The Transit of Venus on Tuesday, June 5, begins for us in Central Maine at 6:03pm, and continues out of our sight well past sundown. This is a once-in-a-lifetime opportunity. If you miss this transit (or, horrors! if clouds hide it), report to the meeting of the Central Maine Astronomical Society hereby scheduled for the next transit, on December 10, 2117.
The transit poses special problems for scheduling, due to its hour and CMAS’s large realm. It would not be possible, for example, for CMASers living on our Eastern frontier near Lewiston to leave work at 5:00pm, and arrive at Galaxy Quest in Lincolnville in time to see the transit. Might or might not catch a peek prior to the Sun’s dropping below the horizon, but would surely miss the ingress, the most interesting part.
The best strategy seems to be to plan a number of sites, so we may all arrive on time and dodge clouds if necessary. Jacob will be at Galaxy Quest with his new collection of solar viewing glasses. Colin will be at a cemetary near Brower Observatory. (Brower itself has too many trees on its Western flank to be a good site for the transit.) I could be at either of those sites, or a third site, if that would help more members to see the transit.
If the third site is not absolutely necessary, it would be better for me to go to Brower, because then each of our two locations could have a solar telescope, rather than the third going without. Then again, it would be wise to have a third or even fourth or fifth site planned. Then if the primary sites were cloudy, we might yet be able to meet elsewhere under clear skies.
For the third site, I propose Metcalf Road, the hill behind the Rite Aid in Winthrop. This would, for example, allow the folks who volunteered at the YMCA camp to arrive in time for the transit. I would need to get the landowner’s permission, so please be in touch immediately if you would want to meet there. Suggestions for other sites in this area are welcome.
The Damariscotta River Association’s site would also work, but it is only half an hour from Brower. If anyone needs DRA in order to arrive on time, please offer to be the host, and let me know so the club can advertise the site. It would be better in terms of available solar viewing equipment to gather at the cemetery near Brower.
I have purchased a sheet of solar filtering film that will allow my refractor and binoculars to be used to look at the Sun. Unlike the club’s specialized solar telescopes, this film will not show solar prominences. That’s fine, as our target will be Venus, and, if we’re lucky, the “black drop” appearing briefly as Venus touches the Sun’s edge.
Solar film and glass filters are selling out worldwide. As of this writing, the film is still in stock at:
Many Web sites recommend #14 welder’s glass as a safe alternative, provided it is of the type to block 100% of the Sun’s ultravilolet rays. (I’ve been warned by a vendor of solar film that some welder’s glass is #14, yet is inadequate in its ultraviolet protection.) Colin uses #9 or #10 when the Sun is low on the horizon, and so is less intense. Transitofvenus.org says that if you can see the surrounding scenery through the glass, it is not dark enough; one should see only the large disk of the Sun with the small black disk of Venus crossing it.
Plenty of details are available online:
http://www.skyandtelescope.com/observing/home/Transits-of-Venus-Explained-152556885.html
