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

Out There

Deep Sky August

Mark Wagner


Open cluster NGC6940 in Vulpecula sketch by Peter Natscher, image by Rob Mackay.

Supernova Remnant NGC6992 "The Veil" by Ray Gralak.

 

August's warm nights offer backyard and armchair astronomers great incentive to venture out. Nearby Coyote Lake Park is a convenient new observing site, available through the efforts of local amateur astronomer Denny Woolaghan. It takes me 40 minutes from Los Gatos on easy roads. The site offers a large paved surface, good horizons, flush toilets, pay phone, bar-b-ques with picnic benches under large shady oaks overlooking the lake ... a great place to relax and visit with other amateur astronomers while waiting for dark. If amateur astronomy has been limited to your backyard, you'll be amazed at the difference a short drive makes. a great Milky Way greeted us our first time at Coyote. Observing with a group is fun and informative. Check the mailing list at http://www.observers.org to see when others are going.

This month's objects are between RA 20:00 and 22:00, in good position in the eastern sky for the 2 hours beginning at astronomical dark. I've included a few notes from other local observers, but remember, there are many other objects to see. This is just a small sampling of some showpiece objects and others off the beaten path.

Orient yourself with Gamma Delphini, a fine double star. It is a beautiful sight, a mag 4.5 and 5.5 pair of stars separated by 9.6" just a stone's throw away at 100 light years. Their color is exquisite and will provide a fine prelude to other gems we'll visit. This star is the front of the dolphin, the northern-most star in the little diamond describing the dolphin's body. I see gold and red stars, others see yellow and blue. What do you see?

Move about three and one half degrees east in Delphinus to locate NGC 7006. This globular cluster is around 200,000 light years across our galaxy, making it perhaps most remote globular clusters we can view in the Milky Way. The cluster is a small 2.8 arc second glow at mag 10.6, not resolvable into individual stars although some granularity has been reported. The reward is seeing an object clear across the expanse of our home galaxy. Imagine how this would look if it were only a few tens of thousands of light years distant, like most globulars we see.

Still in Delphinus, visit NGC 6905. This exotically named Blue Flash Nebula is 4700 light years away, a mag 11.1 planetary nebula, a slightly out of round oval measuring 47" x 37". At higher power the edges have been described as ropy and ragged, and referred to as a copycat M97 (Owl Nebula). I especially like the name, as planetary nebulae are so transitory ... they appear, and in astronomical terms, are gone in a flash!

Look back to Gamma Delphinus, then let your eye wander just about the same distance back beyond Gamma to the east to the wonderful globular cluster M15. I feel its highly condensed shape is rivaled only by M92 in the northern skies. You'll find M15 a gorgeous sight, resolving nicely in modest apertures. It is visible without optical aid under very dark skies at mag 6.3 and 12.3 arc minutes. That glow took 33,000 years to reach your eye! Within M15 is another target very challenging target, Pease 1, a tiny stellar sized planetary nebula. Do you know anyone who has viewed the tiny planetary? How many objects do you know that have a planetary nebula in them that you can observe?

While at Coyote Lake treat yourself to a view of the Veil Nebula as this object performs much better out of the city. It is a supernova remnant in Cygnus, located at and near the star 52 Cygni. Local observer Derek Stonich writes "NGC 6992 looked like a piece of yarn had been laid strung the stars. It was thick and appeared to have depth. This object was amazing, it seemed possible to look into it." There are several parts to this object, and it is large, as large as the full moon. Use an Oxygen III (OIII) or Ultra High Contrast (UHC) filter to enhance the view. For a challenge, after looking at the two brighter sections. hunt down Pickering's Wisp. a small triangular knot glowing almost centered between the two other sections. The Veil is sort of a "bow shock" expanding away from the cataclysmic star that created this delicate yet awesome view.

Next, scoot your scope over two and one half degrees to the south southwest crossing into Vulpecula to the fine open cluster NGC 6940. This rich cluster is the size of our full moon and glows at mag 6.3. You'll remember this position easily, as naked-eye stars 39 Cygni (mag 4.3) and 41 Cygni (mag 4.1) point to it.

Our last object is NGC 7009, the famous Saturn Nebula, which is a fine example of planetary nebulae. Look at Capricornus and think of its shape as a bikini swimsuit bottom. Move above the swimsuit for the "bellybutton". the mag 4.5 star 13-Aquarii. Move your scope a degree west and you'll see a small green ball. That's it! Bump up the magnification and try to see the ansae. the extensions that give the object its name. Sacramento observer Randy Muller writes "The blue-green color of this object is very intense. Using averted vision, the object was relatively large and bright gray. Using direct vision, it became very small and intensely blue-green. There seemed to be some mottling in the disk, and it was definitely very much brighter in the center than at the edges."

Next month I'll describe another popular observing location and a selection of objects between right ascension 22:00 and 24:00. There is a lot to see in the deep sky, but you don't know if you don't go. so get out there! Don't cheat yourself of one of the best 40 minute drives you'll make this month!

 


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