Which 100 degree eyepiece?

[Jinx]

Hi folks,

I am looking at getting my first super / ultra wide angle eyepiece for my 250p explorer reflector, and was wondering what people are finding is the best OR best value 2" 100 degree eyepieces between 26 and 32mm for that huge vista feel. Or is there not much difference from the 82 degree ones?

BST don't seem to do the larger 26-32mm which is a shame, so I was wondering what people would suggest. My current 32mm is a celestron plossl and I only believe in upgrading each item once.

Budget wise - well don't tell the wife but upto £150 second hand or £250 new if I can find one sometime in the next 2-3 months.

So to recap:

2" diameter, 26-32mm, 82 to 100 degree for £150-£250

Anyone?????

[swamp thing]

Hi

You should be able to pick up an UWAN 28mm in your price range second hand. They are very nice indeed. These are 82 deg.

The Meade UWA 30mm, the ES 30mm, and the Celestron Axiom 31mm are also other 82 degree second hand possibilities.

You may find a TV 27mm Panoptic second hand that would be in budget too. This would be my pick.

I dont know of any 100 deg eyepieces in the focal length you are after.

Good hunting

Regards Steve

[Moonshane]

I am sure I read that the 21 Ethos is the longest focal length that can fit in a 2" barrel at 100 degree field?

Above your budget but my best eyepiece is a 26mm Nagler. The 28mm UWAN runs this very close apparently at a lot less cost. At f5, I'd not go above 26-28mm or maybe 30mm max at a push as the exit pupil starts getting large.

[Jinx]

I get the exit pupil size limiting me around the 28-30mm size - the focal length of my scope is 1200 so it is at f4.8.

But why would the 2" or 100 degree field affect it further to reduce me to a maximum 21mm? Or is this simply the largest on the market at the moment, and not a theoretical limit of observable quality?

[Dodge]

I've got a 200P, and my 28 mm UWAN is excellent. I did briefly borrow a friends Ethos (can't remember which one) before buying, and I found the 100 degree thing a bit of a novelty which was short lived. 82 degrees is enough for me - I found myself moving my eye about to view everything the 100 degree was giving me.

Suggest you try 82 degree and 100 degree FOV's before parting with money.

YMMV, IMHO etc etc.

[rwilkey]

I suggest a 32mm SW PanaView, works great in the 200P, alternatively, the Axiom LX's take a lot of beating at 82 degrees, I have the 23mm and it is cracking, not worth paying the horrendous extra for 100 degrees, out of my league I am afraid.

[Moonshane]

I get the exit pupil size limiting me around the 28-30mm size - the focal length of my scope is 1200 so it is at f4.8.

But why would the 2" or 100 degree field affect it further to reduce me to a maximum 21mm? Or is this simply the largest on the market at the moment, and not a theoretical limit of observable quality?

this gives a far better explanation that I could ever do

Exploring Low-Power Limits | Gary Seronik.com

[Damo636]

Another vote for the 28 Uwan/Nirvana. Its a simply superb

eyepiece. I think your 250p is an f4.7 so it will not be very

tolerant of cheaper widefield eyepiece's. The 21mm Ethos is

the longest 100* f/l eyepiece on the market at the moment.

[John]

Explore Scientific are to launch a 25mm 100 degree eyepiece shortly in the US. I guess this will find it's way over here in due course. Tele Vue have said that they won't go longer than 21mm in the Ethos range because it would involve too many optical design compromises, in their judgement. I reckon 25mm is the absolute limit for a 100 degree eyepiece in the 2" format because the field stop (that defines the edge of the field of view) just can't be made any larger.

These are outside your budget though as they will exceed £500 (£700+ in the case of the Ethos 21).

The 28mm UWAN / Nirvana is a good option and can be bought used for £200.

[spaceboy]

I think it may be worth considering the weight of the EP also. I see you have a 250P on a CG5 and longer FL 82' /100' eyepieces often tip the scales around 2+ lbs. An already heavy setup will be made even heavier and having a goto mount means alignment will most likely be lost if you try balancing your scope.

[Jinx]

Well due to the costs involved of a quality EP, I have decided to look at the other end of the scale initially and am thinking about a Explorer Scientific 9mm 100degree 2". However I want to check that it would be suitable for use with a Baader Neodymium and IR Cut Moon and SkyGlow Filter 2 inch, 50.8mm.

Any ideas?

[John]

The ES 9mm 100 degree is a 2" eyepiece so all 2" astro filters should fit.

[Jinx]

Thanks John,

one last hopefully not too stupid question from a newbie - can you use these ultra wide angle lenses with Barlows, or would the additional length of barrel effectively act as a narrowed field stop?

[John]

They do barlow well with good quality 2" barlows. I use an Antares 1.6x 2" which works excellently with the Ethos range. The Tele Vue Powermate 2" 2x is also superb. Neither of those reduce the size of the field of view.

[Jinx]

Well that's it folks, my ES 9mm 100 dgree 2" is on its way, as is my Baader filter and SW autofocuser. Really looking forward to some lunar detail using them with my 250p when they all arrive!

Thanks for all of the advice, I will now immerse myself with lunar detail until I can save for a 2nd hand 21mm Ethos... or if there is one available a 25mm ES 120!!!

Now just looking for a cheap powermate!

[spaceboy]

I'll be interested to know what you think to it Alec. I almost went with an 100' ES myself as they sell for competitive prices S/H.

[Mark Scott]

Alec,

Yes, please post your first light/findings. I think lots of us would love to know how good they are.

Best regards.

[Jinx]

Just to let you know, U.S. suppliers are discounting the 100 degree ES by $200 and with the exchange rate even with shipping they work out quite cheap.

The pre-order 120 degree 25mm is discounted down to $999 though!

As far as reviews go I wouldn't dare to give reviews having not had any other experience as yet. Rest assured I am going to join my local club, share the Ep and hopefully get them to review it.

Hope that is seen as the responsible thing to do.

[John]

It's good to get other views on a piece of kit and to see how it compares against other brands products if possible. You get a better perspective on it's performance that way. Look forward to hearing about it

Sounds like that 25mm 100 degree ES eyepiece could cost around £1K if it ever makes it over here

[spaceboy]

Just to let you know, U.S. suppliers are discounting the 100 degree ES by $200 and with the exchange rate even with shipping they work out quite cheap.

.

No can do to the UK though. I'd already enquired at 2 outlets in the U.S and one in Canada along with TH in the UK to see if the promo was coming this side of the pond.

[WayBig]

In case you can live put up with a mere 82 degrees, the ES 82 degree range can still be had for $99, and they are very nice eps

[Jinx]

Spaceboy, optcorp.com company name is Oceanside Photo and Telescope

[spaceboy]