Stephen Tonkin’s Binocular Tour

A double double and a tricky trio of galaxies in Leo are among this month’s highlights

Tick the box when you’ve seen each one

1 MELOTTE 111

Let’s start our tour with one of the finest celestial sights for binoculars, Melotte 111. It extends for nearly 6° and fills the view of small and medium binoculars. You can see it with your naked eye as a misty patch between Cor Caroli (Alpha (_) Canum Venaticorum) and Denebola (Beta (`) Leonis). Gamma Comae Berenices is at the apex of an inverted ‘V’ of the cluster’s brighter stars. Melotte 111 is unusual in having no stars fainter than mag. +10.5. SEEN IT

2 28 & 29 COMAE AND STRUVE 1678

5° northwest of Vindemiatrix (Epsilon (¡) Virginis) is a pair of white stars separated by half a degree and orientated approximately north-south. The fainter, southerly one is 28 Comae, the brightest of a little parallelogram of stars. 29 is the brightest of a triple star group. Its brighter (mag. +8.6) companion is 5 arcminutes back towards 28 and the fainter (mag. +9.9) one is an arcminute closer, an easy split if your sky lets you see stars that faint. Also visible, a degree to the west of 29, is Struve 1678, a slightly harder split at 38 arcseconds. SEEN IT

3 M49

Our first galaxy is an elliptical radio galaxy, M49. If you locate Rho Virginis (mag. +4.9) and place it on the northeast of your field of view, on the opposite side you should find a pair of 6th magnitude stars, just over a degree apart and orientated southeastnorthwest. M49 is a small (9 x 7.5 arcminutes), slightly oval patch of light between these two stars, very slightly nearer the more southerly one. Using averted vision, you can see lots of galaxies in this region of sky, mostly in the direction of Melotte 111. SEEN IT

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Did you know that Leo has ‘double double’? If you extend a line from Zania

Virginis) to Zavijah (Beta (`) Virginis) a further 6°, mag. + 4.9 Tau Leonis is the brightest star in the field of view. A third of a degree northwest is its mag. +6.5 companion, 83 Leonis. Look carefully and you’ll see that each of these is a double star with a mag. +7.5 companion. SEEN IT

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You may need to wait until Leo is high in the southern sky before you can observe our second galactic target, a trio of galaxies that is a challenge in anything other than a dark, very transparent sky. If you put mag. +3.3 Chort (Theta

Leonis) just outside the northwest of the field of view of 15 70 binoculars, the galaxies will be in the centre. You may need averted vision at first, but they soon become easier to see, although you will still need averted vision to discern the different shape of NGC 3628. SEEN IT

6 /(2 5(*,21

Locate the orange-yellow mag. +5.6 86 Leonis between Denebola (Beta (`) Leonis) and Zosma (Delta Leonis), and compare its colour to hot blue-white 90 Leonis 2° back towards Denebola. Return your attention to 86, and note the curved string of 7th and 8th magnitude stars extending 3° eastward. The nearest one to 86 is FV Leonis, an orange, long-period variable star; the most distant is blue-white FW Leonis, whose brightness variation is too tiny to be visible in binoculars. SEEN IT