Celestron Regal F-ED65 (1 Viewer)

Ok, I would like to discuss two issues at this point.

One, I believe I know where the resolution problem with this setup stems from. The resolution chart.

Steve...I put your "good one" aside last week and was not able to find it today when I went to do the test. I went back online and found a post of yours that had a copy of the resolution embedded in it. I printed out that copy. Even enlarging the chart to twice its normal size I cannot resolve lines 1-5 or 1-6 with my naked eye when the paper is held directly in front of me. The problem isn't my eyes but rather the print quality of the chart.

I do have a 'negative" resolution chart picture also saved. Let me see if the print quality is better with that one.

Second, with regard to the eyepieces, I am a bit confused. Based on previous findings with the Pentax XW and Baader Hyperion eyepieces I expected to find field of view obstructions with several of the eyepieces that CP provided. The truth is that I did not have obstructions with some of the wider apparent field of view eyepieces (70 degree Smart Astronomy in particular) and yet did see the obstruction with some reportedly narrower field of view eyepieces.

Pardon the layman's terminology but....what gives?

Hello to all C-FED fans and interested parties:

just a quick note- i will try and post more later.

recieved my C-FED 65 tuesday, but will have to send the bugger off packing, as the zoom won't. that is, it did for awhile but then quit... zooming that is! After a few turns of the dial, the EP just hung up on the 16X end; the ring turns but nothing happens. OPT is out, so back to Celestron it goes. i have always had nothing but positive results dealing w/ them, and i got thru quickly by phone, and i all ready have a UPS prepaid label. Curiously, when i went to record the serial number i couldn't find one anywhere either on the scope itself or in the enclosed lit.

when i find some time i will post the results of my admitted seat-of-the-pants shootout between the C-FED, a Nikon 50, a Pentax 65ED II, and my "control" 'fractor, an Astrotech
66mm outfitted w/ a star diagonal.

but briefly, i can confirm most of what has been all ready said. this is a very fine spotter for the $$, and blew the doors off my Pentax, even at the 23-30X power i was working with. however i hasten to add i have always felt i managed to cop a sub-par unit of that scope.

the C-FED is heavy, long, and i had to use the heavy duty manfrotto tripod when i was hoping i would be able to use the lighter wt. slik. no dice. the focus on the C-FED, at least my copy, is stiff (the course knob), and laying as it does right up against the body of the scope on the side takes some pressure to push to and fro, and the scope wobbles it not on the bigger release plate of the bogen. i am hoping it will loosen over time. another area where i think there could be some improvement is in the eyepiece collar- it turns 3 or 4 times before the ocular is cinched in tight, as opposed say to the pent which has a similiar arrangement, but grabs on in 3/4 of a rotation or sol.

the spotter performed quite nicely w/ the Hyperion 17mm, and esp. hit it's stride with the 13mm Hype, which renders i believe right at 30power- no vignetting in either ocular, with nice rendering of detail, and little CA that i could see. there is a minor reflection into the EP from some of the dreaded uncoated or barely painted prism or focusing assembly, easily seen a couple of inches or so from the eye end, but seems to move out of the view when the eye is positioned at the proper place. backing up from the EP, details of the innards are ghosted around the exit pupil, something not visible say in the nikon, whose exit pupil is buried in darkness. cant say again if this will affect the performance or not,

hopefully more later,

regards, UTC

Glad to see you posting about the 65 UTC. I can confirm that the course focus does loosen up over time. The 65 I had was sweet right out of the box but the 80 was stiff at first and then much better later.

Sorry to hear about the zoom. I wonder what the deal was. You are sending in just the zoom eyepiece right..and not the whole scope?

On another note I should have a better resolution chart to test the scope either tomorrow or Saturday. I also pulled the trigger on a Smart Astronomy Edge On Flat field 19 mm eyepiece to see how it performs in this scope. I realize it is a slightly different design than the 12.5 mm but I thought I would try it anyway.

Also, I had some time to kill late this afternoon so I pulled out my digiscoping setup and took some shots of the RubyThroated Hummingbirds that visit my feeders. The lighting was poor but I thought this shot was half decent considering the conditions.

