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INTRODUCTION |
UPDATE 2022 - SInce 7th January 2022 we are now located in Norfolk. I am now limited to simple imaging from my front garden using my portable tracker. It is good fun though. For this I have been using a tracker mount, initially a home-made one but this winter a Star Adventurer. The latter has the benefit of allowing guiding although only in RA. The camera is now a modified Canon 250D. I have a variety of lenses, all secondhand, but my favourite is the Samyang 135mm f/2. This is a fabulous performer even wide open. I have found with the Star Adventurer and only RA guiding with the Samyang lens then 5 minute exposures are about the limit. UPDATE 2023 - Over the summer I upgraded to a Sharpstar 130mm f/2.8 Hyperbolic Newtaonian and the ZWO strainwave AM5 mount.
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New home |
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ImageBLOG Archives Archive 2019-21 |
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10th October 2024Globular Cluster M75 & Dwarf Planet Pluto |
It was a poor night with frequent clouds so went for something simple. In the end I only got 13 useable images but just about enough to record Pluto. It seemed fainter than I expected and although catalogued at 14.5 magnitude it appeared nearer to mag 15 than that. This was very low for me with only a short interval between trees when they were visible from my garden.
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M75 and Pluto
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1st October 2024Globular Clusters NGC 6749 & 6760 |
For many years NGC6749 it was uncertain if this was an old open cluster or a globular cluster. It even had an open cluster designation Berkeley 42. However, it was confirmed as a heavily obscured and reddened globular cluster in 1997 by Rosino et. al.. NGC 6760 is more obviously a globular cluster but still obscured and reddened. It is probably most noteworthy having two Millisecond Pulsars. Both are believed to binary pulsars - reference PCC Freire et al., 2005. Planetary Nebula PK36-1.1 is a very odd shaped planetary nebula perhaps with 3 lobes ie a triple star system. It also has a Sharpless number, Sh2-71 but not to be confused with the real emission nebula Sh2-72 nearby. All objects are in Aquila.
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NGC6749 & 6760
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27th September 2024Globular Cluster, M92 |
Hercules' other cluster so often overlooked. I must admit I am one who has forgot about in the past. In fact it is 20 years since I took an image of this globular. It is around 12 billion years old with approximately 1/3rd million stars.
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M92
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16th September 2024Globular Cluster, M13 |
After the summer shut down I chose a nice and bright object to get imaging going again. The Moon was out (72% full) so it had to be something not too faint. Amazingly everything worked. Globular Clusters are old. M13 is almost 12 billion years old and its stars are of population II category, markedly lower in metals than population I stars like the Sun. The number of stars in the cluster has varied over my lifetime from 1 million dropping down to 300,000. Latest figutes tend to be rising to around half a million. The galaxy near the top is NGC 6207, a 12th-magnitude edge-on spiral, class SA(s)c. If you look carefully between NGC6207 and M13 is the very small galaxy, IC 4617.
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M13
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12th May 2024Aurora over Norfolk, 10th May 2024 |
Probably the most spectacular display of aurora over Britain in living memory! Normally at best there could be a greenish glow low on the northern horizon. This time it was all colours and even in the south too. Images were back garden hand-held shots by my son John and myself. Nothing sophisticated. |
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Aurora over Norfolk
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24th April 2024Spiral Galaxy, M106 |
Another galaxy that benefits from having Ha data - with a very complex core. So I returned to collect the narrowband data.M106 (NGC 4258) is one of the largest and brightest nearby galaxies very similar in actual size and luminosity to the Andromeda Galaxy. It was discovered by Pierre Méchain in 1781. M106 contains an active galactic nucleus (AGN) and these days is classified as a type 1.9 Seyfert. It is perhaps most famous for the presence of a water megamaser. Observiations of this enabled the mass of its central black hole to be calculated and also permitted its distance to be determined independently of other standard methods. It is 23 million light years distant. The galaxy to its right is NGC 4217, which is more than likely a companion. M106 also has another hidden feature namely twin powerful jets in its central region- see right. Reference: Jet-related Excitation of the [C II] Emission in the Active Galaxy NGC 4258 with SOFIA P. N. Appleton et al. 2018.
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Galaxy M106
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12th April 2024Open Cluster, M67 |
An old favourite of mine and one a I took many years ago in the film era. That film version was published several times by the US magazine Astronomy - I guess no one else had taken it back then. So more than time to return. Very old for an open cluster but its location well above the plane of the Milky Way means it has been able to survive for around 4 to 5 billion years. Similar age to the Sun and there are Sun like stars present in the cluster. It is though dominated by several yellow/red giants including some off to its right (west) side. Also present are blue stragglers. Normally blue stars signify youth but not in this case.
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M67
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4th April 2024Spiral Galaxy, M101 |
A galaxy that benefits from having Ha data - all those emission nebulae in its spiral arms. So I returned after a 12 year gap to collect the narrowband data plus some more rgb as well. M101 is a giant classic face-on spiral galaxy - nearly twice the diameter of the Mikly Way and around 25 million light years away. M101 is estimated to contain at least one trillion stars. The galaxy’s spiral arms are sprinkled with large regions of star-forming nebulae glowing red in my image. These nebulae are areas of intense star formation regions and are just like our own Orion Nebula.
