While safe solar filters are available for most telescopes, it's easy to knock them off or forget to even put them in place. Projection systems are safer and have the added benefit of allowing groups to observe simultaneously, but they require a fair amount of experience and setup time.

Imagine, then, a solar viewing device that sets up in about one minute and provides a safe viewing environment for even the youngest child. Learning Technologies, home of the STARLAB portable planetarium, has introduced a new solar telescope, the Sunspotter. Its unique "folded-Keplerian" design projects a 3-4" image of the Sun (approximately 56x) onto a white viewing screen.

The telescope is roughly triangular in shape and measures about 16 inches high and 6 inches wide. Instead of tripod mounting, you can it on a flat surface such as a table or directly on the ground.

The two pinholes flanking the objective lens project two points of light against the back wall. The telescope is further adjusted until these two lights fall within a pair of pre-set targets. At this point, the solar image is visible against the white viewing card on the bottom of the telescope.

It takes approximately two minutes for the image of the Sun to travel across the viewing area, requiring small adjustments every minute or so to keep the image centered in the viewing area. Considering that this is a fixed-focus design, the image is reasonably bright, sharp and easily viewable by small groups on either side of the telescope. Even small sunspots were easily viewable against the white background.

Users can trace the Sun's image and record the motion and development of sunspots and solar eclipses by replacing the white observing card with a sheet of white paper (smooth white card stock works best). A set of four clips holds the paper firmly in place.

Here's some more on the pros, cons and costs of this innovative instrument:

Pros:

Its unique design makes it easy to carry using the handle provided at its apex.

The folded-Keplerian design allows a 700-mm focal length to be fitted into a 16"x16"x6" package, consisting of only two pieces: an arc-shaped base and the triangular optics assembly.

A recessed thumbscrew locks the two pieces together for storage and transport.

The Baltic plywood construction is sturdy and attractive.

Instructions and safety warnings are printed directly on the optical assembly, providing an easy checklist for new and infrequent users.

Cons:

As nice as the Sunspotter is to use, it is not without a few problems.

The unit purchased and tested came out of the cardboard shipping box completely covered with sawdust. It took 20 minutes of careful cleaning to remove the sawdust from the telescope while paying particular attention to the lens assembly and the three first-surface mirrors.

One of the mirrors was contaminated with what I expect is the glue used to mount the mirrors to the optical assembly. I left the contaminant in place, as I was afraid of damaging the mirror's surface further.

The pinhole projection targets are nothing more than white, circular paper reinforcers, which I last used in elementary school -- they work fine, but lend a "basement workshop" air to the finished product.

Finally, one of the three wooden feet fell out of its mounting hole as the unit was removed from its box, requiring a bit of wood glue to repair.

The Bottom Line

These minor problems might leave some users feeling like the $300 price tag is a little high, but the bottom line is that it is an easy-to-use way of providing safe solar views to small groups. For more information, see http://www.starlab.com/ltiss.html.

Editor's Note: Dennis Ward is an experienced astronomer who currently publishes the http://www.siliconsky.com Web site.