ES 100° 25mm

[alan potts]

Dunk,

sorry got the wrong end of the stick again, I though you had yours on one of the lovely fork mounts like mine. Using it on a dovetail opens up a whole new field that I have yet to set foot in.

Alan.

[Dunkster]

I was looking at the 30mm 100° but its just too much,especially with the cost of a 3" focuser too.i think im definately going to settle for the 20/14/9mm,the 2" focal reducer and the gso coma corrector

Settle keep us posted, sounds like 3 great eyepieces for the money

[rl]

I have an ES 25MM 100 degree eyepiece recently imported from the USA. To be honest I'm a bit disappointed with it and have put a review on cloudynights.com. I'm using a 12" f/4 scope so the test is a harsh one, but the edge correction on my example falls a long way short of the ethos range. Chromatic abberation is an issue. I realise other ES eyepieces have an excellent reputation, but, you can only review the eyepiece in front of you, and in my limited experience this one falls somewhat short for a premium eyepiece, even at f/4. People in the midlands who know me are welcome to borrow it and make up their own minds...I imported this on the back of ES's excellent reputation and I feel a bit short-changed..caveat emptor.

RL

[John]

I've now read your ES 25 / 100 report on CN rl and the comments that it generated on the forum, a number of which seemed to concur with your findings.

Thanks for posting the review - all information that helps prospective buyers make sound decisions is good

Here is a link to the review for those that are interested:

http://www.cloudynights.com/item.php?item_id=2894

[alan potts]

John,

Do you think this is what Mr Al Nagler was talking about when he said something along the lines of design compromise? BTW thanks for posting a link I will read it.

Read the 25mm review, interesting indeed. I like the point at the end about getting things right first time, maybe don't but then if so, they don't release it to the customer.

Alan

[John]

John,

Do you think this is what Mr Al Nagler was talking about when he said something along the lines of design compromise? BTW thanks for posting a link I will read it.

Alan

I don't know for sure Alan but he clearly indicated that Tele Vue would not be going beyond 21mm because they did not feel that their desired performance criteria could be maintained.

That does not mean that someone else could not do it of course.

[Mark at Beaufort]

I have an ES 25MM 100 degree eyepiece recently imported from the USA. To be honest I'm a bit disappointed with it and have put a review on cloudynights.com. I'm using a 12" f/4 scope so the test is a harsh one, but the edge correction on my example falls a long way short of the ethos range. Chromatic abberation is an issue. I realise other ES eyepieces have an excellent reputation, but, you can only review the eyepiece in front of you, and in my limited experience this one falls somewhat short for a premium eyepiece, even at f/4. People in the midlands who know me are welcome to borrow it and make up their own minds...I imported this on the back of ES's excellent reputation and I feel a bit short-changed..caveat emptor.

RL

Welcome Richard to SGL and from someone in Worcestershire.

I read with interest the article that you produced for Cloudy Nights - you must feel really annoyed spending alot of money on an eyepice that should be a premier product. Have you referred the matter to ES in the States for an opinion.

I thought long and hard about changing my 26mm Nagler to either the 20mm ES or the 21mm Ethos and in the end opted for the Ethos.

As you can see I live in Hereford your neighbouring county and you may have noticed that SGL organise a star party each year at Lucksall in Herefordshire.

Perhaps if you still have the EP next year you could bring it over for a second opinion.

Mark

[rl]

I keep re-reading the review I submitted wondering if I've been too picky; It wasn't the review I expected to write when the box first arrived! But in both the scopes I've tried it in (12"f/4 and 70mm refractor f/6) there is no doubt in my eyes it's not perfect, especially since it cost north of £500 to import and that was the sale price. . I have seen a couple of comments from other owners to the effect that they're perfectly happy with it..good luck to them. Maybe they're all using slow scopes. Don Pensack's comments are interesting...they exactly mirror my own experience (see the cloudynights followup). Quite a few people have commented that I should "frame te subject in the middle 50 degrees" including DP. It's true that is the distortion-free area, but a linear 50 deg useful area is tantamount to saying that 75% of the visible sky is in an unsatisfactory state of focus. Not my idea of optical perfection, and, to my eyes at least, the distortions really get in the way. Half the fun with the really wide field eyepieces is rolling your eye around to take in all the vista.

I'm a sad git rambling on, but seriously, try before you buy.

RL

[Mark in Macc]

Sounds as though they may have over-reached themselves with this EP. Maybe Al Nagler was right afterall. I don't think I have ever read a bad report about the 30mm 82deg or the 20mm 100deg EPs and I certainly won't be trading mine in for one of these in the near future.

