Here is the transcript for my podcast about how to see the partial constellation Serpens Caput, M40, and lenticular galaxy M85 this week.
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Each week, I highlight three different night-sky targets for you to see:
- One object you can find with your naked eyes 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
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Heads or tails?
Our first object is part of the sky’s only divided constellation, Serpens the Serpent. It’s split in two because Ophiuchus the Serpent-bearer is carrying the Serpent, so that constellation lies between Serpens’ two parts. In this podcast, I’ll introduce you to the head of the Serpent, which astronomers call Serpens Caput.
Finding the Serpent’s head takes less effort than imagination. First, be sure you can see two bright orange 1st-magnitude stars, Arcturus and Antares, the Alpha (α) stars in the constellations Boötes and Scorpius, respectively.
Then, draw a line between the two stars. Serpens Caput lies north of the halfway point of that line. It continues to the curved constellation Coma Berenices. The brightest star in this region is Serpens’ Alpha star, magnitude 2.6 Unuk al Hai. Head a little less than 5° north of this medium-bright luminary for magnitude 3.8 Delta (δ) Serpentis. Continue north a bit more than 5°, and you’ll encounter magnitude 3.7 Beta (β) Serpentis.
How did this make the list?
I selected this week’s small telescope target from Charles Messier’s famous catalog. Don’t get too excited, though. M40 is the most unusual entry of the 109 deep-sky targets on that list. But unusual doesn’t necessarily mean good. Unfortunately, the object is a widely spaced double star.
The two stars glow faintly at magnitudes 9.0 and 9.6, and the separation is 53" — nearly an arcminute. That means you can split this star through 10-power binoculars or a finder scope, although it will look better through a telescope.
The brighter star, called the primary, appears light-yellow. Its companion, the secondary, is a deep-yellow. Because color perception in human eyes differs from one person to the next, some of you will see the secondary as pale-orange. I know M40 isn’t much, but it is a Messier object, so you have to observe it … well, at least once.
Through a lens brightly
This week’s large telescope object also comes from Messier’s catalog, but it’s a much better target than M40. Lenticular galaxy M85 lies in Coma Berenices and shines at magnitude 9.1, making it one of the sky’s brightest galaxies. Even so, you’ll want to get away from city lights, which hinder galaxy observing more than any other kind of observing.
A lenticular galaxy like M85 has, as the word implies, a lens shape, so it kind of looks like an edge-on spiral. It doesn’t have a spiral galaxy’s arm structure, however. Also, it’s not a place where stars are forming because the nebulae turned into stars millions of years ago.
To find M85, first locate the magnitude 4.7 star 11 Comae Berenices. From there, head 1.2° east-northeast, and you’ll sweep up M85, also known as NGC 4382.
A small scope’s view is disappointing. It shows only a luminous core surrounded by an oval halo. Through an 8-inch telescope, look for a 13th-magnitude star less than 1' north of the core. Use a 12-inch or larger scope, and you’ll see the brightness difference as you move out from M85’s central region. You’ll also start to see a subtle color — yellow. It seems this galaxy mainly contains old yellow stars.
When you’ve had your fill of M85, look just 8' east for the magnitude 10.9 barred spiral galaxy NGC 4394. This galaxy has a bright core, and its bar runs its full length.
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Previous podcast: Lozenge, globular cluster NGC 5694, and spiral galaxy NGC 3521