That old problem backfocus a - new solution

[oceanheadted]

Guys,

here's a solution to the back focus problem that I stumbled across recently. I bought some camera extension tubes on ebay to take close up photos. When I got them it suddenly occurred to me you could use them instead of the usual telescope extension tubes. They come in 3 different sized sections so you can tune the amount of extension you need plus they click together nicely and they only cost £8.50!

Cheers

Alan

[barkis]

Are you sure they would resist flexure during long exposures Alan.?

Looks a long train in that picture.

Ron.

[oceanheadted]

I'll have to see, just hooked them up today to see if it would work. Everything screws together nicely. A lot of telescope stuff fits together with compression fittings, whereas this uses threaded or bayonet type joints. I would think it would be inherently more stable, but good point!

I would have expected most of the flex to come from the Celestron 2" to 1.25" adaptor on the back of the drawtube.