More Mercury Transit from 9 May

TAAA Support of Public Mercury Transit Event At Brandi Fenton Memorial Park

By Jim O’Connor

Pictures by Jim Knoll

TAAA has a long history of supporting Pima County Natural Resources/Parks and Recreation and their active astronomical outreach programs. Usually these events are at either the Ironwood Picnic Area on the West Side, or Agua Caliente Park on the East side. For the Mercury transit, however, the venue would be Pima County’s Brandi Fenton Memorial Park. TAAA has performed public Astronomy Festivals at that location in the past, so it was a familiar location.

The event was scheduled from 8 AM through 10 AM, which was a segment in the middle of the transit. The transit itself was forecast to occur from 4:12 AM through 11:42 AM, with sunrise around 5:35 AM, so most of us planned on being there at our earliest convenience, and to stay through the end of the event.

I tried to arrive by 6:30 AM, but my guess on how long the drive would take was wrong, and I didn’t show up until around 6:40. Alan Klus had his dual mount already on the sun, while Jim and Sue Knoll were finishing their setup. As I was setting up, Ron Brewster and Bill Yohey arrived and began setting up, as well as a young lady with a 10” Dobsonian reflector who I did not recognize. We ended up with a mix of white light and H-Alpha scopes. I thought about both options, and while my white light choice would be 90mm, larger than my 60mm Lunt solar scope, I also wanted to take a chance on more solar artifacts being available in the Lunt. Jim Knoll also has Lunt 60mm, but while I have a B600 blocking filter, Jim has a B1200, resulting in a tighter frequency band and more detail in his images. This holds true in eyepiece views, but I push mine through a Mallincam Xterminator, and the resulting image in the attached 19” monitor does well at pulling out details. Unfortunately, I left my laptop and camera home, so I couldn’t capture transit images, nor any of the crowd we had attending the event. Jim Knoll provided some photos he took.

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Mercury Transit at Brandi Fenton
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Alan Klus

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As soon as I got completely set up, the first solar image showed Mercury right where it should be. When Jim commented that he was getting prominences in his view, I altered my exposure time and, sure enough, in my view there were two fountains at the top of my screen, one at approximately 11:30 on the face, and the other at about 12:30. Each was three to four Earth diameters, and resembled spraying fans. Positions on the screen are kind of irrelevant, because not only does the telescope and blocking filter diagonal provide an image rotation, but the image orientation itself is dependent on the orientation of the camera in the eyepiece opening. I readjusted the shutter speed to lose the prominences but highlight the surface characteristics. The sun itself was very entertaining, with multiple wide, long, and arching filament groups and several dynamic, bright white active regions. During the morning, I had about 65 or more visitors. Everyone was amazed at the view, not only the crisp, black disk of Mercury, but all of the other artifacts that varied over time. I had two large poster sets at the table; one had solar characteristics, examples, and stellar evolution, the other had displays of the Mercury transit, an image of Mercury, and a fact sheet about Mercury. The visitors to my setup were all very excited to see not only the transit itself, but all of the solar action. I made sure to tell everyone about Saturday’s TAAA Astronomy Festival at the same location. I was also able to hand out about 10 solar tattoos to young children in the visitor groups. Some of the visitors were bicycle riders and people walking their pets who were pleasantly surprised to find us, and it was a great educational opportunity on the nature of the orbits in the Solar System, and also to discuss stellar evolution. There were even some folks, young and old, who wanted to discuss the varying forms in which stars end their existence. We were not terribly busy, and the chance to spread the information was great to have. Toward the end of the session, after about 10 AM, I enclosed the monitor in a box to cut down on reflections from people’s clothing onto the screen, but the matte surface of the monitor does well on its own to put out a good image, as long as the sun is behind or to the side of the observer. The visitors did seem more comfortable with the shadow box, though. And about a dozen people took smart phone pictures of the great solar images.

Many thanks to Bill Yohey and Jim Knoll for helping me get all my equipment over to the truck after it was all over. And thanks to PCNRP&R for having such a great educational event. We opened a lot of minds, and sparked a bit of curiosity in the crowd that showed up.

Jim O’Connor
South Rim Coordinator
Grand Canyon Star Party