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Rolf Wahl Olsen
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Astrophotographer and Software Developer
Astrophotographer and Software Developer

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Antlia Cluster - Extreme Deep Field - 152 Hours

With 152 hours taken over 55 clear nights (January to June 2015) here is finally my latest 'extreme deep field', this time showcasing the mighty (and rarely imaged) Antlia Galaxy Cluster (Abell S0636).
This is likely one of the deepest [i]ground based[/i] images ever taken by either amateur or professional telescopes and the faint Intracluster Light visible between the two subgroups doesn't seem to be described in literature. 
It has been a humbling experience to gather and process all this data. When I embarked on this project I specifically wanted to obtain a very deep view of a galaxy cluster, but I certainly did not expect to uncover such a treasure trove of features in this one little patch of sky. The entire image seems to be bursting with action, ranging from the varied and colourful cluster members themselves to obscure ultra-faint dwarf galaxies, Intracluster Light and Integrated Flux Nebula, red filaments from an ancient supernova remnant and a generous number of deeply reddened extremely distant galaxy clusters littered across in the background.
The H-Alpha filaments were a nice surprise for me. I was oblivious to their existence until very late in the process when some extremely faint streaks began to show up in test stacks. But after I grabbed an extra 8 hours of 2x2 binned H-Alpha data they came up nicely and I think they add a beautiful touch to the final result.
 
Link to full resolution image (4MB): http://goo.gl/hi1ZXx
Link to medium size image: http://goo.gl/lTtHKe

Annotated Version: http://goo.gl/ycigis
Comparison with DSS and GALEX fields: http://goo.gl/sXZniz
Luminance Stacking Progress, 0 to 103 hours: http://goo.gl/023OH5
Contour Plot of Intracluster Light and Integrated Flux Nebula: http://goo.gl/riN2cY
Micro Dust Cloud Superimposed on top of NGC3269: http://goo.gl/TnlDnc

Image details:
Resolution: 0.859 arcsec/pix
Rotation: 175.381 deg
Field of view: 47' 36.1" x 35' 50.2"
Image center: RA: 10 30 10.285, Dec: -35 25 09.18
Date: 55 nights, January to July 2015
Exposure: LRGBHa: 103:20:11:10:8 hours, total 152 hours @ -25 to -32C
Telescope: Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Camera: QSI 683wsg with Lodestar guider 
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand
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Antennae Galaxies Collaboration: Ultra-Deep High Resolution View

Link to full resolution 9MB image: http://www.rolfolsenastrophotography.com/Astrophotography/Antennae-Extreme-Deep-Field/i-4pj8K9X/O

This image is a collaboration between astrophotographers Federico Pelliccia of Italy and Rolf Wahl Olsen of New Zealand and shows an ultra-deep and detailed view of the famous Antennae colliding galaxies in Corvus.
The image was constructed from a number of sources: First a mosaic of panels from the 8.2m Subaru telescope was very patiently put together by Federico Pelliccia. This data was subsequently blended with Rolf Wahl Olsen's Antennae Galaxies Extreme Deep Field - 75 Hours to bring out the faint tidal streams and large scale structures which was not present in the high resolution Subaru data and this deep image also provided the colour information. The core was further enhanced by overlaying an extremely detailed frame from the Hubble Space Telescope.
Together this data represents the deepest and highest resolution view available to date covering the entire Antennae galaxies.

Data: Subaru, NAOJ & NASA/ESA/Hubble & Rolf Wahl Olsen
Processing: Federico Pelliccia & Rolf Wahl Olsen
RA 12h 01m 53.30s, Dec -18° 52' 31.37"
Pixel scale: 0.2"/pixel
Field radius: 0.26 degrees

Optical systems:
Subaru Telescope
8.2m f/1.8 Ritchey–Chrétien
Exposure: 20 x 5 minutes

Hubble Space Telescope
2.4m f/24 Ritchey–Chrétien
The Hubble image uses visible and near-infrared observations from Hubble’s Wide Field Camera 3 (WFC3), along with some of the previously-released observations from Hubble’s Advanced Camera for Surveys (ACS).

