Page 1 of 3 123 LastLast
Results 1 to 10 of 25
Like Tree69Likes

Thread: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

  1. #1
    j.gardavsky's Avatar
    j.gardavsky is offline Super Moderator
    Points: 107,997, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 90.0%
    Achievements:
    Ghost Achievement! Averaging 5+ posts a day!200+ Posts Achievement!400+ Posts AchievementFirst 1000 Experience Points365 Days+ Registered Achievement!
    Join Date
    Feb 2011
    Location
    Germany
    Posts
    14,108
    Points
    107,997
    Level
    100
    Thanks
    14,022
    Thanked 8,575x 5,581 Posts

    Default Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm



    Hello all,

    thanks to favourable circumstances, I am now in the possession of the Tele Vue 17.3mm Delos eyepiece.
    This Delos will be used as a complementary eyepiece to the Zeiss 23x/30x B WW 17.1mm on the Sky-Watcher (Synta) 6” F/5 achromatic refractor at the medium magnification around 44x and for the medium exit pupil close to 3.4mm, whenever such magnification and exit pupil will be required by the type of a deep sky object to be viewed.

    The purpose of this thread is to compare the “new to me” Delos with my old Zeiss B WW, which has served me on the deep sky objects as one of the best 17mm eyepieces for the fast refractors.

    Part I: The first impressions and the specifications

    The attached Picture 1 shows the Delos unboxed, and the attached Picture 2 shows the both eyepieces with the fully retracted eye guards, side by.
    The Zeiss is sitting on the bayonet-to-1.25” adapter)*.

    The specifications so far published by the manufacturers, or tested for this report, read:

    Tele Vue 17.3mm Delos
    Manufactured by Tele Vue (Taiwan ROC) for: Astronomy telescopes, spotting scopes
    Part number: EDL-17.3
    Barrel size: 1.25“
    Focus length: f=17.3mm
    Apparent field of view: 72°
    Eye relief: 20mm
    Adjustment of the eye relief: With the outer draw tube continuously adjustable
    Sizes: Length 106.5mm, maximum outer diameter 57.5mm
    Weight: 400g


    Zeiss 23x/30x B WW f=17.1mm
    Manufactured by Carl Zeiss (Sports Optics) for: Spotting Diascopes 65 T* FL 65mm and 85mm, and for the astronomy telescopes of other manufacturers (see the Carl Zeiss and the Baader Planetarium astronomy accessories for the spotting Diascopes and eyepieces)
    Part number: 52 80 66
    Barrel size: Carl Zeiss Diascope bayonet, and the Carl Zeiss astronomy adapter for the barrel size 1.25”, part number: 52 83 86
    Focus length: f=17.1mm
    Apparent field of view: 68°
    Eye relief: Not specified, estimated as 15mm
    Adjustment of the eye relief: With the eye guard rubber draw continuously adjustable, max extension 11.3mm
    Sizes: Outer diameter 48mm, length without adapter 77mm, length with adapter)* 135mm
    Weight: 230g without adapter, 288.5g with adapter)*
    Multicoatings: Zeiss T* multicoatings, and Zeiss LotuTec protecting coatings on the outside lens surfaces
    Purged with: Dry nitrogen gas

    )* The adapter I am using is DIY machined, not the Zeiss original.

    One of the frequently omitted information is how an eyepiece is parfocal with the other eyepieces.
    The Tele Vue 17.3mm Delos has been reported not to be parfocal with the other eyepieces in the Delos series.
    Regarding the Tele Vue products, I can compare it just with the Tele Vue Plössl f=25mm, and the Tele Vue 17.3mm Delos needs 11mm more focus travel in the OTA.
    With the 3” focuser adapted for both the extrafocal astronomy eyepieces, and for the intrafocal spotting and intrafocal microscopy eyepieces, the 17.3mm Delos is sitting close to the middle position of the focuser, see Picture 3.

    The intrafocal Zeiss needs 27mm more focus travel in the OTA when compared with the 17.3mm Delos, but it is still within the range of the focuser.

