From the July 2005 issue

Glenn Chaple’s observing basics: Solar observing

July 2005: With a little innovation, you can go along way with viewing the Sun.
By | Published: July 1, 2005 | Last updated on May 18, 2023
Last month, I described two safe ways to make telescopic Sun observations — indirect viewing by solar projection and direct viewing with an aperture filter (“Good Sun behavior,” page 16). This month we look at two technological innovations guaranteed to make your backyard explorations of our nearest star even more exciting and rewarding.

If the mere mention of technology puts a knot in your stomach, you’re not alone. Over the years, I’ve developed a love-hate attitude toward technology. I love being able to word-process this column on a computer and instantly e-mail it to Astronomy. I hate that, by pressing the wrong key, I might send the article to a laundromat in Romania.

You’ll be pleased to know that the innovations I’m about to describe are reliable, user-friendly, and relatively inexpensive. And they’ll definitely add pizzazz to your sungazing.

Inexpensive imaging eyepieces
Imaging technology, where a small CCD camera substituted for the eyepiece relays the image to a TV monitor, has been available to professional astronomers for decades. In recent years, several companies, including Meade and Orion, have marketed low-cost imaging eyepieces for amateur use. I purchased one, and quickly discovered its value for solar astronomy.

I place an aperture solar filter at the front end of a 60mm refracting telescope (remember, you don’t need a large-aperture telescope to view the Sun). The imaging eyepiece is secured in the focuser and connected by a cable to the video port of a small TV/VCR combo. Once the scope is aimed properly, the Sun’s image appears on the screen. By pressing the “Record” button on the TV/VCR, I can videotape the Sun’s activity. A collection of these video clips gives me a nice record of sunspot activity.

Low-cost hydrogen-alpha filters
The methods of solar observation I’ve mentioned so far provide what’s known as a white-light image of the Sun. A white-light solar image, which shows sunspots on the solar surface (photosphere), is interesting. A hydrogen-alpha (Hα) image, which reveals prominences and activity in the Sun’s chromosphere, is jaw-dropping.

The Hα filter is another innovation that once was available only to the professional astronomer or the amateur who didn’t mind shelling out a king’s ransom to purchase one. Last year, Coronado Technology Group unveiled its Personal Solar Telescope (PST) — an Hα filter/telescope combination that costs $499. The PST has taken the astronomical world by storm (see “Coronado’s Personal Solar Telescope,” January 2005).

In addition to being affordable, the PST is easy to operate — so easy, in fact, that its “manual” is a one-page flyer. In minutes, I mount my PST on a camera tripod and gaze in awe at a living, breathing star. The Sun’s red disk (an Hα filter lets in a thin sliver of sunlight in the red portion of the spectrum) seems alive with activity — around the solar disk’s edge, prominences arc into space.

A fascinating sight
Whether viewed by traditional means or with high-tech gear, our nearest star is a fascinating telescopic sight, and sungazing is a wonderful way to extend your astronomical pursuits to the daytime.

All right, so maybe the articles I e-mail to this magazine don’t wind up in a Romanian laundromat. A few months ago, however, I learned an e-mail I sent to a fellow amateur astronomer wound up in his junk mail file. I’m conscientious about answering all correspondence sent my way, so if you don’t receive a reply to an e-mail you sent me, try again.

Next month: We revisit the Ring Nebula, then “scoot to Scutum.” Clear skies.