#104: An Open Cluster Tour: Monoceros

This is an article I wrote for our club newsletter, Jan./17 issue.  The club is RASC Windsor, Canada.  Hope you enjoy!

#67 Treasures of Monoceros, Part 2: The Other NGC Objects

In Part 1 I discussed all of the NGC open clusters in this amazing constellation.  Most of the remaining NGC objects are galactic nebula.  There are also two very faint, difficult galaxies and one pretty decent planetary nebula.  In Part 3, I will tackle a wealth of open clusters from other catalogues.

gn 2149:  3' x 2'; Reflection:  Impossible from my light polluted deck, it was an easy target in a dark sky.  It had a bright middle and uneven brightness outwards.  In a bright star field.  Originally, Shapely mistook it for a galaxy.  Good object at low to high powers.
gn 2170:  1':  Involved with two faint stars, it was only seen with the Skyglow filter at 83x.  Unsuitable for suburban skies.
gn 2182:  3':  Involved with a 9 mag. star. The nebula was seen only with the Skyglow filter at 83x.  It was a very faint haze surrounding a white star.
gn 2183: 2' x 2'; Reflection:  A pair with 2185, neither was visible from my light polluted deck. 
gn 2185: 2' x 2': Reflection: However, both were seen well in a dark sky, side by side.  Several bright stars were involved with the two patches.  60x-150x was used.  Worth a stopover.
gn 2237: 80' x 60'; Emission:  Rosette Nebula, associated with oc 2244.  More suitable for photography than eyepiece observing.  Using an Edmund Astroscan 4 1/4 " RFT with a Skyglow filter at 54x, it was not difficult to see  some puffs of nebula, especially south preceding the cluster and north preceding.  The cluster itself is mostly devoid of any nebula.  This is a very large area of nebulosity.
gn 2238: See 2237.
gn 2239:  See 2237.
gn 2246:  See 2237.
gn 2245:  2' x 2'; 10.8 mag. *: Seen fairly well in the 12".  The star was dim enough to allow the reflection nebula to be easily seen, and the nebula was wedge-shaped.  Seen well at 120x, with flaring at 200x.
gn 2247:  2' x 2'; Reflection:  Due to the brightness of the involved 8.5 mag. star, this nebula was seen only faintly at 250x and 300x, not far from the star and also around it.
gn 2261:  Hubble's "Variable Nebula."  An easy target, despite moonshine, reflected snow, and light pollution.  Seen much better with no filter, and it was observed well from 60x-150x.  Fan-shape, very bright in the S, and stellar down there.  As the fan expands it fades away.  Bright enough for much smaller telescopes, and seen well in the 6".
gn 2282:  3' x 3'; Reflection:  Some barely visible haze surrounds a 10 mag. star, especially on the south end.  A few very faint stars are involved.
gn 2316:  4' x 3'; Emission and reflection:  Clearly seen without any filter in a dark sky, it was observed at 60x thru 200x.  A triangle of stars just south helps locate the haze, if black skies are not available.
pn 2346:  60" x 50":  Cent. * mag. 11.3--13.5:  A suspicious, out-of-focus star was seen at 60x, confirmed as a small but bright planetary at 120x.  The central star was not difficult to see, and even at 150x the object appeared round, though with faded, less distinct edges.  It was significantly larger and brighter at 150s with the Skyglow filter.  Not featureless, but nearly so.
eg 2377:  1'7 x 1'.3: Vis. mag. 12.8; Surf. br. 13.5:  Difficult object due to involvement with a star or stars.  Located at 100x and seen using up to 200x.  It was very small and somewhat oval.  Due to star (s) involved the shape was difficult to perceive.
eg 2494:  0'.9 x 0'7: V. mag. 13.1; S. br. 12.4:  A threshold object through my humid skies, it appeared round at 100x-200x.

