Zeta Reticulan

You're welcome.

I make it around 25cm and 10.5cm

Oh (previous actual word mysteriously deleted ), I'm getting predictable. lol

I liked it so much I bought it twice.

They're probably really good single coatings lol.

I think the general consensus is that the 6mm is the best of the range.

Thanks for the info Don. I suspected the single coating was an economic decision. Either that or the Starbase are just an old design. I'm not sure that they're even edge-blacked, which may explain some of the scatter and ghosting I saw.

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. The 6mm and 14mm versions are bundled with the Starbase 80 telescope package. The Starbase achromat and the eyepiece series are apparently both made by the Kubota Optical Corporation in Hanamaki, Japan. The eyepieces are not a traditional Abbe orthoscopic design and are purportedly an asymmetrical doublet defined and designated as an Orthoscopic Plossl (Orthoscopic/PL). They are recommended for use with focal ratios up to f/6. “In the early days, it was made by Cook in England and Steinheil in Germany. This is an achromat type eyepiece that combines two Ramsden lenses. A well-made Japanese-made eyepiece is an almighty eyepiece that can be used from low to high magnification because ghosts are not noticeable and spherical aberration and distortion are small. By the way, NIKON's orthoscopic eyepieces, which are still very popular today, were PL type” ~ op cit (diagram and definition from the Scopetech webpage). Etymologically the compound adjective ‘orthoscopic’ literally means corrected vision. Unlike most contemporary modern eyepieces the Starbase series probably aren’t edge-blacked. They feature a ‘retro’ volcano top without rubber eyeguards. The eyepieces each have a single high quality coating as opposed to being multi-coated (I'll return to this later). The proclaimed rationale behind using only a single coating of superior quality is that it gives much better transmission than relatively inexpensive mass produced multi-coatings. Except for the barrel undercut they have the vintage appearance of an erstwhile era. The AFOV varies between 43° and 53° throughout the range. The 20mm has a 45° AFOV and 14mm of eye relief. I make the eye lens a decent 17mm with a 15mm field stop. I find this a quite pleasant eyepiece to use. Around 13-14mm is my preferred eye relief distance. The field stop is sharp and defined, as the stops are throughout the range. The chromed brass barrel is high quality with good baffling and has a filter thread. Although, to my chagrin, I discovered my broadband Explore Scientific OIII and Astronomik UCE-E filters would only thread in a small amount. This problem was the same with the other focal lengths. It should be enough when placed in a 1.25” diagonal. I would have concerns about it coming loose in a 2” diagonal or a Newtonian focuser. My Baader filters had no problems in any of the four eyepieces. Interestingly the ES OIII has no issues at all threading smoothly and completely into my 1.25” Tele Vue Everbrite and Baader BBHS diagonal nosepieces. So, no surprise there then with the known compatibility issues of Japanese filter threads! The end caps fit well and the undercut gave me no problems. In my f/5.8 Sky-Watcher Evostar 72ED DS Pro, at 21x for a 3.4mm exit pupil, it gave nearly a hundred and twenty nine arc minutes of true field of view. This is nigh on four and a third Full Moons and only around twelve arc minutes less than my 25mm Ohi-made Abbe orthoscopic. I could just about get the entire Coat Hanger (Brocchi’s Cluster) in the FOV. The 20mm eyepiece showed an abundantly bright, well contrasted image, displaying excellent transmission and on-axis acuity. However there is some lateral astigmatism approaching the field stop. I did expect this with the f/5.8 Evostar as it is a bit unforgiving with some eyepiece designs. I tend to observe mainly on-axis anyway so it didn’t really bother me. Apart from the thread issue the ES OIII worked well with the 20mm giving me a vivid view of M27 and nicely revealing the Eastern and Western Veil Nebulae. At 53° the 14mm has the widest AFOV, and in my opinion it definitely shows. My first impression was of a very agreeable field of view for such a physically small eyepiece. I make the eye lens 15mm and the field stop at least 13mm. I find the 12mm eye relief to be quite comfortable. Eye placement is undemanding and the eyepiece has a good ergonomic feel about it. Although it also showed some astigmatism towards the field stop. The transmission was bright, well above average, and I even got a glimpse of M57 at 30x. When deployed in a 2x Vixen Deluxe Barlow for 60x it was equally sharp, the astigmatism had disappeared, and it displayed no vignetting. I found both Hercules clusters at 60x with ease and split several doubles including the beautiful γ Andromedae. The 9mm has a 45° field and the 7mm eye relief is about average for its focal length. By comparison my 9mm