The Transit of Venus 2012

The last time there was a Transit of Venus, in 2004, I didn’t have broadband. I shudder to think what the early hours of Wednesday morning would have been like had I remained a Luddite. For this Transit, the last until 2117, I was monitoring the live webcast from the Mauna Kea observatory in Hawaii on one computer and, on the other, the feed from the Mount Wilson observatory in California. The UK wasn’t going to be able to see anything, in theory, until sunrise on Wednesday, by which time, the planet would be about to reach the point of Interior Egress, where it starts to cross the solar limb for the second time (i.e., where the edge of the disk of Venus just crosses the edge of the disk of the Sun). Under twenty minutes later, at 05:54 BST, Exterior Egress would occur, then the Transit would be over.

I don’t have suitable equipment for solar viewing, so a little improvisation was called for. To view the 1999 Solar Eclipse, I projected the image on to a piece of A4 paper sellotaped to the wall of the building I worked in. 

With me in charge of the camera, I cajoled a couple of my colleagues into holding a monocular at a suitable angle, or securing it to the departmental tripod. Back then, you could have fun like that during working hours.

I returned from holiday late on Tuesday afternoon and dug out some sheets of card, a piece of tinfoil (no, not to make a hat!), sellotape and scissors. I made a pinhole viewer 

and, in case that didn’t work, I attached a piece of card, rather clumsily, to my trusty old monocular to cut down shadows. 

I selected suitable clothing, and set two alarms; one for 03:45 BST and one for 04:00. All I had to do was wait.

It didn’t occur to me that I would be able to watch this phenomenon via the Internet, and this is where Twitter came into its own. I follow a number of accounts associated with astronomy, including Dr. Lucie Green, a solar physicist, and Pete Lawrence, a renowned solar imager and co-presenter of ‘The Sky at Night’. I also follow NASA, and they announced that there would be a live feed from Mauna Kea. There were also links on NASA’s page to a number of other sites, and I settled on the webcast from Mount Wilson. It was difficult to follow both at the same time, especially as the two computers were about 10 feet apart, so I turned the sound down on both and just watched the event unfolding. I also took photographs from the screens.

I have no idea about solar images. I think this Mauna Kea picture is Hydrogen Alpha.

And this, from Mt. Wilson, is a white light, or continuum, image.

Of course, I may be barking up the wrong tree.

The most exciting part is the time between Exterior Ingress and Exterior Ingress (the opposite of what I mentioned earlier), after which the entire disk of Venus is within that of the Sun, then it’s a slow crawl East to West to get the other side (but, if I'm right, it’s not really a straight line, and the angle of the arc is different depending on where you are). After I watched it move away from the edge (or solar limb, if you wish), as in the Mt. Wilson image, above, I went to bed.

The weather forecast wasn’t favourable, and Glasgow has an average cloud cover for June of 75%, so I wasn’t surprised when I looked out of the window at 03:45 and couldn’t see the sky. We had 8 days of clear nights before I went away, and the weather in Perthshire was pleasant, to say the least. Typical, bloody typical. Undeterred, I went out at 04:30, and drove up the hill to a spot with a better take-off to the East than at home. I sat in the car with the intention of waiting until 05:30 then scurrying over to the site in time to set up. A fox appeared, then the rain, and it was obvious that my efforts would not bear fruit.

At 05:55, I made my way back to the car, and headed for Tesco. What else was there to do at that time in the morning?

So, what did I learn and/or what do I have to do now? Let’s see:

1. I need to find a more secluded spot for observing, as a patch of green opposite a row of houses is neither private nor safe.
2. I think that the pinhole viewer will have to be tested with the sun early in the morning on a nice day to see if it works. If so, a pinhole projector could be built out of cardboard boxes for viewing the sun to look for sunspots.
3. Similarly for the monocular.
4. There are designs on the Web for a sun funnel to be used with a telescope. Again, the sun, and sunspots, could be projected using this method, perhaps in conjunction with my reflector, which will have to be modified, first.
5. I'm not very good at this. 

I’ll not be around in 2117, so I guess that’s it.