EPs for binoviewing

Discuss telescope eyepieces.
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Bigzmey United States of America
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EPs for binoviewing

#1

Post by Bigzmey »


I have recently picked a used basic Orion binoviewer. Still waiting for a clear night to give it a shot. In the mean time was playing with my EP collection during daytime to figure out what EP pairs would work for me. Obviously low glass count EPs (Orthos, Plossls, Konigs, etc.) should work in longer focal length. I happened to have a pair of Meade 26mm Plossls, that would be my starting point.

However, I wanted to see which long eye relief EPs I could use since I prefer to observe with eyeglasses. Having wider FOV would not hurt either. At this point I don't have matching pairs, so I used close FLs (like TV Delite 13mm and 15mm) just to test if I can merge unfocused images.

There was no surprise with Vixen SLVs and Pentax XFs, they were very comfortable. They are also in a good price range, in particular on the used market.

I hade high hopes for TV DElites. Unfortunately, I was not able to merge images with them. Straight wide bodies clashed with my nose bridge. Bummer.

I know some people binoview with Baader Mark zooms. No such luck here. The body is straight and even wider than Delites. Shame.

The pleasant surprise was Pentax XWs. Their bodies are wider than Mark IV or Delites, but they taper to the top and feel very comfortable. The price and weight are considerations. However, they are my favorite EPs and certainly an option.

If some had good luck with other EP lines in binoviewers, please share your experience. Since I observe with eyeglasses on I would like at least 15mm ER.
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: EPs for binoviewing

#2

Post by notFritzArgelander »


It all comes down to inter pupillary distance. My eyes are set at the extreme limit of being able to use a binoviewer at all. There are a few folks whose eyes are set so far apart that binoviewers don't accommodate them at all. I use the Baader Zooms comfortably, for instance. I think I have nothing useful to offer because of that. Unfortunately wide angle long eye relief EPs tend to be a bit wide. Check your glasses prescription for your inter pupillary distance and that can give you a start on the necessary geometry at least.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 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 Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: EPs for binoviewing

#3

Post by Lady Fraktor »


I am not much help either as I use mainly Abbe, Mono and Plossl with my binoviewer.
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
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Re: EPs for binoviewing

#4

Post by Ruud »


Morpheus eyepieces have plenty eye relief. I expect that if you use them with their winged eye cups their bulk would be far enough from your face to have a chance of using them comfortably with your binoviewer.

Specs:
https://www.baader-planetarium.com/en/d ... l_data.pdf

Maximum width of the barrel is 55mm, which will be the minimum ipd for a pair. At the eye lens end, without any eye cup the eyepiece diameter is 43mm. With the winged eye cup this becomes about 45mm. Even when the barrels touch you'll have about 10mm nose relief.

The winged eye cups take away only a mm or two from the eye relief on their low side. Where your nose is, the eye cup will be almost flush with the eye lens.

With their large eye relief and considering how close you can actually get to the glass with nothing interfering, Morpheus might be a good option for you. I'm very impressed with the optical quality of the M17.5, btw. To my eye, it's central 70° is on a par with my 12mm Delos, but the Morpheus goes wider (76°).
7x50 Helios Apollo 8x42 Bresser Everest 73mm f/5.9 WO APO 4" f/5 TeleVue Genesis 6" f/10 Celestron 6SE 0.63x reducer 1.8, 2, 2.5 and 3x Barlows eyepieces from 4.5 to 34mm
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Re: EPs for binoviewing

#5

Post by 25585 »


TV 40mm Plossls, Celestron 35mm Ultimas, Takahashi 28mm Erfles and the original Vixen LVs in various focal lengths are what I use most. All have enough effective eye relief & thin enough barrels to accomodate my nose & glasses. None are too heavy either.
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Eyepieces from: Aero, Antares, APM, Baader, Brandon, Bresser, Celestron, Datysun, Docter, Explore Scientific, GSO, I R Poyser, Meade, Nikon, Orion, Pentax, Rodenstock, Siberia, Sky-Watcher, Taiso, Takahashi, TAL, Tele Vue, TS, Vernonscope, Vixen, Zeiss.