    The both eyepieces feel very nicely in my hand. It may be my enthusiasm about the Delos that I don’t notice the large difference between their weights.

    Thanks for reading, and stay tuned for the Part II with the tests,

    JG
    Attached Images Attached Images
    Binoculars: Leica Ultravid 7x42, 8x42HD; Swarovski EL 8.5x42 Swarovision; Nikon 10x70 Astroluxe; Docter Nobilem 7x50 Porro; Jenoptem 7x50W, 10x50W; BA8: 10.5x70, 15x85; 25x100FB, AsahiPentax 8x40, Refractors: Sky-Watcher 150mm/750mm; Leica APO Televid 82mm (25x-50x WW ASPH); EPs:Baader Classic Orthos; Fujiyama ortho, Leica B WW, ultrawide zoom ASPH, Periplan GF, HC Plan S, L; DOCTER UWA; Wild UW mil; Tele Vue Delos, Nagler Zoom, Plössls; Swarovski SW; Pentax XW; ZEISS diascope B WW T*, Carl Zeiss E-Pl; Hensoldt mil; Filters: Astrodon, Astronomik, Baader (CCD), TS; Astrophotography: AstroTrac; Leica R7: Leica 2/50, 2/90mm, 2.8/180mm lenses
    Astronomy Forum Rules and Terms of Service
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  2. The Following 5 Users Say Thank You to j.gardavsky For This Useful Post:

    AbbN (06-16-2018),bladekeeper (06-13-2018),not_Fritz_Argelander (06-13-2018),SpyderwerX (06-14-2018),Voyageur (06-14-2018)

  3. #2
    Shorty Barlow's Avatar
    Shorty Barlow is offline Bronze Supporter
    Points: 24,426, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 69.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!200+ Posts Achievement!
    Join Date
    Nov 2016
    Location
    Lloegr
    Posts
    2,455
    Points
    24,426
    Level
    100
    Thanks
    133
    Thanked 696x 420 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Nice looking Delos JG! I have the 10mm. It doesn't get used as much as I'd like though. I look forward to reading your tests.
    j.gardavsky likes this.
    TS Optics: 150mm, f/6 Newtonian (GSO SVD series). Altair: Starwave 102ED-R. Sky-Watcher: SkyMax 102mm, SkyMax 127mm, Evostar 72ED DS Pro, Evostar 80ED DS Pro, ST80 (TS Focuser), ST102 (TS Focuser), EQ5 Deluxe, AZ5 Deluxe. Vixen: Porta II, SXG Hal-130. Orion: 90mm StarMax , ST80 (TS Focuser). Celestron: NexStar Evolution 9.25". William Optics: E-BINO-P Binoviewer. A shed load of eyepieces including: Antares, Astro Hutech, Baader, Bresser, BST, Bushnell, Celestron, Explore Scientific, GSO, Kokusai, Meade, Orion, Sky-Watcher, Solomark, SvBony, TeleVue, Vixen & one or two I'm not sure of.

  4. The Following User Says Thank You to Shorty Barlow For This Useful Post:

    j.gardavsky (06-13-2018)

  5. #3
    John Baars's Avatar
    John Baars is offline Bronze Supporter
    Points: 15,235, Level: 85
    Level completed: 10%, Points required for next Level: 315
    Overall activity: 49.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!5 Threads Achievement!
    Join Date
    Sep 2017
    Location
    Schiedam, Netherlands
    Posts
    1,144
    Points
    15,235
    Level
    85
    Thanks
    1,138
    Thanked 1,025x 603 Posts
    Blog Entries
    7

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    So far, so good.
    I 'll stay tuned for part 2!
    j.gardavsky likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    in Schiedam : SW Evostar 120ED F/7.5, Vixen 102ED F/9, OMC140 maksutov F/14.3, SW 102MAK F/13 on Vixen GPDX.
    Binoculars: AusJena 10X50 Jenoptem, Swarovski Habicht 7X42, Celestron Skymaster 15X70, Swift Observation 20X80.
    Astronomical Rijswijk observatory telescopes: Astro-Physics Starfire 130 f/8 on EQ6, Meade 14 inch SCT on EQ8, Lunt.
    Amateur since 1970.

