09.12.2021 – Comet C/2021 A1 Leonard

Observation report

On the morning of December 9th, 2021 I managed to take a look at the comet named C/2021 A1 Leonard. Its brightness has now increased significantly in December, so that it was also interesting for my rather simple equipment. Unfortunately, the weather never played along in the past few nights and the following nights will probably not leave any opportunity for observation. Only in the night of December 8th to December 9th, 2021 it should clear up what it did. But first a few details about comet C/2021 A1 Leonard: The comet was discovered on January 3, 2021 by Gregory J. Leonard at the Mount Lemmon Observatory in the USA and flies through our solar system at around 70 kilometers per second, which is quite fast. That is why it changes its position quite clearly from night to night. In the coming days the comet will increase in brightness, but it will also stand lower and lower towards the horizon, which will make observation more difficult. With about 34 million kilometers (about 100 lunar distances) the comet will reach its smallest distance to the earth on December 12th, 2021, the smallest distance to the sun it will reach on January 3rd, 2022.

After the weather played along on the night of December 9th, 2021, I of course didn’t want to miss the opportunity to observe the comet at least once. The observation conditions were still acceptable with a height of around 20° above the horizon. The comet, which had a brightness of approx. 5.2 mag, could not be seen with the naked eye from my small city. Even through the viewfinder of the DSLR, it couldn’t be seen. Of course, he was quickly found in the photos with long exposure. You don’t see a comet with this brightness every year of course, and I was happy to be able to observe the cosmic visitor who will disappear into the depths of the universe after orbiting the sun. Many details could not be seen with my equipment. The bluish-greenish color was recognizable in photos, the little tail also with a little bit of imagination. At least you can see where it is. However, since I took photos without tracking, it was not possible to use a telescope, nor was a longer exposure time possible. The sky was also a bit hazy, which would have made the background too bright. So I just enjoyed the sight as it was and was happy to see another comet in my life. Another nice surprise was a shooting star which I found on a photo of 6.43 a.m.. With temperatures of around 0°C, winter clothing was of course required here, and I could comfortably watch from the inner courtyard.

What’s next: Comet C/2021 A1 Leonard will still be visible in the morning when it is close to Earth on December 12th, 2021, but quite low above the horizon. In addition, it doesn’t rise until around 6 a.m. and then the dawn will soon come into play. So the conditions are not easy, but with good atmospheric conditions it should still be visible until December 12th, 2021 before it disappears into the dawn on December 13th, 2021. It then initially wanders flat over the horizon in the evening sky, whereby the dusk will make sighting more difficult. Depending on how bright the comet is, it could work. On December 17th and 18th he wanders below Venus along the horizon, which can serve as a search aid. The observation window for the comet is already very short here, due to the dusk and the rapid demise of the comet. Here it will need really ideal conditions and it also depends very much on how bright the comet will really get when it approaches the sun.

Below you will of course also find a few photos that I was able to take while observing the comet on the morning of December 9th, 2021 between 5:39 – 6:29 a.m. with a Canon 500D (with a lens up to 300mm focal length):