Scopes from: Altair, Bresser, Lumicon, Orion Optics UK, Sky-Watcher, Takahashi, Tele Vue, TS, Vixen.
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Re: EPs for binoviewing

#6

Post by WilliamPaolini »


I find using longer eye relief eyepieces more effective for me with binoviewers. So I am always using longer focal lengths. I've tried short focal length Plossls and Abbes and just find that it takes away from the experience for me, making it more difficult and too up close to the equipment. I would rather be farther off so it feels like natural naked eye observing. I've also tried tighter eye relief long focal length eyepieces like the 24 Panoptics or 24 ES68 and just not as enjoyable as a longer eye relief long focal length eyepiece for me. And when doing detailed high magnification viewing, like for planetary, I will opt to use a long focal length eyepiece with a Barlow or OCA/GPC to get to the higher magnification. The reason is that the long prism path of the binoviewer usually adds a little SA (spherical aberration) to the view, which blurs the view a little -- not enough to really noticeably see with low magnifications but can be apparent when up at 200x on a planet. So basically will get a little bit of a sharper view when using a Barlow or OCA with most binoviewers as that tames the SA added by the long prism path. I most enjoy my Baader Morpheus pairs I have -- 17.5mm pairs, 9mm pairs. The 17.5mm is so spectacular that when they are in the binoviewer, I typically just leave them in and stay at low power as the views are just engagingly stunning (and comfortable).
-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: EPs for binoviewing

#7

Post by Bigzmey »


Thanks everyone for the feedback. It looks like on top of other EP considerations like eye relief, FOV and image quality binoviewing adds compatibility with your face. :lol:

I have tried a few of wider bodies EPs and while they work for many, they are not compatible with my face. Looks like Pentax XF with 4.3cm body diameter and Vixen SLV with 4.5cm are the widest EPs I can handle. In away this is a relief. I happen to like both EP lines and SLVs cover whole range up to 25mm. I got Baader 32mm Plossls which are quite comfortable with eyeglasses on. Maybe add 40mm Plossls.

Anyone tried Gary Russell 50mm 1.25" Plossls for BVs? :D

http://russell-optics.com/quarter_inch.html
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: EPs for binoviewing

#8

Post by WilliamPaolini »


A 50mm Plossl in a 1.25" format will have a tiny AFOV, somewhere in the 40 degrees I would guess. If you can find one of the discontinued 30mm Celestron Ultimas, Orion Ultrascopics, and other brandings, those are much more engaging IMO than a 32 Plossl and give you the widest TFOV possible for a 1.25" eyepiece (approx 50 degree AFOV). Those are 5-emelent units popularly referred to as pseudo-Masuyama designs.
-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: EPs for binoviewing

#9

Post by Don Pensack »


Bill,
Actually, about 30° in a 50mm 1.25". Just strengthens your point that much more.
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Re: EPs for binoviewing

#10

Post by Bigzmey »


FOV is just one part of the equation. Other considerations are magnification and exit pupil. The issue I have run into with my binoviewers is that in order to reach focus with fracs I need to screw into BVs the lens from 2x barlow. This adds ~3x factor to the light train, so my F7 scope becomes F21 with FL of ~2100mm. Hence desire to add long FL EPs for lowest power possible.
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: EPs for binoviewing

#11

Post by Don Pensack »


Bigzmey wrote: Thu May 27, 2021 7:05 pm FOV is just one part of the equation. Other considerations are magnification and exit pupil. The issue I have run into with my binoviewers is that in order to reach focus with fracs I need to screw into BVs the lens from 2x barlow. This adds ~3x factor to the light train, so my F7 scope becomes F21 with FL of ~2100mm. Hence desire to add long FL EPs for lowest power possible.
That doesn't change the apparent field, though.
A 30° 50mm eyepiece just becomes a 30° 17mm eyepiece.
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Re: EPs for binoviewing

