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asaint
Carpal Tunnel
Reged: 04/25/03
Posts: 2021
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William Optics SPL 3mm
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warf
professor emeritus
Reged: 10/25/04
Posts: 709
Loc: Wisconsin
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Great Review... even though I haven't used this eyepiece, your observations are consistent with what the eyepiece was designed for and that is planets. I have been wrestling between getting this eyepiece or the WO UWAN 4MM since I already own two other UWANS that I like a great deal. I am curious how this eyepiece would perform in a Coronado PST hAlpha scope which is one area I am a bit disappointed in with the my UWAN 7mm.
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Marsh
Celestron NS 11 GPS, Denk Standard Binoviewer, Pair of Denk 21 EP, Denk PowerSwitch Diagonal, Denk PST Corrector, Coronado PST Double Stacked, WO ZS80 Anniversary,Celestron 15x70 Binoculars
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Tom Faller
member
Reged: 08/07/06
Posts: 51
Loc: Atlanta, GA, USA
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Warf: Good question about the PST. I'd have to check whether another 3mm eyepiece would give usable views. As I think I got across in the review, you can operate outside your scope's "comfort zone" pretty quickly with this eyepiece. If the 7mm is the least bit dim, the 3mm will double that. I don't think I've tried a UWAN yet, so I can't give any advice there.
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Tom Faller
80mm StellarVue Nighthawk refractor
127mm Orion Maksutov-Cassegrain
200mm homebuilt Dobsonian with Discovery optics
10x50 Carton Adlerblick Binoculars
12" homebuilt truss Dob with Discovery optics
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WadeVC
Carpal Tunnel
Reged: 12/02/05
Posts: 2799
Loc: Lodi, California,
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Excellent review! 
Not only was this review very well-written, it was done so in a manner that users of all levels can understand and appreciate. The use of photographs aid in the overall review as well as the results of observing several objects through this particular EP.
Nice job!
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Orion XTi10 f/4.7
Orion XTi8 f/5.9
Meade NGC 70mm f/10
Orion UltraView 10x50 Wide-Angle Binoculars
My Sketch Gallery
My Astronomy Blog
A wise man can see more from the bottom of a well than a fool can from a mountain top.
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mysky
member
Reged: 09/06/07
Posts: 84
Loc: CN
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Quote:
Excellent review!
Not only was this review very well-written, it was done so in a manner that users of all levels can understand and appreciate. The use of photographs aid in the overall review as well as the results of observing several objects through this particular EP.
Nice job!
 Good job, Tom.
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timmbottoni
Pooh-Bah
Reged: 08/25/05
Posts: 1112
Loc: W Chicago suburbs, IL USA
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Great job on this review!
Your results are consistent with mine - I am very pleased with all my WO eyepieces at this point.
Timm
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WO Megrez 80FD, Celestron C8
WO SWAN 33mm, UWANs 4mm, 7mm, 16mm, WO SPLs 3mm, 6mm, 12.5mm, WO Zoom II 7.5-22.5
WO EZTouch & Celestron Nexstar GT modified mounts
SV F50B2 Finder in WO Quick Release 50mm bracket
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Mike Hosea
Post Laureate
Reged: 09/24/03
Posts: 3229
Loc: "Metrowest" Boston
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I'm very much encouraged by the photo where you hold the eyepiece up and show the "exit pupil". I don't see any signs of glare around that. I really can't use a 3mm (my scope is f/6.7), but I've been eyeing the 6mm and 12.5mm.
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Mike
- 7" f/6.7 home-built planetary Newt
- 35mm Panoptic
- 13mm Ethos
- 5mm Tak LE
- 2x TV Barlow
- Canon 10x30IS Binoculars
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Tom Faller
member
Reged: 08/07/06
Posts: 51
Loc: Atlanta, GA, USA
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Mike: Thanks. The 3mm is "close to the edge" on longer FL scopes, but the 6mm does just fine. I had a brief chance to try one during the second half of the review. It has the same strengths as the 3mm - wider field, comfortable relief and sharp images without loss of contrast due to over-magnification. If you get a chance, try one.
Tom
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Tom Faller
80mm StellarVue Nighthawk refractor
127mm Orion Maksutov-Cassegrain
200mm homebuilt Dobsonian with Discovery optics
10x50 Carton Adlerblick Binoculars
12" homebuilt truss Dob with Discovery optics
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timmbottoni
Pooh-Bah
Reged: 08/25/05
Posts: 1112
Loc: W Chicago suburbs, IL USA
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Quote:
I'm very much encouraged by the photo where you hold the eyepiece up and show the "exit pupil". I don't see any signs of glare around that. I really can't use a 3mm (my scope is f/6.7), but I've been eyeing the 6mm and 12.5mm.
What about your scope being F/6.7 makes a 3mm eyepiece unusable? Just curious what you mean by that.
Thanks!
