Looking Up, Down Under

Michael Purcell

Straight overhead, at the zenith, were Sagittarius and the center of the Milky Way. The arms of our galaxy curved down to the horizon. To the south, the Large and Small Magellanic Clouds stood out clearly against the dark sky. Next to Sagittarius, almost overhead, was the giant stinger of Scorpius. Further west, the Southern Cross, Coalsack Nebula, and the Eta Carinae Nebula. The beauty of the entire vista was overwhelming. With me were my sister Nancy and her friend Craig. Nancy and I have been to New Mexico several times. We agreed, this was the finest night sky we had ever seen.

This, however, was not how our stay at Grove Creek Observatory began. It is a well-known rule in LCAS that the first visit to a new dark site always includes bad weather. Therefore it should have been no surprise to me that the Australian drought ended and the rains began the same day we arrived. Fortunately, I had booked two full weeks, assuming (correctly) that this would be enough time for any bad weather to end.

The People: Grove Creek Observatory (GCO ) is a private, non-profit observatory, and is owned and operated by Jim Lynch. Jim is an amateur astronomer with an interest in photometry (star brightness, variable stars, etc.) The principal astronomer is Steven Williams. Steven is a volunteer who takes care of the equipment and instructs visitors in its use. He also manages the GCO Web site and has taken most of the astrophotographs posted there.

The Observatory: GCO is located about 4 hours west-southwest of Sydney. The main building includes the dome, control room, living room and kitchenette, comfortable bunk room for guests, and sleeping quarters for the owner/operators. The second building has a rollaway roof, and contains all the other scopes. The hilltop location gives a beautiful view of the local range land (they raise cattle and sheep). The location of GCO really is perfect. They can see 90% of the worthwhile northern objects (as far north as M51) in addition to all the southern sky.

The Equipment: GCO has a good range of equipment. The primary instrument is the C-14 in the dome. It has excellent optics, and is set on a custom mount that supports auto-guiding with their SBIG ST-4. Fortunately for me, they also have their own ST-6B for CCD imaging. (More on that below.) In addition to the C-14, they have a 12 inch Newtonian on a German Equatorial Mount, an 8 inch Newtonian, and Steven's 10 inch LX-200.

The Weather: GCO normally has an abundance of clear dark skies. My arrival changed all that. The first week was like November in Chicago: cold and rainy. The second week cleared enough for observing and photography. Naturally it was in the middle of the only completely perfect night that my ST-7 imaging camera died! I was very grateful to GCO for the use of their ST-6B afterward.

My personal goal had been to view and image as much of the far southern sky as possible. By "far south" I mean everything not visible from New Mexico. I also wanted to improve upon some images I had taken during the LCAS 1996 trip to Gran Quivera. Although our observing time was reduced by the weather, we were still able to enjoy many of the best objects the southern sky has to offer. Some highlights...

The Jewelbox Cluster: A brilliant open cluster, the Jewelbox contains several red giant and blue giant stars. If the orange and blue Albireo is considered to be the most beautiful of the binary star systems, imagine several Albireo-class stars embedded in a bright open cluster!

The Large Magellanic Cloud: The LMC and Tarantula Nebula are a treat at all levels: naked eye, binocular, and telescope. Below is a piggyback image of the LMC. I used Kodak Royal Gold 1000, 300mm, at f/5, for 5 minutes.

Eta Carinae and the Keyhole Nebula: The nebulosity around Eta Carinae has a beauty and texture that is the equal of M42, the Great Nebula in Orion. My ST-7 image is below. The bright object is Eta Carinae, and the "keyhole" is the region to the left of it.

47 Tucanae: 47 Tucanae is one of the Milky Way's largest and intrinsically brightest globular clusters. A naked eye object, it is magnificent in the telescope and in my ST-6B image below.

M83: M83 is a large, face-on, "grand design" spiral galaxy. Steven Williams and I had been having a friendly debate about the merits of the "large pixels" of the ST-6B versus the "small pixels" of the ST-7. When he published a wonderful M83 image on the GCO Web site, I suggested that I take an image using my ST-7 on the GCO scope. This would allow us a real "apples to apples" comparison of the cameras using the same object and same telescope configuration. My image turned out quite well.

Centaurus A: This is an enormous radio-bright galaxy that is actually a galaxy merger in progress: an elliptical galaxy merging with a small spiral galaxy. The image below is the result of an experiment with the ST-7. We took a single 10 minute image guided by the ST-4. We then took a 10 minute unguided image using the ST-7 Track-and-Accumulate feature. Both turned out well, and I combined them into a single image.

These are just a sample of what it is possible to see from GCO.

So, what's our verdict on Grove Creek Observatory? As Siskel and Ebert would say: Two Thumbs Up!

The GCO Web page is at: http://www.gco.org.au/

Published in the November 1998 issue of the NightTimes