Caldwell 1 (The Polarissima Cluster)

I was lucky again with the weather last night as it cleared after a somewhat windy and showery day. In fact the wind dropped completely and at about 11.00pm BST the sky was dark and clear. I again went for an object that was suggested by the Dwarf 3 Atlas and this was Caldwell 1 (the Polarissima Cluster or NGC 188). This open star cluster is actually in the constellation of Cepheus but is very close to the North Celestial Pole and so never rises nor sets. This is what I obtained after 296x15s (1 hour 14 minutes):-

The first frame was taken at 23:13 BST and the last at 00:43 this morning. The astro filter was employed and the gain was 60. Auto parameters were used in Stellar Studio. I have increased the saturation of the image in Photoshop and binned it x2. Here is a close up of the object using the unbinned data:-

At an age of about 7.8 billion years, this is one of oldest open clusters that we know of in our galaxy. In most circumstances a cluster this old would not have survived as a physical unit as it would have been dissolved by the interaction of its members with the disc of the galaxy. However, C1 lies well above the plane and so has survived more or less intact. 

All text and images © Duncan Hale-Sutton 2026 

IC 2574 (Coddington's Nebula)

Last night (the 10th May 2026) we had one of those really clear and dark spring nights. It was marvellous! The Moon was one day past last quarter and didn't rise until 03:03 BST this morning. One of the suggestions that came up on the Atlas in the Dwarf 3 was Coddington's Nebula (IC 2574) in Ursa Major which I had never heard of before, so I decided to try it. This is what I obtained after 432x15s (1 hour 48 minutes) of observation:-

The nebula is the object in the centre of the image. The first frame was taken at 22:36 BST and the last at 00:47 this morning. The astro filter was employed and the gain was 60. Auto parameters were used in Stellar Studio. I have increased the saturation of the image in Photoshop and binned it x2. Here is a close up of the object using the unbinned data:-

This is not actually a nebula in our galaxy but a galaxy in its own right. This dwarf spiral galaxy was discovered by Edwin Foster Coddington in1898 and is an outlying member of the M81 group of galaxies. This galaxy looks like a nebula because of the large amount of star formation that is taking place within it and that gives the galaxy its blue and red appearance (the red colour coming from HII regions). Interestingly, the visible component of this galaxy contributes very little to the overall mass of the galaxy meaning that the majority of the mass is in the form of dark matter (this accounts for 90% of the mass at the last measured velocity point - see Martimbeau and Carignan 1994). This is true of most dwarf spiral galaxies and makes them ideal objects to test theories of dark matter.

All text and images © Duncan Hale-Sutton 2026  

Globular Cluster M3

Last night (the 8th May 2026) we had some more clear weather after having had a period of unsettled conditions. These poor conditions coincided with the full Moon, so it wasn't too much of a bother. Today the Moon is at last quarter and it didn't rise until about 02:35 BST, so it didn't interfere with my observations last night. My object for inspection was the globular cluster M3 which lies on the southern border of the constellation of Canes Venatici next to Bootes. We are getting close to the time now when there is no complete darkness all night and so my observations started quite late in the evening. Here is what I obtained after 475x15s (1 hour 58.75 minutes) of observation on the Dwarf 3:-

The first frame was taken at 22:20 BST and the last at 01:01 today. The astro filter was employed and the gain was 60. Auto parameters were used in Stellar Studio. I have increased the saturation of the image in Photoshop and binned it x2. One thing that I did was to restack all the images in Mega Stack because, weirdly, the automated process for this had included a number of frames that had satellite trails and this was ruining the picture. So I went through all the images again and deleted those with noticeable trails before I restacked. The resulting image is quite letter boxy and this is due to field rotation in the alt-az mode. Stellar Studio crops out parts of the image that have been badly affected by field rotation.

M3 is a pretty spectacular cluster as you can see from the image. Here is a cropped version of the unbinned image:-

What is satisfying here is how so many stars have been resolved almost to the centre of the cluster. M3 is a very fine object and only appears to be somewhat fainter than the famous M13 cluster in Hercules because it is further away (it lies at a distance of 10.4 kpc as apposed to M13's 7.4 kpc). Amazingly there are 250,000 stars contained within a radius of 11 light-years of its centre. Compare this with the fact that there are only 12 known stars within 10 light-years from our sun. It would be very interesting to look up at the night sky from a planet orbiting a star in the core of M3! I am sure it would be like looking at a piece of black velvet studded with thousands of diamonds.

Going back to the wide-field image above, there is another interloper to the upper centre right and this is the galaxy NGC 5263. 

All text and images © Duncan Hale-Sutton 2026 

The Coma Cluster (Caldwell 35)

My final image from last week was taken on the 24th April 2026 using my Dwarf 3. I decided to try a much more difficult and faint object and this was the Coma Cluster of galaxies in Coma Berenices. This cluster appears as number 35 in Patrick Moore's Caldwell Catalogue and the galaxies in it are located 300 million light years from us. On the 24th the Moon was at first quarter and it didn't set until 03:43 BST on the 25th, so light from it was making observation more difficult. Added to this, towards midnight a mist arose which terminated my observing. Here is what I obtained after 368x15s (1 hour 32 minutes) of observation:-

 

The cluster is the faint collection of objects near the centre of the image. The first frame was taken at 22:25 BST and the last at 00:21 on the 25th. The Astro filter was employed and the gain was 60. The image was processed in Stellar Studio using auto settings and binned x2. Here is a more close up version using the unbinned image:-

The cluster is dominated by two supergiant elliptical galaxies, NGC 4889 (left of centre) and NGC 4874 (right of centre). It looks like there is a swarm of stars surrounding these two objects, but these are in fact galaxies (the cluster contains at least 1000 bright ellipticals). Below I have attempted to label some of the brighter galaxies in the full frame image (click to enlarge):-

All text and images © Duncan Hale-Sutton 2026