Astronomical Images - the best from 2018/19
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Clicking on some images won't do anything, and on others might toggle you through an image sequence.
For devotees of shed...
The Moon and Venus shine down on Cols Xmas Shed.
25th December
C/2017-T2. This will be gracing our northern skies for the next few months.
The picture is taken with the Sony A6300, and the 360mm focal length (with reducer/corrector) telescope. 96 single images were taken, all 30 second exposures at ISO 3200. These, together with dark and flat frames were combined using Astro Art 6.
The picture (which you can't 'big') is a half resolution, very heavily cropped image. This is stacked using the manual alignment feature of AA6 in an attempt to align on the comet for each frame.
The star trails are the result of the comet moving across the background of stars.
A cropped and reduced image of the Pleiades taken with the 360mm focal length refractor and the Sony A6300.
The picture is an average of 17 20 second exposures at ISO 3200.
On the right is M52, a cute little cluster of white stars in the constellation of Cassiopeia. It is also known as the Salt and Pepper Cluster apparently, a name it disappointingly shares with M37 (why not call it the Ant-Powder cluster instead).
Stellarium claims the cluster is 500 light years away, most other sources I have seen go for 5000 light years.
On the left, there is 11000 light year distant NGC 7635, the Bubble Nebula. A sensible name. This is an HII region, consisting largely of ionised Hydrogen. The horse head nebula is another example, much of the light from these is at a frequency on or below the edge of transmission for the infra-red filter on your standard camera.
This makes them tricky targets for a standard camera, as I know from attempting to image the Horsehead nebula with my unmodified Canon EOS camera. So I was quite pleased with how this turned out, you can just about make out the left-hand edge of the bubble. Better images can be obtained with dedicated astronomy cameras and filters.
If you click on the image above, you go to an image 40% of the dimensions of the original.
M16, the Eagle nebula.
154 25 second exposures at ISO 3200, again with the Sony A6300. Taken on the 1000mm focal length f/5 'scope. I included dark, bias and flat frames for this one as well, and for once the flat frames seemed to work OK for an image taken with this 'scope.
If you click on the image to big it, you go to a 40% original resolution image.
You may recognise the shape of this nebula. The Eagle nebula is the location of the iconic Pillars of Creation image from the Hubble Space Telescope.
You may also notice that I have tried to replicate the focusing issues present in the HST when first commissioned. That's why the image is only 40% of the original resolution.
This is with the Evostar 72ED, this time with a focal reducer corrector.
This doesn't seem to have done much by way of correcting, but it has done some focal reducing - so the effective focal length is around 360mm. So this is an image with a field of view of 3x2 degrees.
M98 is the edge on spiral to the right of the image, M99 (the Virgo cluster pinwheel) is towards the bottom of the picture and M100 (the Blowdryer Galaxy) is the face on spiral in the top left quadrant.
Standing out because of their closeness to each other are NGC 4298 and NGC 4302 in the bottom left quadrant.
Also visible - NGC 4312 just below M100, NGC 4208 bottom right, and NGC 4237 just above a line between M98 and M100 above the yellow star near the centre of the picture.
Fainter smudges can be associated with other galaxies.
The image is a stack of 159 30 second exposures at ISO 4000, plus darks and flats, with images taken between 23:20 on the 28th to 00:50 on the 29th. The big image you see by clicking on the small one is one third of the original resolution.
The named galaxies are all between 50 and 120 Mly away. Looking at a few of the fainter smudges, they are as close as 38 Mly to as far away as 160 Mly.
(Distances are gleaned from Stellarium - they may not correspond to other sources, by a considerable margin),
I think I need to adjust some spacing to improve the correction aspect.
3 images of Mercury taken (back on the Canon EOS camera) on consecutive days (25th, 26th and 27th February) from approximately the same place at approximately the same time of day (18:50). There is a road just in front of the camera, so times are "traffic permitting".
To the bottom left is Bluntisham Water tower, whose features provided a handy image alignment reference. At the top of the image is the magnitude 4 star 28 Pisces. The top left of the line of three instances of this star was from 25th February, bottom right obviously 27th.
A bit lower and to the right 17 Pisces is performing the same inexorable year long journey back to where it started from (relatively speaking).
