NGC 2477/2451 [credit: European Southern Observatory/J.Perez]
Canis Major-Puppis grouping of Collinder/NGC objects.
Telescope: Takahashi FCT-76
Location: Cedar Park, Texas, USA
Time: 8 pm – 9 pm
Sky Transparency: 6
Limiting Magnitude: ~ 3.5
Lunar Phase: Full Moon
Under a Full Moon, just about the only deep-sky objects worth viewing are the large, bright open clusters [or double stars]. One of my favorite star hops of such clusters is the Canis Major-Puppis grouping of Collinder/NGC objects. Using a wide-field telescope capable of producing 3°+ views, most of these open clusters are easily distinguishable from the starry field in which they lie. The only eyepiece used for this observing session was a 31mm Nagler 5 [4.9° @ 16x].
- Cr 121 – This cluster is in the midsection of Canis Major and has ~ 25 stars [under Moonlight polluted skies] of very uneven symmetry. The central star is yellow white.
- Cr 132 – Huge and covering almost 2.5° of the sky, I can see ~ 28 stars spread out very diffusely into the surrounding field. There’s a nice double over halfway out from the center that looks to be a mild yellow primary with a fainter white companion.
- Cr 140 – There are ~ 24 stars, the brightest of which form a semi-coathanger type asterism.
- Cr 135 – This one’s rather diffuse and has ~ 25 stars. The brightest star is yellow-white.
- NGC 2477 – Non-evident under the current seeing conditions. On a dark night from suburbia I can barely make out a few of the cluster’s stars; however, under dark skies the cluster is round with many stars resolved across its small diameter. You get a beautiful open star cluster combination when you use a wide-field eyepiece that shows both NGC 2477 and NGC 2451 in the same field [see photo above].
- NGC 2451 – There’s a bright yellow-orange star at the center of this large, almost evenly spread out cluster of ~ 30 stars with mild central concentration.
- NGC 2546 – Most of the stars here are faint and without much concentration [this cluster looks better under very dark skies]. Still, there are many bright field stars nearby that make this cluster’s region worth looking at.