Except for the optics and focuser, this is a truly 'home made' telescope.
The tube is made of 3 layers of thin veener glued with epoxy, a very strong and lightweight combination. The low mass of the tube decreases the cooling-down time (an important issue when you are operating at 63 degrees of latitude). The telescope rotates (in Ra) on a "plate" resting on four ball bearings driven by a stepper-motor. A Meade 201XT autoguider attached to a guidescope is used for autoguiding. The photographs (film) are taken with the old faithful Pentax MX; a fully manual, lightweight camera body and for digital images I use a Pentax ist DS or an ir-filter modified Canon 450d (XSi).
I use normal camera lenses 28mm - 50mm and telephoto lenses: 100mm F2.8, 135mm F2.8, 200mm F4, 400mm F5.6.
When taking pictures through telescopes I use a 622mm F6.1 Stellarvue 102EDT refractor and the 1530mm F4.6 Newton.
|Using the equipment in near artic conditions.|
Dew, ice and low temperature are your equipment's worst enemies when doing astrophotography this far up north. If you are unprepared, the photo-session usually ends in less than an hour depending on the circumstances.
The Newton-type telescope is well suited for use in damp and cold conditions. The mirror of the Newton telescope is in a good position deep down in the tube and the secondary mirror is turned upside down facing the primary mirror. That's not the case with refractor-type optics where moisture and ice rapidly condenses on the lenses of refractor telescopes, finderscopes, eyepieces and cameras.
Two ways of protecting your equipment from this are dew shields and heating.
The heating can be done locally near the lens or in separate box. The eyepiece of the finderscope is well suited for local heating with a small resistor as seen in the picture. A "defrosting" box is a good alternative for camera lenses and eyepieces. If you have access to AC power outlet a hairdryer can come in handy if it's handled with care.
The heating will make the air flow and make it instable. Therefore a dew shield is a better solution when using a telescope of long focal length. The length of the dew shield should be at least 2.5 x the diameter of the lens. A dew shield will not stop the condensing, but it will slow down the process and give you more time. It's also important that the inside of the dew shield is dark and matte.
Thermostat controlled "defrosting" box. |
Power: 12V, 2.5A Temp.: 32C/90F
Average power consumption 1 - 1.5A
The eyepiece of the finderscope|
with heating resistor.
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