[crashtestdummy]

The coma is noticable in my 30mm 82 ep at 4.5 but i expected a bit and its only the outside 15%.

[John]

The coma is noticable in my 30mm 82 ep at 4.5 but i expected a bit and its only the outside 15%.

Can't blame the eyepiece for showing coma

[crashtestdummy]

I know,hence why the 25mm 100° showing coma is down to the focal ratio of the scope rather than the ep.

Im still reading coma corrector reviews

[John]

I know,hence why the 25mm 100° showing coma is down to the focal ratio of the scope rather than the ep.

Im still reading coma corrector reviews

What rl describes in his review sounds like astigmatism to me but maybe I'm misinterpreting his description of the aberrations.

[rl]

There certainly is astigmatism off-axis, but the worst defect in my eyes is chromatic aberration as you get anywhere near the edge. Coma is of course to be expected from a short focus newtonian, but not CA!

[crashtestdummy]

I would be sending it back for a refund or atleast speaking to ES about it

[Dunkster]

Indeed, have you contacted your supplier about this? If their customer service is any good, they'd take it back or send you a replacement.

[rl]

I'm very tempted to send it back but I'm trying to get a second opinion on it before I do. If it goes back there will be all the customs hassles both sides of the pond and I'm not sure how the guarantee stands if it's not bought from a dealer outside of the USA. From what other people have said I'm fairly sure there is nothing wrong with it's construction (the mechanical build quality is truly epic..better than TV and as good as Pentax) I used it on the moon last night..the sky was clear but dusty so ther was nothing else on offer. Using a 70mm f/6 refractor the view was typical of big binoculars and was quite pretty with the moon lined up in the middle of the FOV. A slight orange tinge put down to the atmospheric conditions. I then answered a phone call..when I got back the moon had drifted towards the edge . It was now egg-shaped and had gained a red end and a blue end. Ethoses don't do that....

OK.. you would not normally use this ep on the moon, except possibly during a lunar eclipse. If you select your target to fit in the middle 50 deg and there is nothing very bright in the outer field then the view is ok.

It works a lot better on faint DSOs where the aberrations are too dim to pick up, but this is the wrong time of year for a good test on galaxies.

RL

[John]

One of our members bought an ES 20mm 100 from the USA and there was a small fault with it. The dealer he used (I don't know which one I'm afraid) sent a replacement pretty promptly I believe. The fault in this case was physical so could not be disputed. It's a bit harder to prove that the performance is not up to expectations I guess, especially as a number of folks on Cloudynights seem to have experienced similar issues.

[alan potts]

I am rather interested in the comment on build quality, I am sitting here looking at a 26mm Nagler, 41mm Panoptic and a 5mm XW, I don't see anything inferior about any of them, I would agree the Radian adjustable eyeguard could have been better.

Hope you get sorted out but as John said you may have a bit of a battle and it is not easy dealing with trans Atlantic returns.

Alan.

[russ.will]

One of our members bought an ES 20mm 100 from the USA and there was a small fault with it. The dealer he used (I don't know which one I'm afraid) sent a replacement pretty promptly I believe. The fault in this case was physical so could not be disputed. It's a bit harder to prove that the performance is not up to expectations I guess, especially as a number of folks on Cloudynights seem to have experienced similar issues.

My ES82 18mm was replaced within the week by HoO. It could scarcely have been sorted quicker if it had been a UK dealer.

Russell

Sent from my iPhone using Tapatalk 2

[crashtestdummy]

This time next week i will be ordering from the states the 20/14/9mm 100° and keeping my 30mm 82°.i know i always said i wouldnt but i may well buy a tv parcorr 2 at the same time and the 2" es focal extender then sell my 18/14/8.8/6.7 82° eps.will the 30mm 82° be surplus with the 20mm 100° being quite similar field size?

[Mark in Macc]

I have both the 20mm 100 deg and the 30mm 82 deg and use both. They give me 78x and 117x respectively. The difference in the fov is also quite significant. They offer different views that are complementary. Both great EPs.

[John]

I have the Nagler 31 and the ES 20 / 100. They are similar in size and weight but I feel both useful eyepieces. With my 102mm F/6.5 refractor the big Nagler shows some dark space nicely framing the E & W sides of the Veil Nebula but with the ES 20 / 100 they are crammed right up against the field stop so the Nagler is the tool of choice for this object. The ES shows darker background skies though due to it's higher magnification so it's my favourite for hunting faint galaxies.

[crashtestdummy]

That settles that then chaps

[crashtestdummy]

just ordered the 20,14,9mm 100 degree ep's and the focal extender to go with the paracorr.im so glad i dont share a bank account with the girlfriend yet