The Braeside Telescope

The Braeside 16" Cassegrain reflector was completed with first light occurring on Thanksgiving night, 1965. Since then, it has undergone several upgrades so that today, it is 100% remotely controlled by computers from a separate building.

Its computer (the TCC, or Telescope Control Computer), is located inside the dome and is connected to the Bridge console in the Control Building by fiber optics cable. The dome tracks the telescope azimuth and software prevents the telescope from moving below a +10 degree horizon. If, for any reason (like a drunk or dead operator), there is inactivity in the system for more than two hours, the entire system: the telescope, dome, shutter, and drives shut down to protect the equipment.

The telescope is a fork mounted classical Cassegrain with an f3.9 primary of 62.5" fl. The hyperbolic secondary is of 4X magnification resulting in a Cassegrain focal ratio of f15.6. Both mirrors are made of annealed Pyrex. The primary mirror cell is an aluminum casting and incorporates a 9 point flotation system. The telescope main tube is an epoxy impregnated, epoxy finished (inside and out) "Sonotube" with 5/8 inch wall. The secondary spider is a 3-arm support setup cast directly into the telescope's aluminum end ring. The ring also incorporates three manually (...!) operated petals for closing the tube. This spider ring casting incorporates appropriate mounting fittings that hold the screwjack motor assembly for longitudinal (focus) motion of the secondary mirror. It is computer controlled through the operating program.

The telescope base is a 400 pound 3/8" welded steel plate structure. The telescope fork is cast from an aluminum alloy called "Tensilloy". The polar axis is a solid 5 inch diameter cold rolled steel material, machined and heliarc welded to the fork attach plate. The cast fork is held to the fork attach plate by eight 3/4" diameter bolts treaded into the fork. The moving mass of the telescope is approximately 285 pounds.

The declination saddle structure is also made of cast Tensilloy and securely attached to the telescope tube. The fork declination attach points are fitted with 2" wide X 2" ID precision roller bearings. These bearings receive the declination journals. The telescope tail plate is made from the same material, carefully machined to parallelism, and attached to the tail plate support end ring casting. The tail plate has threaded bolt hole patterns for mounting a variety of accessories.

| Home |