Sunday, December 7, 2025

Variable Star observations on the 28th November 2025

Just over a week ago the weather tried to play ball and give us some clear conditions but it wasn't that brilliant. The moon was at first quarter and there was light thin high-level cloud that made for poor variable transparency. I had been planning to have a good session of variable star observing with my 10x50 binoculars but in the end I only managed three stars:-

TX Dra, 18.45 UT, chart 106.04, K(5)V(2)N, mag. 7.5
AH Dra, 18.55 UT, chart 106.04, 2(3)V(2)6, mag 7.6
CH Cyg, 19.12 UT, chart 089.04, =H, mag 9.2
 
CH Cygni was very difficult and right at the limit of what I could observe in these conditions. I could only see it in averted vision. Because of the moon and the poor visibility I was worried that these estimates might not be very good, but on comparison with values from other BAA members it seems that they aren't too bad.
 
All text and images © Duncan Hale-Sutton 2025 

 

Thursday, December 4, 2025

Red Aurora on the 3rd December 2025

Last night I unexpectedly had an aurora warning beginning around 18:00 UT with a strength of 380.8 nT on the Aurora Watch magnetometer. Initially, I thought that the moon would be too bright to see anything (it was one day until full) but a friend alerted me to the fact that the aurora was active. The alerts kept coming - the magnetometer at Sumburgh Head recorded 560.2 nT at 19:00 and before falling back to 218.6 nT at 20:00. At around 19:00 UT I was outside with my telescope trained on Saturn when my friend put something up on WhatsApp about what he could see. I turned round and was surprised that I could see a red glow in the north. I went inside to grab my camera and tripod and my first picture was at 19:11 UT:-

You can see red vertical rays through Ursa Major and a little bit of green glow below this. This was taken on a Sony RX100 with an exposure of 4s at f/1.8, ISO1600. The display continued on until 19:21 UT but seemed to be weakening:-

This image was taken at 19:16 UT and I had reduced the shutter speed to 2.5s. The red vertical rays can still be seen but are now at a lower altitude. I took a picture looking more to the north west but there was little evidence of activity in this direction apart from a vague red glow. 

After this I went inside for a bit (it was pretty cold by then and frost was starting to form on the grass). I came out again 30 minutes later at 19:46 to find that the activity had ramped up considerably:-

This was again a 2.5s exposure at f/1.8, ISO1600. There is now a a much more intense general red glow with slanting vertical rays overlaying this. The green glow is at the base of this is still visible. The top of the rays are still lower in altitude than the ones taken at 19:11UT. Looking in the north west the activity had also increased there:-

This was a 2.5s exposure taken at 19:48 UT. The constellation of Lyra is at the extreme left of this image and strong red rays are just seen over the roof top. To the far right a much stronger underlying green glow is evident. At 19:49 I took an image to the north east:-

Not much activity can be made out in this direction and the moon just creeps into the top of the picture. There is some general pink glow to the far left. The display in the north was getting to be very pretty by 19:50 UT:-

 Again a 2.5s exposure. It constantly changed and towards 19:55 UT began to die down again.


 This picture was taken at 19:53 UT.

All text and images © Duncan Hale-Sutton 2025 

Wednesday, November 19, 2025

A Personal tribute to Heather Couper

I wish to pay a personal tribute to the astronomer, broadcaster and writer Dr Heather Couper (2/6/1949 - 19/02/2020) who died five years ago at the relatively young age of 70. She was a great ambassador for astronomy and somebody who took an interest in young people and encouraged them to be astronomers. This was true of myself and, by way of thanks, I want to write down how she influenced me into trying to become a professional astronomer.