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Galaxy M101
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23rd March 2024Comet 12P/Pons-Brooks |
Been waiting for a clear night to see the comet but the weather did not oblige. However, on the 17th there was a short clear spell between clouds to get enough to record the basics. I used the latest version od Siril for processing. This uses the fits header to enable a stack on the comet to be correctly aligned after the stars have been removed. This was useful as there was a short gap in my sequence due to a cloud passing through so they were not at a constant spacing. The star removal on a sequence is automatic now but took over 1 hour. Still a big improvement on previous manual methods.
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Comet 12p
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1st March 2024The Seagull Nebula, IC2177, Sh2-296 |
Multiple objects in this wide-field view with the Sharpstar including several Van den Bergh (blue) nebulae. Easy to find, just above Sirius but seriously low down for Norfolk. This low I am shooting straight over Norwich city so it does come with added light pollution. It is located half in Monoceros and half in Canis Major This was my second run with the Duo camera. I turned the gain up to high on the guide camera and loads of guidestars appeared. I ran with 4 second guiding although faster guiding is often quoted as being necesaary with the AM5 mount. Not sure about that - could end up chasing seeing fluctuations so I will stick with I have always used ie 4 seconds.
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Seagull Nebula
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17th February 2024Thor's Helmet or the Duck Nebula, NGC 2359 |
Fourteen years in the making! I had got some H-alpha and OIII data way back in 2010 but needed some better colour data. Hence the first test with my new ZWO 2600MC Duo was to at last get around to collecting some. This object is really too low down for the UK so subject to much light pollution but I am happy with the final result. Not a well understood nebula. What is certain is the central star is a very hot Wolf-Rayet type WR7 star but at what stage in its development the nebula formed is uncertain. So just simply classed as an emission nebula which really doen't do it justice or explain the complex filamentary structure.
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NGC2359
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21st January 2024Sharpless Sh2-202 |
One of the wettest and worst winters on record for astronomy - and that is for Norfolk, the supposed dry side of the country. At last in January 2024 we had two clear nights with only a crescent Moon above the horizon. One of the larger Sharpless nebulae at around 3 x 2 degress. Nice and bright too. The little cluster within is Stock 23 or so times called Pazmino's Cluster. The two blue reflection nebulae to the left (east) are VdB 14 and 15.
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Sh2-202
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10th December 2023Andromeda Galaxy, M31 |
A bit of an exploration to see if anything would be visible of the recently discovered OIII nebula adjacent to M31. Absolutely no sign of it in my images so much much longer exposures required. Unfortunately the weather did not cooperate with a wet and gloomy autumn here in Norfolk. This image is actually a 2- panel mosaic.
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M31 Andromeda Galaxy
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26th October 2023Vav den Bergh 152 (& Wolf's Cave Nebula) |
A more challenging object to push the Sharpstar and the Canon 250D a bit harder. Van den Bergh 152 is the bright blueish reflection nebula at the south end (bottom) of the dark nebula B175 (brownish colour). Sometimes referred to as Wolf's Cave Nebula - named after Max Wolf rather than its resemblance to a wolf. The red filaments are part of an ancient supernova remnant. The red and blue nebula above the red filaments is a planetary nebula, PN G111 0+11.6. All located in central Cepheus.
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Wolf's Cave Nebula
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9th October 2023The Coathanger Asterism |
Little bit deeper this time pushing the new scope a bit harder. For the H-alpha set of image I used a 12nm filter as these fast scopes cause the filters to go out of band. I need to get an offset one for fast scopes. Located in Vulpecula this is another fabulous asterism for small telescopes and binoculars. Also known as Brocchi's Cluster.
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Coathanger Asterism
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17th September 2023The Toadstool Asterism |
Something very simple to test everything was working. Some trouble initially with the asiair resetting its location back to China but when I had realised that and reset it to Norfolk it behaved as expected. Decided as this was try 1 to control the camera via a separate timer. Will try the asiair software to do this next time. Located in eastern Delphinus this is a fabulous asterism for small telescopes and binoculars.
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Toadstool Asterism
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20th September 2023New Set-up for WInter 2023/4 |
Over 2023 I sold all my old Astro gear - the RCOS 12.5 Ritchey-Chretien, Paramount ME, Apogee Alta U9 camera and the Takahashi FSQ106N. I came to the conclusion it was too onerous a task to start all over again rebuilding it plus a new observatory. Time for something simpler and lighter. I decided on the Sharpstar 130mmm F/2.8 Hyperbolic Newtonian on an ZWO AM5 mount and the ASIair mini controller/power box. I will continue with the Canon 250D for now and see how it goes. The whole set-up can be carried out and is then already fully assembled and cabled up. Just one power supply to connect when outside. The asiair software on my tablet connects wirelessly. The AM5 has no polar scope so I have mounted a laser (just sticking out over the AM5 control panel) to get close. The asiair software then can take over for final polar alignment. The laser can get close - within a 1/10th degree away. Currently I am parallel guiding with an asi120mm - I need to figure a way of going off-axis. Guiding accuracy is generally below 1 arcsecond. For the payload I am carrying a counterweight is not needed but as I had one handy put it on. In reality it is no where near big enough. The Samyang 135mm can also be mounted on the AM5 should I require an even wider field of view. |
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1st May 2023Polaris and The Integrated Flux Nebula |
Buoyed with a bit of success with the Integrated Flux Nebula around M81 & M82 I thought I would try for another part of this huge nebula - this time around Polaris. WIth nights getting shorter I opted to leave the tracker and camera running all night and switch it off the following morning. I got 6 hours total - 10:00pm to 4:00am. Quite a relief in the morning to find the tracker and camera still there in my front garden. Perhaps confusingly this nebula is included in the Sharpless emission nebula catalogue as Sh2-178. Certainly what I recorded is the integrated flux nebula rather than H-alpha emission. The open cluster visible in the image is NGC188 (Caldwell 1). It is very old for an open cluster at around 6.8 billion years. The clue is that being located well above the plane of the Milky Way so it has been subject to much less interaction with other stars in the disk and so has managed to stay intact.
