Deep Sky Daze
By Mike Benson
Over two decades ago I prepared a series of articles which described star walks, which, if followed, would lead to the completion of the Astronomical League’s list of Messier objects, along with a good start toward the Herschel list as well. I have been asked to update and repeat these articles for the ECLIPSE. This is the first of a monthly series that will continue for the next year or so. If you have questions or comments, please feel free to contact me at email@example.com.
Fall is my favorite time of year. To me it signifies new beginnings, perhaps as a result of our educational system which traditionally began after the harvest, when children were no longer needed in the fields. Even in my late seventies, I still miss the joy of a new school year, the walk to school, kicking my way through crisp, colorful leaves fallen from maples and oaks, birches and poplars and aspens, collecting my new books with their crisp pages; meeting old friends and new teachers. The smell of wood smoke and burning leaves and the transitional weather that brings dry, high pressure systems, cooler temperatures, and clear, steady air out of the north, all invigorated me then, much as they do today.
In the sky, the appearance of the Pleiades and the Hyades, Cassiopeia riding high to the North, the hazy patch of M-31 (the Andromeda Galaxy), first glimpses of the Orion Nebula, and the beautiful triple star system of Omicron2 Eridani all bring a sense of expectancy when I step outside in the evening. Yes, I love Autumn.
Let’s start with seven objects scattered in Capricornus, Aquarius, Pegasus, Perseus, and Cassiopeia, The first two are low in the west as the sky darkens in November, so it would be best to go for the three globular clusters and the asterism located in them first. There will be time for Pegasus and the Vain Queen later in the evening, where we'll find another globular cluster and two galactic clusters.
Capricornus, the Sea Goat is located in a rather dark part of the sky just southeast of Aquila and is the most westerly of the "water constellations". It contains no star brighter than 3rd magnitude. Shaped rather like a triangle with the apex pointed toward the horizon, it may take you a few minutes to trace its shape. Once you have the outline you'll note Alpha and Beta marking the westerly point, Omega to the south, the tip on which the triangle balances, and Delta at the eastern point. A bit over a third of the distance between Delta and Omega is 3.7 magnitude ζ Capricorni with 4.5 magnitude, 36 Capricorni about a degree to the NE. Our first Messier object of the evening, M-30 (NGC 7099), is located about 3.5o ESE of Zeta. This 8th magnitude globular cluster is only about 6' in diameter with soft edges, a much brighter interior, and a stellar core of about 12 Mag which will require a mid sized instrument to detect.
Let's move on to Aquarius, which will prove a bit more productive. Swing your scope about 10 degrees NW to a position about midway between θ Capricorni and ε Aquarii. There you will find two of the more nondescript Messier objects. M-72 (NGC 6981) is an 8.5 magnitude globular cluster only about 3' in diameter. Definitely not an earth shaker!
About 1.5° ESE is M-73 (NGC 6994). Watch out! It'll probably bite you before you recognize it. I wonder how Messier found any nebulosity here to confuse it with a comet. Most telescopes will show you a small asterism containing, perhaps, four stars. Yawwwwwn!
Much more impressive is NGC 7009 located about 2° NE of M-73. Also known as the "Saturn Nebula", this planetary nebula is oblong — about 30" by 15" — and appears to have two ansae — ears — much like Galileo pictured the planet, several centuries ago. It's very bright (8th magnitude) and blue-green in color. A nebula or SkyGlow filter will help, if you have one available.
Our final object in Aquarius is 6.0 magnitude, M-2 (NGC 7089), a fine globular cluster. Under similar conditions of transparency, I achieved partial resolution of stars at the edges of the cluster, but found a dense, solid core with no resolution at about 170X in my 8" SCT, while Clint Bach, a friend with a 12.5" Newtonian at 85X found the core to be partially resolved inn East Tennessee.
Now find the Great Square of Pegasus; then ε Pegasi ("Enif"), the nose of the flying horse. (Remember, Pegasus is flying west, upside down unless you are lying on your back with your feet to the south. θ Pegasi marks the approximate position of Pegasus' ears and our next Messier object, M-15 (NGC 7078), lies on a line extended from θ through ε, about half again the distance between those two stars. At 6.5 magnitude, spread over about 10' of arc, it is not as dense as M-2. Most scopes will show some resolution of the core at powers over 100X. Bright, easy, and very pretty!
Our next two Messier objects are in Cassiopeia, and here you have to be very careful of directions. At this season of the year, the vain mother of Andromeda is actually higher in the sky than Polaris, so North is actually down and to the left as you look at the constellation, a squashed "W" with the base of the figure toward the east. Start with α (the base of the least flattened part of the "W"), extend a line through β (the most westerly of the stars that make up the "W") a bit further than the distance between the two stars. You are now at M-52 (NGC 7654) a 7.0 magnitude, open cluster about 12' in diameter, with over a hundred members, none above 9th magnitude. Believe it or not, you are looking out along the plane of the disk of the Milky Way at this point, away from the center of our galaxy. Finally, swing to δ Cassiopeiae, the base of the squashed part of the "W". Another open cluster, M-103 (NGC 581) lies a degree NW. Clint, using his 12.5" and I in a 17.5", both had difficulty separating the cluster from the background, which is very rich, running right along the galaxy's disk.
Nearby, are three of my favorite telescopic objects. All are in Perseus. M-76 (NGC 650-1) is a bright planetary nebula located just NNE of φ Persei in the western extension of Perseus, right on the Andromeda border. Also known as the "Little Dumbbell," both lobes are clearly visible in my 8" SCT on a good night. A smaller instrument will show a bright, irregularly shaped blob, and averted vision will usually permit the two lobes to be separated. A larger light bucket reveals considerable internal detail with dark lanes and variable brightness in the central bar, along with wispy nebulosity east and west of the bar. Use as much power as your scope permits. I tend to prefer about 150X in my 8".
Next, move to β Persei, better known as Algol (While you're in the area, check to see if the "Demon Star" is in eclipse.) Hop to 16 Persei about 4.5° SW of Algol. From there look for NGC 1023 just less than a degree N and two degrees W. This is a lens shaped, elliptical galaxy with a much brighter center and an odd, bright tuft at its western edge. The tuft was clearly visible in my 8" even through a faint haze layer. Various sources list this galaxy from 11th magnitude to a bright 9.3. I tend to agree with the brighter figure. It's a really pretty object, and worth a sketch, I think.
Now head a degree NNE to 12 Persei and from there, due north 2.5° to M-34 (NGC 1039). This is a big, bright, loose galactic cluster with about 80 stars ranging in brightness from 8.5 magnitude on down. It's the size of the full moon and is best viewed at lower powers, although there are a couple of nice double stars that can be split under high magnification. There are several arcs of stars radiating out from the center of the cluster. Take your time and see how deep you can go. There will be stars all the way down to the limit of your telescope.
Happy Turkey Day, and cloudless skies!