When I was at Haileybury College between 1975 and 1980 I gained an interest in astronomy by accident rather than by design. At the school we had a number of different societies to which we could belong and one time, when I was obviously at a bit of a loss as to which one I should join, someone suggested the Astronomical Society. I knew very little about astronomy at that time. I was very science orientated (particularly in physics) but I knew very little about the stars. We were very lucky in those days because the school had an observatory which was equipped with a 4.5 inch refractor (probably a Cooke telescope). This was a splendid old brass instrument, mounted on a pier and contained within a brick building. Here is a picture of me standing outside it when I returned to visit the school in 2000:-

By then it had begun to look as though it had been abandoned. Looking on Google Maps today, the observatory is still there and the dome is in intact but it sits forlornly at the corner of a machinery yard. It makes me wonder if the telescope is still inside.

I was assisted in my learning about astronomy by one of the society members - a Scottish lad who was a five years my senior and who knew how to work the telescope. This was Barry Gardiner who later went on to be an MP and a junior minister in Tony Blair's government. I can still recall him saying to me that I needed to understand about Right Ascension and Declination and showing me a copy of Norton's Star Atlas. This book was probably the prime atlas for amateur astronomers at that time and in 1980, when I won the Powell-Davis Art Prize at school, I asked to be given a copy as a reward (rather than an art book)! So armed with this book and a knowledge of how to use the school telescope I began to explore the skies and after a while I was hooked (I can still remember my first views of objects like Orion Nebula and the impact it had on me).

So, as I progressed through school I remained in the Astronomical Society and as I entered my A-level years I became its secretary. This meant organising meetings of the society and in the summer of 1980 I arranged for an excursion to the Royal Greenwich Observatory in London. Of course I had a lot of help in this from my physics teacher and mentor Ian R Williams (or Doc Williams as he was known). Ian was a superb teacher and very inspiring as he had himself done a PhD in low-temperature physics. You have to understand at this time I was on course to study architecture at Manchester University. I had taken A levels in Physics, Chemistry and Art (yes, I know, an odd combination) and had an offer of a place at Manchester. This had been my direction for a number of years, mainly because I come a family of architects and it seemed like a good profession to go into.

So the day came for a group of us from school and Doc Williams to head into London to the Royal Observatory at Greenwich. We travelled by train, tube and then by boat up river from the center, which was very exciting. In the morning we were to go to the Planetarium and to be treated to a show by one of the lecturers. This is when I met Heather Couper for the first time (she had been appointed senior lecturer there in 1977) and it was Heather who gave us the an excellent planetarium show that entertained us from start to finish. There was always something sparkly about Heather's talks and she always liked to introduce something slightly risqué and in this case it was alluding to how the constellation of Virgo was seen lying low above the horizon at that time of the season. 

At the end of the talk Heather mentioned that she was organising an event for young budding astronomers later in the year and said that if we were interested we could put our names down for it. At the time I didn't think much more about it. We headed off to look round the observatory buildings and then down to the National Maritime Museum (the girls in our group disappeared off shopping in Greenwich!). However, later on when I was back at school I began to feel that I was more interested in astronomy and physics than I was in architecture and one day in dining hall I had this epiphany moment! I was going to do it, I was going to become an astronomer! For the first time in my life I realised what I really wanted to do with my life.

It was quite a turn around and there were a few obstacles to overcome, not least that I needed an A-level in mathematics. I didn't really know how to go about this. My maths skills had been somewhat mediocre up till that point but I had done very well in physics and I knew that I must have it in me somewhere. I went to the careers advisor who turned out to be Mr Bentley who had, by coincidence, been my maths teacher right up until O-level (I famously got 5 out of 95 for one of his maths tests). To his credit, he didn't try to dissuade me and I am grateful to him for not doing this. He laid out a plan for me and said that I would need to go to a college in London (a "crammer" as they were called then) and see if I could get an A-level in mathematics in a year. So this is what I did and went to Davies's College in Southampton Row and a year later I had a grade A maths A-level to add to my tally.

In the mean time I recalled what Heather had said about her event for budding astronomers and I wrote her a long letter telling her about my desire to change career and to come to her one-day meeting. I am forever grateful that she took the time to write back to me and to add me to the list of participants. Later in the year I found my way back into London and attended the day where a number of current astronomers talked about how they had got into this line of work. One of them was Dr Jim Emerson (now emeritus professor) at Queen Mary College, London where eventually I went to study. I can still recall how he said in his talk that it was determination and not necessarily brains that got you where you wanted to be in work.

