Tag Archives: moon

Lunar occultation of Venus

Last Friday morning the Moon passed in front of Venus. This is not a super rare even (unlike, e.g., a total solar eclipse), but it also does not happen very often; the next Venus occultation (visible from Belgium) will take place on the 9th of November in 2023, but that will be much less spectacular. What makes last week’s event so special, is that it happened only two weeks after the inferior conjunction of Venus (when Venus passes – more or less – between the Earth and the Sun). Around this date Venus shines as a very thin crescent, and the apparent size of the planet is much larger than usual (since it is closest to Earth in space at inferior conjunction). The next time the occultation will happen in a similar configuration will only be in 2028.

Just 45 minutes before Venus was about to disappear I set up my equipment in the shadow of a strategically chosen taller building on the university campus (to block out the Sun), then used my binoculars to find Venus and the Moon. Venus was much brighter, without it finding the dim crescent of the Moon would have been much more difficult on the bright daylight sky. Having established their location relative to the nearby building, I managed to find Venus with the naked eye too. Then I could proceed with aiming the 1000 mm “objective” at the target using a red dot sight that I installed on my camera and aligned with the lens earlier. Manual focus is always a bit of a trial and error, but I got fully ready well in time as the crescent Moon got closer and closer to Venus. From a series of photograph, the nicest one is probably the one where a few clouds also got into the field of view just as the two crescents touched. I did not stay for the exit phase, as more and more clouds began to form…

Thanks to my twitter connections, this picture also made it to the evening news (actually the weather segment) of the VRT (the flemish national radio and television). [Single exposure of 1/340 seconds at ISO 160 with a Fujilim X-T3, using a 1000 mm f/10 Maksutov telescope (from TS-Optics), on a Sky-Watcher Sky Adventurer mount]

The longest lunar eclipse of the century

The longest lunar eclipse of the 21st century was a good occasion/motivation for me to do a bit of astrophotography again (after my wide-field adventures on La Palma last year). I wanted to take some close-up pictures of the Moon, so I bought a relatively inexpensive and compact 1000 mm f/10 Maksutov Telescope (from TS-Optics). My Sky-Watcher Sky Adventurer mount could still take the combined weight of this and my Canon EOS 6D camera, but my old Manfrotto tripod proved to be not exactly as stable as hoped for at this focal length… Of course I did not notice this during my test shots a few nights before the eclipse, because back then there was no wind at all, but later during the eclipse itself the vibrations caused by gusts were quite a bit of a problem.

The day of the eclipse was the hottest day of summer so far (although today might have broken that record), but also the last day of a heatwave, and as such, storms were closing in on the low countries from France during the afternoon. Looking at the satellite pictures and the weather models I was pretty sure that it would not stay clear in Leuven, so we got into the car and drove an hour (93 km) to the East – away from the storms – and set up the equipment on the Southern flanks of the Fort d’Aubin-Neufchâteau (which I scouted on Google Maps making sure that the view towards the Southeast would be more-or-less unobscured, as during the eclipse the Moon would stay quite close to the horizon).

The moon rose already fully submerged inside the shadow of the Earth, so it was very difficult to spot it in front of the bright background of the evening twilight. By the time I found Polaris (and aligned the tracking mount to be able to follow the movement of the Moon during longer exposures), the eclipse was just past its maximal phase.

As mentioned earlier, it became clear already during the initial setup (while focusing on the rings of Saturn), that my tripod was not strong enough to hold the whole system perfectly stable against the wind, so my strategy during the eclipse was the following: I kept taking pictures basically continuously hoping that there would be at least a few during which the wind would be weak or constant enough to not move the tripod too much, so with some luck I would get a few good-enough photographs at the end. This worked out as expected (with Clio’s not small contribution as a paravent), so the expedition became a total success :) The settings I used during the totality: ISO 3200, 2.5-2 sec. Settings in the partial phase: ISO 800-1600, 1/60-2 sec.

We stayed almost until the end of the partial phase, but by midnight the clouds reached us, so we had to pack in and drive home. It was still almost 30°C when we left…

Overall I am satisfied with the results, of course with a bigger budget I could have made better images. While I really like astrophotography, living in one of the most light polluted places means that I do not feel like investing a lot of money into another expensive hobby (right now). As a bonus, here is the first test shot I made a quarter before the eclipse.

Earthshine

I wanted to catch the comet again today, preferably with the Moon in the same picture, but the clouds were not very cooperative. The area around the position of the comet was covered, and only the Moon – situated higher up on the sky – was visible… So I took a picture of the Earthshine (the dark side of the Moon is being dimly lit by Earth, or to be more precise, it is illuminated by reflected sunlight from Earth) instead. Same setup and settings as yesterday, except for the 1.6 sec exposure time.