If it's the one on Ebay, then it's a good buy.
It's a doublet but a very good doublet. Same sized triplets will cost you 30% more. You get what you pay for in this game.
This is an older review of the scope
http://www.cloudynights.com/page/art...efractor-r2383
You need to have a good mount if you want to do deep sky imaging, an EQ6 or similar, plus other accessories as well. For planetary work you will need a barlow as the image scale will be quite small on a 770mm FL.
Cheers
Bo