The 2012 June 5-6 transit of Venus (ToV) is over, and there won't be another one till 2117! Many RASC members successfully viewed the ToV here and abroad, and you can find the graphic record of the observations―and of the astronomers making them―here.
Note: all images are copyright of the attributed photographers and graphic artists, and must not be used without prior permission
Alan Whitman, RASC Okanagan Centre Transit Chasing Group
On Sunday June 3rd I told my wife and Jim Failes (whom I travelled with) that it looked to me like everything was coming together meteorologically for southern Alberta to probably have severe thunderstorms and quite possibly tornadoes on Tuesday the 5th, transit of Venus day. At the time, the Environment Canada public forecast just said "showers" on Tuesday, not even a mention of thunderstorms (although they must have been thinking that severe weather was possible). I packed my 10x30 Canon IS binoculars just in case I had a chance to combine storm chasing with the transit of Venus.
We had ended up in Taber, Alberta for the transit because four consecutive Clear Sky Clocks had forecast a brief clear slot to develop shortly before the transit of Venus began over south central Alberta, and because the convergence zone near Taber was the only area in southern Saskatchewan and Alberta where strong gusty winds were not forecast and occurring, easterly winds over Saskatchewan and eastern Alberta and westerly winds west of Taber. I could not see how you could expect to observe any detail elsewhere on the western Prairies where howling winds would be shaking your telescope and also causing poor seeing. If it had not been necessary to find the one area with only a light breeze, the convergence zone would have been avoided since it causes low level clouds to form (as it did briefly, but only for about 20 minutes, and those cumulus clouds dissipated about an hour before the transit began).
The sky was almost clear 40 minutes before first contact, then mid-level altocumulus castellanus clouds caught us as they raced northwards from Montana faster than we could drive.
We had about twelve brief breaks between the first and second contacts. Jim and I saw the subtle aureole (the backlit atmosphere of Venus) while Venus was crossing the Sun's limb and an amazingly long black drop effect. The black drop lasted about 100 seconds, far longer than I had thought was possible -- presumbably the black drop was due to poor seeing because the jet stream was overhead, flowing from the SSE towards the NNW.
After second contact Ken Barron's car travelled west towards Lethbridge and on home towards BC on Hwy 3. They reported driving through very heavy rain in a thunderstorm. About the same time I pointed out to Jim a strong well-developed thunderstorm in the distant west with an overshooting top above the anvil (one where the updraft is so strong that it penetrates into the stratosphere). Minutes after I pointed out this powerful thunderstorm, the radio announced a tornado watch (not a warning) for Lethbridge. That was the only thunderstorm visible to the west, so I think that our observing buddies drove through the thunderstorm that resulted in the tornado watch!
At some time on Tuesday during daylight (I'm not sure when) a video was shot of a tornado near Taber (the town east of Lethbridge where we had watched the transit).This video was on the Weather Channel the next day.
We spent the night at Strathmore, about 50km east of Calgary on the Trans-Canada Highway. After 9pm we had heavy thunderstorms with strong gusty winds and heavy rain, but fortunately no large hail on my car in the parking lot. At 11:14 pm Environment Canada issued a tornado watch for Strathmore and several adjacent towns, and a tornado warning for Brooks, a town further east that we had been in twice earlier that day.
The next morning the Weather Channel stated that there had been four confirmed tornadoes in southern Alberta, and played the video of the tornado that had occurred somewhere in the Taber area.
On Wednesday morning we had only driven a few minutes west from our hotel when I spotted a tornado damage path crossing the Trans Canada Highway. We don't know whether this was one of the four known tornadoes from the preceeding day and overnight. Jim photographed some of the damage: two grain bins that were blown over and crushed, about a dozen snapped off or uprooted junk trees, about 20 metres of torn up and mangled barb wire fence, very minor damage to a barn (but the barn was on the weak western side of the tornado path where the forward speed of the thunderstorm is SUBTRACTED from the tornado's wind speed -- on the eastern side of the tornado path the two vectors add together), and typical tornadic wind patterns in the flattened long grass. It was a weak tornado, probably about an F1.