Mercury of course is not doing this, the lower left instance is from the 25th.
As a result of merging these three pictures the brightness of Mercury and the stars in the picture is reduced (by a factor of 3). I've brightened up the whole picture to counteract this, the result being that the twilight looks very bright. It really is quite dark at ten to seven in the last week of February.
26th February
Time to try a new 'scope and camera. The telescope is a SkyWatcher (again) Evostar 72ED. A refractor with a 72mm objective lens, a focal length of 420mm, and far better optics in terms of chromatic aberration than the 120mm objective refractor I got rid of a while ago. It comes with no eyepieces or diagonals or mount, so I basically bought it as a camera lens. The camera is a Sony A6300.
I mounted this kit on my old (non-goto) CG2 mount, so I thought I'd start out with some objects that are moderately to find.
The Leo Triplet of galaxies, M65, M66 and NGC3628 are close enough to naked eye visible stars to make finding it in the camera no real problem.
Maybe not quite as crisp as I had hoped, but there is plenty of low light luminance visible in the galaxy picture that is hard to see in previous images I've taken of these three. The "bright" yellow star top right is actually only magnitude 5.3.
The big version of this picture is a crop of the original 6000x4000 resolution, and then reduced by a factor of 3 (to save space). The picture was taken between 20:15 and 23:20 GMT.
After the most miserable Saturday so far of the winter, it cleared at about 22:30 on the 15th December. I'm sure it was warmer at 23:00 than it had been at 10:00 when I took the dogs out, certainly the wind had dropped. In the intervening time it had pissed down, with temperatures not getting above 2 degrees.
No worries, time for two fleeces, the Yosemite hat, and a chance for a proper attempt at comet 42P. It really was very clear between 23:00 and 01:30 on the 16th while I was outside with the camera. In the bins, I very quickly found the comet with the 15x70s. It was impressive.
Again no telescope, this time with the EOS camera on the small equatorial, but with the 75-300 zoom at 75mm focal length f/4, ISO 1600, 60 second exposures.
Comet 46P is near the Pleiades.
If you big the picture you go to a half original resolution image.
7th December
Mars and Neptune about 7 arc minutes apart. In the main picture Mars is grossly overdone, and looks a lot bigger than Neptune, in fact the apparent disk size of Mars is only about 4 times bigger than Neptune. It's a lot further away now than back at the beginning of August when it was virtually the size of Jupiter.
It was in reality far too windy (with very poor seeing even when the gusts weren't rattling the telescope) to attempt to image Mars, so the inset top right is a poor image of Mars at 2.7 times the original magnification - and then with the image size doubled.
Both images produced from video by Registax 6 (Mars just 70 frames out of 1600), with the main image processed in Astro Art 6 to bring out Neptune a bit more (no colour balance changes - just histogram changes to brighten Neptune up a bit).
The camera was the Atik GP.
Moving out of the solar system, here is a field of view in the north western bits of the constellation of Pegasus with plenty of galaxies.
The camera is again the EOS DSLR, this time on the Quattro 800mm f.l. f/4 'scope. The full field of view of the original images was 1.6 degrees by 1.1 degrees, at 1.21 arc seconds per pixel. To avoid explaining why my flat frames failed to work yet again, I've cropped this down to 0.95 degrees by 0.68 degrees - so I may as well have used the 1000mm 'scope and got a better picture as a result.
The main target is NCG 7331, a spiral galaxy 53 Million light years distant. This is part of the Deer Lick Group, the additional galaxies being NGC 7335, NGC 7336, NGC 7337 and NGC 7340. I couldn't find any distances to these smaller galaxies, but their redshifts are between 7.7 and 11 times bigger than that for NGC 7331, suggesting they are much further away. (They may be part of their own gravitationally interacting group?).
In the bottom right corner, we see Stephen's Quintet, consisting of galaxies NGC 7320, NGC 7319, NGC 7318A, NGC7318B and NGC 7317. The brightest of these (7320) is 234 Mly away, this is a foreground galaxy, the other four forming an interacting group over 300 Mly away. In fact NGC 7320C further to the left, is also part of this group.
