Telescope Buying Guide: Dobsonian Mounts

Video Transcript

"Another type of altazimuth mount and a term you may have heard before in astronomy is called the Dobsonian, which refers to the mount itself, not the telescope we're mounting it on. The Dobsonians are typically for reflecting telescopes and they're a more cost effective and practical way of mounting some of the larger Newtonians. Essentially it is pressboard or plywood and Teflon on a rocker that has like a lazy Susan, teeter-totter type of motion. As you can see, the Dobsonian base comes in a variety of shapes and sizes, but still has the basic operation from this four and a half inch reflector here to the big thirteen and a half and twenty five inch guys I've got next to me here. Still on a lazy Susan to move my telescope, up and down I just grab it right here, pull it, leave it where I want to. There is a red dot finder on the scope, which we'll cover here in just a little bit, and I stand back here and I look through the finder to locate objects that I want to see in the eyepiece. And yes, with a Dob this size, a six foot stepladder is standard equipment. Another thing you may have noticed is a solid tube here and this guy, which we call a truss-tube Dobsonian. A truss-tube reflector I should say more accurately, on a Dobsonian mount. Solid tubes come up to about ten or twelve inch size before typically you should consider a truss-tube Dobsonian, and the advantage here is if this was a ten inch solid tube, obviously you would need a bit of room to transport it; a van, a big truck... something to lay it down in. When it's a truss-tube like this, this breaks down into four nice pieces. Once we take the trusses off we travel with these. We have one piece in the base. We have one piece down here where the mirror is, and this telescope lifts right off the base quite easily for transport. So instead of traveling with one large telescope, you can break it down into small bits. This is a truss-tube design as well. If you're wondering about the cloth on the side, this is called a light shroud. These keep stray light out from reflecting into and bouncing off of the trusses here and may distract your view, get to the eyepiece. Also a large light shroud here, and also a truss-tube Dobsonian. So this guy here, in all its size, actually breaks down to about a wheelbarrow size that you could haul around with you. You still need a truck or a U-Haul to haul it around. Good example of get as much aperture as you can travel with."