Timm
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WO Megrez 80FD, Celestron C8
WO SWAN 33mm, UWANs 4mm, 7mm, 16mm, WO SPLs 3mm, 6mm, 12.5mm, WO Zoom II 7.5-22.5
WO EZTouch & Celestron Nexstar GT modified mounts
SV F50B2 Finder in WO Quick Release 50mm bracket
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Jim Rosenstock
Carpal Tunnel
Reged: 07/14/05
Posts: 2402
Loc: MD, south of the DC Nebula
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Quote:
What about your scope being F/6.7 makes a 3mm eyepiece unusable? Just curious what you mean by that.
Thanks!
Timm
It's generally thought that, when an eyepiece's exit pupil gets below .5mm or so, you're getting into the realm of "wasted magnification", that no more useful detail will be seen despite the larger image size.
An eyepiece's exit pupil in a given scope is calculated by dividing the eyepiece's focal length by the scope's f/ratio. So, a 3mm eyepiece in a f/6 scope--regardless of aperture!--will give an exit pupil of .5mm. A slower scope (higher f/ratio) will result in a smaller exit pupil, and wasted magnification.
Now personally, I have gotten "nicer" views with higher magnifications and smaller exit pupils than the "standard" limit of .5mm. Perhaps if my own eyes were a bit sharper, I'd see it as wasted magnification, too....but maybe I just like obscenely big planetary images! 
Very nice article, BTW. Unfortunately, I already have a couple of nice "ridiculous magnification" eyepieces, and am not in the market for any more, since they only come in to play during nights of the very best seeing, anyway....but it's nice to know there's another good option out there!
Clkear, steady skies,
Jim
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QUESTION AUTHORITY!
"errr....sez who??"
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timmbottoni
Pooh-Bah
Reged: 08/25/05
Posts: 1112
Loc: W Chicago suburbs, IL USA
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Quote:
Quote:
What about your scope being F/6.7 makes a 3mm eyepiece unusable? Just curious what you mean by that.
Thanks!
Timm
It's generally thought that, when an eyepiece's exit pupil gets below .5mm or so, you're getting into the realm of "wasted magnification", that no more useful detail will be seen despite the larger image size.
An eyepiece's exit pupil in a given scope is calculated by dividing the eyepiece's focal length by the scope's f/ratio. So, a 3mm eyepiece in a f/6 scope--regardless of aperture!--will give an exit pupil of .5mm. A slower scope (higher f/ratio) will result in a smaller exit pupil, and wasted magnification.
Now personally, I have gotten "nicer" views with higher magnifications and smaller exit pupils than the "standard" limit of .5mm. Perhaps if my own eyes were a bit sharper, I'd see it as wasted magnification, too....but maybe I just like obscenely big planetary images!
Very nice article, BTW. Unfortunately, I already have a couple of nice "ridiculous magnification" eyepieces, and am not in the market for any more, since they only come in to play during nights of the very best seeing, anyway....but it's nice to know there's another good option out there!
Clkear, steady skies,
Jim
Thanks Jim,
Got it! Yes, in my scope the 3mm is producing 185X at an exit pupil of .43mm in my F/6.9 80mm scope. I find it to be usable, but only because of the comfort of the eye relief and size of the lens nearest my eye. I accomplished the same thing more or less with barlowed plossls but I found them to be extremely hard to get comfortable with to get to this magnification. Barlowing an Orion 6.3mm Highlight plossl is not a fun thing to use. 
I tried the 6mm and 3mm SPLs on the comet last night and both worked well, but the atmosphere was wiggly looking in the 3mm, lots of twinkling stars, etc so the 6mm actually seemed to be the best eyepiece for it last night. On a steady night earlier in Summer, I had some suberb looks at Saturn with the 3mm SPL, but I found Jupiter to almost always be better with the 6mm SPL.
Clear skies,
Timm
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WO Megrez 80FD, Celestron C8
WO SWAN 33mm, UWANs 4mm, 7mm, 16mm, WO SPLs 3mm, 6mm, 12.5mm, WO Zoom II 7.5-22.5
WO EZTouch & Celestron Nexstar GT modified mounts
SV F50B2 Finder in WO Quick Release 50mm bracket
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Nebhunter
Pooh-Bah
Reged: 10/04/03
Posts: 1010
Loc: Frostbite Falls
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I also find the 6mm SPL to be a great eyepiece. The moon has shown a sharp image from edge to edge in my F7 scope. I have tried it on M13 and found it surprisingly good considering the amount of glass. I compared it to my 7mm HD ortho and found that only the faintest stars disappeared in the 6mm. Mind you the extra X factor would probably have something to do with that. Very comfortable to use compared to the ortho. I'm thinking that the 12mm SPL may be my next addition.
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Handle me with Care - The Traveling Wilburys.
TEC 140 "Katyusha" - Tec field flattener. Equinox 80 -
Atlas EQ6 SynScan GPS ADM conversion. ST-4 guider.
PENTAX 67 - 400 EDif - 300 - 200 - 135 - 90 lenses.
OM-1 300 Tamron - Konica 35-100 Varifocal STI Pro Stiletto.
http://nightfly.zoomshare.com/
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