  6. The Following User Says Thank You to John Baars For This Useful Post:

    j.gardavsky (06-13-2018)

  7. #4
    not_Fritz_Argelander's Avatar
    not_Fritz_Argelander is online now HYPER GIANT
    Points: 177,590, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.6%
    Achievements:
    365 Days+ Registered Achievement!2 Posts Achievement20 Posts Achievement!750 Days+ Registered Achievement!First 1000 Experience Points
    Awards:
    Thread Award
    Join Date
    Jul 2011
    Location
    US
    Posts
    21,650
    Points
    177,590
    Level
    100
    Thanks
    7,221
    Thanked 45,793x 14,733 Posts
    Blog Entries
    59

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Interested in what you find.....
    j.gardavsky likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    : Refractors:

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ST80 (mods for white light solar), SV ED80 f7 Newtonians: Z12 f5 Catadioptrics: VMC110L, Intes MK66 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binocular Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    EQG

  8. The Following User Says Thank You to not_Fritz_Argelander For This Useful Post:

    j.gardavsky (06-13-2018)

  9. #5
    Don Alvarez's Avatar
    Don Alvarez is offline Bronze Supporter
    Points: 8,871, Level: 65
    Level completed: 41%, Points required for next Level: 179
    Overall activity: 3.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!200+ Posts Achievement!
    Join Date
    Mar 2017
    Location
    Coral Springs, Florida
    Posts
    1,540
    Points
    8,871
    Level
    65
    Thanks
    168
    Thanked 382x 283 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Looking forward to part II JG!

    FYI just to fill out your specs, Trifid optics has the eye relief on the Zeiss listed as 18.5mm
    j.gardavsky likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    10" SkyLine
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , Celestron Nextar GT90, Meade Infinity 80
    EP: The Five Fingers of Doom: 5.5mm, 8.8mm, 14mm, 20mm, 24mm Meade 5000 UWA's
    20mm, 26mm, 32mm, 40mm Meade 4000 Plossls, 30mm, 20mm, 15mm GSO Superview,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Expanse, Baader Classic Orthos, Various others.
    Binocs: 15x70 Celestron Skymaster, 10x50 Levenhuk Karma Pro, 10x42 Bushnell, 8x42 Sans & Streiffe

    Member, South Florida Amateur Astronomers Association

  10. The Following User Says Thank You to Don Alvarez For This Useful Post:

    j.gardavsky (06-14-2018)

  11. #6
    Davesellars's Avatar
    Davesellars is offline HYPER GIANT
    Points: 27,192, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 2.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!200+ Posts Achievement!
    Join Date
    Sep 2014
    Location
    Belper
    Posts
    4,701
    Points
    27,192
    Level
    100
    Thanks
    909
    Thanked 1,570x 1,197 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    The 17.3 is parfocal with the 14mm Delos. Then there’s quite a difference to the 10mm to get focus. Interestingly the 7mm Pentax XW is very nearly parfocal with the Delos 14mm so this can make a good jump without having to adjust too much focus.
    j.gardavsky likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    etc:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    12" Dob; Skywatcher 80ED & 120ST; EQ5; Grab and Go Alt/Az; 60mm RACI & Rigel Quickfinder.
    Eyepieces: Tele Vue Panoptic 24mm, Delos 10/14/17.3mm; Pentax XW 5/7mm; ES Maxvision 28mm; Baader Classic 10/32mm
    Filters: Astronomik UHC and OIII; Baader OIII; ES H-Beta
    Herschel 400 (H1) Count: 162

  12. The Following User Says Thank You to Davesellars For This Useful Post:

    j.gardavsky (06-14-2018)

