How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

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Refractordude
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How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#1

Post by Refractordude »


Anyone familiar with this eyepiece design? How well will it work with a Celestron Yard Canon? Left click the image.
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Lady Fraktor Slovakia
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#2

Post by Lady Fraktor »


It is basically a 2" symmetrical design like the regular so called Plossl eyepiece.
At f/8 it should be alright but I have never used one of these 62° AFOV eyepieces before.
Do you have a link to the eyepiece?
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
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Refractordude
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#3

Post by Refractordude »


Lady Fraktor wrote: Sun Jun 27, 2021 7:10 pm It is basically a 2" symmetrical design like the regular so called Plossl eyepiece.
At f/8 it should be alright but I have never used one of these 62° AFOV eyepieces before.
Do you have a link to the eyepiece?
https://www.firstlightoptics.com/stella ... piece.html

https://www.skyatnightmagazine.com/revi ... eyepieces/
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#4

Post by Bigzmey »


This kind (low count 60-70 deg EPs) are not well corrected for faster scopes, but could perform reasonably well in slower scopes like yours. I am puzzled by price (~$200 US). Not sure what justifies that. I would expect this EP to perform on pair with GSO SV 42 deg which is listed on the same site for half the price. Unless it manufactured to higher standards (like Masuyama) or has some expensive elements in the design (but that would be advertised, right? ;))
Scopes: Stellarvue: SV102ED; Celestron: 9.25" EdgeHD, 8" SCT, 150ST, Onyx 80ED; iOptron: Hankmeister 6" Mak; SW: 7" Mak; Meade: 80ST.
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
Binos: APM: 100-90 APO; Canon: IS 15x50; Orion: Binoviewer, LG II 15x70, WV 10x50, Nikon: AE 16x50, 10x50, 8x40.
EPs: Pentax: XWs & XFs; TeleVue: Delites, Panoptic & Plossls; ES: 68, 62; Vixen: SLVs; Baader: BCOs, Aspherics, Mark IV.
Diagonals: Baader: BBHS mirror, Zeiss Spec T2 prism, Clicklock dielectric; TeleVue: Evebrite dielectric; AltairAstro: 2" prism.
Filters: Lumicon: DeepSky, UHC, OIII, H-beta; Baader: Moon & SkyGlow, Contrast Booster, UHC-S, 6-color set; Astronomik: UHC.

Observing: DSOs: 3106 (Completed: Messier, Herschel 1, 2, 3. In progress: H2,500: 2180, S110: 77). Doubles: 2382, Comets: 34, Asteroids: 255
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#5

Post by Lady Fraktor »


The eyepiece has been around since at least 2016 and I would have to say that the lack of reviews may be a indication.
A $200USD experiment?
I did find a couple of references to it but the designers information page is no longer available.

To be honest since you are in the USA I would look at the various Garry Russel eyepieces instead if you are looking for a low power eyepiece
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#6

Post by Don Pensack »


Astronomer since 1963
Currently using a 12.5" dob and a 4" apo refractor
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#7

Post by WilliamPaolini »


Refractordude wrote: Sun Jun 27, 2021 6:53 pm Anyone familiar with this eyepiece design? How well will it work with a Celestron Yard Canon? Left click the image.

Only familiar with it via the internet. Here is a brief review of the line - https://www.skyatnightmagazine.com/revi ... eyepieces/.

Looks perfectly adequate for your 6" f/8 and should do well. In the review they were using a 4" f/6.5 and stars were good in the 45mm over 85% of the FOV. So in your f/8 should be much better. Has good ER at 22mm. In your 6" f/8 will produce a 5.6mm exit pupil, a bit brighter than I like but should be great as a finder eyepiece or to frame larger objects. It should produce about 2.2 degree TFOV in your 6" f/8 which is the max you can get in that scope from any 2" eyepiece. A 35mm 68 degree eyepiece will get you almost as large of a TFOV (1.98 degrees) at a smaller 4.4mm exit pupil for nicer darker background FOVs to bring out nebula and DSO better, so IMO a better all arounder. However, will be a bit more costly at £239 for the Explore Scientific 34mm 68 degree.
-Bill

U.S.A.F. Veteran - Visual Amateur Astronomer since 1966 - Fully Retired since 2019
8" f/5 Newt - Lunt 152 f/7.9 - TSA 102 f/8 - Vixen 81S f/7.7 - P.S.T. - Pentax 65ED II - Nikon 12x50 AE
Pentax XWs - Baader Morpheus - Takahashi LEs - Edmund RKEs - BST Starguiders - 6ZAO-II/5XO/4Abbe
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#8

Post by WilliamPaolini »


Don Pensack wrote: Mon Jun 28, 2021 11:03 pm Here you go:
http://translate.google.it/translate?hl ... &sandbox=1
Don,

Interesting comment in that link: [A few words from the store manager] There is a lot of distortion in the surrounding area because a wide field of view has been achieved by designing 4 sheets in 2 groups.

