Advice about diagonals ?

[topdude]

Hi, I need a bit of advice regarding star diagonals ?

Just bought a WO Zenithstar 70 from a forum member and i need a diagonal.

What does it all mean, Dielectric / Prism / mirror and which is best ?

Any suggestions what will be suitable for this scope at a reasonable price ?

Thanks in advance.

[kniclander]

dielectric = coated to maximise reflectivity

prism = gives you a right way up image - not necessary for astro and views not great unless you spend £££££

mirror = inverted image; you want a mirror diagonal for astro, ideally dielectric but by no means essential. IIMHO the differences are pretty marginal.

if you want to use a 2" eyepiece you need a 2" diagonal.

good luck:)

[Rossco72]

Dialectric can be had for not too much £££ these days and that's probably what to look out for.

[Peter Drew]

A mirror diagonal will still give an upright image. .

[Moonshane]

as Peter says, upright but of course right left inverted.

[kniclander]

oops!

sometimes i observe lying on my side so it looks inverted to me:glasses1:

[daddio68]

Dielctric diogonal is much harder, it will take a cleaning and keep going. They are getting cheaper too. I use a Astro Tech, seems brighter then standard.

Tom