#12

Post by Bigzmey »


Don Pensack wrote: Thu May 27, 2021 8:04 pm
Bigzmey wrote: Thu May 27, 2021 7:05 pm FOV is just one part of the equation. Other considerations are magnification and exit pupil. The issue I have run into with my binoviewers is that in order to reach focus with fracs I need to screw into BVs the lens from 2x barlow. This adds ~3x factor to the light train, so my F7 scope becomes F21 with FL of ~2100mm. Hence desire to add long FL EPs for lowest power possible.
That doesn't change the apparent field, though.
A 30° 50mm eyepiece just becomes a 30° 17mm eyepiece.
I see at from a different angle. Any 1.25" EP with field stop of ~27mm will give max true field of view. It could be 18mm 82 deg EP, 24mm 68 deg or 32mm 50 deg, they all have their uses despite having the same TFV. When I had 127mm Mak, my most used EP was 40 deg 40mm Plossl. It has the same TFV as the EPs mentioned above, but I preferred the views it delivered. In my SCT I prefer on occasion 2" 55 deg Plossl over wider FOV 2" EPs.
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: EPs for binoviewing

#13

Post by Don Pensack »


Bigzmey wrote: Thu May 27, 2021 8:26 pm
Don Pensack wrote: Thu May 27, 2021 8:04 pm
Bigzmey wrote: Thu May 27, 2021 7:05 pm FOV is just one part of the equation. Other considerations are magnification and exit pupil. The issue I have run into with my binoviewers is that in order to reach focus with fracs I need to screw into BVs the lens from 2x barlow. This adds ~3x factor to the light train, so my F7 scope becomes F21 with FL of ~2100mm. Hence desire to add long FL EPs for lowest power possible.
That doesn't change the apparent field, though.
A 30° 50mm eyepiece just becomes a 30° 17mm eyepiece.
I see at from a different angle. Any 1.25" EP with field stop of ~27mm will give max true field of view. It could be 18mm 82 deg EP, 24mm 68 deg or 32mm 50 deg, they all have their uses despite having the same TFV. When I had 127mm Mak, my most used EP was 40 deg 40mm Plossl. It has the same TFV as the EPs mentioned above, but I preferred the views it delivered. In my SCT I prefer on occasion 2" 55 deg Plossl over wider FOV 2" EPs.
True, but I thought we were talking about a 50mm 1.25" eyepiece for binoviewers. There might be a scope in which 40mm eyepieces would be OK, but you'd have to accept mighty narrow fields to use a 50mm. Yes, the true field would be the same but it would be like looking at it through a straw.
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Currently using a 12.5" dob and a 4" apo refractor
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Re: EPs for binoviewing

#14

Post by Bigzmey »


Don Pensack wrote: Fri May 28, 2021 5:12 am
Bigzmey wrote: Thu May 27, 2021 8:26 pm
Don Pensack wrote: Thu May 27, 2021 8:04 pm

That doesn't change the apparent field, though.
A 30° 50mm eyepiece just becomes a 30° 17mm eyepiece.
I see at from a different angle. Any 1.25" EP with field stop of ~27mm will give max true field of view. It could be 18mm 82 deg EP, 24mm 68 deg or 32mm 50 deg, they all have their uses despite having the same TFV. When I had 127mm Mak, my most used EP was 40 deg 40mm Plossl. It has the same TFV as the EPs mentioned above, but I preferred the views it delivered. In my SCT I prefer on occasion 2" 55 deg Plossl over wider FOV 2" EPs.
True, but I thought we were talking about a 50mm 1.25" eyepiece for binoviewers. There might be a scope in which 40mm eyepieces would be OK, but you'd have to accept mighty narrow fields to use a 50mm. Yes, the true field would be the same but it would be like looking at it through a straw.
Right, binoviewing vs mono adds extra layer of considerations. Finding 1.3 - 1.7x OCA which would fit 1.25" threads of my BV would be better all around solution.
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: EPs for binoviewing

