Quote:Make the widest TFOV 3" eyepiece possible for 100 AFOV and 82 AFOV and 70 AFOV, to take full advantage of 3". I don't feel I would ever be able to afford a 120 AFOV max TFOV.P.S. These may be the eyepieces people will build telescope around (3" refractors, 3" reflectors, and 3" SCTs).
AL MasterObserverC #24
Tom Karpf (tkarpf) Vice President, Astronomical Society of Greater Hartford www.asgh.org
Selsi 60mm f/13 Lunt 35mm Solar Scope Stellarvue SVR70ED
Astronomy Technologies AT6RC Home-built Dobsonian with home-made mirror -
8" f/6.8 Unistar Deluxe on a surveyor's tripod
Quote:OK, 3" is 76.2mm.It's likely an eyepiece barrel for that large and heavy an eyepiece will be 2mm thick, maybe 2.5mm thick counting threads.That means the maximum field stop would be 71.2mm.With a negative/positive design, that might result in vignetting, so I'll go with a more conservative maximum of 70mm.With NO distortion (of course unlikely), that would meanan apparent field of:99 degrees in 30mm90 degrees in 35mm82 degrees in 40mm75 degrees in 45mm70 degrees in 50mmWith a little distortion at the edge, the apparent fields could be slightly larger than that in each focal length. For example, the 24mm 1.25" widefield eyepieces would have a field of 59 degrees instead of 68 were it not for some distortion.Which means 100 degrees for the 30mm 3" is entirely plausible, even if the effective field stop is less than 70mm.
Quote:Should we expect that Explore Scientific will soon be selling refractors with 3" focusers (and 2" inserts and 1.25" inserts)?
"You're not afraid of the dark, are you?" - Riddick "The best scientists are humble. They seek to understand, not to ensure their legacy, but merely to understand." - Mori
Quote:.... The 30mm will be the first in a series of 4 or 5 3" 100 degree eyepieces. ES is contemplating a 40mm as the next in the series and would like CN feedback on what other focal lengths might be desirable...
David-------David Lukehurst UP 20" f/4, Orion Optics ODK12, CFF 180, Borg 125SD, Wiliam Optics FLT98, Borg 71FL, TS 50EDLunt LS60THa + LS60FHa
Quote:Quote:.... The 30mm will be the first in a series of 4 or 5 3" 100 degree eyepieces. ES is contemplating a 40mm as the next in the series and would like CN feedback on what other focal lengths might be desirable... I agree that it would be smart move for ES to offer 35-40mm 100° eyepiece next, since I think this would maximize 100° potential in 3" format. Also, I think many APO and SCT users would prefer this focal length over 30mm, since difference between existing 30-31 mm 82° and new 3" 30mm 100° eyepiece might not be beneficial enough for potential customers to mess with bulk and weight of new system. Contrary, 35-40mm 100° eyepiece would give them significantly increased TFOV to deal with related cost, bulk and weight. This eyepiece would give reasonably small exit pupil for most APOs (f/7 and slower) and SCT users of course.For large SCT users, I think 3" eyepiece with 45-50mm 82° and also 55-60mm 70° would be interested as well.
A 60mm department store refractor started it all....
Quote:Well, I just pre-ordered mine. With the reason being, is that with the 25 F5, I will now have 105x at 1 degree with a 6mm exit pupil.A E21 in a 25 F3.3 gets you .86 with a 5.5mm exit pupil, an E21 in an F3.7 gets you .77, at a 5mm exit both requiring paracorrsSo now I can get wider field of view then the fast scopes, still have the ladder, but am about 15k less invested....Next step will be the 3" feathertouch.In this regard, as there is not a standard for 3" eyepices, would it be possible for Astronomics (who I ordered through), to ask what the exact interpretation of 3" is and what the taper is... Thanks. BTW I dont expec the eyepiece until 14, but hey its on order....
Quote: Until they come up with a Paracorr X in 3",
Quote: Quote: Until they come up with a Paracorr X in 3", But these already exist! Well, sort of...: http://www.astrooptik.com/sonstiges/Newton4Inch/NewtWynne.htmNot really plug 'n play, but it exists!Clear skies!Thomas, Denmark
Quote: This is for a 4" coma corrector.
Ron NS11GPS Pronto
16" dob Vixen NA140SS
127mm F9 Surplus Shed/Crawmach kit scope
Best of ATM
Big and small Questars; TMB and Astro-Tech prototypes and pre-production samples; toting privileges on all scopes set up at Astronomics.
Happy owner of-- A Mag 1, 12.5 inch Porta Ball A Dual Axis Equatorial Platform A PST Double Stack
Quote:I think the point of ridicules had been reached?
Dave Jessie Outreach Events
Quote:I figured out by scaling the photograph (taking perspective into account) that the OD of the widest part of the eyepiece is 4.22 inches. Unless you have REALLY widely separated eyes, don't even think of buying two for a binocular.
.... back yard astronomer ================= Don't forget to look at the moon often. Its a play ground of fun if you throttle up the magnification!
Quote:Scott, I am very interested in a 40mm 100 degree plus a 3 inch diagonal for a 2 inch focuser!!!!!! Larry
Pentax PF-80ED,Meade 102ED APO,Orion EON 72,120ST Apex 127,C6 XLT,C6R,C9.25,XT10 ,Celestron Regal 100 F-ED, CT152 Zeiss 7x42 FL,Canon 10x42L IS WP,15x50 IS 12x36 IS II , Pentax 8x32 ED Garrett Optical 28x110 HD-WP Signature Series Oberwerk BT-80 45, Apogee RA-88-SA Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's. 21mm Ethos,17mm Ethos, 22mm Nagler, 40mm Pentax XW, 14mm Pentax XL, 5.2mm Pentax XL, 8-24mm Pentax XL Zoom, 31mm Axiom LX
.......Curtis MallinCam Extreme 2 + AT8IN + CGEM + Miloslick = WOW WO Binoviewers + Siebert OCA 1.25x-3.5x 10" OPT Starhunter (flocked & upgraded focuser) Celestron FirstScope 10x50 & 15x70 Celestron Bino's 2" 2x GSO Barlow