CAS Sky Notes for May 2026
By the end of this month, astronomical twilight will last all night, the northern skies will never be dark enough for deep sky photography. Andromeda will be low on the horizon and the double cluster a fairly difficult object. Unless very bright, aurorae will be unlikely to be visible for a while now
Planets:
Mercury.
Mercury passes through superior conjunction on the 14th and then becomes an evening object. By the end of the month it may be visible in the twilight after sunset, but is at its best next month.
Venus
Venus is now an easier evening object and increasing its elongation from the Sun throughout the month, reaching nearly 30o by the end of May. It The disc diameter is still only 13 arcsec but the phase decreases to 80% by the end of the month.
Mars
Mars reached conjunction in January and is still not observable this month, or for quite a few months yet.
Jupiter
Jupiter is past its best now now, but is still fairly well placed for observation after sunset in mid evening, high in the western sky. It is still a very prominent object in Gemini, just below the twin stars of Castor and Pollux. It is very well placed for observing and gets very high in the sky, meaning it avoids a lot of the atmospheric turbulence lower down. I recommend the website https://shallowsky.com/jupiter which shows you the position of the Galilean moons and the Great Red Spot at any time you pick.
Saturn
Saturn reached conjunction with the Sun last March and is still not observable this month.
Uranus
Uranus is now a difficult object this month. It lies in Taurus, a little below the Pleiades and sets by 9pm (21:00)UT. Its coordinates: RA 03h 46m , Dec +19.7o, and magnitude +5.7.
Neptune
Neptune is not observable this month as it is too close to the Sun
Moon Phases:
| 1st May: Full Moon | 9th May: Last Quarter |
| 16th May: New Moon | 23rd May: First Quarter |
Meteor Showers
There are no major meteor showers this month
Sun
The Sun is now high in the sky now and we remain near solar maximum, so watch out for major sunspots and sunspot groups. Remember to never look at the Sun directly without a proper solar filter.
Aurora
Aurora may still be visible this month although the northern skies are probably becoming too light for all but the brightest aurorae to be visible.
Deep Sky Objects
The light evenings make deep sky observing difficult now, although the Milky Way will start to be more visible late in the night.
The Whirlpool Galaxy (M51), below Ursa Major, as well as the Pinwheel galaxy (M101) just above the handle of the Plough are now very well placed high in the sky. The M13 globular cluster in Hercules is also now well placed and a good object for binoculars, small telescopes or astrophotography.
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Neil Havard.
Any questions or for more information, contact Neil at coordassist@cotswoldas.org.uk