The big three
BEST TIME TO SEE: 1-5 March, with closest approach on 3 March and Moon nearby on 19 March
Mars has been a beacon in our night skies for many months, but due to the increasing distance between it and Earth, it now appears much dimmer than it did at the end of 2020. In addition, through the eyepiece of a telescope, Mars now appears quite tiny, making its surface markings harder to see.
At the start of March, Mars is located 3˚ south of the beautiful open cluster M45, also known as the Pleiades or Seven Sisters. As it tracks east, Mars also moves slightly north against the background stars. This apparent motion means the planet appears closest to the cluster on the evening of 3 March, the separation distance being around 2.5˚ on this date.
Mars will appear at mag. +1.0 on 3 March, and although a lot dimmer than the mag. –2.6 it achieved last October, its proximity to the Pleiades will no doubt cause considerable interest in the early part of the month.
Binoculars are perfect for watching this conjunction; Mars and the Pleiades will easily fit in the same field of view for typical amateur mid-power binoculars. In addition, the large size of the Pleiades suits such an instrument. Where a scope tends to look through the Pleiades, binoculars reveal many of the fainter stars associated with the cluster while managing to contain it all in a single view.
The conjunction will also be attractive for astro imaging: both objects are bright enough to register on many devices ranging from some smartphones to DSLRs and MILCs. A lens of 200mm focal length combined with a non full-frame DSLR (eg APS-C) will record both objects well.
As we head into the second week of March, Mars will have moved east far enough to sit between the Pleiades and the V-shaped Hyades. The Hyades is an old cluster, the closest to Earth at a distance of 150 lightyears. Estimates put the age of the Hyades at 625 million years, and this explains why its stars appear less vibrant than the 100 million-year-old Pleiades. The distance to the Pleiades is around 444 lightyears, making it appear far more compact than the spread out Hyades.
A 50mm lens on a non-full frame DSLR will capture both clusters and Mars in the same frame. For an added bonus, on 19 March a 32%-lit waxing crescent Moon will sit 2.3˚ to the south of Mars, between the planet and the northmost star in the main Hyades pattern, Ain (Epsilon (e) Tauri).