This month’s highlights include stunning globular M3 and the Black Eye Galaxy, M64
1. Berenice’s Hair (Melotte 111)
Recommended equipment: 10×50
Look at a point midway between mag. +2.9 Cor Caroli (Alpha (α )Canem Venaticorum) and mag. +2.1 Denebola (Beta (β) Leonis) to see a misty patch of sky about 6° across. 10×50 binoculars will reveal 30 or so stars. Nearly 2.5° south of mag. +4.3 Gamma Comae, is the mag. +5.3 double star 17 Comae, whose white mag. +6.6 companion, 145 arcseconds away, is easy to split in binoculars.
2. Black Eye Galaxy, M64
Recommended equipment: 15×70
You’ll need a transparent moonless sky for this mag. +8.5 galaxy which, owing to its high surface brightness, is easy to see in such conditions. Look 1° east-northeast of mag. +5.0 35 Comae, where it appears as a small oval glow, whose long axis is about a quarter of the Moon’s apparent diameter. Binoculars won’t show the dark dust lane that gives it its name, the Black Eye Galaxy.
3. 32 Comae and 33 Comae
Recommended equipment: 10x 50
A little more than 2.5° west of Diadem (Alpha (α) Comae Berenices) is an equally spaced line of three stars that spans 3° of sky. The middle star of the three is our second double star of the tour. Like 17 Comae, it is an easy split at 196 arcseconds, but is slightly fainter, with the two stars shining at mag. +6.3 and mag. +6.9. Can you detect any colour difference in this pair?
4. M3
Recommended equipment: 10×50
Our next target is one of the best globular clusters in the northern sky. There are no nearby bright stars to act as pointers, but if you look in the middle of a line from mag. +3.0 Seginus (Gamma (γ) Boötis) to mag. +4.4 Diadem (Alpha (α) Comae Berenices), you should find what looks like a severely defocused star in the field of view. This is the glow of the half-million stars that comprise the globular cluster M3.
5. RV Boötis 1
Recommended equipment: 0x50
You’ll find the red variable star. RV Boötis a little more than 2.5° northeast of mag. +3.6 Rho (ρ) Boötis, in between two mag. +6.3 stars that are the brightest stars in the field of view. RV Boo is a semi-regular variable with a period of 288 days. Its magnitude supposedly varies from mag. +7.2 to +9.8, but recently it has only been falling to mag. +8.7, so it remains well within binocular capability.
6. Upgren 1
Recommended equipment: 15×70
Return to the line between Cor Caroli and Chara and imagine it as being one side of an equilateral triangle, with the third apex to the southwest. Just inside this third apex, slightly closer to Cor Caroli, you should see a group of six 7th to 9th magnitude stars spanning about 0.25°. This sole member of the Upgren catalogue is a pretty object.