Binocular tour

If January does bring rain, as least you can get an exquisite view of the Orion Nebula

Tick the box when you’ve seen each one

1 COLLINDER 70

10x Our first object this month is Collinder 70, 50 the cluster that nearly everybody has seen and yet almost nobody recognises: it’s the cluster that includes the belt stars of Orion. On a clear night, you should be able to see 70-80 stars, some forming beautiful curving chains, in this magnificent oval cluster. They’re mostly blue-white stars, with a few yellow ones here and there. They form lots of pairs and some beautiful curved chains, in particular the S-shaped chain of brighter stars that weaves its way between Alnilam (Epsilon (¡) Orionis) and Mintaka (Delta Orionis). SEEN IT

2 SIGMA ORIONIS

10x Sigma Orionis is visible to the naked 50 eye as a mag. +3.8 star about 1º to the southeast of mag. +1.9 Alnitak (Zeta Orionis), the easternmost star of Orion’s Belt. It is in fact a multiple star consisting of five components, four of which can be seen visually. You should easily be able to split it into two components

with 10 50 binoculars and see the blue star that is 43 arcseconds from the white primary, but you will need double the magnification to resolve the next two components. SEEN IT

3 THE ORION NEBULA

10x The Orion Nebula, M42, is a highlight of 50 the winter skies and a superb object in binoculars of any size. It’s visible to the naked eye as the central star of Orion’s sword. Although it’s bright enough to be visible in quite poor conditions, it’s sensitive to sky transparency and is usually best observed after rain has cleaned the sky of dust, when you should easily make out the ‘fish’s mouth’ and the ‘wings’. M42 benefits from patience; the longer you look at it, the more detail you’ll be able to see. SEEN IT

4 HIND’S CRIMSON STAR

15x Hind’s Crimson Star, or R Leporis, is the 70 reddest star in the heavens. It’s a Miratype variable with a period of 457 days, and is near its maximum, so should be easily visible

5 GAMMA LEPORIS

10x Gamma Leporis is visible to the naked 50 eye at mag. +3.6. This is a double star, with the fainter (mag. +6.1) component an easy split in binoculars, being just over 1.5 arcminutes to the north. This pair of stars is only 29 lightyears away and the primary three times as bright as the Sun. The fainter companion, AK Leporis, is more interesting from an astrophysical point of view: it’s a BY Draconistype of variable star, the magnitude of which varies with a period of about 17 days as star spots rotate across its surface. SEEN IT

6 M41

10x M41 is 4° south of Sirius (Alpha (_) Canis 50 Majoris). This open cluster is bright enough to be visible to the naked eye in a transparent sky, and has been known since antiquity. It’s large enough to be an obvious cluster of stars in 10 50 binoculars. From a rural site, you should be able to resolve up to 10 brighter stars against the background glow of fainter stars if you use averted vision. If the sky is clear enough, you may be able to detect that the stars differ in colour, with the brightest one, near the centre, being yellowish. SEEN IT