You can just about see the main tidal tail (stretching out from the top right of NGC 7319 and heading down and to the left) produced by the interaction of these galaxies.
The smallish picture here has got some handy identifying text, if you click on it to big it you go to a picture one half of the original image size without the interfering text.
There are a few other galaxies dotted around the image which I have identified. To be honest, I don't really think PGC 2047594 and PGC 2045849 look much different from the fainter stars in the image, and I would not have identified them had I not been looking at www.sky-map.org to identify PGC 2051985.
(PGC is the Principle Galaxies Catalogue).
I've also shown a couple of ??? objects - these look curiously un-star like in the context of this picture, but sky-map.org only has stars in these positions.
You'll notice the lack colour in the small picture here. This was because there were huge patches of different colours in the background of the stacked image (far worse than usual). At the time I couldn't get rid of these without losing a lot of detail, so I opted for monochrome. On Boxing day 2018, I had a go at trying to get some of the foreground colour back into this monochrome version. The colour version is what you will see if you big the picture.
11th November
The Moon and Saturn close enough (by line of sight) on the 11th November 2018 to both be in the field of view of the Canon DSLR on the 1000mm f.l. 'scope.
You might have to big the picture to see Saturn, and then depending on your screen size, you might have to big it again to see Saturn's rings.
The four bright planets are all on view at the moment. Mars at its brightest and biggest is disappointingly low, so I had to wait till after 1:30am for it to clear the trees, by which time it was even lower and just flirting with the top of the hedge.
All four planets taken with the same optics and camera (The Skywatcher Explorer 200P on an AZ/EQ6 mount, 2.7x coma correcting barlow, and the little Atik GP).
I did have a go at Neptune, but it was beyond the abilities of the Atik GP.
Col's shed of wonders.
Comets C/2017-T2 and 46P.
The Pleiades, NGC 7635 (the Bubble nebula) and M52 (open cluster) together, M16 (the Eagle nebula), M98 M99 and M100 (galaxies in Virgo) in one field, the Deer Lick group and Stephan's Quintet galaxies, and the Leo Triplet again (slightly larger field).
An elongation of Mercury, a conjunction of Mars and Neptune, a conjunction of the Moon and Saturn, and a four planet comparison (Venus, Mars, Jupiter and Saturn).
Clicking on some images won't do anything, and on others might toggle you through an image sequence.
December 2019
30th DecemberFor devotees of shed...
The Moon and Venus shine down on Cols Xmas Shed.
25th December
C/2017-T2. This will be gracing our northern skies for the next few months.
The picture is taken with the Sony A6300, and the 360mm focal length (with reducer/corrector) telescope. 96 single images were taken, all 30 second exposures at ISO 3200. These, together with dark and flat frames were combined using Astro Art 6.
The picture (which you can't 'big') is a half resolution, very heavily cropped image. This is stacked using the manual alignment feature of AA6 in an attempt to align on the comet for each frame.
The star trails are the result of the comet moving across the background of stars.
A cropped and reduced image of the Pleiades taken with the 360mm focal length refractor and the Sony A6300.
The picture is an average of 17 20 second exposures at ISO 3200.
October 2019
27th October
On the right is M52, a cute little cluster of white stars in the constellation of Cassiopeia. It is also known as the Salt and Pepper Cluster apparently, a name it disappointingly shares with M37 (why not call it the Ant-Powder cluster instead).
Stellarium claims the cluster is 500 light years away, most other sources I have seen go for 5000 light years.
On the left, there is 11000 light year distant NGC 7635, the Bubble Nebula. A sensible name. This is an HII region, consisting largely of ionised Hydrogen. The horse head nebula is another example, much of the light from these is at a frequency on or below the edge of transmission for the infra-red filter on your standard camera.
This makes them tricky targets for a standard camera, as I know from attempting to image the Horsehead nebula with my unmodified Canon EOS camera. So I was quite pleased with how this turned out, you can just about make out the left-hand edge of the bubble. Better images can be obtained with dedicated astronomy cameras and filters.
If you click on the image above, you go to an image 40% of the dimensions of the original.
July 2019
6th JulyM16, the Eagle nebula.
