April 24, 2014

My Exploits with the Personal Solar Telescope

PST.

All Photos by Author.

There is nothing like a new toy to refresh my interest in Astronomy. A couple of years back, I had a chance to man a loner scope for a solar “star” party at the re-opening of the Fox Theater in Tucson, Arizona. Five minutes of training by Flandrau Science director Mike Terrenzoni, and I was off. It was a new Solar Max 60 telescope by Coronado; I was instantly hooked. Viewing the sun through Hydrogen Alpha is much more dynamic than visual white light. At a wave length of 656.3 nanometers, this frequency effectively blocks the dazzling white light photosphere and reveals the delicate chromosphere, where prominences and filaments lie. Until recently, most amateurs had only briefly glimpsed this region during the totality of a solar eclipse.  Views in H-Alpha can change from moment to moment; some prominences can seem like ruby red acacia trees on the rim of the sun. My loner scope turned out to be the hit of the show. I only got to view the sun when I periodically re-centered and refocused, but I vowed then and there to get one of these scopes! I also nearly went hoarse explaining the photosphere versus chromosphere bit. Another common question I got was “is it safe to view the sun through a telescope?” It is comforting that this piece of astronomical advice has seeped into public consciousness; however, in the case of Coronado instruments, it can be deemed totality safe. Less than 1/10,000th of the light makes it through the band pass; the rest, including dangerous ultraviolet and infrared, are rejected. For more safety info, check here. Incidentally, I’ve always been curious; has anyone been known to have had their vision permanently damaged by solar viewing? I have no doubt that it is in fact possible; I’ve just never met or heard of this actually happening to anyone, despite years of being around astronomical circles. Considering how early astronomers did it, using smoked glass as opposed to projection, I wouldn’t be surprised if they had sustained some optical damage.

A few months later, an opportunity to procure my very own solar telescope presented itself. I purchased a Personal Solar Telescope (PST) from SkyWorks in Tucson.

Like many telescopes, using the PST is an acquired skill. At about 500$ USD, its definitely a bargain; this can be considered the entry level price to the world of hydrogen alpha. Of course, it may be seen by some as a lot to spend for a telescope with only one application. It’s views may not always wow people like the larger 60mm version; I’d definitely spring for the larger SolarMax if you can afford it. And to be successful, the sun needs to co-operate! I try to take a peek at it at least once every sunny day; the PST is definitely a plus in this regard as it’s a quick (<5minutes) set up. A table top tripod can be purchased; It’s also light enough to use on a basic camera tripod. The finder is also truly innovative; simply slew towards the sun until a white dot appears in the “field”. Focusing is likewise an unconventional process; the telescope is equipped with two controls; a focusing knob to the rear and a collar to “tune” the filter. Once tuned, I find that I rarely have to tweak it. Focusing, however, invariably produces a “sweet spot” that wanders around the field as the scope is focused. This flaw is not evident in larger models and can probably be said to be its most objectionable feature. The image with the supplied 20mm eyepiece is also exceedingly tiny: all but the largest prominences may go unnoticed. I’ve noticed at public events some people have difficultly seeing details through the PST. “Cool, a red ball…” Is the response it may elicit. I find using a 3x Barlow of my own helps things considerably.

Flare in H-Alpha.

Photography can also be accomplished, either via webcam or afocal camera alignment. Sometimes, it may be hard to see the LCD image in the broad daylight. To solve this, I simply pull a black t-shirt over my head (the neighbors must think I’m crazy) to create my own mini dark room. Hey, if it looks stupid but works, it ain’t stupid… Generally, the larger the flare, the better chances of a decent image. I also focus, shoot, nudge the focus, and shoot again. Digital film is cheap…

All in all, I find the PST an excellent deal as a cool, gotta have it gadget. And with the solar minimum now behind us, things are only going to get more active in the world of h-alpha. Now, I need to get my hands on Coronado’s new Calcium-K counterpart to the PST…

PST and Maggie.

Trackbacks

  1. [...] and cheap way to get into solar observing… it may even whet your appetite to get a pricier Hydrogen Alpha ’scope to complement it, as well. And best of all, you don’t have to worry about light [...]

  2. [...] in a little astronomy, too! I managed to set up and do a little impromptu solar observing with the Coronado PST shortly after the Manatee encounter for the tour group and the staff of the Dive Shop… and the Sun [...]

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