2" eyepieces on a Celestron C8 SCT

[snowyskiesau]

The subject pretty much says it all. Can this be done and if so, why would it be a bad idea?
I'm in the process of ordering some new eyepieces and was considering 2" as opposed to 1.25" with a view to the future where I may want to upgrade my telescope.

The scope is a Celestron C8, SCT about 14 years old.

[ving]

so does the c8 take 2" eps? if not then you could get an 1.25"-2" diagonal.

[h0ughy]

It would be beautiful, if you can afford it get a WO 2" diagonal and then some good 2" eyepieces (don't have to be Nags, could be University optics, even a few GS ones would be ok to start with) , you will love it. if you can meet a few people in sydney area to have a look through their eyepieces then you will see the difference. This is of course entirely a personal viewpoint from me. You will know what you like after a look through one or two.

I personally like 2" EP's because I normally wear glasses to read etc, the eye relief is wonderful, the downside they can be heavy, filters are dearer, and you get guys like me drooling over them.................

[33South]

You would probably also need to get a 2" visual back.

As h0ughy say get a good 2" diagonal, these come with an insert so you can still use the 1.25 eyepieces until you replace them all.

[snowyskiesau]

Not sure if there is a 2" visual back for the C8, nothing on the Celestron website, only for 9.25" and larger.
A quick web search also failed to turn up a 2" to 1.25" diagonal i.e. to connect to a 1.25" visual back and allow the use of 2" eyepieces. (Any details on these welcome)

Being impatient, I've just ordered a couple of 1.25" UO eyepieces from Frontier Optics. Should keep me going...

[h0ughy]

Mate, a standard SCT is the C8, get a SCT threaded 2" diagonal, even the Bintel or andrews Dielectric one for 149 dollars will do.:D

[h0ughy]

that was you will not need the visual Back unless you want to do astrophotography, then you will need a refracter type 2" diagonal

[snowyskiesau]

My education continues :)
More web research is obviously required into this.

I might have to tell Daniel to hold that 1.25" order and replace it with bigger shiny things...

[JohnG]

You are going to need a 2" SCT adapter if you intend using a refractor type diagonal otherwise as already stated a screw on 2" SCT diagonal, bear in mind that any SCT under 10" will not give you a full 2" opening and, as such, the full potential of a 2" eyepiece is not reached, however, having said that, and having used an 8" SCT for a long time, you will definately get the wow effect with a good diagonal and a 35mm Panoptic.

JohnG

[33South]

One example

https://www.bintelshop.com.au/welcome.htm

Telescope accessories page 2

Bintel Star Diagonal 2" 99% (SCT) $95.00

[gts055]

2" eyepieces are very nice for their expansive views.
Just need to remember that the 8" SCT's have a 38mm diameter exit from the baffle tube, upon which the primary mirror slides. This 38mm aperture may result in vignetting (seen as a gradual darkening of the view towards the edge of the field) if the field stop of the eyepiece exceeds 38mm. A 27mm Panoptic has a 30.5mm field stop so no vignetting, the 35mm Panoptic has a field stop of 38.7 mm, this is very close to 38mm so vignetting would barely be noticed, however, wide view eyepieces like the Konig Mk70 with a field stop of 46mm, or Nagler 31mm (42mm stop), are likely to show darkening towards the edge of the view.
Regards Mark

[snowyskiesau]

I've stuck with the 1.25 eyepieces I've already ordered (16mm Konig, 12mm and 18mm HD Ortho). Perhaps the 2" option next time.
Thanks to everyone for the advice.