Antares/University Optics orthoscopic eyepiece
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?
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.
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
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.
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.
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
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.
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.
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
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