Here is the transcript for my podcast about how to see the
the Alpha Persei Assocation, open cluster M103, and spiral galaxy IC 342.
Check out the Astronomy.com's interactive star chart to see an accurate map of your sky. It'll help you locate some of this week's key targets. Astronomy magazine subscribers have access to a slew of cool functions with StarDome PLUS.
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Hello, I’m Astronomy magazine Senior Editor Michael Bakich. Each week, I highlight three different night-sky targets for you to see:
- One object you can find without optical aid or through binoculars
- One object to find with a small telescope
- One deep-sky object to find with an 8-inch or larger telescope for you avid astronomers
Lots of bright stars
This week’s naked-eye object is the Alpha Persei Association. As the name implies, this brilliant stellar group surrounds the star Mirfak (Alpha [α] Persei). Another name for this famous cluster is Melotte 20.
This large, scattered group of bright stars appears obvious to the naked eye. I point that out because it lies some 600 light-years away in the rich star fields along our galactic plane.
For the best view of Melotte 20, try binoculars or a rich-field telescope. Keep the magnification under 20x. Even at such low power, you’ll see 50 bright stars — most prominent magnitude 1.8 Alpha and magnitude 4.3 Psi (ψ) Persei — mainly to the south and east of Alpha.
All told, more than 100 young stars brighter than magnitude 12 spread across the association’s 3° width. The group’s total magnitude is an impressive 1.2.
A lesser-known Messier object
This week’s small telescope target is M103. This magnitude 7.4 open cluster is really easy to find. It lies 1° east-northeast of magnitude 2.7 Delta (δ) Cassiopeiae.
M103 isn’t a spectacular cluster, but its 40 bright stars stand out well from the rich fields of the Milky Way. Cluster members range from 8th through 13th magnitude and group tightly in a triangle 5' on a side. Most observers report the best views when they use a magnification around 100x.
By any other name
This week’s deep-sky object is IC 342. Many of you are familiar with the NGC catalog. The Index Catalog (abbreviated IC) actually is an extension of the NGC. English astronomer John Louis Emil Dreyer completed the NGC in 1888. It contains some 7,840 objects.
In 1895 and 1908, he added two appendices to the NGC that he called the First and Second Index Catalogs of Nebulae and Star Clusters. Entries are the same deep-sky object types, but with a different catalog designation.
IC 342 lies in the far-northern and ultra-faint constellation Camelopardalis the Giraffe. The galaxy sits 3.2° due south of the magnitude 4.6 star Gamma (γ) Camelopardalis.
As it stands, IC 342 is a magnitude 8.4 galaxy. But it would be truly spectacular if intervening Milky Way dust and gas didn’t dim it by more than 2 magnitudes.
Visually, IC 342 appears 20' across, but, even at its magnitude, it’s not easy to see because its surface brightness is low. Look for a bright central knot about 30" across in a rich star field. Surrounding this is a fainter halo 2' across, while an extremely faint, knotty structure extends over a diameter of 20'.
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