Stephen Tonkin’s Binocular Tour

A hockey stick, an ice giant and tricky triple are waiting to be discovered round the Triangle

Tick the box when you’ve seen each one

1 M34 10x 50

Let’s kick off with a cluster that’s a delight in binoculars of any size. You will find M34 5° (about one field of view in 10x50s) from Algol (Beta (`) Persei) in the direction of star Almaak (Gamma (y) Andromedae); you are looking for a fuzzy patch with a similar apparent size to the Moon. Your 10x50s should show 12 or more stars, the brightest of which form a wonky ‘H’-shape. You are looking at starlight that left this 220 million year-old, 14 lightyear wide cluster about 1,400 years ago.

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2 NGC 752 AND 56 ANDROMEDAE 10x 50

Locate Beta (`) Trianguli and place it at the bottom of the field of view, and NGC 752 should appear near the top, just to the left of a close pair of 6th magnitude deep yellow stars (56 Andromedae). Rising from them is a 1.6° long chain of slightly fainter stars; together with 56 And, they make the Hockey Stick, with NGC 752 as a somewhat oversized ball. It’s twice the diameter of M34 and you should be able to resolve several yellowish stars. Yellow stars are unusual for an open cluster.

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3 M33 10x 50

You’re going to need a transparent sky and dark-adapted eyes for our next object, the galaxy M33, which is 4° from Metallah (Alpha (_) Trianguli) in the direction of Mirach (Beta (`) Andromedae). It is face-on to us and its light is spread out over an area of sky even larger than NGC 752, so all you will see is an ethereal glow. Although its magnitude is given as +5.5, this is an integrated magnitude and it has a very low surface brightness, making it difficult to distinguish if there is any skyglow.

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4 14 ARIETIS 15x 70

2.5° north of Hamal (Alpha ( (a) ) Arietis), in the direction of Gamma (y) Trianguli, lies the triple star, 14 Arietis. The brighter two members (magnitudes +5.0 and +8.0) are easy and separated by 108 arcseconds. The third is why we’ve switched to larger binoculars: it’s easy to split – if you can see it. It is only mag. +10.9, so a real challenge for 15x70 binoculars, even on a very dark night. The primary star seems to be part of an astrometric binary system, meaning that it has a massive invisible companion, probably a neutron star, that it orbits.

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5 PSILj PISCIUM 10x 50

Psi1 (s1) Piscium is in the northern extreme of Pisces, 1.5° from Chi (x) Piscium in the direction of Eta (n) Andromedae. It is a delightful double star with two brilliant white members of similar brightness (mag. +5.33 and mag. +5.55) separated by 30 arcseconds. It is a good test of your optics and the steadiness with which you hold the binoculars. If you find it difficult to split, make sure that your focus is perfect and try mounting the binoculars.

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6 URANUS 10x 50

At mag. +5.7 Uranus is nominally a naked-eye object, but in practice in Britain, that’s rare. However, even small binoculars make the planet spottable. Identify Omicron (o) Piscium and pan about 3.5° east-northeast where Uranus is easily the brightest object in the area. During October it moves 1.25° westward. To be sure of your identification, observe it on several nights and sketch its position in relation to other stars: if it moves, it’s Uranus.

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