Does this look like a good deal?

[weetooner]

Hi folks, just as the title says http://www.gumtree.com/p/other-miscellaneous-goods/callisto-200-telescope-spare-lenses-and-turntable-stand-excellent-condition-/1086051953 have tried googling Callisto 200 but have not found anything about it, also are the eyepieces in the box any good.

Cheers.

[John]

If the mirrors are in good condition then it's a good deal. The Callisto branded scopes are the same as the Telescope Services (TS) dobsonians and the Mk I Revelation dobsonians that were sold by Telescope House a few years back. The scopes are made by GSO who make the Meade Lightbridge range.

Do check the condition of the mirrors though as the coatings on the GSO mirrors a few years back was very variable and I've seen a number of examples that needed re-coating which would add enough cost and hassle for the good deal to become not such a good one at all.

The eyepieces look to be Celestron Omni plossls which are decent but nothing spectacular. Good enough to let you have a lot of fun with an 8" dob though.

[weetooner]

Hi John, thanks for that. Probably a stupid question, but how would I know if the mirrors/coatings are ok? Would the coatings be peeling off or would there be staining on the mirrors. 

Cheers.

[Moonshane]

two tests are do they look shiny with no apparent scratches and if you shine a bright torch at the back of the main mirror. if you see flecks of light plan for a recoat. that said, my 12" fails the torch test and i expect a good few years out of it yet

[John]

As Shane says really. Some dust, the odd hair etc is quite normal but the mirror surface should look bright and evenly shiny right across. Flaking of the mirrored surface and / or milky patches are not what you want to see.

I've just noticed that one looks like it's just got a 1.25" eyepiece fitting. That can be a bit limiting as you might want to use a 2" eyepiece in due course to get a wider view. The larger size focuser can take 1.25" eyepieces as well by using a simple adapter.

It might be worth asking the current owner about the mirror condition and the size of the focuser. I could be wrong on the latter - it's a little hard to tell from the photos.