NavList:

Hello George,

Set up and alignment vary from one manufacturer to another. If you buy one of the latest Meade telescopes (in anything from a 6" to 8" aperture or larger) the entire process is automatic, with the scope taking pictures with a built-in camera to determine where it is pointing at start-up.

With the iOptron Cube, Cube-Pro ad Mini Tower (the latter being a heavy-duty enough mount to easily carry my 6" Maksutov scope, which weighs in at about ten pounds), you adjust three leveling screws at the top of a nice tripod to level the mount head. The mount is supposed to be level wnen you power it up with your telescope attached, and the vertical axis (the axis that swings in a vertical plane--may be obvious but just trying to be clear) needs to be aligned so that it swings in the meridian. I usually use a cross-check level to get the top of the tripod as close as possible, then set the head on the leveling screws and gently engage a locking bolt, work the screws in pairs to level the head according to a bubble level. Then before attatching the scope--which attaches via a dovetail bar--I hold a green laser pointer in the dovetail cradle (bearing against an edge of the dovetail rail) and shoot Polatris, manually setting the cradle/laser at the right angle to do this. Once I'm pointing at Polaris I lock the horizontal axis, so that the vertical axis is in the meridian plane. Now I attach the telescope and galance it "fore-and afte" in its cradle (and with the six-inch scope I use a counterweight on the opposite side, or a second telescope!) and orient it vertically with the scopes controller and a bubble level, and cycle the power off and back on. The scope/mount needs to be level, have the vertical axis in the meridian, and the scope needs to be vertical at power-up. (Somewhere in here I check level and tighten evrything up.) In a perfect world the mount would be aligned, providing it got a GPS lock (or manual position input) and you set a few parameters like time zone, whether or not you're in daylight savings time. At this point you can slew to targets. That simple, the scope finds them and tracks them, and the hand-controller indicates the Right Ascenscion (the astronomers' use this vs. SHA), Declination, and altitude and azimuth.

Generally I then do a two-star alignment procedure, where the scope slews to two stars in succession and you verify (or tweak the aim manually) that the scope is pointing at the alignment star(s). The processor accounts for the corrections you've made and corrects for any errors in initial azimuth, altitude (vertical alignment) and level. A one-star alignment corrects -- I think -- for azimuth but not level. There are a few other possible tricks. I've used a mag compass to align in daylight, slewed to the Sun (using a filter!), tweaked using a "synch-to-target" function, slewed to the Moon, repeated the tweak, then successfully slewed to Venus in broad daylight.

For use as a theodolite, just do the initial leveling -- maybe even not bothering with N-S -- power up and use the hand controller to manually slew. This doesn't give you any tracking, but will read an altitude (to an arcsecond if you're level) for the object you're pointing at.

But to gin up a practice sight reduction problem just turn the system on and slew automatically to several stars in succession, noting the altitude on the hand-controller and the time. You can do this indoors, the numbers will be correct. And yes, you could use planetarium software on your computer to do the same, but I don't.

I've found these things fun and I've actually learned the sky better with them.

Cheers,
Jim
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