Dilithium crystals, of course. Antimatter reactor -small one- in the mirror cell.
Sorry, couldn't resist. I'm going thru Star Trek withdrawal since they (thank God) cancelled Enterprise. Hear a new movie is in teh works, tho....yikes....
Yours is an excellent question, for sure.
Most common solution: mount a battery pack somewhere on the tube. Most commonly this is at back end where it can act as a counterweight. A small 9V battery will run most fans for most or all of a night, really, depending on the length of time you observe. Can get expensive, that approach. But I think most of us that run fans who use batteries a lot use re-chargeable batteries. I like rechargeable 1.5 V AAs. I use a plastic thingie that holds 8 AAs. Came with my GSO but you can get at Dick Smith or comparable store. Velcro it to the corner of the tube…acts as a counterweight, too.
More complex solution: run 12 volt power connection to your tube from the rockerbox. This comes into play when you have a continuous fan and multiple dew heaters for your finder, secondary, focuser, etc. Most folks plop a battery pack or battery on the rocker. From there, to the tube, is the challenge. You'll quickly see the risk: that tube moves in ALT motion and any cords running to either end directly will risk tangling. Many have a system that works, actually, but I’ve not seen one yet that doesn’t risk tangling at some point. My solution is to run the power from the rocker to the tube across the one point with minimal translation between the rocker and tube: the ALT axis. Here, most tubes will accept – with minimal or no risk of tangling - some kind of system for bridging a power cord from rocker trunion to the tube with minimal or no risk of tangling. Could be as simple as duct-taping a cord with enough slack to avoid pulling free or tearing out. You could use semi-elastic style guitar cable, or just plain RCA cord (my favorite) and leave just enough slack so it the tube can move from zenith to horizon without it pulling free or tangling. Even more complicated, you could try to perforate the power in thru the exact alt axis line, maybe using the alt axis pivot bolt as one of the leads or something. Something like a slip-ring or brush plate, they are called, but that also is probably unnecessarily complicated.
Hope this helps.
Scott
Quote:
Originally Posted by snug
Hi folks
I sit here pouring over telescopes and i think i get the gist on why dobs have fans ...but for the life of me i cant work out how they are powered. Is it batteries or mains power. I guess im wondering if i need to buy something else to power the scope i buy..Or do i run an extension cord to the house or a generator...batteries???
Sorry if my questions are bit basic but if i dont ask i'll never get it..
Ta Snug
Ps ta for your patience with L'plater
|