This month we seek out the celestial highlights in Auriga and Perseus
1. IC 2149
Recommended equipment: Small/medium or Large telescope
Our first target is IC 2149 in Auriga, 1.3° north-northwest of Menkalinan (Beta (β) Aurigae), its declination being similar to mag. +4.3 Pi (π) Aurigae, 39 arcminutes to the east. Centre on Pi and drift west by 39 arcminutes to bring IC 2149 into view. IC 2149 is a mag. +10.6 blue-hued planetary nebula that, given its 12-arcsecond diameter, is easily mistaken for a star at low power. Magnifications above 120x show a slightly elongated shape. Its mag. +11.3 central star dominates the view when viewed directly, but with averted vision its elongated nebula appears. An OIII filter helps reveal the nebula with direct vision, radically dimming the central star and keeping the nebula bright.
2. NGC 1857
Recommended equipment: Small/medium or Large telescope
Next up, an open cluster within the misshapen pentagon of Auriga, 9.2° southwest of Menkalinan and 0.8° south and a fraction east of mag. +4.7 Lambda (λ) Aurigae. NGC 1857 is an interesting cluster dominated by bright orange HD 34545, a mag. +7.4 foreground star 1,500 lightyears away. By contrast NGC 1857 is 18,700 lightyears distant. The cluster can be tricky and a magnification of 100x or more is recommended. A 150mm scope shows about 25 members. A 250mm instrument reveals around 40 stars in an area approximately 10 arcminutes across. A number of ‘star-chains’ are visible, more prevalent in the south to southwest part of the cluster.
3. NGC 1664
Recommended equipment: Small/medium or Large telescope
Open cluster NGC 1664 is outside of the Auriga ‘pentagon’, lying 7° northwest of NGC 1857. An easier way to locate it is to first identify 3rd-magnitude Almaaz (Epsilon (ε) Aurigae) and drift 1.9° west of this star. NGC 1664 is a lovely cluster showing over 30 stars through a 150mm instrument, a number that doubles through a 250mm scope. With a magnitude of +7.2 and a diameter around 18 arcminutes, it’s rewarding despite the rich stellar background against which it’s located. Its stand-out feature is an extensive asterism of mostly 10th-magnitude stars at its core that resembles a kite: a small diamond panel and long, dangling tail. For this reason NGC 1664 is sometimes referred to as the Kite Cluster.
4. NGC 1582
Recommended equipment: Small/medium or Large telescope
We can use the equatorial drift trick to locate our next target, another open cluster, NGC 1852, 3.5° due west of NGC 1664. In this position we’ve left Auriga and are now within Perseus. NGC 1852 is listed as having a magnitude of +7.0 and diameter of 37 arcminutes, but despite these impressive statistics it can be tricky to locate, being sparse and very open. The most obvious features are two loose star arcs of similar lengths that appear to contain several dark, almost starless regions. Due to its sprawling nature, we recommend using a relatively low power here, say 30x or 40x. Go much higher and you’ll probably ‘see through’ the cluster.
5. NGC 1513
Recommended equipment: Small/medium or Large telescope
This mag. +8.4, 10-arcminute cluster sits 6.8° north-northwest of NGC 1582 within a hooked region of Perseus formed by Delta (δ), 48, Mu (μ), b and Lambda (λ) Persei, all naked-eye stars. Perseus has a curious shape, a bit like a lower-case Pi (π) with extended arms. The hook forms the eastern arm and represents the Greek hero’s knee. A hazy patch through smaller instruments, with a 150mm scope around 10 stars are revealed to the south of mag. +9.5 TYC 336-0044-1. With a 300mm scope the count goes up to 30 stars. Look out for the dark teardrop region lined by dim stars immediately south of TYC 336-0044-1.
6. NGC 1545
Recommended equipment: Small/medium or Large telescope
Our final target is another open cluster, NGC 1545. Mag. +6.2 and 12 arcminutes across, it lies 1.9° east-northeast of NGC 1513, 26 arcminutes due east of mag. +4.6 b Persei. b Persei is an interesting star in its own right, a spectroscopic triple, 320 lightyears from Earth. The companions to the A-type giant primary have orbital periods of 1.53 days and 702 days. The three main stars at the core of NGC 1545 give the distinct appearance of a southwest-pointing arrowhead. A 250mm scope reveals a loose collection of around 40–50 stars scattered across a 0.5° circle.
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