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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.

Probably the most amazing astronomy book you will buy this year !

February 18, 2014 Leave a comment

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I’m talking about This Is Mars by Alfred S. McEwen, Francis Rocard and Xavier Barral with contributions by Sebastien Girard, Nathalie Chapuis and Nicolas Mangold and published by Aperture.

OK, first thing to note, it’s not cheap ! At £65 this may stretch people, but fortunately you can find it as low as £39.25 now using Amazon marketplace sellers. Second thing to note, it’s huge ! Measuring 30 cm wide and 36 cm tall this will not fit on most standard bookshelves and will almost by default become a coffee table book. You are, however, buying quality here. This hard bound book is beautifully designed and executed and falls somewhere between art and science in content.

The photographs of the surface of Mars presented here are both beautiful and utterly astounding and derive from the HiRISE camera mounted on the Mars Reconnaissance Orbiter, which has been taking ultra high resolution images of Mars since 2006.  The 150 black and white images are just short of A3 size and presented on very high quality art paper with each image covering an area 6km in breadth.  The range of landforms is staggering, from plunging canyons, vast black dune fields, towering volcanoes, craters, glacier flows and swirling trails left by desert twisters to name but a few.

After a brief introduction by the editor, Xavier Barral, about two thirds of the book is taken up with photos while the final third includes a series of short papers. The first is a description of the HiRISE camera and MRO project by Alfred S. McEwen. This is followed by an excellent essay by astrophysicist Francis Rocard covering the evolution of Mars and it’s geology (together with some detailed maps) which includes a timeline of the main observations of Mars from the 2nd century AD through to 2012. Finally, there’s a geomorphological tour of the surface of the Red Planet by Nicolas Mangold using the photographs in the book, which explains the origins of the numerous features you will see in the photographs.

I cannot recommend this book highly enough and I doubt anyone interested in astronomy would be even remotely disappointed to receive this book.

More information at the publisher’s website here http://www.aperture.org/shop/books/this-is-mars-books

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