Updated resolution testing:

I received the new resolution chart today and took it outside in the yard in full sunlight (not on the scope) to see what type of resolution the scope possessed.

I started at 35 yards and checked to see if I could still resolve group 1, element 6. I could so I moved back to 40 yards and checked again. Yes, I can still see the separation in lines so I stepped back to 45 yards...no, just a bit too blurred to confirm that I could see that element so I moved up to 43 yards.....yes, I can see the spaces between the lines in group 1, element 6.

So, 43 yards is 129 feet. 129 feet x 12 inches = 1548 inches. 1548 x 3.56 (value on the chart) = 5510.88. 5510.88 into 8121 = 1.47 arcsec .

Based on earlier comments I would take this to be fairly good?

Frank,

I would check that result a few more times. This one might be too good (117.6/D). It will be impressive if it holds up as it's better than any spotting scope I've measured or heard of anyone else measuring. It's rare in my experience for a spotting scope (even the expensive ones) to do better than 130/D. Most are 140/D or worse.

Forgot to ask. What magnification did you use? The higher the better up to about 100-120x.

Henry

Henry,

I used the 60x zoom setting on the factory included eyepiece.

I would be more than happy to check the results again tomorrow. It is raining at the moment.

For what it is worth I was tinkering with checking resolution measurements for the various binoculars I have on hand. I understand where you were coming from with the need to use some type of booster to really check the results. I have a question on that as well but before that I wanted to mention that I was able to repeatedly get group 1, element 1 with two of the 7x's. I was able to get group 1, element 2 with one of the 7x's and two of the 8x's. The distance was 25 feet...and was without any booster utilization inititally.

300 inches x 2.0 = 600 into 8121 = 13.53 x 7x = 94.71
or
300 inches x 2.24 = 672 into 8121 = 12.08 x 7x = 84.56

I take it from that information that my average visual acuity would fall somewhere in that range?

If I go back to the 1.47 measurement and multiply it by the 60x magnification then I would receive a result of 88.2. That falls within the range of visual acuity mentioned above. So it would seem possible that the 1.47 is plausible, yes?

..and about the booster. What exactly do you use as a booster to check resolution? I was using a "converted" 8x 'monocular" but found it difficult to get a steady enough image to really "push my eyesight". What type of connector do you use to hold the two together?

For what it is worth I can really understand where you were coming from with seeing all the optical issues when you boost the binocular up to that magnification. Even though I could see some of the same details in different binoculars the way those details were represented were drastically different.

Frank,

It's not your eyesight acuity, but the extraordinarily good result for the telescope's resolution that would cause me to check out everything about the set-up and remeasure a few times. Extraordinary results need to be confirmed. When I do this I use a reference scope of known resolution next to the test scope to make sure everything is working as it should. Unfortunately at the moment you don't have a scope of known resolution until you're certain about this one.

I use various things for boosters, but most often one side of a small binocular. It's impossible to hand hold the booster steady enough to do resolution measurements. It needs to be mounted on its own tripod and carefully aligned behind the eyepiece of the binocular being tested. It's a pain in the rear.

Henry

Frank, I agree with Henry about trying to align the booster. I used a riflescope for a while on a home made adapter. The long ER of the riflescope was kind of a pain, I used toilet paper end roll painted flat black inside to keep side light out, pushed this over the eyepiece.. I have been using a 2 1/2 power EO booster that I bought on close out. Power is not high enough but most of what I tested this just fit right over the eyepiece and this was for my own tests.
Regards,Steve

Henry, Steve,

Thanks for sharing your thoughts/experiences with the booster question. I will see what I can come up with on my own for the booster.

I will recheck the measurements later today Henry. I am headed up to the Hawkwatch as it is beautiful day for that sort of thing but afterwards I will pull the resolution chart back out and try again.

I am MOST curious now about the final resolution test of this possible MegaCherry!..
What comes to mi mind is that Frank has looked through some optics by now ,as to readily recognize in this scope an Extraordinary level of performance.
(besides the brutal resolution,I remember Frank mentioning that contrast was very good,and so was brightness)
He sent back the first and already impressing 65mm to favor this larger one(and His early comments about the 65 were very positive.)
So I imagine that this scope MUST be really good indeed
What would be more impressive ,is the fact that this cherry,or perfect specimen came to light being 1 of 1 tested.
Frank..Have You digiscoped with this scope?..If the resolution is so good,You must be able to capture some fine detail indeed..