gn I. 448:  15' x 10'; Reflection:  Oddly enough, this was seen better with the Skyglow filter, perhaps because it dimmed the bright white star involved.  Essentially, some haze surrounds Star 13, having uneven edges.  Poor without the filter.  A line of stars north-following leads to oc Bas 8.  South is Star 14, a fine double.
gn I. 466:  5' x 4'; Reflection:  A faint haze was seen near a faint star.  Nearly impossible without a dark sky.  In such a sky it was very bright, small, round and it took magnification well, resembling a planetary nebula.
gn I. 2169:  25' x 20'; Reflection:  Involved with oc Cr 95.  Nebula easily noticed at 120x with the filter.  More was seen on the preceding half of the cluster, scattered between and amongst the brighter stars.
gn I. 2177:  85' x 25'; Emission:  This massive nebula can be glimpsed as clumps of smokiness with the filter.  Seen best just south of double star Struve 1019, as well as amidst oc Cr 465 and oc Cr 466.  60x and 120x was used to advantage.  1019 is an exquisite trio of stars!

#66 Treasures of Monoceros, Part 1: The NGC Clusters

It was another unusually brutal winter here in Essex Co., Ontario, Canada.  It was too cold for sensible observing until mid-March.  With night temperatures finally up in the high twenties and low thirties, I was able to resume my winter observing program.  I only have a few galaxies left to see in Lepus.  Perhaps on a very late night in November of this year I might be able to complete this constellation, which I have been at for several seasons now.

I recently concluded a multi-season inspection of the deep sky wonders of Monoceros, a busy Milky Way constellation.  Some of the most famous objects of the deep sky are located here, including the Rosette Nebula and the Cone Nebula.  Rich in open clusters and nebula, there are also two tiny galaxies and a single planetary nebula.  There are no globular clusters in Monoceros.  It also has fabulous double and multiple stars.  This first entry will deal with all of the NGC Open Clusters.

oc 2215:  8'; Br. * mag 11; 25 *s:  Noticed at 60x.  Faint members, with a nice double star preceding.  150x shows the group well, with stars all across the field.

oc 2219:  10'; Br. * mag 7.3; 25 *s:  North preceding 2232.  Fainter stars lie N of two brighter ones.  Seen well at 120x, but located at 60x.

oc 2225:  40 *s:  Small group, not dense.  8 brighter stars in a half-circle, with fainter ones showing at higher powers.  Central core is 2226.

oc 2226:  See 2225, above.

oc 2232:  45'; Mag. 4.2; Br. * mag 5; 20 *s:  A huge cluster, best suited for very low power.  Lovely at 43x in the 12".  The main central group is great at 60x.

oc 2236:  8'; Mag. 8.5; Br. * mag 12; 243 *s:  A very small, tight group that took a few moments to locate.  Only one bright star (mag 12), with the remainder being very faint.  Some resolution was apparent at 120x, and it improved at 150x.  At 200x the central knot is resolving.  Stopped to 8", very few stars are resolved in the central area.  Here is a photo.

oc 2244:  30'; Mag. 4.8; Br * mag 7; 100 *s:  15 stars shown on Uranometria!  Those are seen at 60x.  Nebula filter at 83x shows some fuzziness and nebulae.  120x shows many fainter stars.  I used up to 300x on multiple star GAn 3, where I could see 9 stars in all.

oc 2250:  10'; Br. * 8.7; 25 *s:  South following 2232, this one is also called Cr 100.  Moderately rich group with mostly very faint members.  Only one bright member, with the others S of it.  Best at 150x.

oc 2251:  10'; Mag. 7.3; Br. * mag 9.9; 92 *s:  North following and attached to oc Bas 8.  Located at 60x, there are about a dozen stars mag. 9-10, and several fainter ones.  The brightest star is a close double.  A loose group, somewhat crescent-shaped, or at least elongated.  Good views up to 125x.  In a very dense area of clusters and rich star fields.  Unusual and worth a stop, though not a showpiece.

oc 2252:  18'; Mag. 7.7; Br. * mag 9; 30 *s:  A bit of a showpiece in the 12".  Faint members form two distinct lines, meeting at an apex.  To me it looked like the Star Trek badge!  About a dozen brighter members, and many fainter ones.  Looking like a little hazy cloud at 60x, it bears magnification well.