Rolf Wahl Olsen
Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Exposure: LRGB 54:7:7:7 hours, total 75 hours @ -25C
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Photo

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Antennae Galaxies Collaboration: Ultra-Deep High Resolution View

Link to full resolution 9MB image: http://www.rolfolsenastrophotography.com/Astrophotography/Antennae-Extreme-Deep-Field/i-4pj8K9X/O

This image is a collaboration between astrophotographers Federico Pelliccia of Italy and Rolf Wahl Olsen of New Zealand and shows an ultra-deep and detailed view of the famous Antennae colliding galaxies in Corvus.
The image was constructed from a number of sources: First a mosaic of panels from the 8.2m Subaru telescope was very patiently put together by Federico Pelliccia. This data was subsequently blended with Rolf Wahl Olsen's Antennae Galaxies Extreme Deep Field - 75 Hours to bring out the faint tidal streams and large scale structures which was not present in the high resolution Subaru data and this deep image also provided the colour information. The core was further enhanced by overlaying an extremely detailed frame from the Hubble Space Telescope.
Together this data represents the deepest and highest resolution view available to date covering the entire Antennae galaxies.

Data: Subaru, NAOJ & NASA/ESA/Hubble & Rolf Wahl Olsen
Processing: Federico Pelliccia & Rolf Wahl Olsen
RA 12h 01m 53.30s, Dec -18° 52' 31.37"
Pixel scale: 0.2"/pixel
Field radius: 0.26 degrees

Optical systems:
Subaru Telescope
8.2m f/1.8 Ritchey–Chrétien
Exposure: 20 x 5 minutes

Hubble Space Telescope
2.4m f/24 Ritchey–Chrétien
The Hubble image uses visible and near-infrared observations from Hubble’s Wide Field Camera 3 (WFC3), along with some of the previously-released observations from Hubble’s Advanced Camera for Surveys (ACS).

Rolf Wahl Olsen
Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Exposure: LRGB 54:7:7:7 hours, total 75 hours @ -25C
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Photo

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The Antennae Galaxies - Extreme Deep Field - 75 Hours

I have long been working on another large project and as my target has now disappeared for the season behind trees in the West, I've been able to turn to processing and analysing the data. So here is a new Extreme Deep Field image of the famous Antennae galaxies in Corvus.

Link to large image: http://goo.gl/4TTldt
Link to full resolution image (5.5MB): http://goo.gl/CFTr0x

Other images in this gallery:[/B]
Comparison of details with ESO (VLT) and Hubble Space Telescope images: http://goo.gl/CzrLUz
Comparison with deep image from UK Schmidt plates (AAO): http://goo.gl/DZJ8jQ
Gallery of distant background galaxies: http://goo.gl/Kaq3MK
Black and white version, brightened to show the faintest outer extensions: http://goo.gl/OTLVYK

I managed to gather 75 hours for this image, over the first six months of the year. At times it was rather frustrating because clouds kept interrupting my sessions. The weather has definitely been less cooperative this year than during the same period in 2013 when I was working on Centaurus A. Despite this I managed to collect enough data for a very deep image, and thanks to the larger aperture of my new telescope the limiting magnitude is also comparable to that of last year's effort, being around magnitude 25.

Apart from the Antennae itself, what I like most about this scene is the incredible number of distant background galaxies. This area in Corvus seems very rich indeed. The full resolution image is worth having a look at just to see all these faint galaxies littering the background. There are many beautiful interacting pairs and groups which would be fantastic targets in themselves if they were only closer.
I have also put together a collage of some of these background galaxies (linked above).