Manuel,

The pic of the hummingbird on the previous page was with the 80 mm but the lighting was poor. The pic on the first page of the violet flowers was with the 80 mm as well and was in better lighting.

Henry,

My apologies but I have not had the chance to check it again. Today was my first day back to work. As soon as time and circumstances permit I will check it again.

On another note, I have found one situation where there were some annoying reflections in the eyepiece. It was about an hour ago with the sun low on the horizon. Part of the sun was hitting both the objective end of the scope and the eyepiece. In that situation I did see some "ghosting" in the eyepiece.

Frank, unfortunately i had to return the entire package, as Celestron said the zoom was not available as a stand-alone item. in the letter, i did mention a rather less than acceptable coarse focus tension as well, but i suspect they will just pull another off the shelf as opposed to cherry-picking one for lil' ol' me. hopefully as you said it will loosen up w/ a bit of use, as this is one aspect of the scope that i was a bit disappointed in.

also, i did not review the entire thread but somewhere earlier on there was some question about external threads, either under or around the collet that may allow the attachment of a hype zoom? i did note that on the one i kicked back to big orange that there was a series of threads on the outside of the silver EP collar- dark black they were, and not too many of them, maybe a series of 4 turns or so. In any event, i have asked OPT to forward me one of the Hype zooms. i am interested in trying the ocular out both on the C-FED as well as my astro-scopes.

after a bit of further comparison using the C-FED, a Nikon 50, and an Astrotech 66, strictly low-tech in my case, i am fairly confident in saying that these scopes are very close in performance. Of course the mini-Nikon is dimmer, even in fairly bright conditions, but for some odd reason, at least to my eyes with the units i have at hand, is actually capable of delivering just a smidgen more detail to the final image than either the C-FED or the AT. I am pretty baffled at that result, but have been able to duplicate the finding in a number of circumstances in the field. the AT had a fairly decent 1 1/4 " 45-degree erecting prism at the EP end, which is not as good as a star diagonal- i do have several dielectric models, and am interested esp. in a rematch, as well as trying the scope out w/ the hyperion zoom.

but the C-FED is a keeper; I was able to discern great feather detail among a dozen or so Mag Frigatebirds perched on poles out in Galveston bay this past w/end, with the juvies white heads and pinkish-white bills showing a nice, subtle color distinction. how they manage to grip onto the tops of skinny cane poles is a real mystery! also the contrast where the white heads meet the black body feathers was finely drawn, with no CA visible bleeding into the image where those tones meet. this was at about a 1/4 mile distance, using both the hyperion 17 and 13mm. the leg color of least terns was clearly discernable, despite the fact the birds were perched on the top of a breakwater levee, surrounded and backed by water that reflected and refracted light as the wind rippled the surface. they somewhat resemble commons in transition plumage (at least to me!), and w/out another bird to help gauge size, leg color is a nice way to tell them apart. this was a very difficult lighting situation, dealing with small-scale targets at a fair distance, and i was impressed with the way the spotter handled a tough ID.

great views also of about a dozen or so black-bellied whistling ducks; color rendition here is what i was looking for, and it was dead on, again with a nicely etched image, and good delineation of shade and tone, and feather detail. at the hawk watch tower, which looks out over both the bay from one direction, and a wildlife preserve on the other, while we had precious few raptors, other passerine migrants were on the move. Yellow warblers, dozens (hundreds?) of gnatcatchers, scissor-tailed and eastern kingbirds, empids (mostly alders?), and i can say i never felt i was lacking anything in the way of image fidelity.

this may be the best birding specific scope that can use 1 1/4 astro EP's out there right now, and i think the C-FED is going to provide tons of great views!

regards,
UTC

UTC,

It is always reassuring to see someone else familiar with quality optics that can reaffirm one's own experiences. I look forward to hearing future comments once you get the replacement unit.

UTC,

Did you notice the same image cut off that Frank found in his scope, using he different EP's?

Frank:
many thanks for the kind words, and thank you for being insturmental in bringing this fine scope to the birding community's attention!

