Category Archives: Astrophotography

The Great Conjunction of Jupiter and Saturn, 21 December 2020

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Click here to see larger versions of the photographs in a separate tab

 

I had planned to take a series of photographs of Saturn and Jupiter in the days before and after 21 December as the planets appeared to move closer together and then as they moved apart.

However, despite the sky being reasonably clear for several evenings before 21 December, there was always a layer of low clouds over the Vosges themselves. By dusk the elevation of the planets was only 10 degrees about the horizon and getting lower. The planets often appeared and the disappeared in that cloud but were often still covered in a light haze. On the day of the conjunction, 21 December, and for the following days, there was thick obscuring cloud. The next time I saw them (and last, because of clouds for the following week) was briefly on 26 December.

I took several hundred photos in total. Above is one from each of the nights Thursday-Sunday before the actual conjunction on the Monday and one on the following Friday. The second was taken at 1725, so in the dusk light. The third was taken just before 1800 and shows clouds. The fourth shows the closest I captured the planets with some moons of both Saturn and Jupiter and I’ve added a screenshot from the free Stellarium planetarium software http://stellarium.org/ which helps identify the moons. Saturn and the rings weren’t separately identifiable and just appeared as an oval (the 26 December photo is the best).

I was using my 75-300mm lens at 250-300mm. I tried different exposures as the planets seemed over-exposed, but that made no significant difference so I must be at the limit of resolution of the sensor/lens image for that length telephoto. I had to focus manually as autofocus does not work on many cameras for small objects at a distant near infinity (for autofocus the camera needed to be able to focus either side of the correct focus point). When turned on my camera was set to go to an “infinity” point (the setting is 999.9m) which gives a good depth of field but the primary focus is not at infinity (the latest top-of-the-range Olympus DSLR do have a new special Starry Sky autofocus, which reportedly works). The other problem was either the low haze or fine high cloud making the images fuzzy. I’ve since seen photos on an Olympus web site where someone used a 400mm lens and the rings and planet were separately identified.

Geminid meteor shower – 14 December 2020

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A Geminid meteor

The one Geminid meteor

The sky was cloudy when I tried to photograph some of the Geminid meteor shower on 14 Dec. After midnight I set up my  camera with a 7.5mm fisheye lens in one of the nearby fields. I adjusted it to take 120 30s exposures automatically with a one second gap between each exposure to allow the file to be saved.

I’d expected to see perhaps a dozen shooting star images in the resulting photographs over that hour, especially as I’d seen one while I was setting up the tripod. I was wrong. And attached is the only other one in that hour-long set I captured where the clouds cleared enough to see the sky (and I wonder how many I missed in those one second gaps!) It just got gloomier and gloomier. But at least I could just wait indoors in the warm as it was near zero Centigrade outside.

I also made a time-lapse video of the photos. The meteor shows at about 3 seconds.

The International Space Station (ISS) July 2020

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I posted an item on 7 June 2013 on photographing the ISS. As I now have a different camera and lenses and as we have clear skies I decided to do an update.

I now use the ISS Detector app on my phone to notify me of upcoming events. At 22:38 on Monday 27 July 2020 there was a possible nearly overhead ISS sighting (max. height 86°, appearing 27° above WNW disappearing 22° above ESE). The first quarter moon was not too bright and not likely to cause problems. So I set my tripod in the field below the farmhouse, in the best position to avoid the farmhouse and surrounding trees blocking the overflight path. I had a 7.5mm Samyang fisheye lens on my camera and set it at an angle to give me the likely full path across the diagonal of the image . With the lens set at f8, I opened the shutter just before the predicted appearance time. The ISS passed over and disappeared from sight just before the end of the path and I then shut the shutter. This is the resulting unedited image:

ISS 22:44 27 July 2020 ISO 400 f8 371s
Entre-deux-Eaux 48° 13′ 53″ 6° 58′ 48″

As I was satisfied with that photograph, the following day I was just out taking some photographs of the moon with a 75-300mm zoom lens (and also attempting some photographs of Jupiter). I’d forgotten about the ISS but suddenly saw it appear above the orchard trees. Rather than trying to take partial path picture, I wondered whether it was possible to just take a snapshot of the ISS itself. I had no idea of exposure settings and had little time so just took a guess at what to use. I loosened the ball and socket mount so I could swivel the camera to track the ISS and set the lens to 75mm in the hope of seeing the ISS through the viewfinder with the wider view. That wasn’t too difficult and I was then able to zoom to 300mm (= 35mm full-frame 600mm) and to track the ISS, pressing the release several times to take photographs. The results were rather mixed, poorly exposed, and showed camera shake but gave me an indication of what might be possible.

So I decided I might be able to do better the next night with some proper preparation. I set the camera exposure to a faster shutter speed and higher ISO and also set the camera to take an automatic succession of photographs to try to reduce the initial movement from pressing the shutter release (at that focal length the camera is very sensitive to the slightest movement). I had to use the release button on the camera as I needed both hands to help track the ISS smoothly so couldn’t easily use my phone as a remote control.

I took over 100 photographs. About 10% have an image that on close inspection is discernible as an object rather than just a white, slightly blurred, blob. I doubt I would be able to get a better photograph with that lens. I would need the camera attached to a telescope which had automated tracking.

This shows one of the full images with the ISS arrowed. I’ve pasted an enlarged version of that faint white dot in the RH corner. The ISS in the image is only 20×16 pixels overall. It was pleasing as I’d not really expected such a positive result.

ISS 22:48:04 29 July 2020 ISO 3200 f6.7 1/640s 300mm

According to http://www.isstracker.com/historical the ISS was at 45.874N 3.008W (over Volvic in Central France) at an altitude of 262.45 miles and travelling at 17,144.65 mph.