oc 2254:  6'; Mag. 9.1; Br. * mag 12; 93 *s:  A very faint cloud was seen at 120x (in light polluted skies), barely resolving.  8" aperture showed perhaps two stars.  The group is intense, small and faint.  At 150x and 12" it began to resemble a loose globular cluster.  Small and dense at 200x, it was still resolving.  In this range it was hard to even see it using an 8" aperture stop.

oc 2259:  3'.5; Mag. 10.8; Br. * mag. 14; 25 *s:  A small, faint group noticed at 100x as a faint cloud near a mag. 9 star.  Up to 250x was used to resolve about 10 very faint stars.  Observed in a light-polluted area.  (Re-observed in a dark sky)--small, dense group seen well, resolving neatly and looking mildly glorious.  Still a challenge, but so much better in a dark sky!

oc 2260:  20'; Br. * mag 8; 50 *s:  6 *s in Uranometria Chart 116.  Seen well at 60x, it just barely fits in at 120x.  Bright star is orange.  Brighter stars form a sickle shape.  Large, bright and fairly scattered.

oc 2262:  4'; Mag. 11.3; 180 *s:  This is a small, dim circlet of faint stars, and not very rich.  An interesting group zigzags N from it.

oc 2264:  40'; Mag. 4.1; Br. * mag 5; 40 *s:  The Christmas Tree Cluster was studied with the 6" reflector, which was perfect for the task.  It all fits neatly at 28x, and the tree outline is there.  A very large cluster set amidst a very interesting area.  The brightest star in the group is 15, a multiple star.  It was split into three at 125x.

oc 2269:  3'; Mag. 10; Br. * mag 10; 12 *s:  10 stars were counted at 200x.  It is a very faint, small group.

oc 2286:  15'; Mag. 7.5; Br. * mag 9:  Once located within a busy star field, the cluster was quite a minor showpiece!  Though large, it was packed with stars, including several bright ones.  However, most of them are faint, and there are a lot of them.  125x seemed to give me the best view.

oc 2301:  15'; Mag. 6; Br. * mag 8; 80 *s:  A fine cluster!  At 60x 5 bright stars are noticed, resembling a dipper minus a handle star and a top right corner star.  The main part of the cluster is in and around the lower part of the "bowl" of the dipper.  Here it becomes dense with stars, with the final dipper star a lovely double of yellow and blue.  At 100x 15 brighter stars cluster around it, with another 25 fainter ones following seen at 125x.  183x shows many other fainter ones, resolving the haze first seen at 60x and 100x.  A recommended object!  Here is a link to a photo.

oc 2302:  5'; Mag. 8.9; Br. * mag 12; 16 *s:  16 stars were counted at 200x.  The group is tight, and has 3 close brighter stars that precede the fainter ones.  Star V 743 is immediately north preceding.

oc 2306:  20'; Br. * mag 8; 27 *s:  South following oc 2302 is this very large cluster.  Uranometria plots an 8 mag. star in the center, a 9.5 mag star in the north, and HH on the south-following edge.  At 60x I saw the bright stars and not much else.  100x showed the white central star now surrounded by faint ones.  The star in the north also has a group of faint stars around it, with a denser group between it and the central star.  The brightest star had about 15 widely scattered faint stars, while the dimmer one in the north has 12, in a tighter formation.  Observed in a light polluted sky.

oc 2309:  5'; Mag 10.5; Br. * mag 13; 25 *s:  North following oc 2306 is this small cluster, noticed at 60x.  Very faint stars were noted south of a mag. 9 star.  100x resolves the brightest members, forming a loose circle.  The very center resolves at 200x and 250x, where 25 stars were counted in a small area.  Other members straggle out from this central group.

oc 2311:  6'; Mag. 9.6; Br. * mag 12:  A fine cluster, viewed from 60x thru 200x.  It is dense and has an irregular north/south shape, with most stars in the north and others straggling south.  Everything resolves well at 125x.  It precedes three brighter stars in a line.

