May 2021
Discovered by Pierre Mechain on March 22nd, 1781, Charles Messier observed the galaxy two days later. Comparing it to the globular cluster M79 in Lepus, he wrote “it is brilliant in the center and the nebulosity is a little diffuse.”
It’s this bright center that will be most apparent through a telescope, with Messier’s comparison to M79 proving to be an accurate one. The galaxy has a large and circular core which almost appears to reach the edge of the galaxy. Look out for an oval halo that shows some mottling in larger scopes.
Image credit: Bart Delsaert
Mercury makes a welcome return to the evening sky and will be at its best around the middle of the month. Look out for the crescent Moon within the same binocular field of view on the 13th. Venus is also now emerging into the evening twilight, with the 1 day old crescent Moon close by on the 12th. Mars moves through Gemini in May, while first Jupiter and then Saturn rise and shine in the predawn twilight. Both should be visible for at least an hour before sunrise throughout the month with the Moon passing between them from the 3rd to the 5th. Uranus is most likely still too close to the Sun to be observable but you might be able to glimpse Neptune before the dawn sky brightens by the end of the month. Lastly, the Moon turns new on the 11th and then full on the 26th.
Image credit: Pedro Alberni
Often overlooked, the Eta Aquariid meteor shower can produce up to 40 shooting stars an hour under ideal conditions. With bright but fast meteors, this shower peaks in the early hours of May 5th, with a waning crescent Moon nearby.
Image credit: NASA, ESA, STScI, and A. Sarajedini (University of Florida)
A showcase globular, you can spot it with binoculars in Canes Venatici, on the border with Bootes. This particular cluster, like M13, is a fine sight in almost any sized scope.
Image credit: Ken Crawford
One of the best edge-on galaxies in the night sky, you’ll need a medium-sized scope to spot it. Look just a little under two degrees to the east of 17 Comae Berenices.
Image credit: Gary Fildes
Possibly the easiest and one of the most famous double stars in the sky, Mizar & Alcor are a relatively easy sight for naked-eye observers. A telescope at low power will split Mizar itself.
Eye Relief: This is the greatest distance from an eyepiece that a user can see the entire field of view. For example, a good binocular will have an eye relief of around 20mm; in other words, you should be able to hold the binoculars 20mm from your eyes and still be able to clearly see everything through the eyepiece. Eye relief is very important to wearers of eyeglasses.