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Polaris & the Integrated Flux Nebula
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15th April 2023The Integrated Flux Nebula |
Quite a faint nebula but when running at f/2 well within rangs from my front garden! It did though need the bast part of 4 hours. This nebula stretches all the way to Polaris but I chose to centre my image on the galaxies M81 and M82. The new version of Siril was a big help with Starnet now called from a drop down menu. Saved a lot of time and the pre-stretch option seemed to help in producing a very clean starless image. The image has three distinctive zones. The nearest are the stars in the plane of the Milky Way disk. The second is the nebula - part of the Milky Way but above the disk. The third zone is background with the galaxies in the far distance. The Integrated Flux name come from the illumination of the nebula ie it is not illuminated by embedded stars but by the whole integrated light from the Milky Way - galaxy shine. According to Steve Mandel the nebula is composed of dust particles, hydrogen and carbon monoxide and other elements.
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The Integrated Flux Nebula
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13th March 2023Central Orion - the Belt to M42 |
Quite a difficult area for me as it low over Norwich. Siril managed reasonably well to remove the light pollution.This area has to be shot with at some broadband data as the flame nebula's colour is yellowish, which narrowband filters do not record. One peculiarity with the Canon 250D was with this being a vertical shot then live view decided to show the image upside down which was a puzzle at first. Virtually the whole region is covered in nebula. It is wall to wall with no black sky! The main contenders are from north to south: the Flame Nebula, the Horsehead Nebula, the Running Man Nebula and the Great Orion Nebula. That's not counting M78 on the top edge and part of Barnard's Loop in the very top left corner.
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Central Orion
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13th March 2023The Christmas Tree Cluster, the Cone Nebula & the Rosette Nebula Mosaic |
Monoceros might be one the most inconspicuous of constellations but it has some cracking deep-sky objects. In the top half of the image is Sh2-273, the Mon OB1 molecular cloud. At its centre is the open cluster NGC2264 , commonly called the Chritmas Tree Cluster. Its brightest star, the binary S Mon, is one of the primary ionising stars of the nebula although several others are now known. Below it is the dark nebula commonly called the Cone Nebula, actually a pillar of gas and dust containing an infrared source. The blue reflection nebulae are VdB 77-82. In the botton half of the image is Sh2-275 containing the famous Rosette Nebula, all part of Mon OB2, which is believed to be twice as far away as Mon OB1. At the centre of the Rosette is the open cluster NGC2244, which ionises the nebula and its fierce stellar winds has created the cavity at its centre.
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Cone and Rosette nebulae.
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5th March 2023The Jellyfish Nebula, IC443 (Sh2-248) |
The Jellyfish Nebula is located at the centre of this image just to the left (east) of the bright star Eta Geminorum. Believed to be a supernova remnant but because of its proximity to and interaction with dense molecular clouds it is a very complex object. So much so thats its age i.e. when the supernova explosion occurred, is only vaguely known as between 3,000 and 30,000 years ago. The likely remnant pulsar star is the neutron star CXOU J061705.3+222127. The bright nebula bolow the Jellyfish is NGC2175 commonly known as the Monkey Head Nebula. M35 is also in this image, directly above the Monkey Head Nebula towards the top.
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Jellyfish Nebula
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19th February 2023The Flaming Star Nebula,IC405 (Sh2-229) |
This nebula is a combination of an emission (red) and reflection (blue) nebula energised by the irregular variable star AE Aurigae. This star is a runaway star most likely ejected during an interaction of two binary star groups. This event probably also ejected, in the opposite direction, Mu Columbae. The star 53 Arietis and Iota Orionis may also have been involved. This event has been traced to the Trapezium cluster in the Orion Nebula around two million years ago. So AE Auriga was not formed within the the Flaming Star Nebula but is just passing through it at high speed. Also in the image is the Emission Nebula NGC1893 (with the Tadpoles) and the Open clusters M38 and M36.
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Flaming Star Nebula
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10th February 2023Twin Comets, ZTF C/2022 E3 & Atlas C/2022 U2 |
The "Green Comet" ZTF E3 was fading now but on the 6th February is was to pass very close to Comet Atlas U2 just to the south of Capella. Same exposures as last time but no gas tail on ZTK was visible but just to its west (right) was the very much fainter Atlas comet. This was around 11th to 12th magnitude so pretty faint for a simple 135mm lens but it was clearly evident. This comet has 936.5 year period.
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Twin Comets and Capella
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1st February 2023The Green Comet, ZTF C/2022 E3 |
It was a frustrating week with continuous cloud cover as the comet rose higher in the northern sky. At last on the 30th January it was clear and although there was a dazzling Moon almost at the zenith I was able to get a run of images. With the strong moonlight then 15 seconds was about the limit. Comet E3 is a long period comet from the Oort cloud with an orbital period of around 50,000 years. A long time to wait if you missed it this time! Commonly called the Green Comet, which is due to the effect of sunlight on its molecules, especially carbon and cyanogen. The comet reached its perihelion (closest to the Sun) on 12th January 2023, at a distance of 103 million miles so outside the Earth's orbit. Its closest approach to Earth was on 1 February 2023 at a distance of 26 million miles.