The rivers and streams in Banff and Kootenay National Parks were in flood due to the exceptional rainfall event in southern Alberta and southern interior British Columbia.That morning we had learned that Rogers Pass on the Trans-Canada Highway was closed due to a debris slide caused by the exceptional rainfall. So we diverted southwards towards Highway 3 and 6500-foot high Kootenay Pass and the three lower passes to the west of it. I was not looking forward to this since the freezing level was an unseasonably low 4600 feet, my snow tires came off two months ago, and my new car is snaky in snow without snow tires. Sometime shortly before we reached the town of Creston, the valley town on the eastern side of Kootenay Pass, they closed the pass due to snow and an accident. This is the only time in the 45 years that I have lived in British Columbia that both highways have been closed in summer -- this is rare enough in winter.
We assumed that all motels were filled or rapidly filling in the small towns on both sides of Kootenay Pass. There is a round-about route involving a ferry across Kootenay Lake, but we assumed that there would already be a wait of a great many hours for that ferry since all of the heavy traffic from the Trans-Canada Highway had already been diverted south onto Highway 3. [As it turned out, the regular ferry was out for repair and a smaller temporary replacement was in service! Then that road was washed out too!]
We had had enough of mountain passes. We did not even consider Washington Route 20 since it involved 5800-foot high Sherman Pass which would also be snowing heavily. So we went all the way south to Spokane, Washington and avoided all the mountain passes.
Rather fun in a way to actually experience some severe weather for a change: the Okanagan Valley where we live is noted for its extremely boring lack of significant weather. And we saw the transit of Venus.
Dave Whalley, RASC Okanagan Centre Transit Chasing Group
This rare event was not to be missed no matter where I had to travel. The Transit of Venus occurs when Venus passes directly in front of the sun, the next time this happens is 2117, 105 years from now.
As with the eclipse, being within driving distance a group of us local Astronomer/idiots were determined to see this event. As the weather reports were dismal for most of British Columbia and surrounding States and Provinces, it was determined that a long journey would be needed to have any chance of success.
Alan Whitman was our weather guru, he was accompanied by Jim Failes who became contact person for everyone on the road and to pass on weather advice from Alan. I traveled with Ken Barron in his minivan. We loaded all our gear into Kens van, headed up to Kelowna to pickup Serge Fjetland and about 11.30 set off north for Sicamous and Hwy 1 where we turned east towards Alberta or Saskatchewan to find clear sky for the Transit. We took turns driving, through the Rockies where we saw a bear at the side of the road, on through Calgary to Medicine Hat for the night, Approaching Medicine Hat in the dark, a lightning storm was lighting up the sky many miles ahead of us. We booked in to Super 8 hotel for the night.
Next morning I was up bright and early and went for a walk, there was lots of clear sky and the Full Moon was low in the west, it looked hopeful for the transit right there in Medicine Hat. Later in the morning, Alan advised that we need to move so we followed along, traveled to Brooks, then down to Taber where the best weather chance appeared to be. After chasing around we pulled into the entrance to a field with about 15 minutes to setup our telescopes, I decided to just setup the 100mm refractor when I realised I wouldn’t have time to set up the celestron 8”, I only just got setup when Alan announced first contact. When second contact arrived, I saw the famous black drop, I also saw cloud scudding across the field of view in the eyepiece, the sun was covered and uncovered several times and then finally complete cloud cover. So we saw the first 45 minutes of the transit.
There being no chance seeing the sun again at this location everyone packed up, the other group set off north towards Calgary and we decided to take Hwy 3 as we were already on that highway. Leaving Taber we had heavy rainfall and lightning, probably associated with the tornado we just missed in Taber, We drove to Fernie BC where we spent the night. Next day we saw there had been a mudslide on Hwy One and realised the other group now faced a long detour to get home. As we headed west we had constant rain, all the creeks and rivers were high to flooding and any mountain pass was snow, the worst snowy pass was Kootanay Pass where an accident closed the highway later in the day.
We had lunch in Grand Forks and turned off Hwy 3 up Hwy 33 to Kelowna. Just before Kelowna there was a beer truck upside down at a bend in the road and all emergency service vehicles in attendance. Dropped Serge off at home then south on Hwy 97 and home.
Dave's images can be found here.