Mars near opposition

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Mars reached its opposition, when it lined up between the Earth and the Sun, on 13 October 2020. Its closest approach to the Earth, however, was on 6 October 2020 when the two planets were separated by ‘just’ 62 million kilometers. This was when it was at its maximum apparent size of 22.6 arcseconds. You will probably have seen it recently in the eastern evening sky looking like a very bright reddish star.

This astrophotograph of Mars was taken on 12 October between 20:06 and 20:54 UTC, during which time Mars was still relatively large, although still a tiny target for my 102-mm f/7 telescope, even using a 3× Barlow lens and a planetary camera.

The still frame image above is centred on 20:46 UTC. Only albedo features are visible, that is, only large surface expanses which reflect more or less sunlight, making them brighter or darker. My 102-mm-aperture telescope does not have the resolving power for surface details.

The southern polar cap is clearly visible at the bottom. The bright ‘splodge’ towards the top centre is Olympus Mons, a 21-km high volcano (2.5× the height above sea level of Everest), making it the largest mountain discovered in the solar system. The dark expanse on the middle left is an upland area called Mare Sirenum. And to the right of Mare Sirenum is another dark expanse called Solis Lacus, commonly called The Eye of Mars because with the surrounding light area it resembles a pupil. Just to the north of the southern polar cap are various faint features, including Palinuri Fretum.

The animation shows the surface rotation of Mars. Mars has a similar rotation speed to the Earth, rotating once every 24 hours, 39 minutes, and 35 seconds. There are four frames, based on four five-minute videos, as detailed below. There is about a 30-min gap between the first and second frame, due a tree obstructing the view; hence, the large jump! The next 3 frames are spaced 5 minutes apart.

Frames

• 5-min videos with 5-ms exposures starting at 21:06, 21:39, 21:44 and 21:49 BST
• Dark frames used but no other calibration frames
• Tree obstruction (!) between 21:11 and 21:39 BST
• Cropped in PIPP
• Best 50% of frames of each stacked separately in AutoStakkert! 3
• Wavelets sharpening of each stack in Registax
• Animated in ImageMagick
• Final 3 stacks (spanning 15 min) derotated and stacked in WinJUPOS

Equipment

• Explore Scientific ED 102 mm Apo f/7 refractor
• Sky-Watcher EQ6-R PRO SynScan GOTO equatorial mount
• Altair GPCAM3 290C colour camera (with UVIR window fitted)
• Celestron X-Cel LX 3× Barlow

Software

• Sharpcap
• PIPP (Planetary Imaging Preprocessor)
• AutoStakkert!
• Registax
• ImageMagick
• WinJUPOS
• Photoshop