This is a report on my trip last week to the Tammin observing site (some 150km+ east of Perth) which is operated by the Astronomical Society of Western Australia (ASWA). Tammin is in the Central Wheatbelt region of Western Australia, and wheat fields and silos for the storage of the harvest can be seen everywhere.
I spent 3 full nights at the observing site, Fri 20th, Sat 21st, and Sun 22nd April 2012. New Moon was on the 21st. I stayed over during the daytime at the Tammin Hotel in the nearby small settlement of Tammin (about 6 km south of the site). The local Roadhouse (also known as a “Servo”) is open 24/7, has a mini-supermarket, a restaurant which serves hot food, and a petrol station.
I was hosted by Bill, who is ASWA’s Tammin site administrator. He also spent all 3 nights at the Tammin observing site. Many thanks to Bill for hosting and looking after me!
We were quite fortunate
weather-wise, for all 3 nights were very clear. Only the 2nd night had periods of heavy cloud cover before midnight, but that was only for about 3 hours altogether that night. Other than that, about the only clouds present during the 3 nights were the Magellanic ones, and being circumpolar objects they never set during the night. I was told that it was unusual to have 3 consecutive clear nights, and the clear-nights rate (after following weather predictions of clear weather) is around 75% for visual observers. Being late autumn, it got cold those nights, with the temperature dropping to around 8-10 degrees Celsius at its lowest. Sunset was around 5:45pm and sunrise at around 6:30am.
Equipment wise, I brought along from Singapore all that I could carry given the weight allowance of Qantas of 23kg for the checked-in luggage and 7kg for the carry-on bag. Even so, I was about 2.5kg overweight for the carry-on bag. Astro equipment which I brought were:
- Celestron C-6 OTA with Rigel Quickfinder added. (Hand-carried)
- Vixen Porta II alt-azimuth head mounted on a Manfrotto 055 tripod, via a Vixen tripod adapter and a 1/4 to 3/8 inch adapter.
- Canon 15x50 IS bino, which I used mounted on a China-brand Weifeng tripod and ball-head, instead of using the IS feature.
- Astrotrac mounted on a Manfrotto 190 tripod.
- Canon EOS 60D dSLR, a Canon 10-22mm ultrawide lens, and a Sigma 17-70mm lens.
- Eyepieces and accessories: Meade 24mm SWA, Pentax 14mm XL, Celestron 2x Ultima barlow, Celestron f/6.3 focal reducer.
All-in-all, I think the equipment which I brought along were sufficient for the trip and enabled me to make full use of the 3 nights there. I had to weigh every piece of equipment and accessory when planning what to bring and what not to bring along.
During the 1st night (Fri), there were I think altogether 3 cars and 4 people there. During the 2nd night (Sat), there were about 6 cars and 12-15 people, and on the 3rd night there were again 3 cars and 4 persons there (me included). Other scopes there included 14 and 15” Dobs, a 12” Meade SCT, and a 6” Takahashi TOA apo.
All photos below were taken by me, and most astrophotos were taken using the Astrotrac, which performed very well. I used the Astrotrac on the 1st and 2nd nights, but did not deploy it on the 3rd night as I wanted to concentrate on visual. Even so, I ended up taking at lot of photos on the 3rd night with the camera on a photo tripod; couldn’t resist trying to capture what I was seeing. I did rudimentary post-processing of the photos with Photoshop, mainly to remove the (minimal amount of) noise using dark frames, to adjust brightness levels, and to reduce the faint small yellowish glow of distant towns mainly in the south.
The flat observing site has
unobstructed views down to about 2 to 5 degrees all round, with only a few small trees at the site causing any greater obstruction otherwise. Here is a sunset photo, which was actually taken on the 3rd night there (Sunday night):
And this is a photo which I took right after sunset of the eastern horizon opposite the Sun (west), and the shadow of the body of the Earth cast against its atmosphere can be seen as a dark band just above the horizon. This was the first time I closely observed such a phenomenon, and the shadow was seen getting wider and wider as the Sun set further and further down below the horizon in the west. Above the dark shadow band is the pinkish Belt of Venus.
To confirm it was the shadow, I also looked left and right of the shadow band and it could be seen tapering and thinning down to nothingness in the north and southern horizons.
