Get ready for Mars at opposition in December 2022

By Pete Lawrence

Published: Thursday, 12 May 2022 at 12:00 am

Mars reaches an apparent diameter of 6 arcseconds on 31 May 2022: pretty small but a viable size to record the planet as a disc.

A good challenge to take us right through into 2023 is to start observing, imaging or drawing Mars at regular intervals from now until opposition on 8 December 2022, and then through into the following year.

For more observing dates and advice, read our guide to observing Mars and sign up to receive the BBC Sky at Night Magazine e-newsletter.

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Mars before, during and after opposition Keith Johnson, Ferryhill, County Durham, 31 August– 30 October 2020. Equipment: ZWO ASI 290MM mono camera, Celestron 9.25-inch Schmidt-Cassegrain, Sky-Watcher EQ6 Pro mount

The start of this long-term project won’t be too easy because Mars will be located in the brightening morning twilight, with it being best placed at the end of May.

The frequency of recording will need to be adjusted with the weather, but an observation a week or two apart at the start of the sequence should be sufficient.

For help with this, read our guide on weather forecasting for astronomy.

The planet will remain tricky through June 2022 and most of July, but then the lengthening nights and a brightening planet will work in your favour as we pass the summer solstice on 21 June.

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The relative size of Mars as it appears mid-month from May 2022 to April 2023, through opposition on December 2022. Credit: Pete Lawrence

It takes tenacity to remain with a planet like this, especially as the earlier results will probably look quite poor.

However, sticking to your guns and grabbing results when the weather allows is a great way to connect to a distant world like Mars.

Mars reaches opposition on 8 December 2022. The planet will present with a maximum apparent size of 17.2 arcseconds at the start of that month, which is someway short of last opposition’s 22.6 arcseconds, achieved in October 2020.

However, for the UK at least, Mars reaches opposition at a higher altitude this year and this will make a big difference.

If you do manage to stick with Mars all the way from now through to – and possibly past – opposition, comparing results will give you a unique insight into how this planet can change in appearance dramatically.

Photographing Mars

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Mars at Opposition, 2016 by John Chumack, Dayton, Ohio, USA. Equipment: C8, Qhy5IIL CCD, 2x barlow.

If you aim to photograph Mars, or indeed photographing the planets in general, you need to decide whether to capture it in colour, monochrome, or monochrome with filters, to generate a colour result.

If you are intending to do a colour capture, consider investing in an atmospheric dispersion corrector (ADC) to reduce atmospherically induced colour fringing at the start of the project, which is a side-effect of low altitude.

An infrared-sensitive monochrome camera fitted with an infrared pass filter will give you a colour fringe-free result and will go some way to overcoming the effects of atmospheric turbulence.

This is because longer wavelengths tend to be less affected by atmospheric seeing.

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The difference in the apparent size of Mars when it’s at its most favourable opposition and when at its most distant from Earth. Credit: Pete Lawrence

The distance between Mars and Earth will reduce as we approach December 2022 and surface detail should start to become more apparent in the months ahead of this.

Additionally, constant recording will reveal the effects of the Martian weather and seasonal changes in the planet’s polar caps.

This guide originally appeared in the May 2022 issue of BBC Sky at Night Magazine.