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Celestron 65ED + ES 14mm 82-degree EP (1 Viewer)

UTCbirder

Well-known member
Hi to all:

Not sure this really deserves it's own discussion, but I couldnt figure out just where to post w/out co-opting another thread, so thought I might just as well start another!

Seems there had been some questions concerning using one of the 82-degree apparent field-of-view oculars on Celestron Regal FED spotters. I picked up a used Explore Scientific 14mm 82 degree Apparent Field, 1 1/4" Eyepiece from an astro buddy a couple of months back.

A few similiar models from Celestron (Axiom), Meade (Ultrawide) and maybe even some house branded glass from the major astro retailers can be had as well. They may differ in Focal Lenght by a mm or so either way from the ES.

My go to EP for the C-FED has always been a Baader Hyperion 17mm- I had tried the 21 but experienced some FOV cut off due to prism intrusion near the bottom of the field. A 13mm Hype works great as well. Both of those possess an AFOV somewhere in the 70-72 degree range, but the 17mm has always suited the 65mm scope best.

I had used the Explore Scientific star gazing, and was duly impressed with the wide flat field, with stars sharp almost to the extreme edge in a short focus (f/5.9) 127mm refractor. It is a well made, solid ocular with all metal (annodized?) housing, black and chrome and includes a twist-up/twist-down portion designed to aid in eyeplacement. Nicely engraved lettering overall adds up to quite a handsome fellow.

Had a chance to test drive this EP over the w/end, and can say it makes a splendid match w/ the C-FED 65. To sum up:

CONS:

Limited Eye relief: if you must wear glasses while observing as opposed to removing them and refocusing, th ES14 may not be for you. I think the adverted ER may be around 13-15mm, but due to the design of the adjust portion of the barrell you lose some of that- in other words twisted fully down it does not sit nearly flush with the surfact of the eyelens.

Eye Placement: a bit finicky, but nothing I couldnt accomodate to. Allowance for involuntary head sway is there, but some blackout was experienced if I strayed too far from the sweet spot.

Geometric Distortion: a fair amount of pincushion bow was seen on straight lines, like when viewing raptors on wires or poles. It became noticable about 2/3 out to the edge, and might bother some observers, but for me did not detract from the overall view.

SOME LATERAL CA: There is a bit of lateral CA (purple fringing) toward the outer 20% or so of the FOV, but not bad and I did not find it distracting. On axis images in high-contrast or backlit situations the CA was in my estimation quite minor, certainly not greater than the Baader 17.

PROS:

NO IMAGE TRUNCATION: Despite the large FOV, there was no prism intrusion/image truncation anywhere in the field.

VERY SHARP ON and OFF AXIS: When viewing raptors in natural settings, like in bare trees, all the branches were in sharp focus from the center of the FOV to near the edge; not quite the equal of the Nikon single focus EP's I have on hand but not far behind. Really a strong point of the ES 14. Switching back and forth between the Hype 17mm and the ES14 was a dead heat for on-axis sharpness, with perhaps the nod going to the ES14 as one moved toward the periphery.

IMMERSIVE FOV: Well here is, in my opinion, the real reason for C-FED owners to seriously consider picking up one of these (or similiar) oculars. Seriously larger than the Baaders and their kin, such an expansive, sharp to the edge (almost anyway) "picture window with magnification" opening on nature is quite addictive! It was difficult, really impossible, to go back to the constricted(!) looks of the 70-degree Hyperion. Not to engage in too much hyperbole, allow me this one comment: A view you can fall into!

For those looking to add just one fixed focal lenght EP to their quite decent C-FED stock zoom, I would recommend giving this model or one like it a try. They can be had on Astromart or maybe Cloudy Nights resell forums for around $80 bucks or so, and new ES's right now are "on sale" for $119, I believe.

regards,
UTC
 
Thanks for the review, UTC. Any info regarding eyepiece compatibility with the celestron regal series is very welcome.

I find this interesting because the forum's previous findings would suggest that a real field of 2.5-2.7 degrees is the threshold for prism impingement in the regals. The ES 14 you tested would have a real field of 2.97 degrees.

Calculating the real field is unfortunately not straight forward based on apparent field specs provided by the manufacturer, though, which is why it's important to test any of these eyepieces that seem to hang near the threshold.

At any rate, an 82 degree apparent field sounds great for birding. It's a shame that such views usually come at the cost of eye relief.
 
thanks guys for the comments. I apologize for posting in the "tripods" section but was not really sure where the thread belonged!

Had a chance to test out the combo again this w/end, and can say w/out doubt this is my new most best optical friend, destined to stay on the CFED 65 for while. As Asteracea mentioned, previous posts also led me to believe this EP/Spotter combo would suffer from some cutoff near the bottom of the image circle, but i am seeing a very clean, circular FOV all the way around.

i notice big orange has just reissued their axiom line, redubbed "luminos". the 15mm looks very interesting also for this scope, with "Retractable eyecups - Ultra-low profile for eyeglass wearers"- I'm guessing this may be their way of saying the entire 17mm spec for ER is available for spec wearers?
In a lot of astro oculars I have the manufacturers versions of "twist up-twist down" adjustment schemes really leave a lot of housing between the field lens and eyepoint.

The 14ES gives 25.57 and a 15mm would yield 25.7X on the CFED 65, about ideal for around here. The 15 Luminos is "on sale" online right now for $119, and might be had for cheaper if one looks around.

regards,
UTC
 
UTC,

A couple of comments....

For one, you talked me into it. I ordered one of the 15 mm Luminos eyepieces from Adorama. It should be here tomorrow. I don't have any of the Celestron Regals to try it out on but I do have the Theron Mag82 and the Nikon 50 ED. Will let you know if it works on either scope.

Also, keep in mind, the problems with prism cut off weren't with wide angle eyepieces but rather with low magnification, wide angle eyepieces. The XW20 was the first one where I ran into this issue. Several others in the 20-25 mm range are where this problem manifests itself.
 
Just an update. The 15 mm Luminos arrived today. I will say it is one physically impressive eyepiece...about the size of a small can of soup. The ocular diameter if fairly small in comparison to the size of the eyepiece which is why I am guessing the eye relief is good but not generous.

I only had about 20 minutes to play with it indoors and briefly under an overcast sky outside. The good news is that, from what I can tell so far, it seems to be a very respectable eyepiece. The wide field of view is very nice as is the size of the sweet spots. The image seems very sharp close to the edge but there is some type of distortion going on...maybe pincushion. Tough for me to tell at this point. Since it does provide higher magnification than most of what I have on hand, and typically use, it is difficult for me to make judgement calls on a variety of issues such as contrast. Apparent sharpness seems to be very good under first impressions.

Will try more outside tomorrow after the sun rises.

The only bit of bad news is that it does not reach focus in the Theron Mag82 past about 70 yards. The silver lining is that there is a considerable amount of barrel length beyond the last lens element so if I shave 3/4 of an inch off then I should be able to reach focus at all distances.

Will know more tomorrow.
 
Frank,

Curious if you have any further impressions on the Luminos. I'm currently exchanging samples on a 65F-ED. I think the zoom is pretty good, but I'm very interested in a WA fixed, but use glasses so I need more ER than the OP's new eyepiece.

David
 
David,

I think it is a very solid performer at the price point it sells at. It does have a very nice, wide, reasonably flat field. The sweet spot isn't edge to edge...maybe 80% and there is a little more CA in the image than I am accustomed to with what I am currently using. Other than those two issues I think it is a good buy. Definitely one of the best 80+ degree field eyepieces at that price point.
 
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