Baader Classic Ortho & Plossl Review

23 January 2013  |  Steve

We recently sent John Huntley a set of Baader Classic Orthoscopic and Plossl eyepieces to assess and compare with the more expensive (but now discontinued) Baader Genuine Orthoscopics. John is well known on the Stargazerslounge astronomy forum for his knowledge of eyepieces. Here are his thoughts so far. 



As explained below, the weather conditions in the UK in the early days of 2013 have prevented a really thorough examination of the optical performance of these eyepieces. However, I wanted to post something that might be of help to those considering them so I’ve compiled these notes on what I've learned about them so far. This should be considered and interim report really though so please bear that in mind.

Where I use the abbreviation BGO I am referring to the Baader Genuine Orthoscopic and BCO, the Baader Classic Orthoscopic.

The eyepieces compared here are the Baader Classic 6mm, 10mm and 18mm orthos, the Baader Classic 32mm Plossl, the Baader Q-Turret 2.25x Barlow, the Baader Genuine orthos in the 5mm, 6mm, 7mm and 18mm focal lengths and a 6mm Circle-T ortho for some of the physical comparisons. All but the last eyepiece were loaned to me by First Light Optics and I’m very grateful to them for this chance to compare them :smiley:

With regards to cost, the Baader Classic orthos and plossl retail for £49 each and the Q-Turret 2.25x Barlow for £45. The Baader Genuine orthos are £75 each (though stocks are dwindling fast and many focal lengths are no longer available).

I've included some photos of the eyepieces discussed at the end of this post.

Looking At Them

The Baader Classic soft rubber eye cup / glare shield is not to my personal taste. I found it got in the way and always folded it down in use, which is very easy to do. The rubber rim around the top of the eyepiece is nice to have though and I can see that some owners might be tempted to trim the “wing” off the rubber rim although others may well like this design.

The Baader Classics are very light. They feel less substantial in the hand than BGO equivalents although most of this seems due to the use of lightweight alloy barrels rather than the more traditional chromed brass that the Classics use.

The Q-Turret 2.25x barlow’s drawtube proved a rather sloppy fit for eyepieces, both other Baader Classics and other 1.25” eyepiece types I tried. More rattle fit and push fit. The barlow is fitted with a single set screw to secure the eyepiece. There is no compression ring used.

The optical element of the Barlow unscrews from the barrel and can be screwed into other 1.25” eyepieces filter threads, provided they have sufficient clearance inside the barrel, to give a 1.3x amplification. This latter requirement rules out the use of this feature with eyepieces that use lower lens assemblies within their barrels, ie: rather a lot of modern eyepiece types. The Barlow lens assembly is not threaded for filters but is knurled to aid removal and fitting.

The Baader Classic black anodised finish seems rather easily damaged by slight knocks which can leave nicks which show the metal beneath the anodising. The screen printed logo and lettering showing signs of slight flaking in one or two places although this did not worsen while I had them. The optics seem reasonably well protected from dust, eyelashes, etc.

The Baader Classic lens coatings, called HT multicoatings, look quite similar to BGO Phantom MC multi-coatings. The pink and green tints are slightly stronger and richer on the BGO’s depending on the angle you view them from. Viewed from above with the eyepiece barrels capped, the Baader Classic eye lens and interior actually looks a little darker than BCO’s. Internal reflections seem very well controlled.

The inside surface of the Baader Classic 1.25” barrels is micro ridged but has a rather shiny finish. I’d like to see more effective matt blackening in there as the BCO’s have. The Baader Classic lens retaining rings are nicely finished in dull matt black though.

The Classic 32mm Plossl comes with removable plastic extension tube which adds around 10mm to the eye to top of eye lens distance. The eye lens is already recessed a good 15mm or so though. I guess this extension is to help find optimum eye position although I found that did not have a problem doing this without this little accessory. The apparent field of this eyepiece seems to be around 45 degrees so around 10% less than most other plossls on the market.

BCO eye lenses are larger than their BGO equivalents in all 3 focal lengths. In the 6mm focal length I measured the respective eye lens diameters as approximately:

Baader Classic Ortho = 7mm
Baader Genuine Ortho = 5mm
Circle-T Ortho = 6mm

Looking Through Them

The conditions in the UK for testing astro kit have been pretty poor of late so viewing opportunities have not, thus far, been as extensive as I would have liked. I’ve also not be able to closely compare all the permutations of the Q-Turret Barlow as yet.

The objects I’ve viewed with these eyepieces are Jupiter, M42, The Trapezium, M35, Eta Orionis, Sigma Orionis, Rigel. Jupiter, Messier 35 and it’s embedded cluster NGC 2158 , the galaxies Messier 81 & 82 and Messier 1, the Crab Nebula.

The scopes used were my Skywatcher ED120 F/7.5 and Vixen ED102 F/6.5 refractors.

