The 10mm, 8mm, 6mm, 5mm, and 4mm TMB Super Monocentric Eyepieces
A new eyepiece was recently introduced
by Thomas M. Back of TMB Optical based on the Monocentric eyepiece design.
The original monocentric design was introduced in the late 1800's by Adolf
Steinheil. It had a three element cemented triplet with only two air-to-glass
surfaces, which is the minimum of any eyepiece design, and a 30 degree apparent
field of view (AFOV). In an eyepiece, fewer glass surfaces will result in
less light scattering due to the elements and their coating. Thus, there will
be greater light transmission. This helps to bring out low contrast details
on the planets and produces a brighter image. The monocentric design got its
name because all three lenses have one common center of the radii curvative.
For a number of years Zeiss Monocentric
(0.965") were considered the ultimate planetary eyepiece. Thomas Back
studied the original Zeiss monocentric design and through computer analysis
figured out a way to create an all-new eyepiece design. The design uses super
low reflection/narrow angle scatter multicoatings and two of today's exotic
Schott high index glasses. The Schott glass is water white, and does not add
any unnatural color. In addition his partner, APM Markus Ludes of Germany,
found a Zeiss subcontractor to manufacture the TMB eyepieces (TMB). This allows
for the use of some of the best polishing equipment available today to be
used in the manufacture of these eyepieces.
This new design offers more eye
relief, better on and off-axis correction, and a slightly wider AFOV of 32
degrees than the original design. It reduces also light scatter, increases
contrast, and increases light throughput to approximately 99%. As we shall
see these factors play an important part in how well the eyepieces perform
when observing the planets, sun, moon, bright stars, double stars, and deep-sky
The initial run of the eyepieces
that began delivery in August of 2003 included a 4mm, 5mm, 6mm, 8mm, and 10mm.
These eyepieces are not parafocal with each other but the next set of eyepieces
available in December 2003 is. These will include the 4mm, 5mm, 6mm, 8mm,
and 10mm as well as 7mm, 9mm, 12mm, 14mm, and 16mm. Note that there will only
be a slight difference where original version eyepieces and the parafocal
version eyepieces come to focus. Therefore an eyepiece from the original run
and one from the parafocal run can be still be used in a binocular viewer
by adjusting the focus of one eyepiece.
As of December 2003 the price of
the TMB 4mm, 5mm, 6mm, 8mm, and 10mm eyepieces are $225.00 each, while the
12mm, 14mm and 16mm eyepieces are $250.00 each. The eyepieces are available
from TMB Optical, APM Markus Ludes, and other dealers around the world. I
ordered my eyepieces from TMB Optical, and this is my first purchase from
In the TMB the eye relief is 0.85x
the focal length, so 10mm will have 8.5mm of eye relief. By comparison the
eye relief of a Plossl is 0.75x the focal length, while an Orthoscopic is
0.80x the focal length. Here is a table that shows the eye relief of the TMB:
At the shorter focal lengths, such
as the 6mm and 4mm, the eye relief of the TMB is slightly better than that
of the Zeiss Abbe Orthoscopic eyepieces. In practice I found the eye relief
of the TMB to be comfortable when observing. Observers who must wear glasses
while observing may find eyepieces with longer eye relief such as the TV Radians
with 20mm eye relief to be more comfortable. Another option would be to use
the longer focal length TMB that have better eye relief in conjunction with
a 1.8x TMB 1.25" ED Barlow planned for delivery in February 2004. This
Barlow will be designed to match or exceed the performance of the Zeiss 1.25"
ED Abbe barlow.
The following table lists the eyepieces
that were compared with the TMB in this test. The AFOV of the TMB is 32 degrees,
the Zeiss Abbe Orthoscopics (1.25") is 45 degrees, the Pentax SMC Orthoscopics
(0.965") is 42 degrees, and the TeleVue (TV) Plossl's is 50 degrees:
Note that in the cases where an
exact match for an eyepiece in each focal length was not available, such as
the TMB 5mm, I performed a generalized comparison with the next closest focal
length of the other eyepieces.
When I received the TMB I took
them out of their boxes and carefully inspected them. I was impressed by their
quality. They have a solid feel to them yet are relatively lightweight. The
TMB are threaded for 1.25" filters, have a low reflection top surface
to reduce stray light reflections, and have a slightly elevated rubber ring
around the edges that helps to block stray light. The outside of the barrels
has a safety groove, and the inside of the eyepiece barrels has a flat black
interior. All eyepieces come with protective plastic caps. I noted that since
the first TMB eyepiece set is not parafocal the eyepieces all have the same
To check the light transmission
of the TMB, Zeiss, Pentax, and TV Plossl eyepieces I held them up against
white paper. The TMB showed a brighter, more pure white image than the Zeiss
or Pentax, while the TV Plossl was not as bright and appeared slightly yellow.
