Wednesday, June 6, 2012

A suspiciously round sunspot...

Figure 1:
Venus, just appearing at 1609 MDT - in the upper-left edge of
the disk.
Click on the image for a larger version.
I decided that I'll contribute to the frenzy of what are likely to be many thousands (or millions!) of pictures that have/will appear(ed) on the web of the Transit of Venus that occurred yesterday, on the 5th of June in North America.

Here in the Salt Lake area the weather degraded rapidly over the day from the 90's F on Monday to something in the high 50's or low 60's just 24 hours later.  In the valley itself, the broken clouds in the morning degenerated to swirling layers of clouds moving in opposite directions, each conspiring to obscure the view of the event taking place well above them.

Only somewhat daunted, I set up my telescope at work and hoped for the occasional, brief respite of clouds.  Prior to the start of the transit I got enough glimpses to get the telescope aligned so that the tracking motor was doing a reasonable job of keeping the occasionally-visible solar disk within the viewfinder when it was visible, but most of the time the view was completely black, the solar filter being too dark to allow a view of the clouds themselves.

Figure 2:
Just three minutes later, a large nibble taken by Venus!
Click on the image for a larger version.
Finally, at about 9 minutes past 4 PM local time there was a brief clearing and it took a moment of staring at the disk to spot the round imperfection - a small nibble out of the upper-right corner of the picture.  The picture itself is somewhat fuzzy - despite the use of an 8" reflector telescope - because it was shot through a thin layer of clouds.

About 3 minutes later, I had another brief clearing and the apparent imperfection on the sun had visibly changed.

Figure 3:
The view at 1911 MDT.  If you can't spot
Venus now, you need new glasses!
Click on the image for a larger version.
Soon after this, the clouds got darker and thicker and I figured that this was to be the last opportunity to photograph the event from the Salt Lake Valley - which was too bad since I'd planned to haul my telescope across town to my parents place so that they could take a look.

Fortunately, there was a backup plan.  As it turned out, the cloudy weather in the Salt Lake valley was not occurring 40 or so miles south in Utah county, so I packed up the telescope, picked up my Mom (my Dad couldn't leave due to other obligations...) and went south and upon crossing over the traverse mountain range that separates the two valleys, it looked much more promising with Provo and points south being bathed in sunlight.  Coordinating with my younger brother, we met in Provo, setting up in a location with a decent view toward the west, just as the clouds covered the sun.

Fortunately, we didn't have to wait for very long for a view with the clouds scutting past, sometimes providing a dramatic effect to the shot.  Since it had been nearly two hours since I'd last seen the sun, the change in Venus' position was extremely obvious, as you can see from the picture.

Figure 4:
One of the last views of the sun at 2015 MDT
before the sun set below the local horizon.
Click on the image for a larger version.

Over the next hour or so the sun came and went through breaks in the clouds and we finally lost sight of it when it dipped below buildings to the west of us, getting noticeably fuzzier as it got lower in the west - and probably due to thin clouds in front of it.

By this point, it was starting to get cold so we finished our pizza, talked for a while and then headed back home.

All in all, it was certainly worth the time it took to see something that very few alive today will see when it happens again in 2117.

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