  13. #7
    Voyageur's Avatar
    Voyageur is online now SUPER GIANT
    Points: 7,668, Level: 61
    Level completed: 40%, Points required for next Level: 182
    Overall activity: 28.0%
    Achievements:
    2 Posts AchievementGot three Friends20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!
    Join Date
    Jul 2016
    Location
    Leelanau County, Michigan (April-Oct); Barra de Navidad, MX (Nov-March)
    Posts
    1,252
    Points
    7,668
    Level
    61
    Thanks
    337
    Thanked 491x 316 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    I’m interested in your findings and opinions, JG. I’m no expert in optics, but I use my Delos 17.3 a lot on my f/6 80mm refractor and would love to see how it performs on a larger refractor. I also find it works well for planets on my F/9.75 2000mm vixen VMC200L. Thank you for sharing your thoughts.
    j.gardavsky likes this.
    Mary


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    Vixen VMC200L, D=200mm, F=1950, f/9.75; Televue 2" Everbright diagonal. Coronado PST; AstroTech EDT 80mm, F=480, f/6. Mounts: Vixen SXW/Starbook (original); Stellarvue M2C alt-az. Eyepieces: Televue: 55mm Plossl, 22mm Panoptic, 17.3mm Delos, 13mm Nagler, c. 1980, 11mm Plossl, 7mm Nagler; Meade 15mm Super Plossl; VERNONSCOPE 2.4X
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    . Binoculars: Leica 8x32 Trinovids, circa 1997;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Megaview 20x80, Orion Paragon Plus mount.

  14. #8
    j.gardavsky's Avatar
    j.gardavsky is offline Super Moderator
    Points: 107,997, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 90.0%
    Achievements:
    Ghost Achievement! Averaging 5+ posts a day!200+ Posts Achievement!400+ Posts AchievementFirst 1000 Experience Points365 Days+ Registered Achievement!
    Join Date
    Feb 2011
    Location
    Germany
    Posts
    14,108
    Points
    107,997
    Level
    100
    Thanks
    14,022
    Thanked 8,575x 5,581 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Part II: Tests of the Optics

    Looking at and through the lenses

    The Picture 4 shows the reflections of the ambient light on the eye lenses of the both eyepieces, when viewed under an oblique angle. At the normal incidence, the reflections are green, blue, and amber, at an oblique angle, the amber color dominates the reflections.

    A closer look inside the Delos reveals segments of the Newton rings, emerging on the gap in the doublet below the eye lens, see Picture 5.

    And digging deeper...

    The Tele Vue 17.3mm Delos can be easily unscrewed into two parts, see Picture 6.

    The extremely curved lens in the field lens group points towards the heritage of the Tele Vue Ethos design, as X-rayed in 14mm Explore Scientific - 13mm TeleVue Ethos


    Laser tracing the Tele Vue 17.3mm Delos

    As the Delos can be easily unscrewed, the next step has been to pass the green laser beam through its lenses, see Picture 7.

    The laser beam traces reveal the lenses groupings:
    (field stop – 1 – 2 – 1 // 1 – 2 – 1)
    with the field singlet lens concave out, and with the singlet eye lens planar/convex flat out.
    The double slash symbolizes the design consisting of two mechanically separated parts.

    The brightness of the laser beam traces is the indicator of the lens materials quality - les is bright is better.
    The diffuse extent of the air-to-lens spots is an indicator of the quality grade of the surface polish - less bright is better.
    These indicators are similar to what I have seen on the Pentax XW eyepieces, revealing high grade technologies.
    Both the brightness of the laser traces and the brightness of the air-to-lens spots is slightly less in the Zeiss B WW eyepieces.

    The multiple reflections spots away from the laser traces are indicators for the level of suppression of the diffuse scattered light in the ‘normal’ use of the eyepiece.
    The diffuse scattered light, resulting from the multiple reflections, lowers the contrast of the view.

    The intrafocal Zeiss B WW 17.1mm has the lens groups:
    (2 – field stop - 1 - 2 – 1 – 1),
    the eye lens is concave out.


    Tests on the terrestrial objects

    The test objects have been the buildings 6km away across the valley, a house 1km away in the valley, and a roof in the near field 60m away.
    I have repeated the tests on Tuesday, Wednesday, and today, under the overcast skies and outside temperatures ranging between 15°C and 20°C.
    Telescope: Sky-Watcher (Synta) 6” F/5 achromatic refractor, no filter used

    Observing comfort
    Thanks to its 20mm eye relief, the Tele Vue Delos offers an excellent observing comfort for my eye, better than the eye relief of the Zeiss B WW. This is especially important during the long observing sessions.