The following is a panoramic shot stitched together from 3 ultrawide shots which I took just after sunset: one of the west, one right overhead pointed at the zenith, and one of the east. It shows the sky continuously from the western horizon (at left) to the eastern horizon (at right).
As night fell, Orion was setting in the west, as can be seen here in this ultrawide photo:
And here is a self-portrait of me in silhouette looking at the rising Milky Way through the 15x50 binos. I’ve removed the colour to better approximate what was seen in real life.
The skies were simply magnificent! As night fell, the Coal Sack was a prominent dark hole high up in the south. There was no need to try to see if one could discern it, it was just there staring at you. As an almost inverse mirror image of this black gap, the milky grey Large Magellanic Cloud stood opposite the Coal Sack about 30 degrees away, flanked by its Small cousin.
In the early night, the whole southern arm of the Milky Way arched right across the sky from Crux down to the Puppis and Orion region.
I spent hours with the 15x50 bino viewing the nebulosity in Carina esp around Eta-Carinae, the intricate details of milky-white/grey and contrasting dark lane splotches of the Milky Way esp in the central bulge region, the incredibly dark Coal Sack, and the endless star-rich fields around Puppis which seem like one continuous giant open cluster. In my view, the Canon 15x50 IS bino, with its flat 4.5 degree field and pin-sharp optics is an excellent visual instrument and can be sufficient on its own for an astronomy trip. I mounted it on a tripod with ball-head most of the time since it is a bit heavy for prolonged use, and the image stablisation when hand-held is not total esp when compared with having it mounted.
The main highlight for me was seeing the sky with unaided eyes at around 3.30am-4.30am, which was when the
central bulge of the Milky Way stood right overhead at the zenith, with the northern arm arching down to about 10-15 degrees above the northern horizon in Cygnus, and the brighter southern arm arching through Crux-Carina and down to also around 10-15 degrees above the southern horizon in Vela, in symmetrical form. And faithfully perched below the southern arm were the two Magellanic Clouds. It was 3 large naked-eye galaxies at one go! The Milky Way’s Central Bulge seemed like one bright giant space-ship or insect peering down at me, with the two arms enveloping all below in an embrace. It also seemed like one white rainbow that arched across the sky from above one horizon to the zenith and down to the other horizon.
As an aside, here is an interesting note of comparison: though the Coal Sack can only very rarely be discerned at our observing sites in Telok Sari and Kahang (both in Johor) due to the sky-glow caused by Singapore-JB in the south, the Dark Horse dark nebula in the central Milky Way did not seem much more prominent at Tammin as compared with the best times in Telok Sari/Kahang. So the skies in Johor away from the low southern horizon can be rated in many ways as excellent too.
So bright and clear were the stars and the Milky Way at Tammin that it was as if someone had pulled the curtains across the sky and switched on the lights to reveal the entire universe. This was my sense of it throughout the whole night from dusk onwards.
One of the main astronomical features seen was the Emu. This is the bird seen as dark nebulae, with its head and beak comprised by the Coal Sack, and its body, arms and legs made up of other dark lanes/patches of the Milky Way north of the Coal Sack to the central bulge of the Milky Way. It must be the largest feature/asterism of any kind in the sky.
At its brightest, the Milky Way did indeed cast shadows, and I could discern shadows as I waved my hand across a table or book and also faintly around my feet as I walked about, as if someone was following me about. I also managed to just about photograph the shadow here:
Here is an image of the Milky Way’s central bulge region taken with the Sigma 17-70mm lens at 70mm:
At around 4-5am, someone mentioned that the sky in the east near the horizon was glowing, and we then realized it was the zodiacal light. Here is a photograph of it. The bright object just above the horizon is Mercury and the ecliptic runs vertically up from the horizon right where Mercury is. At the time this photo was taken, the Sun was some 21 degrees below the horizon.
And here is me peering through the C-6 OTA:
This was certainly my best astronomy trip ever. Three full nights viewing the full splendor of the Southern Sky!
I’ll add more observing notes on another day, particularly on some the DSOs seen, esp the Tarantula Nebula compared with M42 and Eta Carinae, my impressions of the Large and Small Magellanic Clouds, comparing 47 Tucanae with Omega Centauri, etc. Stay tuned….
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