About the image:
Following on from my previous Extreme Deep Field project of Centaurus A, I turned my attention to a spectacular pair of colliding galaxies known as The Antennae, located around 45 million light years away in the Southern constellation of Corvus.
This interacting galaxy pair was discovered in 1785 by William Herschel. 

To obtain a unique deep view of the faint tidal streams and numerous distant background galaxies I gathered 75 hours on this target during 38 nights from January to June 2014.
This project was not blessed with the same long run of clear nights as I had enjoyed in 2013, so this amount of data took 6 months to accumulate, two months longer than the 120 hours I collected on Centaurus A the year before.
However, the telescope used was my new larger 12.5" f/4 Serrurier Truss Newtonian telescope, which I built in late 2013. This telescope gathers approximately 156% the amount of light over the old 10" f/5. The total integrated signal is therefore theoretically approaching that of the Centaurus A image. The faintest stars and background galaxies visible in the raw image data have magnitudes between 24 and 25, confirmed via photometric calibration of the integrated FITS luminance file against the USNO catalogues. 

Tidal Streams
The iconic features of these two interacting galaxies are the two long tidal streams expelled by the collision of the galaxies. The long upper (Southern) stream seems to actually be a loop and a very faint portion of the material appears falling back towards the galaxies. Along this stream several brighter blue knots can be found, culminating in the large extended clump at its end. These knots are composed of young hot blue stars, likely triggered by the violent forces induced by the collision. The shorter lower (Northern) stream extends into a large faint fan shape with a little curl up towards the right. 

Distant Background Galaxies
Behind the lower fan of speeding intergalactic stars lies a very rich and distant galaxy cluster whose members are visible as innumerable faint fuzzy spots in the area immediately at the end of the lower stream. This densely populated area extends further towards the left below the colliding galaxies.
These background galaxies are so distant that their light is visibly reddened because of the cosmological redshift. In fact, the entire background is littered with such distant background galaxies, and many of these can be seen through the two tidal streams and also through the extended shells and halos of the colliding galaxies. Judged by their colour and apparent size the faintest of these remote galaxy clusters lie several billion light years away. 

Core Area
The main action is happening in the centre where intense starburst activity has been triggered by the merging of the two galaxies. Bright blue arcs of hot young O and B type stars light up the core area, together with the distinct magenta hue from massive glowing hydrogen nebulae. The two galaxy nuclei can still be seen separately, with nebulae, star streams and dark dust bands circling around them in a chaotic dance. 

Galaxy Collisions
Based on computer simulations and observations of other colliding systems it is believed that around 1.2 billion years ago these galaxies were two independent spiral systems similar to our Milky Way. Over the following billion years or so the galaxies passed close to, and through, each other resulting in the long tidal tails being flung from the centre. During such a collision multiple shells and streams of material are expelled and our current view provides a snapshot in time of this entire spectacle. The two nuclei are now in the process of falling back towards each other again and the whole system will eventually merge to form one giant elliptical galaxy some time in the distant future.
Our Milky Way galaxy will likely share this fate in the future when it collides with the Andromeda Galaxy. Although the large Andromeda Galaxy is approaching our own galaxy with the colossal speed of 110 km/s the two galaxies will not begin to merge for another 4 billion years. 

Image details:
Date: 38 nights during January to June 2014
Telescope: Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Exposure: LRGB 54:7:7:7 hours, total 75 hours @ -25C
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand 
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The Antennae Galaxies - Extreme Deep Field - 75 Hours

I have long been working on another large project and as my target has now disappeared for the season behind trees in the West, I've been able to turn to processing and analysing the data. So here is a new Extreme Deep Field image of the famous Antennae galaxies in Corvus.