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The Green Comet
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22nd January 2023The California Nebula, NGC1499 |
The California Nebula in Perseus is just the brightest part of the giant California Molecular Cloud. However, its brightness is nothing to do with the molecular cloud as it is ionised by the runaway O star, Menkib, which is not associated with the cloud i.e. it is just coincidently passing through. The nebula gets its name from its brightest part being similar in shape to California. The California Molecular Cloud is about the same mass as the Orion A molecular cloud and is one of the most massive molecular clouds within 2000 light years of the Sun. However, despite its large mass, it has a much lower star forming rate than Orion A so it is very much a sleeping giant. (Ref Lada et al. 2007 & 2017). Right is an IRIS 3-colour image of the California Molecular Cloud (Lada et al. 2007). The brightest spot to the right is the California Nebula which lends it name to the cloud. The other bright spot to the bottom left in NGC1579 and the yellow crosses denote young stellar objects.
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California Nebula
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15th January 2023The Heart & Soul Nebulae (IC1805 and IC1848) |
This pair of bright emission nebulae are located in the Perseus arm of the Milky Way. Strickly speaking their catalogue numbers refer to the open star clusters within them. They were catalogued well before the extensive nebulae around them were known but today their IC numbers are generally taken to be the nebulae. In the case of the Soul Nebula (left) in film astrophotography days this was known as the Foetus nebula which probably is a better description than the Soul. Within the Heart Nebula but very small and insignificant in the main wide field image below is what I call the Dragon's Head (right). This was shot with my RCOS 12.5 inch telescope with a focal length of 2850mm - somewhat longer than the 135mm Samyang lens!
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The Heart & Soul Nebula
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1st January 2023The Double Cluster in Perseus |
When using the dual narrowband filter (OIII and H-alpha) the star colours are very poor. So I spent most of this night night shooting a few objects without filter (i.e. broadband). These could be then used with deep narrowband images later. However, in the case of the Double Cluster the broadband images were more than enough on their own. Originally referred to as h Persei and χ (chi) Persei, the Double Cluster consists of the twin open clusters NGC 869 and NGC 884. Patrick Moore also included the pair as No. 14 in his Caldwell catalogue. Away from light pollution they are easily visible to the naked eye. For many years there waa a debate as to whether they were asscoiated or a chance alignment. The answer was really pretty obvious - they are associated. They have the same very young age (14 million years) and are both are approaching us at the same speed. Togther they have a large mass equivalent to 20,000 Suns.
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Veil Nebula
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16th December 2022The Veil Nebula |
I had been reaching the limit with unguided images so when a Star Adventurer came up for sale at I price I could not refuse I took the plunge. This has a guiding option for RA only but that would increase the length of exposures that would result in round stars. A SVbony 30mm guide scope and ZWO ASI120mm-mini camera now provides the guiding - well just in RA. The full Veil Nebula, at around 3 degrees across, is too big for most telescopes and a moderate length camera lens is ideal. What we see today is the remnants of a supernova explosion that took place around 10,000 to 20,000 years ago, which is still imprecise and it is surprising a better age estimate has not emerged. Its distance is however now known with a bit more accuracy at around 2400 light years according to wiki. The star that exploded was around 20 times more massive than the Sun. The colours visible are due to Hydrogen (red) and Oxygen (blue/green).
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Veil Nebula
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1st December 2022Northern Milky Way Mosaic - Cygnus to Cassiopeia |
I was planning to do much more coverage but the clouds rolled in - as they often do in Norfolk - so just two frames. Prominent in this mosaic are the constellations Lyra , Cygnus, Cepheus and Cassiopeia (right to left). The Andromeda Galaxy ,M31, is visible at the left corner. It has recorded very yellow which I recall was the colour is was portrayed in the first ever colour picture of this galaxy many many years ago.
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Milky Way Mosaic
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23rd November 2022Southern Cepheus H-alpha Mosaic |
Following on from my IC1396 and Flying Bat image (see below), I decided to extend the h-alpha coverage futher north and east. It does appear (at least to me) as one gigantic emission nebula. As well as the Elephant's Trunk (in IC1396) and the Flying Bat Nebulae also recorded in this frame are the Wizard, Cave and Bubble Nebulae plus of course several less famous deep-sky objects. Note as this is purely h-alpha the Squid Nebula is invisible.
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Cepheus Mosaic
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7th November 2022IC1396 (Sharpless 131) & Flying Bat/Squid Nebulae (Sharpless 129) |
Sharpless 129: A complex object that began life as a H-alpha emission nebula recorded by Sharpless in 1959. This is commonly now known as the Flying Bat Nebula. However, in 2011 French amateur astrophotographer Nicolas Outters noticed an additional object lying within the bounds of Sharpless 129 recorded only in an OIII narrowband image. This is now commonly called the Squid Nebula but officially it is Ou4 after its discoverer. OIII nebulae are typically planetary nebula and this has the appearance of a bi-polar type. There is a hot blue star (actually a triple system HR 8119 ) at its centre adding weight to this probable conclusion. Sharpless 131: This very large emission nebula in southern Cepheus contain the famous Elephant's Trunk Nebula (NGC 1396A) . It is around 2400 light years away. The Elephant's Trunk is a dark gas and dust region that is being eroded away by hot young stars within the main nebula.
