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University Optics HD and Antares Orthos
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Antares/University Optics orthoscopic eyepiece shoot out.
I have been a casual but enthusiastic amateur astronomer for about 4 years now and do most of my observing through a Meade ETX90EC. I use this scope because it is light-weight (I have a bad back) and quick and easy to set up. A while ago I realised that I needed an eyepiece with just a bit more magnification than my 9.7mm Plossl, primarily for planetary work but also for help with splitting doubles. After much research I decided to plump for an orthoscopic design, but which make?
The University Optics HD range of orthoscopic eyepieces, manufactured by the Kokusai Kohki factory in Japan seem to get universally good reviews. However, there has been some debate over whether similar-looking eyepieces marketed by Antares (www.antaresoptical.com) and more recently Baader Planetarium (www.baader-planetarium.com) are made at the same factory and are the same as the HD range (www.universityoptics.com). The Baader eyepieces even appear to use the same colour scheme and typeface on the barrel as the University Optics models. Whilst the three brands certainly look more or less identical, the companies involved charge very different prices for the three eyepiece ranges. For example, in the United States, the Antares 7mm costs $56, the University Optics is $79.95 and the Baader Planetarium model is $119.
So are they the same? I had a chance to briefly own brand new examples of the 7mm orthoscopic from the both the University Optics HD and Antares ranges and carried out a comparison.
Both eyepieces came well wrapped in identical green stiff cardboard boxes with two plastic end caps and separately-wrapped winged rubber eye guards. The general level of finish appeared very good on both eyepieces with a nice matt black baffled finish on the inside of a heavy chrome-plated barrel.
Both eyepieces appear to have identical internal baffling and a thread to receive filters. A noticeable difference on the labels of the two eyepieces was that the Antares model is described as being Multi-coated whilst the University Optics model is described a Fully Multi-coated. There certainly seems to be difference in the appearance of the main objective lens with the Antares model having a slightly green appearance, whilst the University Optics model had a distinctly magenta colour to the coating.
Strangely, the University Optics model is advertised as coming with a captive screw groove on the barrel, but the item I received had a slightly shorter barrel than the Antares model and no groove.
Both eyepieces were tested with my ETX90 using the television aerial on a neighbour’s house as the target. Both eyepieces were a good tight (but not too tight) fit in the eyepiece holder. They both rendered clear views with a nice sharp edge and both snapped into focus well. Interestingly, when using the same barrel, the eyepieces were exactly parfocal, suggesting that the internal optics are probably the same.
I tested both eyepieces on my ETX 90 (f13.6) from the back garden of my house in Worcester, UK on the night of 2nd April 2005. There was no moon visible and the seeing was excellent with very steady skies, but transparency was only moderate with a haze noticeable near the horizon. Objects observed included Jupiter, Saturn and Castor.
I could find no discernable difference in on-axis sharpness on any of the three targets. The Cassini division in the rings around Saturn was equally well defined in both eyepieces. Off-axis sharpness was similarly good as was field flatness. I did detect very slight geometric distortion right at the edge of the field of view of the University Optics eyepiece which was not apparent on the Antares, but at no point was this distortion bothersome. There was no chromatic aberration seen on either eyepiece.
The differences found between the two eyepieces were in colour, scatter and contrast. The University Optics orthoscopic had a consistently warmer tone than the Antares although the difference was subtle and which you prefer is, I suspect, purely a matter of personal preference. I would be happy with the colour rendition of either of them.
When looking at Saturn and Castor I could not see any difference in background light scatter. However, the sky was definitely slightly blacker around Jupiter in the University Optics eyepiece. When viewing Saturn the University Optics eyepiece displayed slightly better contrast, with the Cassini division and cloud belts showing up slightly better than in the Antares.
In summary, the differences between these two eyepieces were very subtle. Both are excellent planetary eyepieces and I would highly recommend either of them. Interestingly, a comparison between the University Optics Abbe orthoscopic range (also made by Kokusai Kohki) and their HD range on the Cloudy Nights forum (http://www.cloudynights.com/documents/orthos.pdf) found similar differences. This leads me to suspect that the Antares orthoscopics may simply be the University Optics HD range with inferior coatings.
Is it worth selling an Antares to buy the HD range orthoscopics if you have a long focal length scope like mine? Probably not. I would be interested to see whether the differences are more marked on a faster telescope. Whether you think that spending the extra on the HD range is justified is a financial decision only you can make. However, in the UK you will not have to agonise over this. In the UK the Antares model cost £69.95, but, due to a very favourable exchange rate at the time of writing (£1 = $1.87), you can get a University Optics HD orthoscopic direct from the US for a total of only £63 including postage and the VAT and post office administration charge for collecting the VAT Be prepared for a 2-3 week wait for delivery from University Optics to the UK.