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Nebulae, Clusters and a Galaxy


Qualia

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Monday 15th December was probably one of the wettest days I have ever witnessed in Spain. It rained and it didn't stop, but by Tuesday morning the skies had cleared and the next few nights turned out to be extremely clear and dark.

During the next three nights, I concentrated predominately around the area of Canis Major and Puppis and although it is both physically and mentally impossible to sketch everything witnessed, I did manage to make a few. 

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Messier 46 is a rich open cluster made up of around 150 stars of magnitude 10 to 13 and with a total population of probably over 500. The brightest stars are spectral type A, and each is about 100 times more luminous than the Sun. M 46 is receding from us around 150,000 km an hour, it has a diameter of about 30 light years, a distance of about 5,400 light years and an age of around 300 million years.

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Within the apparent borders of M 46 is also the planetary nebula, NGC 2438. Measurements have found that it is receding from us at about twice the speed of M 46 and is around 2,900 light years away. This suggests that the nebula is most likely a foreground object, rather than a true member of the cluster. The sketch was made using the magnificent 10" Moonshane, 10mm Delos and to tweak maximum information from the nebula, I used a UHC-S filter.

M47 is a less imposing cluster, containing about 50 stars in a region 12 light years across. Its distance is about 1,600 light years with an estimated age of around 78 million years and is receding from us at about 9 km/sec. The bright star nearest to the left of the sketch is loosely identified as the fine double Sigma 1121. Again, the sketch was made using the 10" Moonshane and a 14mm Delos eyepiece.

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This entire area of the night sky is made up of numerous open clusters, each gorgeous in its own particular fashion. One memorable sight was to align a small, wide-field refractor with M 47 and either M 46, NGC 2423 and its brilliant red giant or NGC 2425 within the field of view, offering views equal to the more gorgeous double cluster in Perseus. Anyone with an eyepiece providing a true field of view of about 2º degrees can do the same.

Moving from M 47 towards Sirius, it’s worth making a detour to observe NGC 2414, 2374 and 2345. These are splendid open clusters, in particular the busy NGC 2360 otherwise known as Caroline’s Cluster.

Between M46 and M93 in the constellation of Puppis is the planetary nebula NGC 2440, about 1.5  light-years across, located some 4,000 light-years away and moving from us at approximately 63 kilometers per second. At 125x magnification in the 10”, NGC 2440 revealed quite a bright inner core and a slightly fainter outer region which was augmented with the use of a UHC filter. For the sketch, I decided to use a x2 TV Barlow, the 14mm Delos along with the 10" Moonshane. Even at this power I was unable to discern the bow tie-shape of the nebula depicted in astro-photos. 

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A few degrees southwest of M93 is the curious star forming region catalogued as NGC 2467, or more romantically termed, The Skull and Crossbones Nebula. Although star atlases typically refer to this object as an open cluster with a nebula embedded within it, in fact NGC 2467 does not represent a distinct open cluster. Rather, it appears to be a superimposition of several stellar groups along the same line of sight that have distinct distances and radial velocities. The star which dominates the central area of the emission nebula has been identified as HD 64315, a massive young star of spectral type O.

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With the 10" and 14mm Delos, the entire region is ablaze with stars and it is a stunningly beautiful area to observe. Indeed, it was so complex that I decided just to concentrate on the more prominent stars and leave a more detailed sketch for another night. It is certainly an area I must return to. NGC 2467 is a few million years old at most, located some 13,000 to 17,000 light-years from Earth and moving away from us at about 56km per second. It is an extremely active stellar nursery, looking like a cosmic finger smudge in the 10” embedded with the glow of new born stars.

The report could continue but to round things off for now, I also include a little sketch of a spiral galaxy in Lepus, NGC 1744 and a sketch of the Rosette Nebula with NGC 2244 with its associated open cluster. The cluster and nebula lie at a distance of some 5,200 light years from Earth and measures around 130 light years across. The sketch was made using a TV 76 APO which is turning out to be a stunning little telescope, along with a 24mm Panoptic and for the nebula, the use of a UHC filter.

In another report, I'll try to include some of the sketches I've made of the Sun and Jupiter this week. Both of which have put on a stunning display of activity and beauty.

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Great report with some fine sketches in. Thanks for sharing Rob :)

I have been wondering if the rosette is doable with just the naked eye and possibly an O-III filter from a dark sky. Looking forward to giving it a bash this winter coming.

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