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Southern Cepheus Deep-Sky Objects
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30th October 2022North American Nebula |
This giant emission nebula (HII) is known as the North American Nebula because of its very obvious resemblance especially as it has a prominent "Gulf of Mexico". To its right (west) is the Pelican Nebula - the two forming Sharpless Sh2-117. Thanks to the GAIA space observatory we at long last have an accurate distance to these nebulae. Gaia was able to measure the precise distance to 395 stars lying within the HII region, giving the North America and Pelican nebulae a distance of 2,590 light years. The entire HII region is estimated to be 140 light years across, and the North America nebula stretches 90 light years north to south. (ref. Wiki)
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North American Nebula
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25th October 2022Partial Solar Eclipse - 25th October 2022 |
For once the weather smiled and here in Norfolk we had just a few hazy clouds covering the Sun. The image was taken well after maximum after we had enjoyed a very good viewing session. Note the sunspot group at 4:00 o’clock – this is about the size of the earth! There a couple of other less obvious sunspots - more towards the middle and down a bit. Also if you look closely at the edge of the Moon it is a bit jagged due to its mountains and craters. The solar ganularity is also evident.
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Partial Eclipse 2022
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23rd October 2022Northern Cygnus in H-alpha (3 panel mosaic) |
It began as test of a Hydrogen alpha filter with the Samyang lens on the North American Nebula in Cygnus and expanded as interesting features both north and south were evident. Because I was using a narrowband filter I stopped the lens down to f/3.5 as these filters do not like steep light cones passing through them. Deneb is the brightest star (right of centre) in my view and is where the Great Rift begins and heads south towards where the centre of the galaxy lies. Not a rift at all but a series of dark molecular clouds in the plane of our galaxy that blocks our view and appears to divide the Milky Way in two. Under darks skies it is obvious to the naked eye. However, most prominent in this image is the giant emission nebula (HII) commonly known as the North American Nebula - complete with the "Gulf of Mexico". To its right (west) is the Pelican Nebula - the two forming Sharpless Sh2-117. Thanks to the GAIA space observatory we at long last have an accurate distance to these nebulae. Gaia was able to measure the precise distance to 395 stars lying within the HII region, giving the North America and Pelican nebulae a distance of 2,590 light years. The entire HII region is estimated to be 140 light years across, and the North America nebula stretches 90 light years north to south. (ref. Wiki)
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Northern Cygnus in H-alpha
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16th October 2022Open Clusters IC4756 & NGC6633 |
IC 4756 is a bright and very large, well over half a degree, open cluster in the constellation Serpens. Known as Graff's Cluster, it is bright enough to be easily seen in binoculars and is a bit too large for most telescopes. It is seen best in (image stabilised) binoculars and forms a bright pair with NGC663. It is surprining it was not included in either the Messier or Caldwell catalogues. IC4756 is probably one of the most (professionally) studied open clusters with several papers covering its stars and their chemical properties e.g. Chemical composition of giant stars in the open cluster IC 4756 by Bagdonas1 et al., 2018. Its age is around 800 miliion years and at a distance of approximately 1500 light years, although some estimates place it further. NGC 6633 is just over the boundary in the constellation Ophiuchus. Discovered in 1745-46 by Philippe Loys de Chéseaux and rediscovered by Caroline Herschel in 1783. It was included by her brother William in his catalogue as H VIII.72.
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IC4756 and Ngc6633
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9th October 2022Sagitta Constellation & M71 |
Sagitta is one the few constellations that is small enough for the 135mm lens to fit it in - well the bright stars of the constellation if not its full extent. It wasn't the best of nights and I lost several frames to passing clouds. Sagitta is a dim but distinctive constellation in the northern sky not to be confused with the bigger and more spectacular Sagittarius. Sagitta is Latin for 'arrow'. One of the original 48 constellations listed by Ptolemy. It needs a dark sky to see it clearly as it has no star brighter than 3rd magnitude. Although overlying the Milky Way it is located in the "great rift" which is where dust clouds obscure the view so not a spectacular background. The most famous deep-sky object within it is Messier 71. For many years there was great confusion and debate as to whether this cluster was a open type or a globular. It is now accepted to be a very loose globular cluster at a distance of about 13,000 light-yearswith a mass of around 53,000 Suns. It was the detection of a short "horizontal branch" in the H-R diagram, which characterises globular clusters, that resolved the issue. The shortness of the branch means it has a lack of RR Lyrae variables normally expected in globulars. M71 is relatively young for a globular at 9–10 billion years. My M71 image (right) was shot 20 years ago with a 0.25 megapixel (512x512) camera - how things have advanced!
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Sagitta Constellation
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4th October 2022The Wild Duck Cluster & the Scutum Star Cloud |
We had a very untypical month of cloudy weather which meant September was totally clouded out. Fortunately this changed in October and I was able to try out my new (to me) Samyang 135mm lens and Canon 250D camera. This lens has an awesome reputation for astromomy being supposedly perfectly useable wide open at f/2. I must I admit I did not believe this but I was proved wrong. It is pin sharp in the corners at f/2 - well at least on my APS-C camera. The main image below was shot with the Samyang and as this target is very low from Norfolk, plus south is straight at Norwich for me, I decided to use just 30 second exposures. It turned out to be about right for f/2. M11, the Wild Duck Cluster, is just left of the Scutum Star Cloud. This area of the Milky Way is renowned for the number of Barnard Dark Nebulae (B numbers) with very little H-alpha clouds present. In other words a very dirty and dusty region of our galaxy. Middle bottom edge is Globular Cluster NGC 6712. One object I could not identify is what looks like a faint blue nebula about 3/4 up and left of centre. One issue with shooting at f/2 is the problem with narrowband filters and the steepness of the cone of light. It could well be I will have to stop down when using a filter. The image right was shot several years ago with a Takahashi at 525mm focal length so shows much more detail.
