Which eyepiece focal length??

[John]

I was looking at that on Amazon also but wasn't sure how good the quality would be

They are good for the price. As are the 2.5x Revelation barlows as well.

[Peje]

My last query to find out is how the Baader works in 2" mode. Do you simply remove the bottle 1.25" part?

[John]

My last query to find out is how the Baader works in 2" mode. Do you simply remove the bottle 1.25" part?

Do you mean the fixed focal length Hyperion or the zoom ?.

[Peje]

Sorry I should have been more specific, fixed focal length

[John]

Sorry I should have been more specific, fixed focal length

You leave the 1.25" section in place and use the 2" diameter barrel section straight into the drawtube of the scope. This does not turn them into 2" eyepieces though, it just gives you the convenience / security of the wider barrel fitting. You will need to move the eyepiece away from the scope quite a bit to reach focus in this mode so you will need that amount of outward focuser travel available.

In all but the 24mm Hyperion there are optical elements built into the 1.25" barrels which give the eyepiece it's stated focal length and eye relief. If you remove the 1.25" barrel you get an eyepiece with a focal length of around 22mm I think but it's not very well corrected because the optical correction that the lower lens set provides is missing. The standard Hyperions are not 2" eyepieces, they are 1.25" eyepieces with a hybrid 1.25" / 2" barrel really.

[Peje]

Thats great info. So this is not a 2" eyepiece that fits a 1.25" focuser?

[John]

Thats great info. So this is not a 2" eyepiece that fits a 1.25" focuser?

No. If you put a 2" eyepiece into a 1.25" focuser you need an adapter which would reduce the field of view down. Thats the main benefit of a true 2" eyepiece - the wider barrel allows a wider field of view than the same focal length in a 1.25" fitting.

The Baader Hyperion Aspheric 31mm and 36mm eyepieces are true 2" eyepieces. They come with an optional 1.25" barrel so they will fit into the smaller size of focuser but the field of view is reduced by these smaller barrels.

[Peje]

Thanks, that's exactly what I needed to know. Back to the Celestron for me I think

[John]

Thanks, that's exactly what I needed to know. Back to the Celestron for me I think

I still think they are the same eyepieces as the Hyperions with a slightly different body shape !

[Peje]

I still think they are the same eyepieces as the Hyperions with a slightly different body shape !

I like that, means I get the good optics but also the functionality I wanted

[Peje]

Thanks for the input everyone,

Order placed for Baader Hyperion 8mm with 14mm fine tune ring and T adaptor

Potentially clear skies on Thursday so might even get to use it this week.