Tour of Puppis Clusters (3/2/08)

Steve Gottlieb

I've already posted an observing report from Tuesday, 3/4/08, from Lake Sonoma but just two days earlier on Sunday night, I got together with Carter Scholz for another nice outing at Lake Sonoma. Conditions were dry, clear and calm with fair seeing. Open clusters are generally not my favorite targets, but I was in the mood for a change of pace from chasing faint galaxies and planetaries. I figured the winter Milky Way would soon be slipping away to the west and this would be a good opportunity to delve into Puppis one more time this year. The sky at Lake Sonoma has a light dome from Santa Rosa to the south and southeast, but once southern objects pass the meridian and head southwest, they are in a very dark portion of the sky and deep sky objects can be followed to the horizon. I started at the western side of the constellation near Canis Major and worked my way until I reached the east border of the constellation near Hydra --

NGC 2396 07 28.1 -11 44 Size 10'
At 94x, roughly three dozen stars are resolved, mostly mag 11-13.5 with a pale orange mag 8.5 star on the W side. At 175x, roughly 50 stars are resolved in a 10' region. A chain of stars extends a few arcminutes NE from the mag 8.5 star and then abruptly loops due south for the same distance. This chain the curves around making a large oval loop forming the east side of the cluster. Located 10' S of a triple star (ADS 6104) consisting of a mag 8.5 primary with mag 8.5 and 9.5 companions at 20" and 23". The brighter two stars have an orange/blue color contrast. Located in a rich star field so the borders of the cluster are ill-defined. Visible at 25x as a roundish, glowing region just following a mag 8 star in my 80mm finder.

NGC 2401 07 29 24 -13 58.0 Size 2'
At 225x appears as a rich, glowing 1.5' knot with roughly a dozen very faint mag 14-14 stars peppered over the glow. Appears rich with averted but only partially resolved. A mag 7 star (HD 59543) is the field, 7' ESE. Situated in a rich Milky Way star field at 175x with a patchy background.

NGC 2409 07 31 37 -17 11.4 V = 7.3; Size 2'
At 175x, this is a 2' group of 8 stars with no faint members, so appears to be an asterism. The two brightest mag 8.5/9 stars are part of a boxy quadrilateral with the other 4 stars grouped into two wide pairs. The 3 brightest stars are resolved in the 80mm finder at 25x.

NGC 2414 07 33 13 -15 27.2 V = 7.9; Size 4'
Very pretty cluster with ~40 stars mag 12-14 resolved in a 4'x3' group using the 13mm Ethos (175x). A mag 8.2 star (HD 60308) is superimposed at the center and sprays of stars to the NW, N and E appear to radiate outward from the bright star. A half a dozen brighter mag 10-10.5 stars form an 8' incomplete ring that partially encompasses the cluster (open to the east).

NGC 2421 07 36 12 -20 36.7 V = 8.3; Size 10'
~80 stars mag 10-15 stars are resolved at 175x within a 10' region. Includes a large number of mag 11-12 stars. The group is well-detached in the field, particularly on the W, N and SE sides. One concentration of stars is on the SW side. Just to the NE, a number of the cluster's stars form the outline of a large, equilateral triangle. A rich clump of stars is the center of this triangle including a mag 11/11.5 pair at 18". At 225x, ~100 stars are visible, although the cluster spreads out too much to be pleasing at this power. At 25x, appears as a fairly large, richly glowing region with a few brighter stars resolved in my 80mm finder.

M47 07 36 35 -14 29.0 V = 4.4; Size 30'
This naked-eye cluster is stunning at 73x (31 Nagler), though at 30' diameter is too spread out for higher powers. The stars are arranged in beautiful chains and groups. The brightest half-dozen stars are in 10' subgroup in the center including a striking white double star (7.0/7.3 at 7") that is is surrounded by many stars in chains and loops. The brightest star on the W side (5.7/9.7 at 20") is a wide, unequal double. Perhaps 200 stars are scattered around at low power.

NGC 2423 07 37 07 -13 52.3 V = 6.7; Size 19'
At 175x, ~100 stars are resolved in a 18' region with an excellent double at the center (h3983 = 9.1/9.7 at 8") . The stars are pretty evenly distributed with no rich subgroups though with several doubles and small groupings. At 25x in my 80mm finder, a chain of stars extends N from M47 to this obvious glow with a few resolved stars superimposed.

NGC 2425 07 38 18 -14 52.7 Size 3'
At 175x, ~18 stars are resolved over haze in a small 4'x2' group elongated WSW-ENE. At 225x, perhaps two dozen stars are visible. On the E end is a distinctive line of 5 stars oriented SW-NE, though the richest clump of stars is at the W end of the cluster.

NGC 2428 07 39.3 -16 32 Size 10'
At 175x, roughly 40 stars in 10' barely stand out as a group within a rich Milky Way field. Most eye-catching is a small trapezoidal group with a double star at the NW vertex and a wide pair at the SE vertex. A string of 3 stars oriented SW-NE is within the trapezoid. Off the SE vertex an oval chain of stars extends south and west before looping back towards the trapezoid. There are no dense regions and this appears to be an asterism. An even weaker concentration of stars about 10' NNE may be N2430. Listed as nonexistent in the RNGC.