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Wild Duck Cluster
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12th August 2022Hercules Constellation (with Lyra & Corona Borealis) |
A much better cloud-free night and this time I stopped the Canon 24mm lens down to f/5 for better stars in the corners - it seems to have worked. Hercules was the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the second-century astronomer Ptolemy. However, today its four relatively bright stars namely: Pi, Eta, Zeta and Epsilon Herculis are commonly known as the Keystone Asterism. Perhaps it is a the modern lack of truly dark skies that makes this asterism stand out. This trapezoid-shaped pattern makes it easy for observers to locate the great globular cluster M13. One of the showpieces of the summer sky for amateur astronomers, the great globular cluster M13 never fails to disappoint. The number stars within it has varied over the years from 1 million to 100,000 but today somewhere in between is the accepted number ie several 100,000s. It was discovered by Edmond Halley in 1714, and Charles Messier added it to his list of objects not to mistake for comets - the Messier Catalogue.
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Hercules
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21st July 2022Stephan's Quintet |
I couldn't resist digging out my old image of Stephan's Quintet to see how it compares to the billion-dollar James Webb Telescope. Obviously we see different features due to the different wavelengths used. Probably the biggest difference is the foreground galaxy (left) which in the visible has blue spiral arms but these are invisible in the infra-red. It should be pointed out in all fairness that at the wavelengths the James Webb is viewing then resolution is much lower. I recall reading somewhere at mid infra-red it has the same resolution as an 8-inch telescope in the visible. |
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Stephan's Quintet
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1st July 2022Virgo Constellation |
In the UK Virgo is always low in the sky and not seen at its best but is easy to spot in spring thanks to its bright star Spica. Spica is a close binary star whose components orbit each other every four days classed as a spectroscopic binary although with an interferometer the pair can be separated. My image of the constellation was thwarted by numerous passing clouds and I was surprised that anything presentable emerged - only due to the power of sigma clipping. As regards deep-sky objects is of course famous for the Virgo Galaxy Cluster which spreads into Coma Berenicesas well. and Virgo. Close to the centre is the giant M87 elliptical galaxy with its supemassive black hole that has recently been "imaged" by the Event Horizon Telescope. However, I have chosen to show here probably the most obscure of Virgo's deep-sky objects namely Zwicky's Necklace (8 Zw 388), a group of extremely remote galaxies (right). Despite being known for over 50 years there is virtually no data available for it - even the NASA/IPAC Extragalactic Database still has zero infomation. However, we do know Zwicky's Necklace comprises 10 to 12 galaxies arranged in an usual shape with magnitudes from 18 and fainter. Its distance is unknown but on the basis of its brightness it must be of the order of 1 billion light years distant - perhaps more.
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Virgo
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23rd June 2022Corona Borealis Constellation |
One of Ptolemy's original constellations and one that looks like its name ie Northern Crown. There are no bright deep-sky objects in the constellation but visible in the top left corner is the giant globular cluster M13 in Hercules. Towards the bottom of my image actually in Sextans is a famous group of interacting galaxies, Seyfert's Sextet (right) - see below for details and right for my image. Seyfert's Sextet is a group of galaxies about 190 million light-years away although it would appear it is really should be called Seyfert's Quartet - just 4 galaxies are associated. One of the 6 galaxies, NGC 6027d, is a background object and another "galaxy," NGC 6027e, is actually a part of the tail from galaxy NGC 6027. The 4 associated galaxies will eventually merge to form probably a single giant elliptical galaxy.
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Corona Borealis
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12th June 2022Bootes Constellation |
At last one of Ptolemy's original 48 constellations! It is of course dominated by the orange giant Acrturus, the fourth-brightest star in the night sky. Bootes is latin for the 'herdsman' or 'plowman' (literally, 'ox-driver'. Ptolemy depicts him with 2 hunting dogs - now the separate constellation of Canes Venatici. Epsilon Bootis, Izar, is a popular triple star although double only in most scopes. Its brightest galaxy is NGC 5248 (Caldwell 45). Originally classed as an Sc spiral galaxy (e.g. similar to M33) it has been re-classified as SAB(rs)bc, meaning it has a small bar. Viewed not quite face-on, it has a very bright extended core (hiding the bar) and two bright main spiral arms. It is a member of a small group of galaxies and part of the Virgo III Grouping strung out to the east of the Virgo Supercluster of galaxies. Distance measurements to NGC 5248 are somewhat variable varying from 35 million light-years to 74 million light-years. The latest measurements I could find were from 2014 giving a distance of 35-38 million light years.
