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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 ASASSN-15so in Galaxy NGC 3583

December 17, 2015 Leave a comment

NGC-3583-SNalt3-750

The bright spot at the centre of the spiral galaxy NGC 3583 in Ursa Major is the Type Ia supernova ASASSN-15so discovered by the All Sky Automated Survey for Super Novae (ASAS-SN) on 8/11/15. It is currently magnitude 13.7. The faint barred spiral galaxy above and slightly to the right of NGC 3583 is NGC 3577.

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Images taken 16/12/15 2.37am New Mexico time on iTelescope.Net T11. Luminance 5 x 300 sec. RA: 11h 14m 12.1s DEC: 48° 19′ 01″ (J2000)

 

Supernova SN2015F in Galaxy NGC 2442 28-3-15

March 28, 2015 Leave a comment

ngc-2442-stacked4

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.

New Supernova SN 2014J in Galaxy M82

January 26, 2014 Leave a comment

Discovered on 21/1/14 by Steve J. Fossey when it was at magnitude 11.7 SN 2014J has continued to brighten to about magnitude 10.7. This supernova is a Type Ia-HV (high-velocity) with exploded gases escaping at about 12,400 miles per second. The progenitor star was a white dwarf made of carbon and oxygen, which have now fused into silicon during the explosion.

This is the closest and brightest supernova for the last 21 years and will be visible in 3″ and 4″ amateur telescopes.

Images taken 26/1/14 between 5.23 to 6.07 am New Mexico time on iTelescope T11 (black and white ) and T3 (colour) RA: 09h 55m 54.1s DEC: 69° 40′ 59″ (J2000)

Click on images to enlarge….

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Supernova SN 2013ct in galaxy NGC 428

August 13, 2013 Leave a comment

Supernova 2013ct is a Type Ia discovered by Stu Parker (BOSS – New Zealand) on 10/5/13 when it was at it’s peak magnitude of around 12.2.  It has now faded to approx mag 15.4

NGC 428 lies in the constellation Cetus approx. 37 million light years away. The galaxy has a distorted shape perhaps resulting from the collision of two galaxies.

Image taken 12/8/13 4.46 am local observatory time at Nerpio, Spain using remote iTelescope T07 (Planewave 17″ CDK, SBIG STL-11000M ABG). 4 x 300 secs Lum. Processed in Maxim DL5, Adobe Photoshop CS2, DeepSkyStacker 3.3.2

Click image to enlarge:

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AAVSO Light Curve:

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Supernova SN 2013dy in galaxy NGC 7250

August 6, 2013 Leave a comment

This Type Ia supernova was discovered on 10/7/13 by the Lick Observatory Supernova Search programme and Kuniaki Goto two weeks before it reached it’s peak brightness of around magnitude 12.7 on 25/7/13. The supernova is currently at magnitude 13.0

NGC 7250 (PGC 68535) lies some 55 million light years away and is a rather small object which is difficult to image. It was discovered by William Herschel on November 8th 1790 and is classed as a starburst galaxy.

Image taken 6/8/13 4.18 am local observatory time at Nerpio, Spain using remote iTelescope T07 (Planewave 17″ CDK, SBIG STL-11000M ABG). 4 x 300 secs Lum. Processed in Maxim DL5, Adobe Photoshop CS2, DeepSkyStacker 3.3.2  RA 22 18 17.7, Dec +40 33 47

Click image to enlarge:

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AAVSO Light Curve:

Light Curve

Supernova SN 2013ej in galaxy M74

August 4, 2013 Leave a comment

A new Type IIP supernova was discovered in spiral galaxy M74 in the constellation Pisces by the Lick Observatory Supernova Search on 25th July. It has brightened rapidly to around magnitude 12.4 and is visible in 8″ amateur telescopes, but will show up readily in images taken on lower aperture telescopes of 4-6″ under dark and clear skies.

This star was originally a supergiant about 8x the size of the sun before it ran out of fuel to burn, collapsed due to gravitational forces and then exploded into the bright source of light that we can now see. Besides blasting new heavy elements out into space the supernova may leave behind a neutron star, which is the compressed remnant of the stars original core.

Image taken 4/8/13 4.01am local observatory time at Nerpio, Spain using remote iTelescope T07 (Planewave 17″ CDK, SBIG STL-11000M ABG). 5 x 300 secs Lum. Processed in Maxim DL5, Adobe Photoshop CS2, DeepSkyStacker 3.3.2

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AAVSO Light Curve:

M74-2013ej-AAVSO-light-curv

Bright new Supernova SN2012cg in Galaxy NGC 4424

On May 17th the automated Lick Supernova Search discovered the SN 2012cg supernova in galaxy NGC 4424 in the constellation Virgo. From 18th magnitude it has now brightened to 12.0 and rivals the core of the galaxy for brightness. This exploding star was originally a White Dwarf star equivalent in mass to our own Sun and locked in a binary orbit with a much larger star. It steadily drew matter from this companion star up to a point where it became unstable, collapsed in on itself and exploded, producing what is known as a Type Ia supernova. This spectacular event should be visible in telescopes of 6″ diameter and above.

Image taken Sunday June 11th 00.59 am from Nerpio, Spain with iTelescope T7 Planewave 17″ CDK, SBIG STL-11000M. 300 sec Bin 2. RA: 12h 27m 11.9s DEC: 09° 25′ 01″ (J2000)

M51 Whirlpool Galaxy Supernova 2011dh

September 10, 2011 Leave a comment

As I mentioned in my last post supernova 2011dh is still visible in the Whirlpool Galaxy (M51) with the aid of a telescope. Magnitude is currently around 14.8 and fading so there’s still time to catch this one. I used the GRAS G07 17″ Planewave to capture an image tonight, but even though the moon is 116 degrees away to the south there was significant moonglow and this created a pretty horrible gradient across the image which could not be edited out using the usual gradient and light pollution removal tools. I therefore turned the image negative and increased the contrast to bring out some detail. The supernova is clearly visible at the marked location.

Here’s the current AAVSO light curve for this supernova…….