Hyperion Question

[dwc]

I have a couple of Hyperion eyepieces, and just acquired a 2" diagonal for my LX90 so I can make use of the capability to remove the 1.25" nosepiece.

Is there any reason why I shouldn't use the 2" fitting without removing the nosepiece, to save me from having to swap out the 1.25 adaptor that came with the diagonal?

I already checked that the 1.25" nosepiece doesn't hit the diagonal mirror when using the 2" fitting.

(I hope that makes sense - at least to Hyperion users!)

[michael.h.f.wilkinson]

As I gather, the 31mm and 36mm aspherics are restricted in their FOV by the nose-piece, so for them removing the nose piece widens the FOV. For the shorter focal lengths (24 and shorter) this is not the case

[PDW]

I ran out of focusing range fitting my Hyperion into a 2" diagonal on the Feathertouch focuser on my Stellarvue 102ED. When I used the 1.25" adapter full focus ability was restored.

[alanjgreen]

I believe the original question posted is NOT referring to the Aspheric lenses (which are not the same design as the rest of the range)

* the 31 & 36mm aspeherics do NOT have the same removable nose piece as the other size Hyperions

* I have the 31mm Hyperion and it comes as a 2inch eyepiece (there is a converted/downsize in the box) but this is not required and serves no purpose except to be able to put this 2inch lense in a 1.25 slot - there is no real point in doing this as you reduce the FOV - aspeherics are 2inch eyepieces

The other Hyperions (to which this question relates) are really 1.25 inch eyepieces. (But they can be fitted into a 2inch slot for convenience)

* the front can be unscrewed BUT it has a barlow lens inside!!

* with the front removed the lense will default back to 22mm size. These lenses NEED the front fitted to work to the length specified.

* the front comes off to allow you to fit "spacers" that can change the focal length (optional extra)

[dwc]

Sorry for the confusion, should have been more specific.

The eyepieces I have are the Hyperion 68degree Modular in 21mm and10mm.

My understanding is that if you remove the nosepiece from the 21mm it becomes a 32.2mm, just as adding the 14mm spacer makes it a 17.6mm.

You can only use it with the nosepiece removed in a 2" diagonal.

But the question is, any reason not to use it as a 2" dia eyepiece regardless of whether the nosepiece is attached, providing it doesn't contact the diagonal mirror?

[John]

Sorry for the confusion, should have been more specific.

The eyepieces I have are the Hyperion 68degree Modular in 21mm and10mm.

My understanding is that if you remove the nosepiece from the 21mm it becomes a 32.2mm, just as adding the 14mm spacer makes it a 17.6mm.

You can only use it with the nosepiece removed in a 2" diagonal.

But the question is, any reason not to use it as a 2" dia eyepiece regardless of whether the nosepiece is attached, providing it doesn't contact the diagonal mirror?

No reason why you should not use it in 2" mode with an SCT as you have lots of focus travel with those scopes. With an adaptor in the diagonal you can use them in 1.25" mode too of course. The only disadvantage with using them in 2" mode is that much re-focusing could be needed when you swap to a non-Hyperion eyepiece.

By the way, if the 1.25" nosepiece and lower lens elements are removed from a Hyperion (apart from the 24mm) you do get a longer focal length eyepiece but it's not a very good one !

[M4lcs67]

Just picked up on this post. Going off topic slighty, I have always had problems with the knurled screws that hold the eyepiece in place on the stardiagonal coming into contact with my hyperions and stopping it from sitting flush as the screws protrude above the top edge of the stardiagonal. It is the standard diagonal that came with the scope, so maybe If I changed it for one where the knurled screws are set lower down so that the eyepiece will sit flush?

Back on topic again. I have 3 Hyperions and both ftr's. 24mm, 17mm and 10mm. I know that the 24mm is fixed and cannot be altered to accomodate the ftr's.

Alan. you have the 31mm and 36mm aspherics and I am intrigued by their potential wide fov. I assume they would fit and work well in my C9.25?. As you mentioned in your comment above, the Aspherics are meant to be used at 2" so by using the 1.25 reducer you are really restricting the potential of the ep?

I would obviosly need to buy a 2" stardiagonal?.

