General discussion and Q&A about all makes and models of oculars, barlows, and filters for astronomy. Mon, 10 Aug 2026 01:15:20 +0000 Mon, 10 Aug 2026 01:15:20 +0000 AstronomyConnect https://astronomyconnect.com/forums/node/eyepieces-barlows-and-filters/ Mon, 27 Nov 2023 03:24:52 +0000 https://astronomyconnect.com/forums/threads/new-eyepieces-soon.15558/ https://astronomyconnect.com/forums/threads/new-eyepieces-soon.15558/ invalid@example.com (Gabby76) Gabby76 These are the ones many copied and called super plossls in the 90s.

Though Hutech calls them Plossl in the article they are actually a variation of the Zeiss Astroplanar design.
These are superb eyepieces and if you are looking for some very good all round eyepieces, I would recommend them.
Once available I will be purchasing the set.

I am not sure of the 2 barlows offered as they are new items, hopefully they will be as...

New eyepieces soon]]> 11 Tue, 03 Oct 2023 18:28:29 +0000 https://astronomyconnect.com/forums/threads/new-svbony-solar-filter.15514/ https://astronomyconnect.com/forums/threads/new-svbony-solar-filter.15514/ invalid@example.com (sojourneyer) sojourneyer
It says that the filter meets ISO 12312-2:2015 Standard.

The price on Svbony.com is $29.99 . It is not available on Amazon as of yet.

I personally would not be amongst the first to get one of these. You never know the quality control and the risk to your eyes.

https://www.svbony.com/solar-eclipse-telescope-filter/#W9183B]]> 11 Wed, 20 Sep 2023 16:00:47 +0000 https://astronomyconnect.com/forums/threads/brandon-eyepieces.15475/ https://astronomyconnect.com/forums/threads/brandon-eyepieces.15475/ invalid@example.com (Gabby76) Gabby76 I have had one for almost 10 months now and the planetary and lunar viewing with it are superb.

If looking for a 20 mm I would highly recommend it as I would have to say it is the best of the lineup.

1.25" barrel without safety undercuts, 45° AFOV, 16 mm eye relief (flat top or eyecup version)

I tried viewing with sunglasses on and never contacted the eyepiece so eye relief should be good...

Brandon eyepieces]]> 8 Fri, 15 Sep 2023 17:04:07 +0000 https://astronomyconnect.com/forums/threads/prism-diagonals.15339/ https://astronomyconnect.com/forums/threads/prism-diagonals.15339/ invalid@example.com (Gabby76) Gabby76 1.25" prisms have the shortest lightpath when compared to mirrors and a 2" prism lightpath falls between a 1.25"and 2" mirror. This can get you into focus without adapters or extension pieces.

The issue with using a prism is that if the telescope is not made for prism use it can actually degrade the views.

So how do you find out if a prism will work with your refractor? Keep reading...

Prism diagonals]]> 3 Sun, 27 Aug 2023 22:00:39 +0000 https://astronomyconnect.com/forums/threads/wide-band-vs-narrow-band-filters.15354/ https://astronomyconnect.com/forums/threads/wide-band-vs-narrow-band-filters.15354/ invalid@example.com (sojourneyer) sojourneyer thanks]]> 3 Thu, 17 Aug 2023 03:12:08 +0000 https://astronomyconnect.com/forums/threads/long-perng-lanthanum-eyepieces.15336/ https://astronomyconnect.com/forums/threads/long-perng-lanthanum-eyepieces.15336/ invalid@example.com (Gabby76) Gabby76 https://www.longperng.com.tw/goods.php?act=view&no=253

On a different forum this topic came up and there is very little reported on them in use and the only retailer I know that sells some of them is Altair Astro.
Sky At Night did a review of them in 2018 which did not inspire confidence in the Othoscopic claim as they reported edge of field colour and aberations 15-20% out from edge of field....

The 45 mm would need to be used in a telescope above f/7 as the exit pupil is at...

