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Constellation
Report |
| Our Constellation report is an easy way for people to
become familiar with the nighttime sky. We’ll discuss myths associated
with the various constellations as well as describing the numerous deep
sky objects residing in the area. No equipment is required to view the
constellations, though a star chart can be quite helpful. This ease of
observing makes constellations a natural place to begin your journey to
the stars.
 This weekend we move on to the constellation
Puppis
the Stern.
This constellation is actually part of the much larger historical constellation - Argo Navis. Given the size of this ancient naval vessel, astronomers divided it up into three modern constellations. Puppis, the Stern; Carina, the Keel; and Vela, the Sail. To see the entirety of this huge ancient ship requires a trip to the south...almost to the equator!
Anyway.... the northern portions of Puppis should be easy to spot from middle northern latitudes.
To find it, look east of the tail of the big dog Canis
Major, which we visited last week.
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Deep
Sky Report
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Puppis is home to a few very interesting stars.
First up is Zeta Puppis mag2.25. This super giant star is one of the most
luminous known in our galaxy. It is located about 2400 light years away and it's
actual luminosity is about 60,000 times brighter than our Sun!
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 First up is
the Open Star Cluster M46(mag6.2). This is a very rich star cluster with upwards of 500 members. Of these, perhaps 150 are visible to
viewers in small telescopes. The cluster spans about 27', which translates into
about 30 light years in diameter. Best estimates place the cluster's distance
around 5,400 light years.
As you look at this image, you'll immediately take note of the bluish object
near the center. This interesting little object is planetary nebula NGC2438
(mag10). While it appears within the borders of M46 it is most likely not a true
member... just superimposed in that location. Astronomers estimate the nebula to be about 3000 light years distant.
This image was taken by Utah Skies own
Don Brown on 2/4/05 from a
campsite at Gooseberry Mesa in southern Utah. Don was shooting through a
Takahashi
FS/102 refractor at prime focus with a Canon 20D digital camera. Guiding
was handled via an SBIG STV.
To find M46 & NGC2438, travel about 15°(a fist & two fingers) east of Sirius.
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 Since it is such a beauty, I figured a close-up of
Planetary Nebula NGC2438(10.1) was in order. This object is fairly small, but should be within reach of telescopes in the 4-6" range. Many readers will instantly note the similarity to
M57, The Ring
Nebula. The shape is quite similar....even the star visible in the middle of the nebula is reminiscent of The Ring. The most interesting aspect of this image (to me anyway:) is the wide angle view. Seeing multiple objects in one field of view is always exciting. M81&M82... The Trio in Leo. These are some of my favorite deep sky objects. But... to see two different types of objects together like this is really cool! You'll see a "fuzzy" star mixed in with the others. Pumping up the magnification will turn the fuzz into a planetary nebula. Once you've decided to focus on the nebula, you might want to try a nebula filter.
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 Next up is another beautiful
Open Star Cluster, M47 mag(4.4)Click here to view a star chart! This is a big, bright cluster which can be glimpsed with the naked eye under dark skies. It is a loose cluster made up of a handful bright stars. Total cluster membership is about 50 stars.
With an estimated distance of about 1,600 light years and an apparent diameter of about the same size as the full moon, 30 arc minutes. This cluster physically spans an area 12 light years in diameter. One of the first things you'll notice is that this cluster resembles
The
Pleiades. It has several dominating stars surrounded by an bunch of lesser stars. All this is layered against a very rich backdrop of Milky Way stars. The whole view is beautiful.
The bright star nearest to the center of the image is actually a beautiful double Sigma 1121. It is made up of components of mag 7.9 each and a separation of only 7.4 arc seconds. You should be able to split this pair fairly easily. You'll reasonably steady skies and a bit of magnification.
To find M47, move about 1.5° east of M46. While these two star clusters are quite close to each other, they look quite different. M46 appears as a fairly even distribution of similar stars, while M47 is much more loosely spaced and much less evenly matched in brightness.
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 Continuing along, we come to another fine
Open Star Cluster M93(6.2). M93 is a bright, beautiful open clusters. It's stars are grouped in a triangular shape. It contains at least 80 true members. With an apparent diameter of over 22', and an estimated distance of about 3,600 light years, this cluster is believed to have an actual diameter of 20-25 light years.
To find M93, find the star Azmidiske and then travel about 1° or so to the northwest.
This beautiful image was taken by the National Optical Astronomy
Observatories/National Science Foundation
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 Continuing,
we come to yet another beautiful Open Star Cluster NGC2451(mag2.8).
This is another cluster that will immediately remind you of The
Pleiades. It is absolutely spectacular in binoculars... with a handful
of extremely bright stars... including one red star.
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 Let's wrap things up with this weeks
Utah Skies Challenge Object, Open Star Cluster NGC2477(mag5.8)
This just might be the brightest Utah Skies Challenge Objects ever! However, it's extreme southern declination (-38°) will challenge any northern observers. To find this cluster, first find Zeta Puppis and then travel about 2.5° to the northwest.
Or... better yet, if you found NGC2451, travel 1.5° southwest. Regardless,
once you find it, you're in for a treat. At almost the size of a full moon, this beauty will fill your eyepiece from
edge to edge. In fact, given it's size, (and the fact that you should
still have them handy from our previous object) I'd recommend that you try to find it in your binoculars first. In a decent pair of Astro-binoculars, this object is a large "smudge" of light. In a 6" or larger telescope, it's absolutely beautiful. Here
again, aperture rules. By the time you point a big light bucket at this,
you'd better be ready to be overwhelmed by stars. There are reported to be
over 180 stars brighter than about mag10... resolvable by telescopes from
4" and up... and many, many fainter ones.
Good Luck!
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Did you ever consider... |
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"A hypothesis or theory is clear, decisive, and positive, but it is believed by no one but the man who created it. Experimental findings, on the other hand, are messy, inexact things, which are believed by everyone except the man who did that work." - Harlow Shapley (1885-1972) |
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