I inspected also the coatings on the eyelens of each of the eyepieces. The
coatings in the TMB appeared darker then the others, and when held up to a
bright light seemed to show less reflections. When compared to the other eyepieces,
I believe the whiter image and the reduced reflections in the TMB were a result
of the Schott glass and super low reflection/narrow angle scatter multicasting
The TMB eyepieces, like the Zeiss,
Pentax, and TV eyepieces, have a color band around the outside of the eyepiece
housing to distinguish one focal length eyepiece from another. However they
are much wider and distinctive on the TMB and I found it easy to determine
which focal length was which when using them during the day. The same was
true when using them at night with a red filtered flashlight. Some observers
have reported that they found it difficult to read the lettering of the TMB
8mm eyepiece band when using a red filtered flashlight at night due to the
color of the band. So starting with the December 2003 delivery of the TMB
the color band of the TMB 8mm will be changed to a more contrasty color.
Pentax 7mm SMC Orthoscopic eyepiece in a 1.25"/0.965" adapter next
to a TMB Super Monocentric 6mm eyepiece. Note the wider color band and larger
lettering on the TMB eyepiece.
Before comparing the eyepieces
with the TMB I carefully cleaned the Zeiss Abbe Orthoscopics, Pentax SMC Orthoscopics,
and TV Plossls. For the past seven years the Zeiss Abbe Orthoscopics and Pentax
SMC Orthoscopics were the eyepieces I used most for my planetary, lunar, solar,
and high power views of deep-sky objects. I have compared the Zeiss and Pentax
with other eyepieces such as the Aus Jena Orthoscopics (0.965"), Brandon
Orthoscopics, Clave Plossls, Meade Research Grade Orthoscopics, TeleVue Naglers,
Plossls, and Radians, and University Optics Orthoscopics. Based on these comparisons
I felt that the Zeiss and Pentax were the finest eyepieces I have used since
I began observing in the early 1970's in terms of their light transmission,
contrast, lower light scatter, and overall sharpness.
Prior to purchasing the TMB I wondered
if they would perform better than the Zeiss and Pentax Orthoscopics. Also,
since I often use my telescopes on homemade Dobsonian-style alt-az mounts
that do not have tracking, I wondered if I would find these eyepieces less
desirable to use due to their smaller field of view than either the Zeiss
or Pentax. A smaller field of view meant I would have to re-center the object
more often when observing.
The eyepiece comparisons were conducted
during numerous observing sessions over a five-month period using my AP 7.1"
f/9 and AP 5.1" f/8.35 refractors. The AP 7.1" was used on both
the homemade Dobsonian style-mount, as well as a German equatorial mount.
The AP 5.1" was used only on the homemade Dobsonian-style mount. A friend
of mine who was interested in trying out the TMB eyepieces brought over his
AP 92mm f/4.9 refractor on a German equatorial mount on several occasions.
During some of these eyepiece comparisons I used an AP/Baader/Zeiss binocular
viewer that had a 1.25x corrector. This increased the focal ratio of the AP
92mm from f/4.9 to f/6, the AP 130mm from f/8.35 to f/10.3, and the AP 180mm
f/9 to f/11.3. This provided an opportunity to test the eyepieces using telescopes
with focal ratios that ranged from f/4.9 to f/11.3. It was noted that at f/4.9
the Zeiss, Pentax, and TMB showed some field curvature at the edge of the
field of view. At f/8.35 and longer the Zeiss, Pentax, and TMB were pretty
much sharp right to the edge.
A variety of objects were observed
during these eyepiece comparisons, including the solar system objects such
as the sun, moon, Venus, Mars, Jupiter, and Saturn, as well as double stars,
bright stars, and deep-sky objects. I enjoy using my TV Naglers and Panoptics
when observing deep-sky objects, but for pulling out the last bit of fine
detail I have been using the Zeiss and Pentax.
An AP Maxbright diagonal was used
when observing deep-sky objects, bright and double stars, and sometimes when
observing the moon and planets. Most of the time an AP/Baader/Zeiss binocular
viewer was used for observing the sun, moon, and planets. When using the binocular
viewer, it was often possible to have a TMB eyepiece inserted into one of
the eyepiece holders and a Zeiss, Pentax or TV inserted into the other and,
after adjusting the height of the eyepieces, bring both to focus. To insure
that the differences noted during testing the eyepieces in this manner were
not due to the binocular viewer the TMB and Zeiss, Pentax or TV were switched
from one of the holders to the other.