Laura:
i did not notice the vignetting w/ the Hyperion 17 or 13mm. these focal lenghts in the hyperion line are a great match for the FED 65.

regards,

UTC

UTCbirder said:

also, i did not review the entire thread but somewhere earlier on there was some question about external threads, either under or around the collet that may allow the attachment of a hype zoom? i did note that on the one i kicked back to big orange that there was a series of threads on the outside of the silver EP collar- dark black they were, and not too many of them, maybe a series of 4 turns or so. In any event, i have asked OPT to forward me one of the Hype zooms. i am interested in trying the ocular out both on the C-FED as well as my astro-scopes.

after a bit of further comparison using the C-FED, a Nikon 50, and an Astrotech 66, strictly low-tech in my case, i am fairly confident in saying that these scopes are very close in performance. Of course the mini-Nikon is dimmer, even in fairly bright conditions, but for some odd reason, at least to my eyes with the units i have at hand, is actually capable of delivering just a smidgen more detail to the final image than either the C-FED or the AT. I am pretty baffled at that result, but have been able to duplicate the finding in a number of circumstances in the field. the AT had a fairly decent 1 1/4 " 45-degree erecting prism at the EP end, which is not as good as a star diagonal- i do have several dielectric models, and am interested esp. in a rematch, as well as trying the scope out w/ the hyperion zoom.

Click to expand...

UTC,

The Baader zoom screws right onto those Synta/Celestron M35 threads you saw. There is no problem screwing the Baader onto the Ultima scopes, but it looks to me like the silver eyepiece collar on the Regal scopes will have to be removed before the Baader zoom will fit them and reach infinity focus. You can see how it works by scrolling down to the Hyperion Zoom and downloading the instruction manual from this site:

http://www.alpineastro.com/Eyepieces_Accessories/Eyepieces_Accessories.htm

I agree that a 50mm scope should not show more detail than a 65mm scope, unless something is wrong with the 65mm. Your 45 degree prism is almost certainly degrading the image of the Astrotech 66. There could be other problems with the scope itself, but I've never seen one of these prisms that didn't ruin the performance of the scope it's used on. They're often advertised as Amici prisms, but they're actually Schmidt roof prisms without phase correction. Any decent prism or mirror star diagonal will be much better.

Henry

Henry,I disagree...a 50mm scope,at the same power(low power)should show same detail,perhaps a bit dimmer image..but if there is plenty of light ,it is going to depend in the quality of the optics,not the aperture....Also the nikon ED50 focus really close therefore getting an advantage in those ranges ...I have taken photos at closer range with both my ED80 vixen geoma and the ED50 and the ED50 shows more detail(lower power at closer range)

Mayoayo,

We agree about low magnification. At 20x the smallest line pairs my eyesight can resolve are about 4.5 arcsec. Any decent 50mm scope will do better than that, but I assumed UTCbirder was referring to the true resolving power of the scopes at magnifications high enough to see it.

I think what you call "quality of the optics" is probably what I call "something is wrong". There are always reasons, excessive aberrations and/or defects, that explain why the "quality of the optics" is low enough to prevent diffraction limited resolution.

Henry

Henry,

My apologies for the long delay but I had some time over the last day or so to do further resolution testing with the Celestron ED-F 80 mm. I placed the target in the same location as before and proceeded to do the same procedure starting with 35 yards and then moving backwards.

Both yesterday and today I was able to obtain measurements of approximately 40-41 yards as my limit of resolution for the scope at 60x. That is approximately 2-3 yards shorter than my earlier measurement but, on both occasions, I was not able to get the sun on the target. I am guessing that may make a difference? Then again it might not.

Doing the math:

41 yards is 123 feet. 123 feet is 1476 inches. 1476 x 3.56 = 5254.56. 5254.56 into 8121 = 1.55 arc seconds.

Not as good as the earlier result but if I can get a time when the sun hits the target I will see if it makes a difference.

Hi Frank, I have used something white[white cardboard etc.] a little at an angle towards the chart and this has helped sometimes. Thanks for the second measurement and it seems this is an excellent scope. I know all this takes time and I know what you have to go through to do it and I really appreciate it.:t:
Regards,Steve