154 25 second exposures at ISO 3200, again with the Sony A6300. Taken on the 1000mm focal length f/5 'scope. I included dark, bias and flat frames for this one as well, and for once the flat frames seemed to work OK for an image taken with this 'scope.
If you click on the image to big it, you go to a 40% original resolution image.
You may recognise the shape of this nebula. The Eagle nebula is the location of the iconic Pillars of Creation image from the Hubble Space Telescope.
You may also notice that I have tried to replicate the focusing issues present in the HST when first commissioned. That's why the image is only 40% of the original resolution.
March 2019
28th MarchThis is with the Evostar 72ED, this time with a focal reducer corrector.
This doesn't seem to have done much by way of correcting, but it has done some focal reducing - so the effective focal length is around 360mm. So this is an image with a field of view of 3x2 degrees.
M98 is the edge on spiral to the right of the image, M99 (the Virgo cluster pinwheel) is towards the bottom of the picture and M100 (the Blowdryer Galaxy) is the face on spiral in the top left quadrant.
Standing out because of their closeness to each other are NGC 4298 and NGC 4302 in the bottom left quadrant.
Also visible - NGC 4312 just below M100, NGC 4208 bottom right, and NGC 4237 just above a line between M98 and M100 above the yellow star near the centre of the picture.
Fainter smudges can be associated with other galaxies.
The image is a stack of 159 30 second exposures at ISO 4000, plus darks and flats, with images taken between 23:20 on the 28th to 00:50 on the 29th. The big image you see by clicking on the small one is one third of the original resolution.
The named galaxies are all between 50 and 120 Mly away. Looking at a few of the fainter smudges, they are as close as 38 Mly to as far away as 160 Mly.
(Distances are gleaned from Stellarium - they may not correspond to other sources, by a considerable margin),
I think I need to adjust some spacing to improve the correction aspect.
February 2019
25th, 26th, 28th February3 images of Mercury taken (back on the Canon EOS camera) on consecutive days (25th, 26th and 27th February) from approximately the same place at approximately the same time of day (18:50). There is a road just in front of the camera, so times are "traffic permitting".
To the bottom left is Bluntisham Water tower, whose features provided a handy image alignment reference. At the top of the image is the magnitude 4 star 28 Pisces. The top left of the line of three instances of this star was from 25th February, bottom right obviously 27th.
A bit lower and to the right 17 Pisces is performing the same inexorable year long journey back to where it started from (relatively speaking).
Mercury of course is not doing this, the lower left instance is from the 25th.
As a result of merging these three pictures the brightness of Mercury and the stars in the picture is reduced (by a factor of 3). I've brightened up the whole picture to counteract this, the result being that the twilight looks very bright. It really is quite dark at ten to seven in the last week of February.
26th February
Time to try a new 'scope and camera. The telescope is a SkyWatcher (again) Evostar 72ED. A refractor with a 72mm objective lens, a focal length of 420mm, and far better optics in terms of chromatic aberration than the 120mm objective refractor I got rid of a while ago. It comes with no eyepieces or diagonals or mount, so I basically bought it as a camera lens. The camera is a Sony A6300.
I mounted this kit on my old (non-goto) CG2 mount, so I thought I'd start out with some objects that are moderately to find.
The Leo Triplet of galaxies, M65, M66 and NGC3628 are close enough to naked eye visible stars to make finding it in the camera no real problem.
Maybe not quite as crisp as I had hoped, but there is plenty of low light luminance visible in the galaxy picture that is hard to see in previous images I've taken of these three. The "bright" yellow star top right is actually only magnitude 5.3.
The big version of this picture is a crop of the original 6000x4000 resolution, and then reduced by a factor of 3 (to save space). The picture was taken between 20:15 and 23:20 GMT.
December 2018
16th DecemberAfter the most miserable Saturday so far of the winter, it cleared at about 22:30 on the 15th December. I'm sure it was warmer at 23:00 than it had been at 10:00 when I took the dogs out, certainly the wind had dropped. In the intervening time it had pissed down, with temperatures not getting above 2 degrees.
No worries, time for two fleeces, the Yosemite hat, and a chance for a proper attempt at comet 42P. It really was very clear between 23:00 and 01:30 on the 16th while I was outside with the camera. In the bins, I very quickly found the comet with the 15x70s. It was impressive.
