Showing posts with label hydrogen-alpha. Show all posts
Showing posts with label hydrogen-alpha. Show all posts

Tuesday, August 22, 2017

Eclipse: Tired, dirty, and happy

The Sun at Maximum Eclipse - 2:32 PM EDT - Note Sunspot at Lower Left

Yesterday (August 21) millions gathered along a thin path crossing the continental United States to watch a total eclipse of the Sun. Those with favorable viewing conditions along the path of totality enjoyed an amazing sight and experience. Totality fell close enough to a west-to-east center line across the continent that at least a partial eclipse was visible to anyone with access to clear sky.

Since, with some self-doubt, I had decided not to travel to the path of totality, I organized the Hiram Eclipse Watch event. With the support of the Hiram College Physics Department, it took place on the campus of the college.

I set up two telescopes: a six-inch Meade refractor with a Baader Planetarium Safety Herschel Wedge, and a 90mm Meade refractor with a Thousand Oaks glass/metal filter. I also went equipped with my Canon EOS 50D camera, 400mm telephoto, and 2X teleconverter (>1,200mm focal length equivalent), and white light film filter. Physics staff ran a Lunt Ha scope and an experiment recording temperature and solar energy changes during the eclipse.

Progressing Toward Maximum - Silhouette of the Moon Moves Across the Solar Disk

Summarizing, despite last-minute worries over cloud cover, we had clear to partly-cloudy skies for the duration of our 80-percent partial eclipse. An estimated 375 visitors came out to share the experience, and by all reports had an excellent time. Some families even brought blankets and enjoyed a picnic on the lawn in the shade of old trees!

Detail from Above - Look Along Moon's Edge and Notice Bumps: Lunar Mountains and Ridges in Silhouette

It was very hot and fairly humid and I labored in the sunshine erecting and operating the telescopes, rationing out eclipse viewing glasses, explaining the eclipse event and solar features, and making a few photographs of my own. By the end I was dripping with sweat and very tired but had to rush home to process and upload a photograph of maximum eclipse to a newspaper.

By the end of day, I was was tired, dirty, and happy.

The (Ravenna) Record-Courier - August 22, 2017 - Page 1

Friday, August 6, 2010

Great views of the sun with a Lunt

Today I had the opportunity to work with (okay, play with) a new Lunt solar telescope (35mm) recently purchased by the Physics Department. I was charged with the responsibility of determining what accessories might be necessary to make the scope easy to set up and use in astronomy education. The scope is nicely made and finished --a small refractor equipped with a diagonal-- complete with built-in hydrogen-alpha (Ha) filters. Easiest for the instructor is a system that allows mounting the telescope to a camera tripod; that reduces setup time to five minutes or less. The scope came with a set of mounting rings and set screws and is attached to a base frame. The base is threaded in two places to mate with a dovetail rail but those threads are standard camera threads as well. So, while not elegant, attachment to a tripod is easy and secure.

The sky was reasonably clear so I set up the telescope outdoors, added an eyepiece, and set about finding the sun. By the way, one nice thing about the Lunt is that you can use regular 1.25-inch eyepieces because all of the solar filtration is internal to the scope! The actual hard part can be getting aimed at the sun... that's one object you want to be careful when aiming toward.

Trying several eyepieces and various focal lengths I found my ideal combination with the Lunt was an ancient Kellner 12mm. The field of view includes the entire solar disk and presents an excellent combination of magnification (33X), brightness, and clarity. After focusing and tuning the filter I was rewarded with very good views of three areas of prominences in the same quarter of the sun's limb. I briefly made out a filament on the sun's surface and saw two sunspot groups, though they were not very clear -- attributable to seeing conditions. I took the scope down and stowed my gear. The next thing I did was order the simple Tele Vue Sol-Searcher --not included in the basic telescope kit-- which will be a big help in quickly and safely aiming.

I set up the telescope one more time, at about 5:45 PM, to take one more look at old Sol. Seeing had improved and, to my delight, I could now make out structure in the prominences and, with a slight tuning adjustment, filaments and some granulation. Much better than the smaller Personal Solar Telescope by Coronado. It's a fine instrument, that Lunt, and makes me want my own!

After I receive and install the Sol-Searcher I'll be returning the telescope to Physics. Before that, I hope to try a bit of digital imaging of the sun's now-active face -- but I'll need a little camera.