    Contrast, and color contrast
    The both eyepieces offer a very high contrast, even on the buildings 6km away.
    The RGB and yellow colors look to me through the Zeiss B WW more ‘vivid’.

    Transmissivity
    The polychromatic transmissivity of light has been tested holding the eyepieces against the daylight skies. The Tele Vue Delos, thanks to the missing ‘light eating’ antifog protecting multicoatings on the outer lenses, may be with 3% or 4% ahead of the Zeiss B WW.

    Distortion
    The both eyepieces show a pincushion distortion. This distortion is slightly less on the Zeiss B WW. in this sense, the both eyepieces are not orthoscopic, and even not within the 40° central field.

    Chromatic aberration
    The CA on the both eyepieces is hardly visible in the central field, unless you try to ruin your eyesight to find it.
    The highest contrast objects reveal a CA fringe at the edge of the field of view.

    Edge to edge performance
    The both eyepieces are remarkably sharp down to the edge of the field of view, see also the ‘Chromatic aberration’ above.

    Sharpness
    The both eyepieces reveal very sharp views, resolving the finest details with a very comfortable contrast on the tested scenes. It has been very difficult to find any difference in sharpness between the both eyepieces.

    The Picture 8 shows the cropped captures of the house 1km far away, taken with the hand held Panasonic Lumix GF7 camera plus the Olympus 1.8/25 fix focus lens (f stop fully opened) on the eyepieces.
    The capture through the Tele Vue Delos is at left, and the capture through the Zeiss B WW is at right.

    The intended shootout on the nebulae will be posted in August/September.

    Thanks for reading,

    JG
    Attached Images Attached Images
    Binoculars: Leica Ultravid 7x42, 8x42HD; Swarovski EL 8.5x42 Swarovision; Nikon 10x70 Astroluxe; Docter Nobilem 7x50 Porro; Jenoptem 7x50W, 10x50W; BA8: 10.5x70, 15x85; 25x100FB, AsahiPentax 8x40, Refractors: Sky-Watcher 150mm/750mm; Leica APO Televid 82mm (25x-50x WW ASPH); EPs:Baader Classic Orthos; Fujiyama ortho, Leica B WW, ultrawide zoom ASPH, Periplan GF, HC Plan S, L; DOCTER UWA; Wild UW mil; Tele Vue Delos, Nagler Zoom, Plössls; Swarovski SW; Pentax XW; ZEISS diascope B WW T*, Carl Zeiss E-Pl; Hensoldt mil; Filters: Astrodon, Astronomik, Baader (CCD), TS; Astrophotography: AstroTrac; Leica R7: Leica 2/50, 2/90mm, 2.8/180mm lenses
    Astronomy Forum Rules and Terms of Service
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  15. The Following 6 Users Say Thank You to j.gardavsky For This Useful Post:

    DeanD (08-01-2018),Don Alvarez (06-14-2018),kanadalainen (06-14-2018),not_Fritz_Argelander (06-14-2018),SpyderwerX (06-15-2018),Voyageur (06-15-2018)

  16. #9
    Don Alvarez's Avatar
    Don Alvarez is offline Bronze Supporter
    Points: 8,871, Level: 65
    Level completed: 41%, Points required for next Level: 179
    Overall activity: 3.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!200+ Posts Achievement!
    Join Date
    Mar 2017
    Location
    Coral Springs, Florida
    Posts
    1,540
    Points
    8,871
    Level
    65
    Thanks
    168
    Thanked 382x 283 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Awesome stuff as always JG.

    Is it me, or is there a marked difference on the foreground shrubbery, the awning mounted on the wall behind it and the doorframe on the left? The image on the Delos looks noticeably softer in this area. Trick of the camera maybe?