Again no telescope, this time with the EOS camera on the small equatorial, but with the 75-300 zoom at 75mm focal length f/4, ISO 1600, 60 second exposures.
Comet 46P is near the Pleiades.
If you big the picture you go to a half original resolution image.
7th December
Mars and Neptune about 7 arc minutes apart. In the main picture Mars is grossly overdone, and looks a lot bigger than Neptune, in fact the apparent disk size of Mars is only about 4 times bigger than Neptune. It's a lot further away now than back at the beginning of August when it was virtually the size of Jupiter.
It was in reality far too windy (with very poor seeing even when the gusts weren't rattling the telescope) to attempt to image Mars, so the inset top right is a poor image of Mars at 2.7 times the original magnification - and then with the image size doubled.
Both images produced from video by Registax 6 (Mars just 70 frames out of 1600), with the main image processed in Astro Art 6 to bring out Neptune a bit more (no colour balance changes - just histogram changes to brighten Neptune up a bit).
The camera was the Atik GP.
November 2018
29th NovemberMoving out of the solar system, here is a field of view in the north western bits of the constellation of Pegasus with plenty of galaxies.
The camera is again the EOS DSLR, this time on the Quattro 800mm f.l. f/4 'scope. The full field of view of the original images was 1.6 degrees by 1.1 degrees, at 1.21 arc seconds per pixel. To avoid explaining why my flat frames failed to work yet again, I've cropped this down to 0.95 degrees by 0.68 degrees - so I may as well have used the 1000mm 'scope and got a better picture as a result.
The main target is NCG 7331, a spiral galaxy 53 Million light years distant. This is part of the Deer Lick Group, the additional galaxies being NGC 7335, NGC 7336, NGC 7337 and NGC 7340. I couldn't find any distances to these smaller galaxies, but their redshifts are between 7.7 and 11 times bigger than that for NGC 7331, suggesting they are much further away. (They may be part of their own gravitationally interacting group?).
In the bottom right corner, we see Stephen's Quintet, consisting of galaxies NGC 7320, NGC 7319, NGC 7318A, NGC7318B and NGC 7317. The brightest of these (7320) is 234 Mly away, this is a foreground galaxy, the other four forming an interacting group over 300 Mly away. In fact NGC 7320C further to the left, is also part of this group.
You can just about see the main tidal tail (stretching out from the top right of NGC 7319 and heading down and to the left) produced by the interaction of these galaxies.
The smallish picture here has got some handy identifying text, if you click on it to big it you go to a picture one half of the original image size without the interfering text.
There are a few other galaxies dotted around the image which I have identified. To be honest, I don't really think PGC 2047594 and PGC 2045849 look much different from the fainter stars in the image, and I would not have identified them had I not been looking at www.sky-map.org to identify PGC 2051985.
(PGC is the Principle Galaxies Catalogue).
I've also shown a couple of ??? objects - these look curiously un-star like in the context of this picture, but sky-map.org only has stars in these positions.
You'll notice the lack colour in the small picture here. This was because there were huge patches of different colours in the background of the stacked image (far worse than usual). At the time I couldn't get rid of these without losing a lot of detail, so I opted for monochrome. On Boxing day 2018, I had a go at trying to get some of the foreground colour back into this monochrome version. The colour version is what you will see if you big the picture.
11th November
The Moon and Saturn close enough (by line of sight) on the 11th November 2018 to both be in the field of view of the Canon DSLR on the 1000mm f.l. 'scope.
You might have to big the picture to see Saturn, and then depending on your screen size, you might have to big it again to see Saturn's rings.
August 2018
5th/6th AugustThe four bright planets are all on view at the moment. Mars at its brightest and biggest is disappointingly low, so I had to wait till after 1:30am for it to clear the trees, by which time it was even lower and just flirting with the top of the hedge.
All four planets taken with the same optics and camera (The Skywatcher Explorer 200P on an AZ/EQ6 mount, 2.7x coma correcting barlow, and the little Atik GP).
I did have a go at Neptune, but it was beyond the abilities of the Atik GP.
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