Link to large image: http://goo.gl/4TTldt
Link to full resolution image (5.5MB): http://goo.gl/CFTr0x

Other images in this gallery:[/B]
Comparison of details with ESO (VLT) and Hubble Space Telescope images: http://goo.gl/CzrLUz
Comparison with deep image from UK Schmidt plates (AAO): http://goo.gl/DZJ8jQ
Gallery of distant background galaxies: http://goo.gl/Kaq3MK
Black and white version, brightened to show the faintest outer extensions: http://goo.gl/OTLVYK

I managed to gather 75 hours for this image, over the first six months of the year. At times it was rather frustrating because clouds kept interrupting my sessions. The weather has definitely been less cooperative this year than during the same period in 2013 when I was working on Centaurus A. Despite this I managed to collect enough data for a very deep image, and thanks to the larger aperture of my new telescope the limiting magnitude is also comparable to that of last year's effort, being around magnitude 25.

Apart from the Antennae itself, what I like most about this scene is the incredible number of distant background galaxies. This area in Corvus seems very rich indeed. The full resolution image is worth having a look at just to see all these faint galaxies littering the background. There are many beautiful interacting pairs and groups which would be fantastic targets in themselves if they were only closer.
I have also put together a collage of some of these background galaxies (linked above).

About the image:
Following on from my previous Extreme Deep Field project of Centaurus A, I turned my attention to a spectacular pair of colliding galaxies known as The Antennae, located around 45 million light years away in the Southern constellation of Corvus.
This interacting galaxy pair was discovered in 1785 by William Herschel. 

To obtain a unique deep view of the faint tidal streams and numerous distant background galaxies I gathered 75 hours on this target during 38 nights from January to June 2014.
This project was not blessed with the same long run of clear nights as I had enjoyed in 2013, so this amount of data took 6 months to accumulate, two months longer than the 120 hours I collected on Centaurus A the year before.
However, the telescope used was my new larger 12.5" f/4 Serrurier Truss Newtonian telescope, which I built in late 2013. This telescope gathers approximately 156% the amount of light over the old 10" f/5. The total integrated signal is therefore theoretically approaching that of the Centaurus A image. The faintest stars and background galaxies visible in the raw image data have magnitudes between 24 and 25, confirmed via photometric calibration of the integrated FITS luminance file against the USNO catalogues. 

Tidal Streams
The iconic features of these two interacting galaxies are the two long tidal streams expelled by the collision of the galaxies. The long upper (Southern) stream seems to actually be a loop and a very faint portion of the material appears falling back towards the galaxies. Along this stream several brighter blue knots can be found, culminating in the large extended clump at its end. These knots are composed of young hot blue stars, likely triggered by the violent forces induced by the collision. The shorter lower (Northern) stream extends into a large faint fan shape with a little curl up towards the right. 

Distant Background Galaxies
Behind the lower fan of speeding intergalactic stars lies a very rich and distant galaxy cluster whose members are visible as innumerable faint fuzzy spots in the area immediately at the end of the lower stream. This densely populated area extends further towards the left below the colliding galaxies.
These background galaxies are so distant that their light is visibly reddened because of the cosmological redshift. In fact, the entire background is littered with such distant background galaxies, and many of these can be seen through the two tidal streams and also through the extended shells and halos of the colliding galaxies. Judged by their colour and apparent size the faintest of these remote galaxy clusters lie several billion light years away. 

Core Area
The main action is happening in the centre where intense starburst activity has been triggered by the merging of the two galaxies. Bright blue arcs of hot young O and B type stars light up the core area, together with the distinct magenta hue from massive glowing hydrogen nebulae. The two galaxy nuclei can still be seen separately, with nebulae, star streams and dark dust bands circling around them in a chaotic dance. 

Galaxy Collisions
Based on computer simulations and observations of other colliding systems it is believed that around 1.2 billion years ago these galaxies were two independent spiral systems similar to our Milky Way. Over the following billion years or so the galaxies passed close to, and through, each other resulting in the long tidal tails being flung from the centre. During such a collision multiple shells and streams of material are expelled and our current view provides a snapshot in time of this entire spectacle. The two nuclei are now in the process of falling back towards each other again and the whole system will eventually merge to form one giant elliptical galaxy some time in the distant future.
Our Milky Way galaxy will likely share this fate in the future when it collides with the Andromeda Galaxy. Although the large Andromeda Galaxy is approaching our own galaxy with the colossal speed of 110 km/s the two galaxies will not begin to merge for another 4 billion years. 