On the first day I received the
eyepieces I set up the AP 130mm f/8.35 refractor on a home-made alt-az mount
to observe the sun. However the seeing was only poor to fair and clouds kept
obscuring the view so it was difficult to determine which eyepiece performed
better. So I decided to compare the eyepieces on some flowers that were located
across the backyard. I inserted the 10mm Zeiss Abbe Orthoscopic first and
carefully focused on the center of the flower and noted it had a couple of
small bugs crawling on it. The 10mm Zeiss showed very fine detail, as I expected
from these eyepieces. Then I inserted the 10mm TMB and after focusing could
tell there was a difference between these two eyepieces right away. In the
10mm TMB the contrast was higher as the detail in the flower and bugs on it
was sharper and better defined. Also, the colors were brighter and more pronounced
in the 10mm TMB, indicating the light transmission was higher as well. I noted
also the flowers had a more natural look to them.
I repeated the test with the other
TMB and Zeiss, Pentax, and TV Plossl: the TMB 8mm Super Monocentric with TV
8mm Plossl and Pentax SMC 9mm Orthoscopic; TMB 6mm Super Monocentric with
Zeiss 6mm Abbe Orthoscopic and Pentax SMC 7mm Orthoscopic; the TMB 5mm Super
Monocentric with Zeiss 4mm Abbe Orthoscopic and Zeiss 6mm Abbe Orthoscopic;
and the TMB 4mm Super Monocentric with Zeiss 4mm Abbe Orthoscopic, and results
were the same: in each case the contrast, sharpness, light transmission were
better in the TMB.
Solar System Objects
Eyepiece comparisons for solar
system objects were conducted only when the seeing conditions were good. If
the seeing conditions were poor it was not possible to get a steady enough
view to determine how the eyepieces performed.
A comparison was made between the
Zeiss 10mm, 6mm, and 4mm with the TMB 10mm, 6mm, and 4mm using my friend's
AP 92mm equipped with Baader white light solar filter. The TMB provided a
sharper, brighter and contrastier images, with less light scatter around the
edge of the sun. This helped to bring out the detail better in the sunspots,
as well as in the facula.
A few days after I received the
TMB eyepieces I observed the moon with my friend using his 92mm and compared
the Zeiss 10mm and Pentax 9mm with the TMB 10mm, as well as the TMB 8mm with
the Pentax 9mm and 7mm, and the TV 8mm. The moon during these tests was a
couple of days past full and the sunset terminator was near Mare Crisium and
Palus Somnii. Due to the better contrast and sharpness in the TMB the elevation
between the mare and mountainous wall surrounding it seemed higher and more
3 dimensional than in the other eyepieces. In addition the color of the lunar
features appeared whiter, brighter, and much more natural in the TMB than
we had seen before. For example the bright rays which radiate out from the
crater Proculus and border Palus Somnii appeared whiter. Because of the very
natural appearance of the moon, we almost felt like we were looking at a NASA
photograph taken from a spacecraft, or were orbiting the moon in a spacecraft,
rather than observing it through a telescope.
On another night when observing
the moon with the AP 5.1" a half dozen craterlets visible on the floor
of Plato were resolved better in the TMB than the Zeiss and Pentax eyepieces,
as were portions of the Alpine Valley rille.
When the moon was at last quarter
phase I compared the Zeiss 10mm with the TMB 10mm, as well as the TMB 8mm
with the TV 8mm using the AP 7.1". At last quarter phase, the Apenninus
Mountains stood out in bold relief and appeared white as they are illuminated
by the setting sun. There appeared to be many areas of debris that seem to
have flowed down from the tops of these mountains. This included what appeared
to be large boulders. While these features were visible in both the Zeiss
and the TMB, the higher contrast, sharpness, and more natural appearance to
the lunar features seen with the TMB gave the impression that these features
were similar to what I have seen on the Earth, which was the first time I
have felt this way when observing the moon. Some of the isolated mountains
on Mare Imbrium looked also more natural and were better defined in the TMB
than the Zeiss, and Hadley Rille was easier to resolve in the TMB. When comparing
the TMB 8mm with the TV 8mm the color appeared more off white or yellow in
the TV, and it had lower contrast, as well as lower image brightness and sharpness
than the TMB.
At crescent phase, the lower light
scatter in the TMB made it easier to see faint stars near the earthlit portion
of the moon than in the Pentax.
Venus was observed in the western
sky one evening with my friend's AP 92mm and we compared the TMB 8mm with
the Pentax 7mm. We both felt that the planet appeared brighter, whiter, and
the gibbous shape more sharply defined in the TMB than the Pentax. Also the
sky background adjacent to Venus was darker in the TMB than in the Pentax,
and the dusky appearance along the terminator was easier to see in the TMB
than the Pentax.
