[mura_gadi (Steve)]

Hello,

A few things about the GSO and SW dobs, at either 6">12" they are are all 1200mm F/l. If you can sit and view comfortably from one you can get good viewing for all.

The 6" is a lot easier to make, you'll see them advertised at 1/12wave, for a Chinese scope that's pretty darn good. Also excellent for visual use at F8 and will take cheaper EP's very well. As you go bigger you'll get faster to keep the same F/l, faster mirrors are harder to make to high wave lengths and do not come close to those wave specs from GSO/SW models.

I'd suggest an adjustable stool with a flat wooden seat and flat back and strap a booster chair to it if she still fits one. Most chairs will get you from 60/80cm as a seat height.

Good condition, well priced dobs come up often, you could use the 6" for moon/planets and bright clusters, star splitter etc. And a 2nd XXinch newt for the DSO and camera work at F5.

The 6" you'll never think twice about setting up, a 12" you might be hesitant about if you haven't got a trolley or fixed site.

A F8 newt will hold collimation better and be easier to collimate than the F5 by a long shot. The collimation area in proportional to the F ratio squared, so a 64mm or 25mm landing zone for good collimation.

*the tabletop F5 6" is hard to beat, or at the very least the bench mark for aperture and easy of use.

If your daughter can use her own table and chairs, have the SW Gti 6" tabletop so its can be moved either free hand or via the controller. You'll have a great little scope that can track and be used at child heights. For $650 new and resale later, the scope may not owe you a lot for its use... (if she's a little rough with it, at F5 you may find you learn to collimate very very quickly! The tabletop will make that a lot easier as you can view and change collimation while seated and not have to take your eye from the ep to make adjustments.)