The same evening I imaged Jupiter under good seeing conditions, Mars was also favorably placed for imaging, but not until much later. Mars’ oppositions vary in quality. In favorable oppositions—like that in 2020, Mars is relatively close to the Earth. Its disc has a relatively large angular diameter and lots of detail is visible. In less favorable oppositions, the planet is further away from Earth, with smaller angular diameter and much less detail visible. In 2018, the planet had an angular diameter of 24.2 arcseconds. In 2020, it was 22.4 arcseconds. In 2022, it is only 17 arcseconds. 2025 and 2027 will be even worse, with 14.5 and 13.8 arcseconds respectively.
While I can image Mars early in the evening, it is currently
low in the sky and detail is lost in the thicker atmosphere the light passes through.
It is not until 11 pm that the planet rises above blocking trees and offers an
optimal imaging target. The image below is the best 30% of 15,000 captured
frames. Given the angular size of the planet and the small scope used, the
captured image is quite decent. I have included a map to show the features
captured, including (most obviously), Syrtis Major, the North Polar Cap and a
suspicion of the South Polar Cap at the 2 o’clock position.
Tech Card: 5 inch Mak, SLP imager, 2x Barlow. Best 30% of 15,000
frames stacked in AstroSurface with wavelets in Registax.
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