Locate this month’s selection of wide-field targets in and around Orion, the Hunter
1. The Stream
Recommended equipment: 10×50
Follow a line from Mintaka (Delta (δ) Orionis) through Rigel (Beta (β) Orionis) the same distance further on, to the most northerly of a colourful string of mostly 5th and 6th magnitude stars running down to the southwest. Note the colour gradation from orange 60 Eridani at the top of the chain, through yellow 59 and 58 Eridani, down to a fainter white star – then an abrupt change to the reddish 54 Eridani at the end.
2. Orion’s Pelt
Recommended equipment: 10×50
The Pi (π) Orionis stars were traditionally depicted as an animal hide. They stretch over 9° of sky, so you will have to pan along it to see it all, but it is worth it as binoculars bring out the star colours. They range from white Pi 1 (π ) and Pi (π ) Orionis, through yellow Pi (π ), down to blue Pi (π ) and Pi (π ), which contrasts well with the ruddy 5 Orionis and orange Pi (π ) Orionis.
3. Collinder 70
Recommended equipment: 10×50
Collinder 70 is the cluster nearly everybody has seen, but hardly anyone knows: it is the huge oval-shaped group of mostly blue-white stars surrounding Orion’s Belt. On a clear night, you should be able to see about 70 stars. Can you see the swan whose S-shaped neck weaves its way down between Alnilam (Epsilon (ε) Orionis) and Mintaka, then rises up as it’s wing between Alnilam and Alnitak (Zeta (ζ) Orionis)?
4. M42
Recommended equipment: 15×70
You can see the Orion Nebula, M42, with your naked eye as the central ‘star’ of Orion’s Sword. Although it is a lovely object in binoculars of any size, especially in a dark transparent sky, use the biggest you have to help you tease out more detail. This showpiece of the winter skies is a star-forming region about 12 lightyears across and it will reveal more of itself the longer you gaze at it.
5. NGC 2232
Recommended equipment: 10×50
Start at Beta (β) Monocerotis, and navigate a little more than 2° north of it to a small fuzzy patch, that you may be able to see without binoculars. Binoculars reveal two distinct wedgeshaped groups of stars, with the two brightest stars (10 Monocerotis and 9 Monocerotis), each at the tip of a wedge. On a good night you should be able to count about 20 stars in 10x50s.
6. The 37 Cluster
Recommended equipment: 15×70
Take a line from Alnitak to Betelgeuse (Alpha (α) Orionis) and extend it 8° northwards to a pair of white stars, Nu (ν) and Xi (ξ) Orionis. Go back ½° towards Betelgeuse and you will find a rectangular cluster of stars, NGC 2169, with a void in the middle. If you mount them, 15×70 binoculars will show you that the brighter stars make a number ‘37’.