The Celestron Cometron

I have only had three telescopes given to me this year. Telescopes in various states of disrepair. I usually fix them up, clean them up, and find a new home for them.

It was Julia who gave me this little bit of fun… A Celestron 62mm f/4.8 Cometron. A small refractor intended for low power viewing. Prefect for viewing comets or other wide field objects.

Celestron Cometron
A Celestron Cometron 62mm f/4.8 telescope.
These little refracting telescopes were sold in the 1980’s to capitalize on the comet Halley mania. Sold bearing the Celestron name, they were actually built by Vixen. They continued in production for many years as they proved relatively popular. The Cometron name has been used for a number of small telescopes over the years, but, as far as I know, this is the original.

The ‘scope I was given was in pretty good shape. Nothing broken or badly damaged. The optics dirty but free of coating damage or uncleanable grime. All that was require was disassembly and a good cleaning to remove dirt, spider webs, and a few cockroach egg cases.

Continue reading “The Celestron Cometron”

Atop Mt. Hamilton

The visitor directions on the website had specifically cautioned that the summit road was curvy, something I found to be a drastic understatement. From the very bottom it is curve after curve all the way up, with almost no straight sections. S-curves followed sharp bends leading to hairpins. Nearer the observatory the curve intensity only increases as the road narrows. Local history indicates that the horse-drawn wagons that transported heavy equipment up this road could not negotiate steep grades, the only solution was to follow the contour of the mountain, resulting in an incredibly curvy road.

On a sunny Saturday afternoon there were other users, the road is apparently popular with local cyclists. With the density of the sharp curves there was often little choice but to follow at bicycle speeds at times. I would much rather drive up Mauna Kea than this road again. Next time up Saddle to the summit I will recall Mt. Hamilton road and consider myself lucky.

The reason I was climbing this winding road was simply to be a tourist. Unlike the previous seven days, this day was to be fun. For much of the previous week there had been full day sessions of lectures and labs covering the intricacies of adaptive optics systems. Spending a full week in Santa Cruz might be considered a vacation, aside from the fact there had been very little open time to explore the surrounding area. There was only one open day in my travel plans, and I had specific plans for that day, a visit to an observatory.

The 36" refractor at Lick Observatory
The 36″ refractor at Lick Observatory
I arrived well ahead of my late afternoon tour appointment, no problem, just play tourist for a while. At the gift shop / information desk I met Lotus Baker, a longtime Mt. Hamilton resident. She was full of stories and information. We chatted for a while, until her turn to lead a tour of the classic 36″ Lick refractor. Lotus proved to be an excellent tour guide, providing an enjoyable tour of this beautiful telescope.

Continue reading “Atop Mt. Hamilton”

Violet Haze, A 90mm f/13 Apochromat

Violet Haze
Violet Haze, a 90mm f/13 apochromatic telescope
I had wanted a high quality APO refractor for some time. Mostly for photographic use. Opportunity presented itself when Roger Ceragioli offered me a 90mm telescope he had finished the year before and was willing to sell. Working for the Steward Mirror Lab, Roger normally grinds very large optics, things like secondaries for six to eight meter telescopes. But as a hobby he makes somewhat smaller telescopes. This particular lens set had won him a merit award at RTMC in 2002. I had previously seen this telescope and after some negotiation we settled on a price.

The lens triplet is exquisite, providing absolutely perfect airy disks at high power. The photo below shows an example of the out of focus image of Antares taken with the telescope. Pulling out my copy of Suiter’s Star Testing Astronomical Telescopes shows nearly identical images for the ideal diffraction pattern. No wonder the ‘scope won a RTMC merit award.

Photographically it has proven to be almost perfectly free of color, corrected across the spectrum. There do not seem to be any detectable UV or IR halos around bright stars. This is partly a result of good design, and aided by the long focal length of f/13. No field flattener is required, with pinpoint stars across the focal plane.

Continue reading “Violet Haze, A 90mm f/13 Apochromat”