Binocular & Small Telescope Session

Date: 13 January 2008
Time: 3:05: 3:25 U.T.
Binoculars: 8x42 & 20x80
Telescope: 80mm f/5 Achromat
NELM: 6.0 to 6.5

Comet Holmes was visible to the unaided eye, but it was significantly better with the binoculars. A crescent moon was above the horizon to the southwest, but appeared to have little if any adverse effect on the evening's viewing. Clouds were approaching from the west.

Mars looked like a tiny, yellow-orange disk in the ST-80 at 105x without filters. Markings on the planet were difficult to see with the small telescope, but they became easier when the planet's brightness was reduced and contrast was increased via the use of a #23A Light Red filter. The #23A filter transformed the color of the planet to a orange-red. Normally I wouldn't consider using such a small telescope on Mars, but I was curious concerning what could be seen with minimal optical aid. Without any filters, the ST-80 is likely to disappoint just about anyone when viewing Mars. With filters, a fair amount of patience, a bit of observer experience (and a good solid mount!) it's possible to conduct some regular study of Mars when the planet is near opposition, but I would strongly suggest that any interested observer use a larger, higher quality telescope.

Surface markings were ill-defined and difficult to pinpoint in location due to the telescope's small aperture, the relatively low (for Mars) magnification, the less than perfect (achromatic) optics, and the somewhat uncooperative, home-made mount (One of these days I should add a friction adjustment to the mount's altitude axis).

After Mars I lowered the magnification to 22x using a wide-angle eyepiece. I took quick looks at the Great Orion Nebula, the Andromeda Galaxy (and its two nearby satellite galaxies), M33, and Comet Holmes. The ST-80 and its home-made, alt-az mount seem to perform at their best when used for such low magnification purposes. All of these objects were very pleasing in the small, short telescope. Comet Holmes looked like a fairly bright, diffuse (amorphous) cloud occupying approximately one-third of the 3.34 degree field of view.

In the course of the evening's short session I never felt any need to uncap the telescope's finder. It was easy enough to point the telescope at Mars, etc. with the 22x eyepiece in place prior to switching to higher power.

I brought the telescope and mount inside, leaving the tripod out in case I decided to try out a 102mm (4-inch) SCT on Mars. Later, when I went back outside, I discovered a cloud covered sky and frost on the tripod. It was clearly time to bring the tripod inside and wait for another clear night.