From the pics on the site looks like the eye and field lens outer surfaces are concave, so using the TV Plossl type of design. However, not sure what distortion that store manager is talking about, but when Long Perng made the Sterling Plossls and pushed their AFOVs (although not as much), the 25mm of that series certainly had a lot of off-axis distortion that severely distorts the Moon when it is near the field stop. Reminded me of what the old 24mm TV Wide Field did to the Moon in the off-axis.
-Bill

U.S.A.F. Veteran - Visual Amateur Astronomer since 1966 - Fully Retired since 2019
8" f/5 Newt - Lunt 152 f/7.9 - TSA 102 f/8 - Vixen 81S f/7.7 - P.S.T. - Pentax 65ED II - Nikon 12x50 AE
Pentax XWs - Baader Morpheus - Takahashi LEs - Edmund RKEs - BST Starguiders - 6ZAO-II/5XO/4Abbe
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#9

Post by Lady Fraktor »


Looking through the user links some say there is distortion, others say there is none.

If you hav e issues using Don provided link, go to www.starcloud.jp and you will find the eyepieces quite easily.

Someone at CN claimed these were asymmetrical designs but I have not looked close enough to confirm that.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#10

Post by Bigzmey »


Lady Fraktor wrote: Thu Jul 01, 2021 7:21 pm Looking through the user links some say there is distortion, others say there is none.

If you hav e issues using Don provided link, go to www.starcloud.jp and you will find the eyepieces quite easily.

Someone at CN claimed these were asymmetrical designs but I have not looked close enough to confirm that.
There are have to be distortions for 4 element EP with 60 deg FOV, the question is how tolerable in F8 frac?

For $200 + shipping from Europe I would either pay a bit more and get Vixen LVW 42mm or Pentax XW40; or pay less and get GSO 2" SV 42mm. :)
Scopes: Stellarvue: SV102ED; Celestron: 9.25" EdgeHD, 8" SCT, 150ST, Onyx 80ED; iOptron: Hankmeister 6" Mak; SW: 7" Mak; Meade: 80ST.
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
Binos: APM: 100-90 APO; Canon: IS 15x50; Orion: Binoviewer, LG II 15x70, WV 10x50, Nikon: AE 16x50, 10x50, 8x40.
EPs: Pentax: XWs & XFs; TeleVue: Delites, Panoptic & Plossls; ES: 68, 62; Vixen: SLVs; Baader: BCOs, Aspherics, Mark IV.
Diagonals: Baader: BBHS mirror, Zeiss Spec T2 prism, Clicklock dielectric; TeleVue: Evebrite dielectric; AltairAstro: 2" prism.
Filters: Lumicon: DeepSky, UHC, OIII, H-beta; Baader: Moon & SkyGlow, Contrast Booster, UHC-S, 6-color set; Astronomik: UHC.

Observing: DSOs: 3106 (Completed: Messier, Herschel 1, 2, 3. In progress: H2,500: 2180, S110: 77). Doubles: 2382, Comets: 34, Asteroids: 255
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#11

Post by WilliamPaolini »


Lady Fraktor wrote: Thu Jul 01, 2021 7:21 pm Looking through the user links some say there is distortion, others say there is none.
...
Someone at CN claimed these were asymmetrical designs but I have not looked close enough to confirm that.
If it has significant AMD or RD or AMD+RD in the off-axis, many observers likely not to notice these in such a long focal length eyepiece unless they are scanning rich star fields or have the Moon or a larger planet in the far off-axis. The latter probably unlikely again which such a long focal length low magnification eyepiece. So it may be there they just did not notice. Sometimes things like this only appear if you go looking for them.

As far as the optical design, if you scroll down in this link you will see that it is an Asymmetrical Plossl-like design. So the two doublets are not the same diameter, unlike all modern Plossls (Clave's were more the true asymmetrical Plossl design). The diagram also shows the outward eye and field lens surfaces are concave like the TV patented Plossl-like design to improve star points at the edge. However, it also shows the inward facing surfaces are convex which is not in the TV design or the standard True-Plossl or modern Symmetrical-Plossl design. I have seen similar to this particular design though in the Tal Super Plossls (http://www.talteleoptics.com/images/TAL ... Review.pdf) in that they have convex inward facing surfaces, but they are different again in that their outward facing surfaces are convex as well. So this RPL series seems to be a bit of a different take on the Plossl-like design. Of course, this assumes the pic in that thread is accurate.

https://cosmicpeople.sakura.ne.jp/kitak ... tLens.html
-Bill

U.S.A.F. Veteran - Visual Amateur Astronomer since 1966 - Fully Retired since 2019
8" f/5 Newt - Lunt 152 f/7.9 - TSA 102 f/8 - Vixen 81S f/7.7 - P.S.T. - Pentax 65ED II - Nikon 12x50 AE
Pentax XWs - Baader Morpheus - Takahashi LEs - Edmund RKEs - BST Starguiders - 6ZAO-II/5XO/4Abbe
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Re: How Would This Eyepice Do In A 1200mm f/8 Achromatic Refractor?

#12

Post by Lady Fraktor »


Thank you for the link Bill, I had not seen your TAL review before.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
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