Geminid Meteor Shower 13th December 2022

Two weeks ago we had the Geminid meteor shower which peaked over the night of the 13th/14th December. The moon on this date was waning gibbous and about 3 days from last quarter. It rose about 20:44 UT and so would interfere with observations after this time. Nevertheless, this is now the best meteor shower of the year and so I decided to see if I could capture any events on my camera.

I am glad to say that I was quite successful in spite of the moon. In all I caught 6 meteors on camera in the period 22:00 UT (approximately) to 23:17 UT. I had a few problems to begin with and it took me a while to settle on a successful method. After 22:18 I had the correct date and time (UT to the nearest second) recorded in my camera (prior to this I still had the year as 2021! and the time was out by a few minutes). At 22:27 I settled on taking successive 15 second exposures at ISO1600. I was using a D90 camera with a 18-105mm lens set at 18mm. This gave me a field of view of about 66x46 degrees. I made a note of the frame numbers where I had seen a meteor which was in or near the part of the sky where the camera was pointing.

I noted that I had seen 10 meteors in all. Initially I was pointing the camera south and then later I pointed it east. The first meteor I detected was this one at 22:18 UT.

This was a 30s rather than a 15s exposure. If you click on the image you will see an enlarged version. The meteor crosses the boundary between Orion and Taurus near pi 1 Orionis. The Hyades, Mars and the Pleiades can be seen clearly above the short trail of the meteor.

The second meteor that was recorded was at 22:42.

This one is more difficult to see but it is found just above the cloud to the right of Orion. This meteor lies entirely in the constellation of Eridanus near 47 Eridani.

The third Geminid was the best of the night and recorded at 22:45 UT.

This was a bright meteor and as bright as Mars which was nearby and magnitude -1.8. It also had a similar yellowish orange colour. The trail starts in Taurus (passing 5 Tauri) and ends in Cetus crossing a little bit of Aries. A couple of things to note: 1) there is a bit of ghostly train left behind the trail where the meteor has passed and 2) the trail is wiggly in structure near the start. This latter point may have been caused by camera shake as the meteor appeared very shortly after I pressed the camera shutter. However, Mars is just as bright and there is no camera shake noticeable in its image.

The third meteor I detected was at 22:54 UT.

This was a noticeable meteor and can be seen just above the figure of Orion the hunter. The trail of this meteor starts in Orion but then crosses into part of Taurus (it ends between 131 and 133 Tauri).

The next meteor to be captured was at 23:08 UT. By this time I had moved the camera to look eastwards.

This one is very faint and difficult to see. The short trail appears in the constellation of Cepheus not far from the triangle of stars made by delta, epsilon and zeta.

The final capture was at 23:12 UT.

This meteor is in virtually the same part of the sky as the previous one but, perhaps, a bit brighter. It passes between 18 and 19 Cephei.

All text and images © Duncan Hale-Sutton 2022

RW Cephei 12th and 24th December 2022

I decided to have a go at observing a different variable star this month and that is RW Cephei. The star is located near the triangle of stars made by zeta, delta and epsilon Cephei (the "foot" at the base of the constellation's main rhombus of stars). RW is a red hypergiant whose apparent brightness ranges between 6.0 and 7.6 over a period of about 346 days. It is classified as a semi-regular SRd type. Earlier this month this star has become the focus of attention because it may be going through a period of exceptional dimming as did Betelgeuse in Orion in January 2020.

I had a look at this star on Monday the 12th December 2022 in the early evening. At this time the moon was 4 days past full and not due to rise until 19:32 UT. At 18:30 the sky was clear and dark and astronomical twilight had just ended.

At 18:32 UT RW was fainter than star E (=7.3 mag.) on chart 312.02. At 18:50 UT I thought it was marginally brighter than star H (=7.8 mag.) and my estimate was E(2)V(1)H or magnitude 7.6 (to 1 d.p.).

I had another go at this star a few days ago on Christmas Eve (24th December). Then it was just one day past new moon and again the sky was clear and dark but there may have been a slight mist.

At 18:45 UT RW was again fainter than star E (=7.3 mag.) but this time it was closer brightness to this star than star H (=7.8 mag.). My estimate at 18:55 UT was that it was E(1)V(2)H or magnitude 7.5. So not much different to 12 days ago.

I don't have much to compare my results to as there hasn't been any further data added to the BAA VSS database by other observers since the 10th December, though one BAA VSS member did say that he had measured it to be visual magnitude 7.7 on the 21st December (via baavss-alert).

All text and images © Duncan Hale-Sutton 2022