Monthly Messier Star-Hop; March #1
By Art Russell

This month we start off with an open cluster, NGC 2244, and its associated nebula, the Rosette Nebula. From there we'll look at a series of Messier's open clusters, M50, M41, M47, M46, and lastly, M93. Along the way, we'll also make a stop at the unique planetary NGC 2438, one of the few planetary nebulae associated with an open or globular clusters. This is a full plate for observing, so lets get started! First, get out your own star charts so you can follow along. Then to star-hop #1.

Star-Hop #1. NGC 2244
Star-Hop #2. M50, NGC 2323
Star-Hop #3. M41, NGC 2287
Star-Hop #4. M47, NGC 2422
Star-Hop #5. M46, NGC 2437
Star-Hop #6. M48, NGC 2548
Star-Hop #7. M93, NGC 2447

Star-Hop #1. NGC 2244. To begin, start at Lambda (l) Orionis, the head of Orion the Hunter, in the constellation Orion. From there, extend a line through the star Betelgeuse for a distance a little more than half again as much as that between Lambda Orionis and Betelgeuse. At that point you'll come to the star Epsilon (e) Monocerotis. The open cluster NGC 2244 is at the right angle of a right triangle formed with 13 Monocerotis on the left end and Epsilon Monocerotis at the right end. At 90X (magnification), I noted that the cluster did not seem remarkable, but that it seemed to form a double row of stars oriented northeast to southwest]. The interesting thing about NGC 2244 is that it is associated with the Rosette Nebula, NGC 2237, which you can easily see in telescopes and even binoculars. It is well worth taking the time to find. At 51X and using an OIII filter, the nebula was very apparent and formed a distinct crescent around NGC 2244. Try to find this one if you can. It is well worth the trip. Can you do it with binoculars?

Star-Hop #2. M50, NGC 2323. Our next star-hops take us southeast of Orion. The best way to get there is to start at the three aligned stars which make up the Belt of Orion and use it to point to the southeast and the constellation Canis Major. There we find the star Sirius, Alpha (a) Canis Majoris, the "Dog Star," the brightest star in the sky. From there we'll head to the open cluster M50, NGC 2323, also known as the "Galactic Smiley Face" J (I don't know which one of the club's Deep-Sky Zombies christened it: Dave Riddle, Clay McHann, or Rich Jakiel. Will the real culprit please stand up?). To get the M50, extend a line from Sirius through the star Theta (q) Canis Majoris for a distance equal to that between Sirius and Theta Canis Majoris. At 34X, M50 fits within the field of view and is easily distinguished from the background. Overall shape is similar to a "Galactic Smiley Face" with a triangular aspect. Stars concentrated towards the center of the cluster. No noticed nebulosity. At 93X, M50 looses some of the triangular appearance, but with increased resolution of the cluster's stars.

Star-Hop #3. M41, NGC 2287. Our next star-hop takes us to the open cluster M41, NGC 2287. You should have no problem finding this cluster from dark skies. I have even found it deep in Atlanta's severe light pollution from the roof top of Fernbank Science Center with a pair of binoculars! The quickest way I have found to locate M41 is to start at Sirius. From Sirius extend a line southeast to the 3rd magnitude star Omicron (o) Canis Majoris. Half way there you'll arrive at the much dimmer, 4.3 magnitude star 15 Canis Majoris. 15 Canis Majoris and M41 form the apex of the legs of an isosceles triangle with Sirius as its apex. M41 is distinct in the finder, but looses distinction at 93X. Stars seem to form several arcs and arms of stars streaming radially away from the center of the cluster.

Star-Hop #4. M47, NGC 2422. A 4.4 magnitude open cluster, is our next stop. Can you guess where we start? You're right! Its Sirius again! From Sirius extend a line through the star Gamma(g) Canis Majoris to a distance about twice that between Sirius and Gamma Canis Majoris to arrive at M47 in the constellation Puppis. At 34X, M47 is easily found from Sirius. The open cluster is almost entirely within the filed of view. The cluster seems to have an "X" of stars in its center. No other deep-sky objects are visible. Possible color hinted in some of the stars in the cluster. Very pretty and easy to find. Pretty yellow-orange star is visible just on the edge of the field of view. You might also take a look about half a degree tot he north of M47 in your field of view. There you'll find the open cluster NGC 2423.

Star-Hop #5. M46, NGC 2437. Now lets head to M46, also in Puppis, and find two objects at once. In this case the planetary nebula NGC 2438 seems to be a member of M46. M46 is relatively easy to find from M47 as it is only a little more than a degree to the southeast away. The best way to get there is to simply use your finder and gently nudge your scope in that direction away from M47. Don't go too far. At low power, it won't take much, perhaps just one field of view. Those using binoculars may find that they can see both M47 and M46 in the same field of view. At 34X, M46 is very clearly visible. Most of the cluster is contained within the field of view. Planetary nebula NGC 2438 is easily seen in the cluster. Crescent shape, but with bulge at one end. No noticeable color in stars. No other nebulosity visible. At 109X, the planetary nebula easily stands out. At 163X, the central star seems located slightly off-center of the ring. The planetary nebula has a distorted annular appearance and is blue-gray in color. At 175X without an OIII filter, there seems to be an annular there is no additional detail visible.

Star-Hop #6. M48, NGC 2548. Don't give up yet! We've got only two more star-hops to go! Our next star-hop takes us out of Canis Major, through the constellation Monoceros, and into the constellation Hydra. There we find the open cluster M48. Starting at Sirius (not surprised are you?), extend a line through the star Alpha (a) Monocerotis for a distance a little more than half that between Sirius and Alpha Monocerotis and you'll arrive at M48. You may also note that M48 and Zeta (z) Monocerotis form the base legs for an isosceles triangle formed with Alpha Monocerotis at the apex. At 34X, M48 is immediately visible. It seems to form a triangle within another triangle. No other deep-sky objects are visible within the field of view. At 93X, M48 fills the entire field of view. At 163X, M48 appears to have arcs of stars comprising a larger arc of stars at the north edge of the cluster.

Star-Hop #7. M93, NGC 2447. Our last star-hop takes us to the 6.2 magnitude open cluster M93 which is located in Puppis. Start at Sirius and extend a line south through Canis Major to the star Xi (x) Puppis. M93 is about 1 1/2 degrees northwest of Xi Puppis and should be easy to find. Using binoculars, you should see M93 and Xi Puppis in the same field of view. At 51X, M93 is an easy object to see with most of the cluster in the field of view. The cluster seems to form an arc of stars.

Art Russell - 2.28.99