Image details:
Date: 38 nights during January to June 2014
Telescope: Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Exposure: LRGB 54:7:7:7 hours, total 75 hours @ -25C
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand 
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The Antennae Galaxies - Extreme Deep Field - 75 Hours

I have long been working on another large project and as my target has now disappeared for the season behind trees in the West, I've been able to turn to processing and analysing the data. So here is a new Extreme Deep Field image of the famous Antennae galaxies in Corvus.

Link to large image: http://goo.gl/4TTldt
Link to full resolution image (5.5MB): http://goo.gl/CFTr0x

Other images in this gallery:[/B]
Comparison of details with ESO (VLT) and Hubble Space Telescope images: http://goo.gl/CzrLUz
Comparison with deep image from UK Schmidt plates (AAO): http://goo.gl/DZJ8jQ
Gallery of distant background galaxies: http://goo.gl/Kaq3MK
Black and white version, brightened to show the faintest outer extensions: http://goo.gl/OTLVYK

I managed to gather 75 hours for this image, over the first six months of the year. At times it was rather frustrating because clouds kept interrupting my sessions. The weather has definitely been less cooperative this year than during the same period in 2013 when I was working on Centaurus A. Despite this I managed to collect enough data for a very deep image, and thanks to the larger aperture of my new telescope the limiting magnitude is also comparable to that of last year's effort, being around magnitude 25.

Apart from the Antennae itself, what I like most about this scene is the incredible number of distant background galaxies. This area in Corvus seems very rich indeed. The full resolution image is worth having a look at just to see all these faint galaxies littering the background. There are many beautiful interacting pairs and groups which would be fantastic targets in themselves if they were only closer.
I have also put together a collage of some of these background galaxies (linked above).

About the image:
Following on from my previous Extreme Deep Field project of Centaurus A, I turned my attention to a spectacular pair of colliding galaxies known as The Antennae, located around 45 million light years away in the Southern constellation of Corvus.
This interacting galaxy pair was discovered in 1785 by William Herschel. 

To obtain a unique deep view of the faint tidal streams and numerous distant background galaxies I gathered 75 hours on this target during 38 nights from January to June 2014.
This project was not blessed with the same long run of clear nights as I had enjoyed in 2013, so this amount of data took 6 months to accumulate, two months longer than the 120 hours I collected on Centaurus A the year before.
However, the telescope used was my new larger 12.5" f/4 Serrurier Truss Newtonian telescope, which I built in late 2013. This telescope gathers approximately 156% the amount of light over the old 10" f/5. The total integrated signal is therefore theoretically approaching that of the Centaurus A image. The faintest stars and background galaxies visible in the raw image data have magnitudes between 24 and 25, confirmed via photometric calibration of the integrated FITS luminance file against the USNO catalogues. 

Tidal Streams
The iconic features of these two interacting galaxies are the two long tidal streams expelled by the collision of the galaxies. The long upper (Southern) stream seems to actually be a loop and a very faint portion of the material appears falling back towards the galaxies. Along this stream several brighter blue knots can be found, culminating in the large extended clump at its end. These knots are composed of young hot blue stars, likely triggered by the violent forces induced by the collision. The shorter lower (Northern) stream extends into a large faint fan shape with a little curl up towards the right. 

Distant Background Galaxies
Behind the lower fan of speeding intergalactic stars lies a very rich and distant galaxy cluster whose members are visible as innumerable faint fuzzy spots in the area immediately at the end of the lower stream. This densely populated area extends further towards the left below the colliding galaxies.
These background galaxies are so distant that their light is visibly reddened because of the cosmological redshift. In fact, the entire background is littered with such distant background galaxies, and many of these can be seen through the two tidal streams and also through the extended shells and halos of the colliding galaxies. Judged by their colour and apparent size the faintest of these remote galaxy clusters lie several billion light years away. 