I guess sometimes people are obsessed with how close you can get and how much magnification is possible. It would be nice to think differently and go the other way sometimes, so you can get large areas of the sky into your eyepiece rather than a tiny amount.

[alanjgreen]

I have the 31mm Asperic which I use as my main "finder" eyepiece in my 8" SCT

I really like the field of view but I reckon my advice would be to get the 36mm if you can. For example, the "double double" does not quite fit in the FOV, with 36mm you may get it all in! Also with the slightly longer focal length, you may end up with same magnification as I get with the 31mm in the 8 inch (2350mm compared to 2000mm)

The eyepiece does give crisp views and is well capable of resolving double stars that lesser mm eyepieces do not. With my goto system, the target will generally always appear somewhere in the "view" so I can centre and switch to greater mag if required.

[alanjgreen]

And just to add that I use the Williams optics 2 inch dilectric diagonal and I like it a lot. It feels like real quality when you touch it.

The asperic drops right in with no issues. The screw does not catch.

when removing the lense from the diagonal then it can catch - I think it is because Baader have a slightly deeper ridge on the front of the lense as a "anti fall out" feature but I may be wrong

[Macavity]

I always use my Hyperions (Standard & 31mm Asp.) in 2" mode.

A heavy-ish eyepiece just seems far SAFER in a 2" diagonal.

If you don't want a full-blown 2" diagonal, invest in a: Baader Maxbright T2 (!)

Expensive, but good. Perfect fit for Hyperion nose-pieces but smaller & lighter.

Still gives sufficient (35mm) optical path for MOST commonly used 2" eyepieces.

[alanjgreen]

I made a mistake above - when I said "double double", I meant to say "double cluster"

With the 31mm in my 8" SCT you can just about get all the double cluster into the view (but not quite) - I reckon that the 36mm in an 8" SCT would get it all in the FOV

Apologies, Alan

[John]

... the Aspherics are meant to be used at 2" so by using the 1.25 reducer you are really restricting the potential of the ep?

I would obviosly need to buy a 2" stardiagonal?.

I guess sometimes people are obsessed with how close you can get and how much magnification is possible. It would be nice to think differently and go the other way sometimes, so you can get large areas of the sky into your eyepiece rather than a tiny amount.

You will loose some of the apparent field of view (AFoV) when you use the 1.25" barrel adapter as it's the barrel diameter that limits the size of the AFoV. It will drop from 70 ish degrees down to around 52 degrees.

There often seems to be an initial obsession with getting high magnifications which, with a little experience, changes into the "how wide can I go" urges. Sometimes the latter is accompanied by the realisation that a second scope is needed !

The current generation of 82 and 100 degree eyepieces can go someway to slaking the thirst for "wide" though even in slow scopes like SCT's.

Some experienced astronomers choose their eyepieces based on exit pupil as the priority which is probably the best way to do it in terms of maximising the performance potential.

[M4lcs67]

Thanks folks,

You have all come back with very useful information which I will digest. Some additional pieces of gear to think about as well.

[dwc]

Yes, thanks all for your contributions.

I also went for the Williams Optics 2" Diagonal, sounds like I made a good choice.

[M4lcs67]

Hey Macavity,

Followed your link. Ouch. V pricey, although It was a bit difficult understanding what you got for your money. Looked like the diagonal on it's own for 190 odd euro's then you pay extra for the ends. Very expensive, but I did like the anti fall-out device built into the ends. Very much like on my Hyperion eyepieces where you have the full diameter to slide into the diagonal, then the area which is machined a little thinner, giving you a ridge where you can screw the locking nut in and in the event that it works it way loose the ep wont fall out onto the ground. That happened to me last week where the diagonal and eyepiece fell out onto the ground. Thank goodness I was set-up on grass, so there was no damage done. If I had been on something harder, then there would have been a serious breakage.

Just as a footnote. Would I need to change the visual back if I switch to a 2" diagonal?????

[John]

....Just as a footnote. Would I need to change the visual back if I switch to a 2" diagonal?????..

If you go for a "push fit" 2" diagonal then, yes, you will need to change the visual back. If you go for an SCT screw fit 2" diagonal then you can mount it straight onto the thread at the rear port of the scope.