NGC 2430 07 39.5 -16 20.4 Size 8'
Scattered, undistinguished group with 3 brighter stars (separations of 3'-4') including mag 8.5 HD 61553 and two mag 10-10.5 stars. A small group of fainter stars is the south of the mag 9 star and a larger group of faint stars is just north of the triangle of brighter stars. Even so, there is really nothing here to catch my eye and it clearly appears to be a random Milky Way star field. Just 10' SSW is N2428, another unimpressive Milky Way concentration. Listed as nonexistent in the RNGC.

NGC 2432 07 40 54 -19 05.2 Size 8'
At 175x, appears a very distinctive 5' N-S string with a total of ~60 stars resolved in a 5'x3' area. The richest part is along the string with numerous mag 13-14.5 stars packed tightly. The N side of the string bifurcates into two prongs. Faintly visible in the finder as a thin, elongated glow N-S.

M93 07 44 29 -23 51.2 V = 6.2; Size 22'
Very easy with any optical aid and just at naked-eye visibility. A few of the brighter stars are resolved in 15x50 IS binoculars. The cluster is fairly well resolved at 25x in the 80mm finder. The central region is superb in the 18" at 175x (13mm Ethos) with ~100 stars resolved in the 10' region and richest in the core. Appears fully resolved into mag 10-14 stars. A small, near parallelogram of 4 stars (sides ~40"x20") stands out near the center with numerous fainter stars nearby. The brightest star on the SW side of the cluster is a nice, unequal double (ARA 2066 = 8.3/11.3 at 10").

NGC 2452 07 47 26.2 -27 20 08 V = 11.9; Size 31"x24"
Very interesting, bipolar appearance at 450x. Appears elongated N-S, ~30"x22", with a brighter lobes and rim on the N and S ends. The center appears slightly darker and pinched in. The small open cluster N2453 lies 7' N.

NGC 2453 07 47 34 -27 11.7 V = 8.3; Size 5'
At 220x appears as a fairly rich group of two dozen stars in a 3' clump, just SE of a mag 9.5 star (HD 63360). The densest section is a 1' knot on the SE side with a mag 11 star on its south edge. Shares the same field with pn NGC 2452, located 7' SSW.

NGC 2455 07 48 59 -21 17.9 Size 8'
At 175x, this is a fairly rich group of ~45 stars, mostly mag 12.5-13.5, situated ~7' W of mag 8 HD 63719. Most distinctive is a 6' string of stars oriented NW-SE on the west side of the cluster. Shorter strings with a similar orientation are in the center and east side. Appears fully resolved. Further west is a larger, brighter but more scattered grouping in a triangular arrangement (no catalogue designation).

NGC 2482 07 55 09 -24 15.0 V = 7.3; Size 12'
Distinctive group of 80-100 stars at 175x in a 10'-12' field. A long, rich string of stars oriented NW-SE passes through the middle of the cluster with arms or sprays of stars extending outwards from this string. The stars are fairly evenly distributed and similar in magnitude with several close doubles. A mag 8 star (HD 64820) is off the west side of the cluster.

NGC 2479 07 55 07 -17 42.8 Size 7'
At 175x, over 80 stars mag 12-14 are resolved in a 9' region with the cluster extended WSW-ENE. A semi-circular loop of stars is near the center that is open on the east side. The cluster is ~10' NE of fairly well matched, bright wide pair (h4015 = 9.1/9.5 at 20"). In the finder this cluster appears as a hazy 8' cloud with no resolution.

NGC 2483 07 55 39 -27 53.2 V = 7.6; Size 10'
At 175x, ~60 stars are resolved, many in a long WNW to ESE chain extending to the NW of the central core of the cluster. Near the SE end of the string is a trio of stars and a wide, equal mag pair. Extending from this pair are two additional strings to the SW and towards the E. Easy visible in the 80mm finder at 25x as a hazy cloud with several faint stars superimposed.

NGC 2509 08 00 48 -19 03.0 Size 8'
Beautiful cluster of 80-100 stars at 175x, highlighted by a dense 2-2.5' clump of fainter stars resolved over some remaining haze. Double or multiple stars are at the NE and NW corners of this central knot. At 220x the SE corner of the clump is very rich in faint stars with averted! The brightest star is at the SW side with a string of mag 10-11 stars extending outside of the cluster to the SE from of this star. The cluster is situated ~6' NW of mag 8.8 HD 66034.

NGC 2539 08 10 37 -12 49.2 V = 6.5; Size 22'
This cluster is situated 10' NW of 4.7-magnitude 19 Pup. Roughly 125 stars are spread out over a 20' region. At the NW end is a roughly equal mag pair, an 11" pair is on the E side and a brighter mag 10/11 pair at 20" is on the NE side.

Steve