Circle- T Abbe has a 7.6mm eye relief. When used in conjunction with the Vixen Barlow in my 72ED DS Pro the 9mm Orthoscopic/PL really came into its own as a planetary eyepiece. The Barlow slightly improved the close eye relief. Both Saturn and Jupiter were very sharp at 93.3x. Colour separation and contrast were excellent. The Cassini Division and some surface detail on Saturn were easily observed as was Titan. I was impressed with the amount of detail I could actually see as Jupiter approached transit. Although occasionally I thought I detected a tiny bit of scatter. The planet is quite bright and only a few weeks from opposition though. I was also using a Baader Neodymium filter in the diagonal nosepiece which may have contributed to this effect in some way. It was a damp and dew laden early morning session. With excessive humidity filters can often have a tendency to fog slightly in the nosepiece. I believe I also occasionally saw a hint of the reflection of my own cornea, which may be a consequence of the single coating. After some use this disappeared. In later sessions I didn’t notice either phenomena. The barrel undercut plays well in the Vixen Barlow as it has no compression ring. With only 4mm of eye relief and a 43° apparent field the 6mm Orthoscopic/PL is the least ergonomic of the quartet. Again, compared to an Abbe of the same focal length, it has almost a millimetre less eye relief. Images of Saturn and Jupiter used without a Barlow in the 72ED at 70x were very sharp and bright. The intensity of the rich colours and excellent contrast impressed me. I was immediately quite taken with the 6mm O/PL, especially when used in the Vixen Barlow. The volcano top almost certainly contributed to the comparative ease of viewing and eye positioning. I’d expected it to be more demanding to use, so this was a pleasant surprise. At 140x (with the Barlow) the 6mm O/PL gave an approximate 0.5mm exit pupil. I split ε Boötis and I thought it was one of the best views of the binary I’ve had so far this year. As Cassiopeia got higher in the sky I discovered ι Cassiopeiae also split beautifully. I’m convinced these views were enhanced by the above average transmission of the single coating. Saturn still looked excellent even when it was past transit. During the first session it wasn’t quite as sharp on Jupiter at 140x. This wasn’t surprising however as the seeing was only average and the transparency was relatively poor. What was surprising was just how well the 6mm performed on Jupiter at 140x in a 72mm ED doublet. In a later session of better conditions I could see what appeared like Ganymede’s shadow on the surface near the limb. I actually first witnessed this at 93x with the Barlowed 9mm. I knew Ganymede would eventually become visible as it transited the surface. I impatiently switched back to the 6mm as I wanted to view this emergence before I lost the transparency. Eventually I was rewarded with the bright point of light of Ganymede seemingly separating itself from the planetary limb. The Starbase O/PL’s were originally acquired for my 102mm Sky-Watcher SkyMax Maksutov Cassegrain. Its focal ratio of f/12.7 should ameliorate any aberration problems that were noticed in the faster scope. The initial rationale behind buying these eyepieces was that they were relatively light in weight, ergonomic (I like volcano tops), and had good build quality. The whole SkyMax grab and go kit needed to be light and portable and fit into a small holdall-type bag. The 20mm Starbase gave me a nice view of Saturn and Jupiter at 65x. It was when I started using the 14mm it started getting interesting. Although I did notice the undercut snagging occasionally when swapping eyepieces. The three screws of the Baader helical compression ring can often be a little finicky with barrel undercuts. The 14mm O/PL gave a fairly sharp 92.8x. The seeing was above average, but not as good as the previous night. Jupiter’s GRS was just noticeable near the western limb and would be about central at transit (03:20). Ganymede, Callisto, and Io were close together on the western side of the planet with Europa on the opposite side. I could perceive colour in the moons and discern some Jovian surface detail. As the planet rotated the GRS became more easily visible. I decided it was time for the 9mm ‘Orthoscopic Plossl’. At 144x I lost a lot of acuity and furthermore there appeared to be quite noticeable ghosting. Jupiter was very bright with a visual magnitude of -2.8. Overall I like these 'retro' eyepieces. Although purists may find they perform better at f/8 or slower. However, they do have certain faults in my opinion. The single coating is probably the biggest contributing factor. The advantage is above average transmission, ideal for many deep sky objects. Unfortunately the single coating appears to be responsible for a fair amount of ghosting and light scatter. On the other hand, the colour separation, contrast and acuity are very good. Swings and roundabouts.