#15

Post by Lady Fraktor »


Bigzmey wrote: Fri May 28, 2021 5:07 pm Finding 1.3 - 1.7x OCA which would fit 1.25" threads of my BV would be better all around solution.
Check Siebert Optics, he sells various powers of OCA
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: EPs for binoviewing

#16

Post by Bigzmey »


Lady Fraktor wrote: Fri May 28, 2021 5:10 pm
Bigzmey wrote: Fri May 28, 2021 5:07 pm Finding 1.3 - 1.7x OCA which would fit 1.25" threads of my BV would be better all around solution.
Check Siebert Optics, he sells various powers of OCA
Thanks Gabby! I will check them out.
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: EPs for binoviewing

#17

Post by 25585 »


WilliamPaolini wrote: Wed May 26, 2021 4:36 pm I find using longer eye relief eyepieces more effective for me with binoviewers. So I am always using longer focal lengths. I've tried short focal length Plossls and Abbes and just find that it takes away from the experience for me, making it more difficult and too up close to the equipment. I would rather be farther off so it feels like natural naked eye observing. I've also tried tighter eye relief long focal length eyepieces like the 24 Panoptics or 24 ES68 and just not as enjoyable as a longer eye relief long focal length eyepiece for me. And when doing detailed high magnification viewing, like for planetary, I will opt to use a long focal length eyepiece with a Barlow or OCA/GPC to get to the higher magnification. The reason is that the long prism path of the binoviewer usually adds a little SA (spherical aberration) to the view, which blurs the view a little -- not enough to really noticeably see with low magnifications but can be apparent when up at 200x on a planet. So basically will get a little bit of a sharper view when using a Barlow or OCA with most binoviewers as that tames the SA added by the long prism path. I most enjoy my Baader Morpheus pairs I have -- 17.5mm pairs, 9mm pairs. The 17.5mm is so spectacular that when they are in the binoviewer, I typically just leave them in and stay at low power as the views are just engagingly stunning (and comfortable).
The 17.5 is superb & I may follow in getting a 2nd 9mm. Not sure if its just Morpheus, but their eye relief gets a little longer using certain scopes, I noticed with my 17.5 anyway.
Unashamed Linda Ronstadt ♡ fan! :dance: :Clap:

Eyepieces from: Aero, Antares, APM, Baader, Brandon, Bresser, Celestron, Datysun, Docter, Explore Scientific, GSO, I R Poyser, Meade, Nikon, Orion, Pentax, Rodenstock, Siberia, Sky-Watcher, Taiso, Takahashi, TAL, Tele Vue, TS, Vernonscope, Vixen, Zeiss.

Scopes from: Altair, Bresser, Lumicon, Orion Optics UK, Sky-Watcher, Takahashi, Tele Vue, TS, Vixen.
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Re: EPs for binoviewing

#18

Post by 25585 »


Bigzmey wrote: Thu May 27, 2021 7:05 pm FOV is just one part of the equation. Other considerations are magnification and exit pupil. The issue I have run into with my binoviewers is that in order to reach focus with fracs I need to screw into BVs the lens from 2x barlow. This adds ~3x factor to the light train, so my F7 scope becomes F21 with FL of ~2100mm. Hence desire to add long FL EPs for lowest power possible.
Try a couple of shorty Barlows right behind your eyepieces. I use Ultima 2x.
Unashamed Linda Ronstadt ♡ fan! :dance: :Clap:

Eyepieces from: Aero, Antares, APM, Baader, Brandon, Bresser, Celestron, Datysun, Docter, Explore Scientific, GSO, I R Poyser, Meade, Nikon, Orion, Pentax, Rodenstock, Siberia, Sky-Watcher, Taiso, Takahashi, TAL, Tele Vue, TS, Vernonscope, Vixen, Zeiss.

Scopes from: Altair, Bresser, Lumicon, Orion Optics UK, Sky-Watcher, Takahashi, Tele Vue, TS, Vixen.
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