by Albert Highe
Approximately 27 hours after leaving home in California, Bob and I arrived in Hawker, population 300, 365 km north of Adelaide. We spent two nights at a small cottage just north of town. Despite only a few hours sleep on the plane, Bob and I couldn't resist the dark skies. We assembled our telescopes and managed to observe three hours before collapsing from exhaustion.
David spent the first night with his cousin in Adelaide. He joined us in Hawker the second night. Conditions this night turned out to be the worst of the trip. Clouds moved in during the day, and took their time dissipating after sunset. Transparency suffered. Clouds returned in earnest and shut us down by 1:30AM.
The skies were partly cloudy all day during our drive north to Wirrealpa Station, population 2, 550 km north of Adelaide. The homestead and our cabin were the only occupied structures on the 35 km by 45 km working sheep ranch. The nearest town, Blinman (population 25), is 40km to the West. When you look up "middle of no where" in the dictionary, you'll see a picture of where we were. The terrain looks similar to the Mojave or Arizona deserts, except for the dried up stream beds which are cluttered with large gum trees, hundreds of years old. As you might expect, the sky is as dark as it is going to get and light domes were non-existent. In fact, around 3-4AM each night we experienced our worst light pollution. At that time the sky was noticeably brighter and the ground and surroundings were easier to see. This is when Sagittarius was directly overhead and the Milky Way was a broad bright band of light extending east to west all the way to the horizon. I've read descriptions of the Milky Way casting shadows. Now I understand why. Consequently, I don't think the skies were any darker than mag 6.5.
During the first of three nights at Wirrealpa, the clouds cleared around Midnight and we observed until dawn. The second and third nights were clear throughout. All three of us observed from dusk until dawn the second night. The third night David managed a second marathon all-nighter. Bob and I had to call it quits at 3AM. Our accommodations were rustic but functional and comfortable. More importantly, when we called it quits, we walked less than 10 yards from our scopes to our beds.
Our hosts, Warren and Barbara Fargher, are among the few remaining authentic Australian ranchers. Although they have a difficult life working the 5500 head of sheep and 1000 head of cattle in the semi-arid Outback, they are out-going, gracious, and considerate people who made us feel welcome. For example, Warren thoughtfully drove out one morning at 4AM with only his parking lights on. He couldn't tell if we were observing, but he surmised the lights would disturb us if we were. He also noticed a flat on David's car and fixed it for free. They invited us over to their house for a barbecue one night. We learned a lot about South Australia over grilled chicken, sausage, and steaks. For dessert, we ate homemade quandong pie, made from the fruit Barbara gathered from the wild quandong trees on their property. The evening was one of the highlights of the trip.
We then drove 130 km over rough gravel roads north to Arkaroola (http://www.arkaroola.com.au/) where we spent our final three nights. Arkaroola is an oasis in the middle of no where. This wilderness sanctuary lies 700 km north of Adelaide. Our rooms were almost plush. The complex can hold as many as 200 guests. The owner, Doug Sprigg, understands astronomers' needs and was exceptionally accommodating. He has a C-14 set up in two different domed observatory buildings which he uses to conduct sky tours for the guests. Although we could have used these instruments for free, we opted to use our own telescopes - equipment familiar to us. He allowed us to set up our scopes in a large roll-top observatory sitting atop a hill 150 feet above, and overlooking, the complex, approximately ¼ mile away. When we were done observing for the night, we just closed the roof, locked the door, and drove to our rooms. Very convenient. Doug also is an accomplished pilot, conducting daily scenic flights over the surrounding mountains. We took one of his flights our last day there.
Observing conditions were very pleasant. Temperatures were in the mid to low 70's from sunset until after midnight and dropping into the 60's by early the next morning. We typically observed in our shirtsleeves until 2AM. A light jacket was the most anyone wore. Humidity was typically 40-50%. There was little to no wind during most nights. One night at Wirrealpa the wind rose to10-12 mph for a couple of hours. The gusts were strong enough to occasionally move the scope.
The ever-present outback flies were a nuisance during the day. However, after the sun went down, the night was completely bug-free. We never saw any of the legendary poisonous snakes. Emus and Euros (medium-sized kangaroos) were rather plentiful. We saw at least a dozen of each.
My list of potential targets had grown to almost 1000. It included all the NGC objects between Right Ascension 5 - 20 hr and below Declination -40. It also included selected IC and ESO targets, a few Gum nebulas, and brighter showpieces between Declination -20 and -40 that would be more favorably placed from the southern hemisphere. Although the position of the Large Magellanic Cloud wasn't optimal, I placed heavy emphasis on observing objects within it. I hoped to observe a large fraction of the 300 LMC objects plotted on pages A24 and A25 in the new Uranometria - South.
I ended up logging approximately 650 observations - 325 within the LMC. Although this number exceeds the number plotted in Uranometria, I didn't finish observing all of those objects. However, the LMC is so rich, I frequently encountered other bright targets not plotted in Uranometria. I saw more than 325 objects, but only counted those objects I wrote descriptions for and was able to unambiguously identify.
During the next several days I'll follow up with more detailed observations of some of the observing highlights.
I used a 13" f/4.5 travel scope I built for the trip. You can read about it at http://ultralightscopes.com/MarkIVtravel.htm
No GOTO. 10-15 objects per hour is my typical observing rate during the past few years. The all-nighter at Wirrealpa was my most productive night - I averaged 18 objects an hour for 9 hours. I was exhausted. It's difficult to achieve those rates if the objects are spread across the sky. However, that night almost all of the objects were within the LMC or the Centaurus galaxy cluster, Abell 3526. Within such dense object fields one uses the orientation of the objects themselves to hop to the next one. In fact, GOTO isn't much use in these fields, although tracking would be nice.
I didn't use to be so efficient. And during my observing sessions in New Zealand last year, I didn't come close to that rate. The key factors were:
By the way, I now do own a GOTO scope. I added a ServoCat drive system to my 12-1/5" f/5. Although the primary goal was to have tracking for high power observations of planets and dense galaxy fields, I've enjoyed using the GOTO as well.
Posted on sf-bay-tac Apr 14, 2005 18:45:43 PT
Converted by report.pm 1.2 Apr 23, 2005 20:09:06 PT