Here is the transcript for my podcast about how to see
the extinct constellation Musca Borealis the Northern Fly, open cluster Collinder 464, and spiral galaxy NGC 2403.
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.
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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A swatted fly
This week’s naked-eye object is the extinct constellation Musca Borealis the Northern Fly. Dutch mapmaker Petrus Plancius (1552–1622) introduced this constellation around 1614 under the name Apes. He formed it from four stars — 33, 35, 39, and 41 Arietis — in the present-day constellation Aries the Ram.
To find these stars, look about 9° east-northeast of Aries’ brightest star Hamal (Alpha [α] Arietis). And although I do rate this as a naked-eye object from a dark site, be forewarned: The brightest of these stars, 41 Arietis, shines at only magnitude 3.6, and the faintest, 39 Ari, glows at magnitude 5.3. If you have any trouble seeing the group, use binoculars. The Northern Fly spans only 2.5°.
Sweet little cluster
This week’s small telescope target is Collinder 464 (Cr 464) in Camelopardalis. You’ll spot it roughly 7° north-northeast of magnitude 4.3 Alpha Camelopardalis.
I hesitate to use that star as a guide because it’s actually fainter than the magnitude 4 cluster. Unfortunately, Alpha Cam is the only reasonably bright nearby star. If you’re into geometrical figures, Cr 464 makes an equilateral triangle with Alpha Cam and magnitude 4.6 Gamma Cam.
Cr 464 is a large cluster that spans 2°. The stars appear scattered, with the eastern and western sides sharply divided. The west section contains the brightest stars, with five brighter than magnitude 6.5. The five brightest stars in the east half range from magnitudes 6.2 to 7.3. Binoculars reveal the cluster, but I prefer a telescope with a magnification between 25x and 50x to really plumb Cr 464’s depths.
Spectacular spiral
This week’s deep-sky object is spiral galaxy NGC 2403, which also lies in the constellation Camelopardalis. NGC 2403 is one of the sky’s brightest galaxies, shining with a magnitude of 8.2. It’s large, however, so that brightness spreads over an area defined by the galaxy’s 23' by 12' dimensions. That size, by the way, makes NGC 2403 30 percent as large as the Full Moon.
Small telescopes show this object as an indistinct haze roughly twice as long as wide, with a bright central region. Through a 12-inch scope, you’ll begin to see the galaxy’s spiral arms, but you’ll need an even larger instrument to trace them all the way back to the nucleus.
Look for stellar associations in NGC 2403’s spiral arms. Associations are a type of star cluster resembling open clusters but larger and holding only up to about 100 stars. The presence of these clusters indicates star formation is ongoing within this galaxy.
Plan to spend a lot of time observing NGC 2403. It’s one of the sky’s most spectacular wonders.
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Previous episode: planet Mercury, the star Rigel, and globular cluster M79
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