DeepSkyStacker 3 and Adobe Photoshop CS2.

Supernova SN2015F in Galaxy NGC 2442 28-3-15

March 28, 2015 Leave a comment

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I fancied a change of scenery after all of the recent solar activity of various sorts and ventured south of the equator this time. As many of you who read this blog will know I often like to take images of supernovae which briefly appear in distant galaxies and the current brightest supernova is SN2015F. I reserved some time at the iTelescope Siding Spring observatory in Australia and used their half metre T31 Planewave telescope to capture this image.

Supernova 2015F was discovered on 9/3/15 by Berto Monard. It is a Type Ia currently at magnitude 13.3 and is located within the intermediate spiral galaxy NGC 2442, more commonly known as the Meathook Galaxy, in the constellation Volans (southern hemisphere). The Meathook Galaxy lies 50 million light years away and was first discovered by John Herschel.

Type Ia supernovae are fairly common in galaxies with old star populations and are really useful for determining distances between objects and even the age of the universe. Type Ia’s are the result of a white dwarf star exploding in a binary star system due to complex gravitational interactions between the white dwarf and a much larger companion star. The white dwarf grows to approximately 1.4 times the size of the Sun and then becomes unstable and explodes, destroying the star completely.

Imaged 28/3/15 10.28pm Australia time (11.28am UTC) on iTelescope T31 CDK 500mm Planewave with FLI-PL09000 camera. 3×300 sec, Bin 1, Luminance, RA: 07h 36m 18.0s DEC: -69° 31′ 59″ (J2000). Processed in MaxImDL5, DeepSkyStacker 3 and Photoshop CS2.