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
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