Long Perng Lanthanum eyepieces]]> 2 Fri, 11 Aug 2023 18:05:51 +0000 https://astronomyconnect.com/forums/threads/focuser-eyepiece.7460/ https://astronomyconnect.com/forums/threads/focuser-eyepiece.7460/ invalid@example.com (ObiWan) ObiWan 3 Mon, 24 Jul 2023 03:06:33 +0000 https://astronomyconnect.com/forums/threads/does-using-a-barlow-affect-astrophotography.15230/ https://astronomyconnect.com/forums/threads/does-using-a-barlow-affect-astrophotography.15230/ invalid@example.com (sojurneyer) sojurneyer 4 Fri, 23 Dec 2022 21:51:52 +0000 https://astronomyconnect.com/forums/threads/starbase-orthoscopic-plossls-revisited.13086/ https://astronomyconnect.com/forums/threads/starbase-orthoscopic-plossls-revisited.13086/ invalid@example.com (Mak the Night) Mak the Night
Starbase 'Orthoscopic Plossls' Revisited]]> 80 Sat, 06 Aug 2022 05:25:31 +0000 https://astronomyconnect.com/forums/threads/svbony-f9125a-barlow-element.13776/ https://astronomyconnect.com/forums/threads/svbony-f9125a-barlow-element.13776/ invalid@example.com (Mak the Night) Mak the Night SVBONY 1.25'' 2X Barlow Lens Telescope M28.5*0.6 Thread for Standard Monocular Optics Compact Eyepiece 31.7mm SvBony (sic)



I thought I was being pretty clever using a stand-alone 2x SvBony Barlow element to decrease the focal length of my 6mm Vixen SLV. The element itself was threaded from off my rather shiny silver coloured SvBony 2x Barlow housing.



Imagine my surprise when I discovered...

SvBony F9125A Barlow Element]]> 16 Sun, 09 Jan 2022 17:38:16 +0000 https://astronomyconnect.com/forums/threads/orion-tri-mag-1-25-3x-barlow-lens.13123/ https://astronomyconnect.com/forums/threads/orion-tri-mag-1-25-3x-barlow-lens.13123/ invalid@example.com (Mak the Night) Mak the Night

They say all things come to those who wait. I don’t know who ‘they’ are, but they may actually have a good argument. I still required a relatively lightweight, uncomplicated 3x Barlow for my ST80 grab and go kit bag. My Tele Vue 3x is a little weighty for the ST80’s aftermarket GSO focuser, especially combined with a zoom. The TV was the first 3x Barlow I ever owned and (rightly or wrongly) I tend to compare all subsequent 3x Barlows with it....

Orion Tri-Mag 1.25" 3x Barlow Lens]]> 3 Fri, 31 Dec 2021 11:09:19 +0000 https://astronomyconnect.com/forums/threads/orion-e-series-7-21mm-zoom.13081/ https://astronomyconnect.com/forums/threads/orion-e-series-7-21mm-zoom.13081/ invalid@example.com (Mak the Night) Mak the Night View attachment 7541

I bought the Orion E-Series 7-21mm Zoom for £56.99. There are other zooms that appear identical to this eyepiece selling under other brand names. They undoubtedly originate from the same OEM. There doesn’t seem to be a great difference in their respective retail prices. The first thing that I noticed with the Orion ‘E-Series’ was how physically light it was.

View attachment 7542

The Orion website says it...

Orion E-Series 7-21mm Zoom]]> 6 Sun, 26 Dec 2021 18:04:59 +0000 https://astronomyconnect.com/forums/threads/altair-lightwave-3x-flat-field-tele-extender-barlow.13093/ https://astronomyconnect.com/forums/threads/altair-lightwave-3x-flat-field-tele-extender-barlow.13093/ invalid@example.com (Mak the Night) Mak the Night

The 1.25“ Altair Lightwave 3x Flat Field Tele Extender Barlow weighs in at 195 grams and I make it 105mm tall. One of the reasons (if not the predominant one) I acquired this Barlow/amplifier was that its barrel is only 35mm leaving the remaining 70mm for the housing. This makes deployment in a 2“ diagonal (with an adapter) a lot safer as it helps ensure that the end of the unit doesn’t make contact with the mirror or prism surface. In my...