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Bootes
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1st June 2022Canes Venatici Constellation |
Yet another constellation added by Hevelius in 1687 although it was known to to the ancients including Ptolemy. Canes Venatici is Latin for hunting dogs, and the constellation is often depicted in illustrations as representing the dogs of Boötes the Herdsman, the constellation to its south. Canes Venatici has 2 main stars, the double star Cor Caroli is the constellation's brightest star (left) at mag 2.9. Beta CVn (right) is a yellowish main sequence star of mag 4.2 ). Possibly the most interesting star though is "La Superba" (Y CVn) as it is one of the reddest naked-eye stars and one of the brightest carbon stars (centre towards top). There are several prominet galaxies in the constellation but the Whirlpool Galaxy is the most famous and was the first galaxy whose spiral form was observed in 1845 by Lord Rosse at Birr Castle, Ireland. Possibly the most imaged galaxy but no excuses needed for including it here. Named the Whirlpool Galaxy for obvious reasons. It is around 30 million light-years from Earth with an estimated diameter of 76,000 light-years. The distorted spiral structure is the result of the close interaction between it and its companion galaxy NGC 5195 (top, north), which is in effect orbiting M51. About 500 to 600 million years ago it passed from behind and below M51 and then passed in front of M51 before passing through the top edge of M51 about 50 to 100 million years ago. It now lies somewhat behind M51 hence the dust lane of M51 appearing in front of NGC 5195. My image right was a combination of images taken in 2009 and 2020.
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Canes Venatici
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19th May 2022 |
Corvus & Crater from Norfolk
These southern hemisphere constellations are very low form the UK and I was pushing my luck aiming directly over Norwich. Consequently there was a lot of light pollution to deal with as well foreground trees. Obviously the trees were blurred in the sequence of images so an unblurred one was added over. Corvus (The Crow) is on the left and Crater (The Cup) on the right. On the border of Corvus and Virgo is the famous Sombrero Galaxy, M104. Because its centre is so bright and normally over-exposed, I used a combination of 5 minute and 15 minute exposures to achieve the necessary high dynamic range when I took the image to the right. Despite being obviously a spiral galaxy with a very prominent dust lane tilted just 6 degrees from exactly edge-on, M104 does share some features with elliptical galaxies. Namely it has a huge central halo, an active galactic nucleus with a supermassive black hole of around 1 billion solar masses and a large retinue of globular clusters (2000). It is classed as LINER (low ionization nuclear emission region) galaxy. Its distance is around 30 million light years and seems to located somewhat on its own rather than part of a group. All in all - a very untypical spiral galaxy and the presence of an UCD (Ultra Compact Dwarf) only addsto its uniqueness - see my 2013 page for details.
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Corvus and Crater
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11th May 2022Coma Berenices Constellation |
Known to the ancients more as an asterism than a constellation. Tycho Brahe included it in his 1602 star catalogue as a constellation. Brahe recorded 14 stars in the constellation, Hevelius increased this to 21, and John Flamsteed to 43. The Coma Star Cluster (Melotte 111, Collinder 256) is a small but nearby open cluster located in the constellation. It contains about 40 brighter stars (between magnitudes 5 and 10) with a common proper motion. This is the mythological Berenice's Hair. As well as the star cluster, Coma Berenices contains one galactic supercluster (right and see later), two galactic clusters, eight Messier objects and the famous edge-on galaxy NG4565 (right). This was missed by Messier but is bright enough to be visible in the constellation image below (left of the star cluster). However, Coma Berenices has lent its name to the famous Coma Galaxy Cluster (Abell 1656), which is more than 350 million light years away (right). At the cluster core are two giant elliptical galaxies, NGC 4889 (right) and NGC 4874 (left). These two dominate a very rich cluster of around 1000 galaxies. The cluster is nearly spherical and consists mostly of elliptical (many highly-flattened) and dust free SO type galaxies. In a recent study of redshifts in the cluster (Colless & Dunn, 1996) found evidence for the cluster to be a merger of two clusters, one each centred on NGC 4889 and NGC 4784. There is even evidence for other sub-concentrations centred on other massive galaxies in the cluster (Gurzadyan & Mazure, 1998). Backing up this merger(s) hypothesis, Trentham & Mobasher (1998) found evidence in the form of giant stellar debris that could have resulted from damaging galaxy collisions.
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Coma Berenices
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1st May 2022Leo Minor Constellation |
Another small inconspicuous constellation that is not original and was created by Hevelius in 1687. However it was noted by Ptolemy but he regrared it as not belonging to a constellation pattern. Due to an error by Bayer there is no star designated alpha and the actual brightest star is not Beta either - it is 46 Leonis Minoris and is the easterly (left) star of the constellation at mag 3.8. Prominent in the images though is the little group of 4/5 stars (the northern one is double) at its centre. Very much an area containg many galaxies but non of them bright enough to have become Messier objects. I have selected the galaxy NGC 2859 to show (right) which I took several years ago. NGC 2859 is a barred lenticular galaxy at a distance of around 83million light years. It classed as a (R)SB(r)0 where the S0+ notation indicates ait is lacking visible spiral arms. It has a strong bar (B) of the "ansae" type, which means it grows brighter or wider toward the tips. These features are surrounded by a weak inner ring (r) that appears diffuse. The outer region of the galaxy has a prominent detached ring (R) - ref wiki.
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Leo Minor
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25th April 2022Sextans Constellation |
Not an original constellation but one added by Johannes Hevelius in 1687. Sextans is Latin for the astronomical sextant, an instrument that Hevelius used for his observations. Sextans is in a sparse area of the sky - no wonder there was no ancient constellation here. It has only one star above the fifth magnitude, namely alpha at 4.5. The most prominent deep-sky object in Sextans is the Spindle Galaxy, NGC 3115. This edge-on lenticular galaxy is about 32 million light-years away and is several times bigger than the Milky Way. It is classed as a lenticular (S0) galaxy as it contains a disk and a central bulge of stars but has no spiral pattern (see right). Observations with the Chandra X-ray Observatory in 2011 indicated that the galaxy has a central black hole with a mass of about two billion solar masses. This would make NGC 3115 the nearest billion-solar-mass black hole to Earth. NGC3115 is just visible in the main constellation image - central about 1/5th the way up.