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    10" SkyLine
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , Celestron Nextar GT90, Meade Infinity 80
    EP: The Five Fingers of Doom: 5.5mm, 8.8mm, 14mm, 20mm, 24mm Meade 5000 UWA's
    20mm, 26mm, 32mm, 40mm Meade 4000 Plossls, 30mm, 20mm, 15mm GSO Superview,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Expanse, Baader Classic Orthos, Various others.
    Binocs: 15x70 Celestron Skymaster, 10x50 Levenhuk Karma Pro, 10x42 Bushnell, 8x42 Sans & Streiffe

    Member, South Florida Amateur Astronomers Association

  17. #10
    j.gardavsky's Avatar
    j.gardavsky is offline Super Moderator
    Points: 107,997, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 90.0%
    Achievements:
    Ghost Achievement! Averaging 5+ posts a day!200+ Posts Achievement!400+ Posts AchievementFirst 1000 Experience Points365 Days+ Registered Achievement!
    Join Date
    Feb 2011
    Location
    Germany
    Posts
    14,108
    Points
    107,997
    Level
    100
    Thanks
    14,022
    Thanked 8,575x 5,581 Posts

    Default Re: Tele Vue 17.3mm Delos against Zeiss 23x 30x B WW 17.1mm

    Quote Originally Posted by Don Alvarez View Post
    Awesome stuff as always JG.

    Is it me, or is there a marked difference on the foreground shrubbery, the awning mounted on the wall behind it and the doorframe on the left? The image on the Delos looks noticeably softer in this area. Trick of the camera maybe?
    Hello Don,

    it is very difficult to exclude 'a trick' of the camera, as the camera makes internally some picture processing, even if switched off in the settings. Moreover, the crops are heavily enlarged.
    The finest visually detected details on the pic are close to the diffraction limit of the telescope, and the different optics designs of the both eyepieces may response differently to the finest details depending on their contrast.
    Here we are at the bottom right side of the modulation transfer function on the highest spatial frequencies.
    Visually, I have not noticed any softening on the Delos.

    Regarding the eye relief of the Zeiss B WW, it is no way 18mm, not possible, just a marketing statement.
    With the wide field, more eye relief would require a larger diameter eye lens to see the full AFOV, it's just the math.

    Thank you for your comments,

    JG
    Binoculars: Leica Ultravid 7x42, 8x42HD; Swarovski EL 8.5x42 Swarovision; Nikon 10x70 Astroluxe; Docter Nobilem 7x50 Porro; Jenoptem 7x50W, 10x50W; BA8: 10.5x70, 15x85; 25x100FB, AsahiPentax 8x40, Refractors: Sky-Watcher 150mm/750mm; Leica APO Televid 82mm (25x-50x WW ASPH); EPs:Baader Classic Orthos; Fujiyama ortho, Leica B WW, ultrawide zoom ASPH, Periplan GF, HC Plan S, L; DOCTER UWA; Wild UW mil; Tele Vue Delos, Nagler Zoom, Plössls; Swarovski SW; Pentax XW; ZEISS diascope B WW T*, Carl Zeiss E-Pl; Hensoldt mil; Filters: Astrodon, Astronomik, Baader (CCD), TS; Astrophotography: AstroTrac; Leica R7: Leica 2/50, 2/90mm, 2.8/180mm lenses
    Astronomy Forum Rules and Terms of Service
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

 

 
Page 1 of 3 123 LastLast

Similar Threads

  1. Thoughts on Tele Vue Delos 10 mm
    By Theo1 in forum Telescope Eyepieces Forum
    Replies: 17
    Last Post: 05-02-2018, 05:28 PM
  2. Tele Vue 14mm Delos - First impression
    By fishmike in forum Telescope Eyepieces Forum
    Replies: 7
    Last Post: 06-10-2015, 07:34 PM
  3. First Tele Vue Delos purchase
    By pragmatist in forum Telescope Eyepieces Forum
    Replies: 10
    Last Post: 06-10-2013, 01:53 PM
  4. Tele Vue Delos or Ethos
    By Setre in forum Astronomy Beginners Forum
    Replies: 15
    Last Post: 08-25-2012, 03:56 PM
  5. Replies: 0
    Last Post: 01-02-2007, 01:30 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 04:06 AM.