|
 prices & ordering
how it works
features
photo gallery
SCTs & Maks need ventilation
Why SCTs and Maksutovs Need Ventilation
Catadioptric telescopes - or "cats" - have closed optical tubes. These closed tubes are great for keeping the optics clean, but they also prevent air circulation. This lack of circulation limits conductive heat transfer and greatly prolongs the time required for the optical tube to reach the ambient outdoor temperature. The temperature differential between the telescope and the surrounding air cause "heat pillars" and "tube currents". These tube currents cause distortion similar to the wavering mirages you might see over a road on a hot day. Until the telescope tube and the optics it houses reach a temperature close to that of the surrounding environment (equilibrates), it will not give the best images. In fact, fine details on planets or in deep sky objects may be completely invisible while the scope is changing temperature, but are easily visible when it has reached ambient temperature. Some high quality Maksutov telescopes have built-in fans because their thick front lenses can trap heat for many hours - making them almost unusable without some sort of ventilation. Schmidt-Cassegrain Telescopes (SCT) have thinner Schmidt corrector lenses sealing the front of the tube, but they still suffer from the same effects as the Maksutov design. Very few SCTs have any sort of ventilation system.
|
|