So, after reapplying to study astronomy at a number of universities, I ended up at Queen Mary College doing a BSc in astrophysics. I continued to see Heather from time to time socially (as she was friends with another student on my course) and she was always encouraging to me and interested in my progress. I was so pleased when she and Nigel Henbest came to my 21st birthday party - it was a real honour to have her there (but then parties were Heather's thing!). My career in astronomy carried on for a number of years until 1992. I left QMC with first class honours and a very good background in mathematics (I had even managed to pass the General Relativity course in the mathematics department). It all went to my head and I tried Part III of the Mathematical Tripos at Cambridge (which had a lot of theory of astrophysics in it) but failed. I picked myself up and dusted myself down and went to do a PhD at Durham University which I finally finished in 1990. My subject was cosmology and the large-scale structure of the universe. I was awarded my PhD and carried on for a couple of years doing research but eventually I found myself in the real world with what my mother would call a proper job in business.

However, my interests in astronomy continue and I will forever be grateful to Heather for being there at the right moment and providing me with the idea that I really could do this and get into the professional world of astronomy. We need more people like her and the other teachers that helped me along my way to inspire and to encourage.


Heather Couper and Nigel Henbest in their garden in Greenwich in about 1983.

All text and images © Duncan Hale-Sutton 2025 

 

Tuesday, November 11, 2025

Comet C/2025 A6 (Lemmon)

We have been fortunate to have several comets grace our skies recently and the brightest of these has been comet Lemmon. This comet was discovered by David Fuls on the 3rd January 2025 during a survey at Mount Lemmon Observatory. During the intervening months it has significantly brightened and around the end of the October it reached its maximum luminosity of about 4th magnitude. On October 25th I was fortunate enough to get a good view of the comet when we had some clear skies in the early evening. At 19:41 UT I took this wide-field view:-

 

The comet has been marked on the image with green lines (the image can be better viewed by clicking on it). It sits in the constellation of Serpens (Caput - i.e. the head) and below the distinctive crown of the constellation of Corona Borealis. The field of view this image is approximately 64x46 degrees. I used a Sony RX100 camera with an exposure of 10s at f/1.8 (ISO 1600). I took another image with the same camera and pointing in the same direction but used a focal length of 20mm rather than 10mm:-

 

This was again a 10s exposure at ISO1600 but this time at f/3.5. The comet has again been marked. Looking closely at this image you can see that the comet tail extends quite a long way up towards the crown of Corona Borealis (some 12 degrees). The field of view of this image is approximately 36x25 degrees.

Finally, I wanted to look at how the comet's position compared with ephemeris predictions. For this I took a chart produced by Nick James at the BAA and overlaid it on my first image that I took:-

 

It was difficult getting the orientation and scaling correct but by making sure that the stars near the comet overlap reasonably well, you can see that the comet does indeed sit on the predicted path. As the observation time was 19:41 UT on the 25th which is 0.820 of the day, you can see that the comet is about the right distance along the track towards the 26th tick mark from the 25th tick mark (taking that the tick marks are for midnight UT).

The comet is now beginning to fade and passed perihelion on the 7th November. 

All text and images © Duncan Hale-Sutton 2025 


 

Wednesday, October 8, 2025

Variable star observations in September 2025

I was able to make some further variable star observations in September. Firstly, on the 13th where the moon was one day before last quarter, I had a go at three stars with my 10x50 binoculars. Twilight ended at about 20:30 UT and the moon rose at 20:27. The skies were clear but the sky transparency was average. Here are my results:-

TX Dra, 20.59 UT, chart 106.04, K(4)V(3)N, mag. 7.4
AH Dra, 21.14 UT, chart 106.04, 2(2)V(3)6, mag 7.5
CH Cyg, 22.03 UT, chart 089.04, F(1)V(6)H, mag 8.6 
 
CH Cygni has been fading quite a bit recently. It is now approaching 9th magnitude, which makes it difficult to measure in smaller aperture binoculars. It may not get any fainter than 9.5.
 