On a general point, the Baader Classic Orthoscopics come to focus around 10mm further out than BGO’s. The same applies to the 32mm Classic Plossl. The Classics are not precisely par-focal though – a small adjustment is needed when swapping between them.

The eye relief of these eyepieces seemed to conform to the usual orthoscopic and plossl standard of around 80% of the focal length. The soft rubber rim that forms part of the eye cup (the useful part for me !) means that you can snuggle the eyepieces into your eye socket comfortably though. Despite this, I doubt those that wear glasses to observe will find the 10mm or 6mm BCO’s usable.

Jupiter with the BCO 6mm and BGO 6mm. The view with the BCO seemed as sharp and contrasty as the BGO 6mm but showed just a touch more light scatter / glare from the bright planetary disk. The extra field of view provided by the BCO shows some distortion when objects enter the outer part of the field. This seems to happen quite suddenly and I’d estimate that the sharp portion of the field is around 45 degrees or so of the 50 that the BCO’s deliver. The effect on Jupiter was to stretch its slightly oblate disk into an oval with noticeably less definition, but this was only in the most outer part of the field of view.

The field stop of the BCO 6mm was not sharply defined as the razor sharp BGO an Circle-T 6mm orthos, which was slightly annoying but did not seem to affect the optical performance as far as I could see.

Jupiter with the BCO 10mm. A nice sharp, contrasty view. Distortion at edges of the field of view was less apparent than it was with the BCO 6mm and glare / light scatter seemed better controlled too although the lower magnification would help with that as well.

10mm BCO used with 2.25x Barlow (4.44mm) works very nicely but there does seem to be just a little more light scatter and a little less contrast than the BGO 5mm delivers on Jupiter. The barlowed 10mm BCO was able to rival the BGO 5mm on some close binary stars though.

Jupiters Great Red Spot seemed to me to be equally well defined with BCO’s as with BGO’s

In Orion, the faint Trapezium stars E & F were spotted with the BCO 10mm with the ED120 scope. These can be a challenge for the 120mm refractor under my typical skies. With the 102mm scope the 6mm BCO showed the E star with F only being “suspected” once or twice. This was the same with the 6mm BGO.

The BCO 18mm. Rather like the 10mm, a very nice eyepiece. BGO 18mm seemed very much the same but greater FoV of BCO seemed more effective with this focal length but stars were still slightly astigmatic in last 10% of this. Very nice views of M42 showing extensive nebulosity and structure within it with both scopes. If anything I felt the BCO showed a touch more nebulosity than the BGO.

The 18mm BCO showed itself to be a very nice DSO eyepiece on M42, M81 & M82 and M35 and embedded cluster NGC 2158 plus, later M1, the Crab Nebula. These objects did seem to show a little better with the BCO 18mm than the BGO 18mm and M1 in particular was well seen for the 4” scope under my skies, I thought.

Baader Classic Plossl 32mm. A nice plossl but not quite sharp to the edge though even at F/7.5 and despite having a slightly smaller apparent field of view than other plossls. I used it without the plastic extension piece and had no difficulty finding the correct eye position. Somehow I felt slightly under whelmed with this eyepiece.

For kicks I tried the 6mm BCO and the 2.25x barlow for 2.67mm and 248x with the Vixen 102mm scope. The close pair of Eta Orionis (1.7 arc seconds) was split nicely and colour contrast of stars seen well despite very high magnification.

Final Thoughts

In some ways the Baader Classic Orthos remind me of the Circle-T “volcano top” orthos but with better coatings and better light transmission. I still feel that the BGO’s just edge the BCO’s in the way they control glare and light scatter but it’s very close indeed on this. In the 18mm focal length the light transmission and contrast provided by the BCO seemed to actually exceed the BGO equivalent.

The fall off in edge sharpness and slight distortion at the edges of the field of view of the Classic orthos should not really be a surprise I guess. The orthoscopic design has remained the samewith these as far as I know and I believe Baader have simply increased the field stop apertures a bit, presumably to aid framing / finding objects rather than intending critical examination of them close to the field stop edge.

The Q-Turret 2.25x Barlow lens seems an excellent barlow lens for it’s price despite the slightly sloppy push fit of it’s drawtube for eyepieces inserted into it. I’ve not have a chance so far to try fitting the optical element of the Barlow into eyepieces to see what the 1.3x amplification looks like.

The finish of the Baader Classics does not try to rival the immaculately finished Baader Genuine Orthos. It’s workmanlike and reasonably practical though I'd try not to let the eyepieces rattle together with other kit if you want to keep them looking their best.

To me the 32mm Baader Classic Plossl was perhaps the least impressive eyepiece in the set. It’s a perfectly competent plossl of course, albeit with a slightly smaller field of view, but I do wonder whether a 25mm Classic ortho would have been a nicer option?

Thanks again to First Light Optics for the loan of these eyepieces and apologies that this report is a little chaotic and not as comprehensive as I’d have liked. Blame the UK weather for that !