Choosing a Diagonal

[david o]

Hi there, I have recently bought a scope and am thinking of getting a new diagonal for it. Reading around on the internet I've seen it mentioned that this is one area where the manufacturers really cut corners on quality.

Is there any advantage to a 2" diagonal over a 1 1/4", as some suggest?

Are there any brands/models to avoid, or to go for?

Are there any that would work particularly well with the Celestron C80ED-R refractor (d 80mm, fl 600mm, f/7.5)?

Thankyou.

[John]

Hi David,

I would definately consider a 2" diagonal for the C80ED. Even if you do not use 2" eyepieces now it gives you that option in the future so you can experience really wide angle views that 1.25" eyepieces can't provide.

The William Optics 2" diagonals are well thought of. I also think these are worth considering:

Diagonal Dielectric 99% Quartz 2"

John

[david o]

Hi John,

Thanks for the reply.

Now I have more questions :

As a newbie would I find any appreciable difference between the cheaper Revelation diagonal you linked and this Wiliam Optics 2" Dielectric?

Is this Celestron 2" XLT Diagonal worth considering?.

Thanks.

[John]

To be honest David, I've found that the differences between diagonals of this type are almost impossible to discern to me and I've been at this for 25+ years !.

I've just bought an old 2" Meade mirror diagonal (made in Japan) for £25 and that seems to work just as well as my £180 Tele Vue one !.

So I would not pay the extra for the William Optics or the Celeston one - they are probably all made in the same factory anyway ! (you get a lot of that with astro equipment)

John

[david o]

Thanks for the advice John, much appreciated.

[tinvek]

i bought a celestron 2" xlt diaganol for my c80 ed a while back when there were a few at half price and it's been worth every penny, the views are noticably better and the 2" not only gives you the option in the future of 2" eyepieces but also means that you aren't using the edges of the diagonal with 1.25" eyepieces.

one thing i would say is you posted a link to the celestron diagonal at a certain retailer which has got rather a lot of posts complaining about their customer service or rather the lack of it so may be worth looking elsewhere

[david o]

Thanks tinvek for the heads up on Telescope Planet - it's where I bought my C80ED-R. And, yes, I have had a bit of a taste of the problems mentioned in some of those posts. However things did get put right - eventually (won't bore anyone with the story as enough seems to have been written on them already).

[david o]

Can anyone tell me if most/all 2" diagonals come with filter threads on the 1.25" adapter, or is it only this Stellarvue? You see, I already have a couple of 1.25" filters - a moon filter (Opticstar ND96 25%) and a light pollution filter (Skywatcher LPR).