I think for low power sweeping or rich field a 2" diagonal/eyepiece takes some beating. I like to use my BHZ with its 2" skirt as it sits lower in the diagonal itself. Although I prefer a 1.25" diagonal for higher magnifications. I take a 2" Baader dielectric and a Tak' prism out usually with my 80 ED Evostar. The Tak's so light it helps keep down vibration. I bought this TV Everbrite for my 60 EDF, unfortunately the nosepiece undercut didn't play well with the visual back compression ring. I had no problems with the Baader. These days I use the 60 EDF with 1.25" accessories predominantly because of weight and balance issues. I do kind of miss the 2" stuff with it for rich field.

Could depend on the mount. I can use a 2" prism if I use a Porta II/HAL-130 plus half pillar. The main advantage is that I can use 2" eyepieces. Bear in mind a heavier eyepiece/diagonal can add a kilo or more. I'm more likely to use 1.25" accessories on the TL-130.

Did anyone catch the opposition? I saw it for about an hour right up until transit with my 127mm Mak'. It had been cooling for over two hours beforehand. I could see Rhea and Titan, highest magnification was 171x. The rings were quite bright, possible Seeliger Effect.

I won't comment again on this thread. If the OP wants to communicate with me he can do it through a PM. I didn't answer this thread to start a flame war. I just gave an opinion. I have no idea why you are beleaguering this.

I find the 72ED very easy to use, especially for doubles. Does it have limitations? Of course. The OP told me that he would prefer a light grab and go scope that could take advantage of breaks in the weather. I regularly use my 72ED on an AZ5 Deluxe. It's my most used scope. Everything fits into these two bags. In a perfect world I wouldn't have a physical disability and I'd take a six inch ED refractor out every night. Unfortunately we don't live in a perfect world. I thought the 72ED/AZ5 was a reasonable grab and go compromise. 335 quid is still good for an ED scope. 265 quid is pretty good for a mount with a decent tripod and slo mo. Furthermore, the 72ED sits very well on the mount with no real vibration return issues. IMO astronomy isn't always about the biggest aperture. I'd rather be out looking at the stars than sitting inside wondering about whether it's worth setting-up.

How much were the 140's new? I think the Synta Mak's are pretty decent for what they cost. I'm not the only person who has noticed the bright diffraction ring on them. I don't know what's going on with Newt's, getting an f/6 isn't so easy nowadays. My guess is that they're mostly aimed at the AP market. It's where the money is lol. I believe the OP wants a reasonably priced, portable scope with a rapid cool down. I think the 72ED is a contender. Unless he wants to spend more money.

Links to the Baader site often end up 404. I don't know why.

They're just Synta Mak's. There's nothing 'poor' about the optics. They just don't cost seven grand. I'm not the only person who has noticed this with Synta Mak's. I thought the OP was on a budget. I think it's not realistic to recommend a a seven grand scope. Comparing it to a Synta Mak is downright disingenuous.

I don't want to stray off-topic, but where computer security is relevant, some browsers and some extensions can even remove social media links from webpages.

I don't like Mak's for doubles as they have a bright first diffraction ring. So close doubles can be tricky. A slow achromat would be preferable IMO. Failing that I'd consider a smaller aperture ED refractor. I split more doubles with my 72ED DS Pro than any other scope I own. The 72 has a limiting magnitude of 11.9. A 102mm has a limit of 12.74. Which is less than one magnitude difference.

I've recently had a few early morning sessions with Jupiter and Mars using my 127mm Maksutov. A couple of them have been outstandingly good with magnifications ranging between 170x and 257x. The rest I've struggled to get 123x. It's more about the conditions than the scope.

Ooh, I like that one!

Magnification with any scope will depend on conditions. I've had sharp views of the planets with an ST80 at 120x plus. Often higher. I wouldn't say it was the norm though. Refractors will always have better acuity/contrast as, unlike reflecting scopes, they have no central obstruction. I find I can quite regularly reach 125x with my ST102, especially lunar observing. I do use yellow filters however.

Technically it should achieve 160x as a theoretical maximum. A fast achromat will suffer from chromatic aberration, particularly noticeable at higher magnifications. TBH the ST80 is fairly well colour corrected. If the CA bothers you a yellow filter is an inexpensive way to ameliorate the cyan fringing. An old trick is stacking it with an LP filter that naturalises the colour slightly (the LP takes out some Sodium lines). A yellow filter absorbs all coloured light except yellow. Yellow is the colour wavelength between 575-585 nm. Green is the colour between cyan and yellow in the spectrum. It has a dominant wavelength of roughly between 495–570 nm. A Wratten #8 or fringe killer/ minus-cyan filter is a longpass filter blocking visible wavelengths below 465 nm. Blue light is between 450-495 nm and cyan light is between 490-520 nm. Yellow light is between 570-590 nm and light produced from low pressure sodium lamps is around 589 nm (589.0 ~ 589.3 nm) on average. Light pollution, Moon & Skyglow and basic contrast filters are designed to attenuate sodium light skyglow. A Wratten #8 will attenuate or block blue/cyan light below 465 nm and a contrast filter stacked behind it will further attenuate the 589 nm length of sodium light.The effect the stacked contrast filter has is to reintroduce a very slight blue tint to the image effectively slightly naturalising it. If you want to splash some cash you can stack a Baader Fringe Killer with a Baader Neodymium. TBH, the cheaper stack is almost as good.

Could be an Orion RACI. It's been a few years. Might be an EQ2. The ST80 is basically a widefield achromat. I think an alt-az mount is more intuitive to use.

Depends on the particular refractor. I can see a lot with this (Altair 60mm EDF). I can see nebulae, open clusters, globular clusters, asterisms and split doubles. I've witnessed Galilean eclipses and shadow transits and at least two of the moons of Saturn (Titan. Rhea).

De gustibus non est disputandum.