[Macavity]

Ouch. V pricey, although It was a bit difficult understanding what you got for your money. Looked like the diagonal on it's own for 190 odd euro's then you pay extra for the ends. Very expensive, but I did like the anti fall-out device built into the ends.

When I bought mine (as an "investment"?), I was confused as to what "extras" I might need! The guys at TS (DE) were kind enough to sort out my needs re. (default) eyepiece adapters, nose-pieces etc. via Email. Expensive, but a versatile thing for several scopes.

Having "bounced" a couple of eyepieces - Even a complete MAK127, onto the (softish) surfaces, it is a personal neurosis? Whatever! I gain a lot knowing my eyepieces are secure. But still forget to "screw things up properly" ... sometimes.

[M4lcs67]

Thanks John,

Can always rely on you for great info. In that case case I might look into the screw fit one. At least it wont fall out of the scope and one of the little foibles I discovered with owning a mount like the CG5 is when slewing between objects, the eyepiece can go from being vertical to pointing downwards in one movement as it is obviously fixed to the ota. At the mo I have to slacken off the diagonal and re-position it in the visual back. That is probably why it fell out the other night. With a screwfit visual back all I will need to do is slacken it off at the back of the tube, re-align it and nip it up. 100% more secure. FLO don't seem to sell the screwfit 2" visual back/diagonal. Can anyone else recommend a suitable one. I assume Celestron will???? One last thing. Is there an adaptor/sleeve available for it to go from it's 2" state down to 1.25" for smaller eyepieces?

Thanks also to you Macavity,

I too like Baader gear and the fact that is is so adaptable with a lot of it being modular. Several functions out of one item. Brilliant stuff.

[alanjgreen]

FLO include the SCT screw fitting in the price of the Williams 2" Dielectric Diagnal @£115

It comes in a separate box.

[M4lcs67]

Hi Alan,

Cheers for that. However does the diagonal actually screw into the visual back with a thread or is it still a push fit affair with a locking screw?

[M4lcs67]

I have been hunting around for a few days now and lo and behold, Celestron do exactly what I am looking for in this diagonal.

http://www.celestron.com/astronomy/celestron-2-inch-xlt-diagonal-sct.html

Looking at it the diagonal and visual back are one thing with a threaded ring that screws directly into the back of the scope. That is more preferable to me as the diagonal is actually physically attached to the back, NOT just a push fit, so if it wont become detached.

I was outside with my scope last week and the locking screw holding the diagonal became loose and both that and my eyepiece fell out (luckily it was onto my lawn, so there wasn't any damage), but because it is a push fit affair there isn't any protection in the event that the locking screw works loose. I am having my back garden paved in a few weeks and I am having a telescope pad built at the same time, so I don't want this kind of thing to happen again, as it will be falling onto hard stone next time and it will be certain to break something. This is just a belt and braces approach on my part to ensure that there will be no accidents next time

[M4lcs67]

I had read after more investigation that Celestron don't give you much in the way of threads on the lockring that screws the diagonal onto the visual back and someone said that the whole lot fell off on him. I guess as long as you have 3 or 4 threads to work with then it would work ok. This really does seem to be the answer to my prayers (if it does what I think it does)......

[Andymod]

I had read after more investigation that Celestron don't give you much in the way of threads on the lockring that screws the diagonal onto the visual back and someone said that the whole lot fell off on him. I guess as long as you have 3 or 4 threads to work with then it would work ok. This really does seem to be the answer to my prayers (if it does what I think it does)......

I have one of these for my C9.25 and find it secures very nicely to the scope, there are plenty of threads to screw it onto the scope.

http://www.rothervalleyoptics.co.uk/revelation-quartz-2-quot-dielectric-diagonal-sct-fit_d3161.html

[M4lcs67]

Thanks Andymod,

This really appears to be just the ticket. Is the diagonal physically attached to the visual back? I really would like to get a couple of 2" eyepieces and the Baader Aspherics are currently on my hit list. It would be nice to have some nice widefield ep's. As I mentioned before in my earlier post, I was out the other week and because the stock diagonal that came with my C9.25 is of a push fit variety, the knurled lock screw worked loose and it and my new Hyperion fell out onto the ground. Luckily it was on soft grass, so it didn't break anything.