focal length

[schrodingersCat]

hello :)
I just had a little question. I apologise if it seems silly :p
what effect apart from focal length does the curve of the primary mirror have? what advantages/disadvantages come from a more highly curved mirror with a shorter focal length, than vica verca?
I drew it...and stared at it for a while...and decided to just ask :shrug:tehehe

[iceman]

For a newtonian, a shorter focal length means a wider field of view and a faster focal ratio. That in turn means the eyepiece is closer to the ground when pointed at zenith.

A few people these days like to get a f/4 or f/4.5 newtonian so that they don't need to climb so far up the ladder - or sometimes, don't need a ladder at all.

Mirrors with a faster focal ratio will suffer more from coma, and collimation becomes more critical too. So for large dobsonians a paracorr is a handy accessory, and knowing how to collimate is essential for every newtonian owner.

Not sure if i've answered your question?

[Orion]

The more concave the mirror is the shorter the foal length the shorter the telescope.
Also, longer f/ratio mirrors are a little easier to figure that short ones.

[schrodingersCat]

aaah I see. Thankyou that did answer my questions :D

[StevenA]

Excellent Book. Don't know many that have actually read Schrodinger's Cat. It was quite some time ago now. Smiled when I saw your 'handle'; Flood of memories. Steven A