Altair Lightwave 3x Flat Field Tele Extender Barlow]]> Sun, 26 Dec 2021 17:55:34 +0000 https://astronomyconnect.com/forums/threads/svbony-sv137-2x-barlow.13092/ https://astronomyconnect.com/forums/threads/svbony-sv137-2x-barlow.13092/ invalid@example.com (Mak the Night) Mak the Night


My first impression of the Barlow, after taking it out of the box, was that it felt like it could have come out of a Christmas cracker. It’s not heavy, lighter (barely 55 grams) in fact than its GSO equivalent, which is mostly made...

SvBony SV137 2x Barlow]]> Sun, 26 Dec 2021 17:15:31 +0000 https://astronomyconnect.com/forums/threads/unusual-4-8mm-orthoscopic.13090/ https://astronomyconnect.com/forums/threads/unusual-4-8mm-orthoscopic.13090/ invalid@example.com (Mak the Night) Mak the Night

This unusual ‘alleged’ Abbe fully multi-coated orthoscopic has a focal length of 4.8mm. I say ‘alleged’ as I don’t actually know if this is indeed a genuine Abbe design. From what I can gather it has two lens groups consisting of a triplet and a single lens. So, the odds are it is an Abbe eyepiece and very probably manufactured in China. Mine has no brand name but these eyepieces have also been sold as Kson, Ascension, Apogee and University...

Unusual 4.8mm Orthoscopic]]> Thu, 23 Dec 2021 12:31:05 +0000 https://astronomyconnect.com/forums/threads/gso-3x-ed-barlow.13084/ https://astronomyconnect.com/forums/threads/gso-3x-ed-barlow.13084/ invalid@example.com (Mak the Night) Mak the Night
View attachment 7548

I desired a basic 3x lightweight Barlow. Among various criteria it would require good ergonomics. Basically I’d need to like the overall feel of...

GSO 3x ED Barlow]]> Wed, 22 Dec 2021 23:18:13 +0000 https://astronomyconnect.com/forums/threads/starbase-orthoscopic-plossls.13079/ https://astronomyconnect.com/forums/threads/starbase-orthoscopic-plossls.13079/ invalid@example.com (Mak the Night) Mak the Night View attachment 7532

The Starbase four element ‘orthoscopic’ series of eyepieces are distributed by Takahashi Seisakusho Ltd. There are supposedly five in the range consisting of: 20mm, 18mm, 14mm, 9mm and 6mm focal lengths. However the 18mm doesn’t seem to be available outside of Japan yet. The 6mm and 14mm versions are bundled with the Starbase 80 telescope package.

View attachment 7533

The Starbase achromat and the eyepiece series are apparently both made by the Kubota...

Starbase 'Orthoscopic Plossls']]> Wed, 09 Jun 2021 06:13:09 +0000 https://astronomyconnect.com/forums/threads/altair-ultraflat-eyepiece.6289/ https://astronomyconnect.com/forums/threads/altair-ultraflat-eyepiece.6289/ invalid@example.com (Mak the Night) Mak the Night
https://www.altairastro.com/Altair-15mm-ULTRAFLAT-Eyepiece-Stainless-Steel.html

View attachment 6625

They're new to me. They don't appear to be Guan Sheng, Long Perng, Synta or Kunming.]]> 69 Wed, 09 Sep 2020 18:33:33 +0000 https://astronomyconnect.com/forums/threads/filter-size-question.7903/ https://astronomyconnect.com/forums/threads/filter-size-question.7903/ invalid@example.com (geoffoto) geoffoto Sat, 27 Jun 2020 15:41:13 +0000 https://astronomyconnect.com/forums/threads/a-cautionary-undercut-tale.7667/ https://astronomyconnect.com/forums/threads/a-cautionary-undercut-tale.7667/ invalid@example.com (Mak the Night) Mak the Night
View attachment 7354

The Fast Lock type has rods or binders inside the draw tube which engage the eyepiece barrel when the lock is twisted. As a further measure the lever itself can be threaded in as an extra safety lock.

View attachment 7355

The lighter Baader ClickLock mechanism uses a compression ring type 'collet'...

A Cautionary Undercut Tale]]>