Core Area
The main action is happening in the centre where intense starburst activity has been triggered by the merging of the two galaxies. Bright blue arcs of hot young O and B type stars light up the core area, together with the distinct magenta hue from massive glowing hydrogen nebulae. The two galaxy nuclei can still be seen separately, with nebulae, star streams and dark dust bands circling around them in a chaotic dance. 

Galaxy Collisions
Based on computer simulations and observations of other colliding systems it is believed that around 1.2 billion years ago these galaxies were two independent spiral systems similar to our Milky Way. Over the following billion years or so the galaxies passed close to, and through, each other resulting in the long tidal tails being flung from the centre. During such a collision multiple shells and streams of material are expelled and our current view provides a snapshot in time of this entire spectacle. The two nuclei are now in the process of falling back towards each other again and the whole system will eventually merge to form one giant elliptical galaxy some time in the distant future.
Our Milky Way galaxy will likely share this fate in the future when it collides with the Andromeda Galaxy. Although the large Andromeda Galaxy is approaching our own galaxy with the colossal speed of 110 km/s the two galaxies will not begin to merge for another 4 billion years. 

Image details:
Date: 38 nights during January to June 2014
Telescope: Homebuilt 12.5" f/4 Serrurier Truss Newtonian
Exposure: LRGB 54:7:7:7 hours, total 75 hours @ -25C
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand 
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A big thank you to Astronomy Picture of the Day (APOD) for selecting my recent version of Voyager 2's Neptune as today's image: http://apod.nasa.gov/apod/ap140515.html

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Here is a new Neptune image I assembled from images in NASA's Voyager 2 archives.
The Magnificent Neptunian System - Voyager 2 Data Revisited

Inspired by the spectacular images that are now regularly produced by amateurs using data from the Hubble Legacy Archive and other sources I thought I'd have a go at playing with professional data as well.
I have always been fascinated with the outer gas giants, and given that there is so little image data available I wanted to see if there were perhaps some previously unseen gems in there. To my knowledge a comprehensive high resolution image of the entire Neptunian system has never been released. However, image data for both the planet itself as well as the ring system and the largest moon Triton, taken within fairly short intervals from similar vantage points, do exist in NASA image archives. So here is what I was able to put together:

Link to large image: http://goo.gl/DMoslq

This image is made from data acquired during Voyager 2's closest approach to Neptune on August 25, 1989. Visible is the backlit planet viewed from Voyager 2 on its way out of the Solar System after the spacecraft had passed closest approach. The crescent shape of Neptune shows bright cirrus clouds and a dark band encircling the South Pole region, as well as a cyclonic structure at the pole itself, perhaps similar in nature to Saturn's now famous hexagon. Encircling the planet is the very faint ring system and the three bright ring arcs in the Adams ring; Liberté, Égalité and Fraternité, which were discovered by Voyager 2 during the fly-by.

To produce the image I scoured the Voyager 2 image data freely available from NASA's Planetary Data System. I was able to find raw images of a crescent Neptune showing intriguing cloud bands around the South Pole.
No complete image of the ring system exist, but based on available long exposure images of portions of the rings I was able to create a model of the density profile. I then fitted this model around the crescent planet to get a complete view, in accordance with the viewing angle as seen in the raw Voyager 2 images. A raw image of the brighter ring arcs was then processed and overlaid on the rings in a position corresponding with the original image data.

Visible to the right of Neptune is the small crescent of its largest moon Triton.
This part of the image is based on Voyager 2 data that shows Triton here in front of Neptune, but which was not taken until 3 days after the fly-by. I decided to include this data to achieve a more complete picture of the magnificent Neptunian system. Because the viewing angle of Neptune as seen from the spacecraft did not change significantly while it was receding out towards interstellar space, the entire scene would at this time have appeared very similar to what is depicted here. Only the positions of clouds and ring arcs would have changed since the closer image of the Neptune crescent was taken.