oc 2319:  16'; Br. * mag 8.9; 12 *s:  Seen well at 60x and 100x.  There were 25-30 stars, many of them bright, mostly in 2 straggly lines.  One of the lines is longer and denser.  Up to 125x was used, and all stars were resolved.

oc 2323 (M 50):  16'; mag. 5.9; Br. * mag 9; 80 *s:  The cluster is a wonder to behold at 60x in a 12" mirror, even in a light-polluted sky!  The brightest star is orange, and has a bright double star nearby.  A chain of bright stars outlines a large, open smile shape, with lines of stars passing perpendicular to it and thru its denser core.  The core lies near the center of the smile shape.  100x shows 100+ stars, including many faint ones.  The cluster is very rich, with 125x and 150x filling the viewfinder with stars, though there is a darker area between the orange star and the rich center.  200x takes the viewer into the very center.  A fabulous cluster!

oc 2324:  8'; Mag. 8.4; Br. * mag 12; 25 *s:  At 60x this cluster is already promising much!  100x gives good resolution of this faint, large and medium-dense cluster.  Beyond the main central group, the cluster spreads north a bit.  125x gives fabulous views, as does 150x and 183x, where most of the haze is resolved into tiny stars.  Viewing was good up to 200x.  A minor showpiece in a 12" scope!  Here is a good photo.

oc 2335:  7'; Mag. 7.2; Br. * mag 10; 40 *s:  Seen well and resolved at 100x, where I noticed 10 faint stars close to a brighter orange one.  At 125x the cluster was pretty large and scattered into 3 groups.  The central group was the most dense, with a preceding group and a following one less so, and with fainter stars.  I counted 30 stars at 200x.

oc 2338:  3 degrees north-following M 50, this is a virtually unknown group.  The Deep Sky Field Guide says it might be an asterism.  There is definitely a 4-star asterism present.  However, the cluster seems to be "behind" and around these stars.  The 4 stars make a rough parallelogram.  A medium-rich group of faint stars lies around it, in 2 distinct clumps.  The north-following bright star of the asterism is a close double.  Here is a photo of the lone Messier object in Monoceros.

oc 2343:  6'; mag. 6.7; Br. star mag 8; 55 *s:  I first mistook this for nearby Cr 465.  Along with Cr 466 all three clusters fit in a low power field.  20 stars were seen at 100x in the central group of 2343.  Like 2335, this cluster is dominated by a bright orange star, itself a fine double.  At 125x this is a pretty decent cluster.

oc 2353:  18'; Mag. 7.1; Br. * mag 9; 106 *s:  A fun cluster to observe, big and with a fair number of brighter stars.  Breathtaking at 60x, with too many stars to easily count.  Shaped like a big oval, this is a fine group for 6" scopes and higher.

oc 2364:  2 lines of brighter stars, looking like a mirror view at first glance and low power.  I focussed on the following group, which had 5 stars in a curving line.  2 of these were brighter.  150x gave a good view, and a few fainter members could be seen now.  At 200x 5 or 6 very faint members were added to the original 5 brighter ones.  The bright star field is pretty interesting, but the "cluster" isn't much to see.

oc 2368:  3'; Mag. 11.8; 15 *s:  Not a bad object in the 12", it is led by a bright star on its preceding edge (mag 11?), which turns out to be a double with a faint companion.  At 200x there are 20+ stars, all faint except the one.  It is somewhat triangular, or wedge-shaped.

oc 2506:  10';  Br. * mag. 11; 75 *s.  60x shows a dense central area.  120x resolves many of the fainter stars, and 150x shows the central knot well.  Bright foreground stars make resolving this one very challenging.  In a really dark sky, this cluster is a treasure!  Here is a link to a great photo of this object.

In Part 2 I will discuss the remaining NGC objects, along with the IC ones observed.  In Part 3 I will discuss the clusters from other catalogues in Monoceros.  Until then, clear skies.
Mapman Mike