Tube size for 10" F/4 Newtonian

[Benno85 (Ben)]

Hello guys and girls,

I've decided that I'm going to build a 254mm f/4 reflector for imaging - at least a few years off but I would like to start off with some preliminary costings and designs.

My first question relates to the size of aluminium tube required - I'm assuming that one would allow for the circumference of the mirror (2xpixR), but how much extra is required to actually join the rolled sheet together? Similarly, what would be an acceptable amount of "overhang" at the opening of the tube past the secondary?

As you can tell this is going to be a loooooooooooooooooooooooooong project


Cheers,

Ben.

[Garyh]

Hi Ben,
Just use the little program "newt" for windows and you can play with the tube dia and position of secondary in relation to the end of the tube..
cheers Gary

[chrisp9au (Chris)]

G'day Ben,

The link to the 'Newt' program is:

http://www.dalekeller.net/ATM/newton...t/newtsoft.htm

Download the program in to a folder of your choosing, and start playing!

Good luck!

Chris

[Benno85 (Ben)]

Thanks Gents, will have to have a further play with it......after downloading the files the program won't open, I'm running Windows XP on an Apple laptop but seeing as it's runniong natively and not trhough emulation I would have thought I'd have no dramas

I shall keep at it