On the 30th September the moon was one day after last quarter and wouldn't set until about 22:03. Twilight ended at 19:45 UT. The skies were clear apart from some cloud in the south west. The sky transparency was again average. I observed TX and AH Draconis again. I also had a go at CH Cygni but I gave up as it was too faint. Here are my results:-
 
TX Dra, 22.22 UT, chart 106.04, K(3)V(4)N, mag. 7.3
AH Dra, 22.34 UT, chart 106.04, 2(2)V(3)6, mag 7.5
 
All my results are in very good agreement with other observers from the BAA.
 
All text and images © Duncan Hale-Sutton 2025 

Thursday, September 11, 2025

Some observations over the summer

It has been a couple of months since I last added anything to this blog. The summer season of twlight filled nights is coming to an end now and I am looking forward to more dark observing sessions in the coming months.

There have been a couple of things to note. On the night of the 12th/13th August I spent half an hour or so looking out for Perseid meteors. It was three days after full moon and so this made the sky pretty bright. However, I did spot five meteors, two of which were significant and left long trails.

Two weeks ago, on the 25th August, I dug out my 10x50 binoculars and did a couple of variable star observations.  This was the last time we had the moon out of the way and on this night it was two days after new moon. Astronomical twilight ended at 21.20 UT. The skies were clear and we had good sky transparency. Using BAA chart 217.02 I made observations of Z and RY UMa:-

Z UMa, 21:37 UT, chart 217.02, D(3)V(2)E, mag. 8.2 
RY UMa, 21:45 UT, chart 217.02, =4,  mag. 7.7
 
Z is beginning to fade rapidly since its peak in May.
 
Finally, on Sunday, the 7th September, there was a total eclipse of the moon. This was always going to be a difficult eclipse to see as the moon wouldn't rise until 18.31 UT and by then a lot of the full eclipse had already happened. As it turned out there was a bank of cloud from our observing location however we did see part of the umbra covering the moon as it rose through a gap in our hedges! This was somewhere between 18:52 and 19:56 UT (19:52 and 20:56 BST). I did try to take a photograph but by the time I got a scope set up, the umbral part of the eclipse was over.
 
All text and images © Duncan Hale-Sutton 2025 

Tuesday, July 1, 2025

Start of the NLC season

Just over a week ago, on the 23rd June 2025, we had our first display of Noctilucent Clouds (NLC) this summer season. I have written about how these high altitude clouds are formed in a previous post. Here is what I saw at just after 11pm BST (22:04 UT):-

This image was taken with a Sony RX100 (1/3s, f/1.8, ISO 1600) and has been cropped so that the cloud features can be seen more clearly (click on the image to obtain the full size version). To the right, near the chimney pot, the head of the constellation of Perseus is rising. The maximum elevation of the clouds is about 16 degrees above the horizon and the display stretches about 49 degrees in azimuth across the sky. I thought that there were three types of cloud present here - type I which is a type of veil, type II which are lines or streaks and type III which appears as a fine herring-bone pattern (this can be seen most clearly to the left of the picture just above the old TV aerial).

It is interesting to me that I have seen these clouds on exactly the same date on 23rd June last year (2024) and the 23rd June 2021. It makes me wonder if this may be the time when these clouds can first be seen in the season. 

A few days later on the 28th June 2025 I saw some more:-

This was not such a good photograph as it was hand held (Sony RX100, 1/2s, f/1.8, ISO 400) but it does show the type III herring-bone pattern at low elevation (much lower than before, the maximum elevation was only about 7 degrees). This was taken a bit later at 22:37 UT.

What is an odd coincidence is that I saw NLC's on the 28th June last year too. Next year I must see if this pattern in dates of appearance repeats again (provided we get some clear weather).

All text and images © Duncan Hale-Sutton 2025