SJAA Ephemeris October 2002 | SJAA Home | Contents | Previous | Next

Out There

October deep sky from Montebello

Mark Wagner


 

“Get out of your backyard; you'll find a big sky, friendly and knowledgeable observers, and plenty to see.”

 

NGC 7662, the Blue Snowball planetary nebula in Andromeda at 305X with O-III filter, sketched by Iiro Sairanen, Finland

NGC7479, barred spiral in Pegasus at 276, sketched by Andreas Domenico, Germany

NGC7789, the Magnificent Cluster, open cluster in Cassiopeia, sketched by Bill Ferris using an 18mm SWA, TeleVue 3X Barlow combination through a 10-inch Newtonian

 

How many of you are backyard astronomers, taking your telescope outside for an hour once in a while? Peek here and there, see hints of this or that, and you decide planets and the moon are all that's worth looking at? There's much more to see from a place virtually in your backyard, an observing site used by dozens of experienced deep sky observers. A place that you can use too! While not actually in your backyard, within about 30 minutes drive is a site that's a huge improvement over most suburban backyards. It is called Montebello Open Space Preserve, atop Page Mill Road in Palo Alto. Nice, close, good skies, pretty drive, good company, lots to see at sunset and after dark.

Here is where it is convenient to dip your toes into the deep end and leave wanting more! Directions to "Montebello" can be found at http://www.sjaa.net or http://www.observers.org on the internet. While Montebello is a popular and excellent resource for local amateur astronomers, use is limited to permit holders and their guests (you). Check on the observers.org mailing list where permit holders regularly post their plans to go.

There is plenty to see from Montebello during the moonless night this first month of fall. Let's concentrate on some selected objects between R.A. 22:00 and 00:00, well placed rising in the east for the first two hours after astronomical twilight around new moon.

NGC7662 may look like nothing more than a bright ball upon casual inspection. But there is much more to it if you take time to study. The common name is The Blue Snowball, a bright turquoise mag 8.3 planetary nebula in Andromeda. The central star is in and out with averted vision. Can you see it? As you increase magnification the object transforms into two if not three concentric rings. My most pleasing view was through an 18-inch Newtonian at 294X from a good dark sky site in the Sierra foothills. The planetary resolved into a grey ring with another glowing green ring overlaying it 2/3rd out to the edge. At the edges were small "sparks" - or parts of the glowing ring jutting out toward the perimeter of the gray disc. This was a beautiful object with lots of detail at higher power. The neon green glow of the middle ring was mesmerizing.

NGC40 is a mag 12.3 planetary nebula in Cepheus. It is nearly identical in size to the Blue Snowball, but that's where the similarities end. NGC40 contains a bright central star surrounded by a dimly lit shell. With sufficient magnification two dim shells show with a pair of darker lanes inside the inner shell curving slightly inward, cupping the central star and extending north and south. Look carefully to pick out a star involved at the southern tip of the outer shell, and another dimmer star involved in the eastern edge. With some imagination, the dark lanes and bright central star reminded me of a spiral galaxy with arms tightly winding around it.

So how about a galaxy with its arms showing? Find NGC7479 in Pegasus. This mag 10.8 galaxy is a great barred spiral. A stellar core lies buried dimly in the bar that thins toward its northern and southern extremes. The brighter arm sweeps around off the southern end bending around to the west. The northern arm is thicker but much dimmer, just revealing some hints as it turns east then back closely alongside the central bar. This is an object for dark skies and higher magnification.

The last two objects are open clusters, both in Cassiopeia, both large and rich, but visually very different from each other.

M52 is about 15 arc minutes in diameter and shines at mag 6.9. My notes refer to it as a bright version of NGC7789, which happens to be the next target. M52 has a bright star at its western edge, leading it as it drifts through an undriven eyepiece. The brightest stars are in the "leading" western two-thirds of the cluster. Two long streamers of stars flow back, extending out to the east. A third streamer trails off to the north. Many dim stars fill the cluster, with extensive dim outliers to the north east. M52 is a study in diversity - note the wide magnitude range of its components.

NGC7789 seems much dimmer, and you'll immediately note that virtually all the stars are quite similar in magnitude. How different from M52 it looks, but interestingly it is virtually the same size and magintude! At about 100x I am always struck by the dark channels that wind north/south. There are two of them, dividing outliers from and somewhat cradling the central ball of stars. With enough study, I see another channel curving around the core from west to east. The stars along the western edge seem brighter than the others, almost glowing like they are heated by friction as they move through space to the west. Some tail off the chain at its southern edge toward the east. Make sure to use a low power eyepiece to offset the cluster against the emptiness of surrounding fields. I am sure once you view this one, you'll return many times.

Other objects to hunt down this month are NGCs 6934, 7448, 7492, 7541, 9619, 7723, 7727, 7815, 7457, 7640 and 7678. A few noteworthy double stars are Struve 2816 (SAO 33626) in Cepheus, 41, 53 and Zeta Aquarii.

All objects described this month are visible from Montebello. Get out of your backyard; you'll find a big sky, friendly and knowledgeable observers, and plenty to see. What a difference just a short drive from home makes!

 


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