In order to include the background star field I plate solved one of the raw long exposure images of the rings which showed some stars. The successful plate solving revealed that the background was centered around RA 06h 09m 52.213s Dec +67° 31' 20.258" in Camelopardalis. I then downloaded corresponding DSS image data from Google Sky and inserted it as a background, sufficiently toned down so as to not interfere too much with the grandeur of Neptune while still providing a realistic context. This field of view as seen from Voyager 2 is approximately 5.5° x 7.5°.

Image Assembly & Processing: Rolf Wahl Olsen
Image Data: NASA/JPL (Voyager 2, NASA Planetary Data System)

For more information about the Voyager spacecraft, visit: www.nasa.gov/voyager
Photo

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The Magnificent Neptunian System - Voyager 2 Data Revisited

Inspired by the spectacular images that are now regularly produced by amateurs using data from the Hubble Legacy Archive and other sources I thought I'd have a go at playing with professional data as well.
I have always been fascinated with the outer gas giants, and given that there is so little image data available I wanted to see if there were perhaps some previously unseen gems in there. To my knowledge a comprehensive high resolution image of the entire Neptunian system has never been released. However, image data for both the planet itself as well as the ring system and the largest moon Triton, taken within fairly short intervals from similar vantage points, do exist in NASA image archives. So here is what I was able to put together:

Link to large image: http://goo.gl/DMoslq

This image is made from data acquired during Voyager 2's closest approach to Neptune on August 25, 1989. Visible is the backlit planet viewed from Voyager 2 on its way out of the Solar System after the spacecraft had passed closest approach. The crescent shape of Neptune shows bright cirrus clouds and a dark band encircling the South Pole region, as well as a cyclonic structure at the pole itself, perhaps similar in nature to Saturn's now famous hexagon. Encircling the planet is the very faint ring system and the three bright ring arcs in the Adams ring; Liberté, Égalité and Fraternité, which were discovered by Voyager 2 during the fly-by.

To produce the image I scoured the Voyager 2 image data freely available from NASA's Planetary Data System. I was able to find raw images of a crescent Neptune showing intriguing cloud bands around the South Pole.
No complete image of the ring system exist, but based on available long exposure images of portions of the rings I was able to create a model of the density profile. I then fitted this model around the crescent planet to get a complete view, in accordance with the viewing angle as seen in the raw Voyager 2 images. A raw image of the brighter ring arcs was then processed and overlaid on the rings in a position corresponding with the original image data.

Visible to the right of Neptune is the small crescent of its largest moon Triton.
This part of the image is based on Voyager 2 data that shows Triton here in front of Neptune, but which was not taken until 3 days after the fly-by. I decided to include this data to achieve a more complete picture of the magnificent Neptunian system. Because the viewing angle of Neptune as seen from the spacecraft did not change significantly while it was receding out towards interstellar space, the entire scene would at this time have appeared very similar to what is depicted here. Only the positions of clouds and ring arcs would have changed since the closer image of the Neptune crescent was taken.

In order to include the background star field I plate solved one of the raw long exposure images of the rings which showed some stars. The successful plate solving revealed that the background was centered around RA 06h 09m 52.213s Dec +67° 31' 20.258" in Camelopardalis. I then downloaded corresponding DSS image data from Google Sky and inserted it as a background, sufficiently toned down so as to not interfere too much with the grandeur of Neptune while still providing a realistic context. This field of view as seen from Voyager 2 is approximately 5.5° x 7.5°.

Image Assembly & Processing: Rolf Wahl Olsen
Image Data: NASA/JPL (Voyager 2, NASA Planetary Data System)

For more information about the Voyager spacecraft, visit: www.nasa.gov/voyager
Photo
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