March 2025 – What’s Up!

Week of 31st March

• Astronomical twilight ends at 21:37 BST at the start of the week and at 21:51 BST by the end of the week.
• Spot the thin 15% Waxing Crescent Moon next to M45, The Pleiades, on Tuesday evening, making a beautiful sight close to the western horizon at around 21:00 BST.
• Jupiter (-2.1) and Mars (+0.5) are well into the western hemisphere of our evening sky as they march towards the horizon. Observe them both now as the planet season is drawing to a close.
• Spend some time in the constellation Cancer with your binoculars or telescope this week. Start with two open clusters, M44 (+3.1), the Beehive Cluster, which covers over 1° of sky, so a larger field of view is needed, and oft overlooked cousin M67 (+6.9) 8° to the south. Next to two double stars, starting with the easy split of Iota Cancri (+4.0) at 31 arcseconds separation, then challenge yourself with multiple star system Tegmine, Zeta Cancri (+5.9) at a tricky 5.9 arcseconds separation. The two visible main components are both double stars, though you won’t manage to split them at under 1 arcsecond each!
• The Moon is First Quarter on Saturday.
• The Sun currently has 7 active regions and the sunspot number is 107.
• There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 24th March

• Astronomical twilight ends at 20:22 GMT at the start of the week and at 21:35 BST by the end of the week.
• British Summer Time (BST) starts at 01:00 GMT on Sunday, when the clocks will ‘spring forwards’ to be 02:00 BST.
• There is a Partial Solar Eclipse on Saturday morning, starting at 10:05 GMT, maximum eclipse (about 30%) will occur at 11:02 GMT, with the eclipse ending at 11:59 GMT. WARNING: ***Take great care and only observe the Sun with a proper solar filter.***
• Jupiter (-2.2) dominates our southwestern evening sky, setting at around 01:00 GMT this week. Mars (+0.3) is moving eastwards below the twins, Castor and Pollux.
• This is the perfect week to attempt the Messier Marathon. How many of the 110 objects in the catalogue can you observe in one night? Good luck if you give it a go!
• The Moon is New on Saturday.
• The Sun currently has 13 active regions and the sunspot number is 177.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 17th March

• Astronomical twilight ends at 20:08 GMT at the start of the week and at 20:20 GMT by the end of the week.
• The Vernal Equinox is at 09:01 GMT on Thursday. This is when the Sun will cross the celestial equator heading north, day and night will be equal length, and here in the northern hemisphere we celebrate the start of astronomical spring. Happy Equinox!
• Venus (-4.2) is approaching the Sun, reaching inferior conjunction on Sunday. It will pass over the top of the Sun, so no transit this time. Take great care if trying to spot the planet so close to the Sun.
• Jupiter (-2.2) remains well placed in our evening sky, not setting until 01:24 GMT. Mars (+0.1) remains visible, culminating at 19:51 GMT, but is shrinking in apparent size as we move away from the red planet.
• With the waning Moon, go galaxy hunting in Leo this week and seek out a plethora of Messier objects. Start with M95 (+9.7), M96 (+9.3) and M105 (+9.3) below the middle of the Lion’s body, before moving on to the tail end and the Leo Triplet, consisting of M65 (+9.3), M66 (+8.9) and NGC 3628 (+9.5). You will need a telescope to find these faint fuzzies, which all lie around 30 to 40 million light years away.
• The Moon is Last Quarter on Saturday.
• The Sun currently has 13 active regions and the sunspot number is 185.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 10th March

• Astronomical twilight ends at 19:55 GMT at the start of the week and at 20:06 GMT by the end of the week.
• There is a Total Lunar Eclipse on Friday; unfortunately the Moon will not be fully eclipsed before it sets as seen from Marlborough. The penumbral eclipse starts at 03:57 GMT, and umbral eclipse at 05:09 GMT. Total eclipse starts at 06:26 GMT, which is a few minutes after the Moon has set. Look to the West to spot the reddening Moon.
• Venus (-4.3), Mercury (+0.4), Jupiter (-2.2), and Mars (0.0) remain visible in our evening sky. Use a telescope to find Uranus (+5.8) in the southwest about 19° to the west of Jupiter.
• Jupiter (-2.2) has two good evening GRS transits this week, the first is on Wednesday starting at 20:01 GMT, and the second is on Friday at 21:40 GMT.
• The Moon is Full on Friday – the Worm Moon.
• The Sun currently has 5 active regions and the sunspot number is 90.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 3rd March

• Astronomical twilight ends at 19:42 GMT at the start of the week and at 19:53 GMT by the end of the week.
• Mercury (-0.2) reaches Greatest Eastern Elongation on Saturday, meaning that it will be at its greatest apparent separation from the Sun, putting it in the best place for observation just after sunset. It will be about 6° below and to the east of Venus (-4.4).
• Three bright planets continue to be well placed for observation: Venus (-4.4) in the west, Jupiter (-2.3) in the south, and Mars (-0.1) in the southeast.
• Spend some time this week in Ursa Major with your telescope searching for ‘faint fuzzy blobs’, better known as galaxies. Start just above the Great Bear’s head with M81, Bode’s Galaxy (+6.9) and M82, the Cigar Galaxy (+8.4), both around 12 million light years from Earth. Then move to the end of the Bear’s tail to find M51, the Whirlpool Galaxy (+8.4) with its partner M51b, the pair are about 28 million light years from Earth.
• The Moon is First Quarter on Thursday.
• The Sun currently has 7 active regions and the sunspot number is 105.
• There are no visible evening ISS passes this week (click here for full ISS pass details).