Wednesday, June 6, 2012

Transit! (part 1)

Venus captured in H-Alpha (PST; Microsoft Lifecam)

Tuesday, June 5 dawned clear and calm.  Intellicast forecast a cloud-free day here in "the warm heart of the world."  I got up, checked the scopes (PST and my trusty ETX-90 RA) and loaded the equipment into the truck. 

By lunchtime, fluffy, white clouds were sailing sedately in from the Northeast--rarely a good sign in Indiana; but the forecast still said, "clear skies."  By 3pm, there was an almost solid overcast, with glimpses of sun here and there.  The forecast now said, "partly cloudy," but skies were forecast to be clear by 6 pm.

The site I chose to observe the transit is about a quarter mile from my new observatory site, but on the same property.  The chosen site has a superb view to the west from an elevation. I set out to the site with family in tow a little after 5 pm for the 10-mile drive. 

Of course, we hit what passes for rush hour in this small town and roadworks delayed us for 10 minutes or more.  The sky continued obstinately overcast, but with glimpses of sun in small gaps.

We arrived with time to set up (but none to waste).  I got the PST and the ETX up and running, then cloud covered the sun.  I had my iphone app ready and running, but the clouds seemed to have slowed down and the sun remained invisible.  As the cloud cleared a little, I could see the first "bite" of Venus as the transit began.  My iphone app was designed to capture and submit data from Contact II, where the edge of Venus touches the edge of the solar disk as it ingresses.  The "teardrop" effect is supposed to make this difficult to time.  However, I saw no effect, and, at 18:21:46, I hit the phone to capture the time.  Nothing happened.  The app that had been working perfectly all day decided to malfunction.  I wrote the time down on a card.  Later in the evening, after sunset, I checked the official time for Contact II--it was 18:21:53!  I was amazed at how close I'd come in my measurement.  Clouds continued intermittently, but I was able to watch pretty much the whole transit as visible here from Indiana.,