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Questar's Qmax Spectometer.

I CAN'T DECIDE WHAT MOST FASCINATES me about Questar's Maximum-Resolution Solar Spectrometer (Qmax for short). First there's the amazing amount of precision optical and mechanical technology crammed into this attractive, palm-size package. Then there's the absolutely incredible high-resolution view of the solar spectrum from 3850 angstroms in the violet to 6900 in the red. And, for the history buff, there's the thrill of using Qmax to reenact seminal observations of the 19th century. Regardless of which aspect I like best, taken together they make Qmax one of the coolest gadgets I've tested recently. But I'm also quick to admit that even if you ignore the $4,295 price, Qmax is not an accessory for everyone. The reason is best explained with a little anecdote.

On the first sunny day after I was loaned the Qmax for testing, I spirited the 3.5-inch Questar Maksutov telescope from my colleague Gary Seronik's desk and set it up in the yard behind our offices. As often happens, one telescope begat more, and it wasn't long before other editors joined me with scopes equipped for white-light and hydrogen-alpha solar observing. That brought even more people into the yard.

Views through the hydrogen-alpha scope were a big crowd pleaser, but people were equally anticipating the view through Qmax because of my excited comments as I identified various features in the Sun's spectrum. Some shared my enthusiasm, but several others turned to me as they looked up from the eyepiece and said, "Lines?"

Yup. That's what you see. Lines, and lots of them. And even though they are set against the spectrum's spectacular panoply of colors, lines are not exactly everyone's cup o' tea. Nevertheless, buried among these lines is a cornerstone, if not a major portion of the whole foundation, upon which modern astrophysics is built. As with deep-sky observing, it is as much what you see with your mind's eye as in the eyepiece itself that makes viewing the solar spectrum exciting.

Qmax is the brainchild of Michael Olshausen, who worked with the folks at Questar to develop the product. While the 37-ounce device is perfectly integrated for use on the axial port of 3.5- and 7-inch Questar telescopes, Qmax can be adapted to other instruments having focal lengths close to 1,400 or 2,800 millimeters. It comes with an appropriate counterweight and an infrared-blocking filter, which must be placed over the telescope's aperture.

The supplied 8-mm Brandon eyepiece shows an approximately 70-angstrom-wide portion of the spectrum, and a small knob and digital counter that reads angstroms directly allow you to "dial" any wavelength into the center of the field of view with an accuracy of several angstroms. The resolution is an astounding 0.17 angstrom, which is sufficient for viewing the Zeeman splitting of the iron absorption line (under appropriate conditions) caused by the strong magnetic fields associated with some sunspots.

Using the spectrograph is as simple as pointing the telescope at the Sun and looking into Qmax's eyepiece. But targeting specific points on the solar disk for analysis can be an exercise in patience. For example, to study the spectrum of a particular sunspot requires that you place the image of that sunspot on Qmax's small entrance slit. While not entirely a hit-or-miss process, doing this should be much easier after Questar completes the development of a special reticle eyepiece that fits in the telescope's eyepiece holder. The prototype is currently being tested by Olshausen.

I can't begin to describe all the things you can see in the solar spectrum given Qmax's resolution. Volumes have been written on the subject, which brings up an interesting point. While the Sun is certainly the most spectroscopically studied star, very little of the resulting literature has been aimed at amateurs. Qmax's instruction manual includes a list of current and recently out-of-print books that are worthwhile. But I also found myself combing through my collection of 19th-century books. Norman Lockyer's Solar Physics and The Chemistry of the Sun, as well as H. Schellen's Spectrum Analysis, make great companions for the Qmax. All three were written after the discovery of the helium-emission line in the solar spectrum in the late 1860s but well before the 1890s, when the hitherto unknown element was finally identified. Using Qmax to reproduce the observations described in these books made history come alive in a truly exciting way.

"You've seen the lines. So now what?" asked a friend who was amused by my intense fascination with the view through Qmax. Rather than defend my own interests, I responded with a simple observation on human nature. "Some people wandering through the Louvre in Paris are content to spend just a minute or two looking at the Mona Lisa," I noted. "Others could return day after day and never feel they've seen it completely. And the Mona Lisa doesn't change--the Sun does!"

Lots of Lines

Qmax high-resolution solar spectrometer U.S. Price: $4,295

<ADD> Questar Corporation 6204 Ingham Rd. New Hope, PA 18938 Phone: 215-862-5277 </ADD>

DENNIS DI CICCO notes that while his colleague Gary Seronik is hoping for a $6,800 raise this year, he's pushing for $11,095 (plus a little extra for SPF 45 sunscreen).
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Author:di Cicco, Dennis
Publication:Sky & Telescope
Geographic Code:1USA
Date:Nov 1, 2002
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