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Sextans
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18th April 2022Canis Minor Constellation |
Canis Minor is hardly the most spectacular of constellations having only two prominent stars, Procyon at mag 0.4 and Beta at mag 2.9. However, it was one I had not shot before but was ideal for the 50mm lens I was using. In Norfolk we had had several nights of Sahara sand in the atmosphere but this was shot on a night after it had been washed out of the atmosphere. Procyon obviously dominates the constellation and is the 8th brightest star visible from Earth. The reason it is so bright is it is only 12 light-years away. It is binary with a white dwarf companion. Canis Minor is not noted for deep-sky objects but the planetary nebula Abell 24 (see right) is probably the most noteworthy. This I shot in 2013 and for more details see my blog post for thet year.
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Canis Minor
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7th April 2022Ursa Minor Constellation |
Returned to the 50mm lens as this is a perfect match for the constellation of Ursa Minor. Polaris, the northern star, is towards the top left. It is the brightest Cepheid type star in the night sky i.e. its intrinsic brightness is related to its period. Cepheids are a fundamental rung on the distance ladder enabling nearby galaxies to have their distances calculated. Perhaps the most interesting deep-sky object in Ursa Minor is the galaxy Polarisma Borealis, NGC3172 - inset right. Also visible in this image is the Diamond or Engagement Ring asterism - the little circlet of stars with Polaris acting as the diamond. Visible at the left edge is another popular asterism, the Seven Sistesrs of the Pole. This resembles the Pleiades but is somewhat larger. At the extreme left edge is the open cluste NGC188, one of the oldest of open clusters.
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Ursa Minor
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29th March 2022The Open Cluster M46 & M47 |
Another 2 hour run with the 200mm lens on the tracker but this time it was a very low down target near Sirius but actually in Puppis. Consequently only 66 images out of the 120 were sharp. Still this was sufficient to record the clusters clearly and also the Planetary Nebula (NGC2438) in M46 (right). M46: A relatively youngish cluster at around 250 million years with an estimated 500 member stars. The planetary nebula NGC 2438 near its northern edge is most likely unassociated since it does not share the cluster's proper motion - enlarged on right. M47: A very young cluster at only 78 million years old (wiki). This cluster was for a long time a "missing" Messier object. The coordinates he recorded for M47 were in error and the puzzle was only solved in 1959 by TF Morris. Messier used relative coordinates rather than absolute ones ie offsets from a known star. When the signs for the offset were switched it was obvious he had meant this cluster. There are around 500 members with the brightest being HD 60855, a mag 5.7 Be star. The fainter cluster above (north) of M47 is NGC2423
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M46 & M47
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19th March 2022The Praesepe or Beehive Cluster, M44 |
Decided to switch to a 200mm lens as this is a good fit for the 4 bright stars (the hive?) around the cluster. It is also better than the Pentax for stars, which suffers from halos. Shot for 2 hours and selected the best 80 frames from 120 - quite a few were mis-tracked as a 200mm lens is pushing your luck on a simple unguided tracker. A youngish cluster at around 600 million years and relatively close at 600 light years. It shares a proper motion with the Hyades Cluster suggesting a common origin. It has just over 1000 gravitationally bound members. One of the first objects observed by Galileo with his telescope (1609) and he was able to count 40 stars.
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The beehive Cluster, M44
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17th February 2022Rigel & the Witch Head Nebula (IC 2118) |
I noticed that on my recent Orion shot there was a bit of the Witch Head Nebula on one edge so decided to give it a try with my old Pentax 135mm lens. I reduced the exposure to 3 mins as 135mm unguided would be pushing my luck. There was a lot of light pollution as I was shooting in the direction of Norwich and this object is always low from here. South is up in this view. It is a faint reflection nebula i.e. it shines by the star light from Rigel and is slightly blueish rather than the red of the nearby Orion Nebula and Barnard's Loop. It is unsure whether its shape is due to it being ancient supernova remnant (wiki) or just an odd shaped gas cloud.
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Witch Head Nebula
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30th January 2022Orion |
This time I ran for 4 hours as there is plenty to record in Orion. With the 50mm lens on the 60D it needed to be switched to protrait mode to get the best bits of the constellation in. Again I used the green laser for polar alignment and over the 4 hours there was just a small amount of drift and rotation but nothing to worry about. Quite a lot of light pollution as I was pointing in the direction of Norwich but Siril made a good job of getting rid of most of it.
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Orion from Norfolk
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22nd January 2022The Hyades-Pleiades Region |
Unpacked the tracker and decided to see what was possible with a simple 50mm lens. Yes there was some light pollution to get rid of but much less than it would have been from Lancashire. Used a green laser inside the pole axis for polar alignment. Very easy and super fast with no crouching down on wet/frozen ground to look up a pole finder scope. Still assessing the best spot in the garden for an observatory - the issue I have is too many overhead phone lines.
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Hyades - Pleiades from Norfolk
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The imageBLOG continues at Archive 2019-21 Click Here
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