Although Mars had its closest approach
to Earth in August 2003 in nearly 60,000 years and attained a diameter of
25.11", due to its relatively low elevation at my observing location
(around 30 degrees), my observations of Mars often were adversely affected
by mediocre seeing. I actually had more periods of steady seeing when Mars
was slightly smaller in September 1988 when it obtained a diameter of 23.81"
and its elevation reached 46 degrees.
Still there were a few nights during
the 2003 opposition when the seeing settled down and some good detail was
observed. On these occasions the TMB had less light scatter, provided more
natural looking and pronounced colors, and gave sharper and more detailed
views than either the Zeiss or Pentax Orthoscopics. This included rifts in
the South Polar Cap (SPC), as well as Lowell's melt band around the SPC. Also
the TMB eyepieces showed Mare Hadriacum with a feathered or striated appearance
to it. Atmospheric details were better defined in the TMB such as the limb
clouds, the North Polar Hood clouds, and a small dust cloud in Hellas.
On one night of very good seeing
Mare Erythraeum and Aurorae Sinus appeared mottled with many variations in
tone, and I felt that for the first time I was accurately seeing and resolving
its surface detail. Neither the Zeiss nor Pentax Orthoscopics provided the
same amount of subtle detail, nor the sense that I was accurately resolving
its surface features.
Jupiter has a mix of high contrast
and low contrast features which is a good test to see how well eyepieces perform
for the planets. Examples of high contrast features include belts and zones
such the North and South Equatorial Belts (NEB and SEB), and the Equatorial
Zone (EZ). Low contrast features would include festoons, veil or shading in
the zones, mottling in the polar regions, and the Equatorial Band (EB).
When observing Jupiter I noted
that the TMB showed lower light scatter, higher contrast and sharpness, and
a blacker sky background than the Zeiss and Pentax. In addition the colors
of the belts and zones were brighter, more pronounced, and had a more natural
appearance in the TMB. The importance of lower light scatter, blacker sky
background, and better light transmission and contrast in an eyepiece designed
for planetary observations became very apparent one night with steady seeing
conditions while I was observing Jupiter with the AP 7.1". The TMB resolved
detail better, including mottling in the North Polar Region, bays, ovals,
and festoons along the NEB south, and a faint EB in a dusky EZ. This, in addition
to the natural appearance of planet, reminded me of a view from a spacecraft,
rather than through a telescope. It was the most realistic and natural view
of Jupiter I have ever had.
Also during periods of steady seeing
conditions and observing with the AP 7.1" and 5.1" the moons of
Jupiter appear as disks with subtle but noticeable differences in color. For
example Ganymede is the largest and appears light-medium yellow, Callisto
is the smallest and appeared light gray in color, and Io appears white/light
yellow/light orange, while Europa appears white in color. In the TMB the disks
are more sharply defined and the subtle colors are more pronounced.
Saturn is one of my favorite objects
to observe, and I have been impressed by the amount of fine detail that the
Zeiss and Pentax eyepieces have shown me in my telescopes. So I was curious
if the TMB eyepieces would show me any additional detail. One of the first
things I noticed when comparing the view through the Zeiss and Pentax with
the TMB eyepieces was that there was less light scatter in the TMB, and that
Saturn appeared whiter and brighter. In addition the globe in front of the
rings appeared more 3 dimensional, perhaps because of the increased contrast
and sharper image in the TMB. The colors of the planet were more pronounced
and natural looking as well.
Using the TMB eyepieces I found
it easier to see the atmospheric detail on Saturn than when using the Zeiss
or Pentax. For example the Equatorial Zone, Equatorial Band, South Equatorial
Belt, South Equatorial Belt Zone, South Tropical Zone, South Temperate Belt
and Zone, South South Temperate Zone and Belt, and North Polar Region were
easier to denote in the TMB. The results were more pronounced when comparing
the 8mm TMB with the TV 8mm Plossl, as the colors in the TV were less saturated,
more yellowish, and the overall sharpness and contrast was less detailed than
in the 8mm TMB.
Detail in the ring system was easier
to note in the TMB as well. This included the Encke Minima in the A-Ring,
the globe of the planet visible through the Cassini Division, shading along
the inner portion of the B-Ring and intensity Minima in the B-Ring, and the
Titan, which under steady conditions
in the AP 7.1" appears resolved as a reddish-orange color disk, was more
sharply defined in the TMB and the colors more pronounced. In addition faint
moons near Saturn were easier to see in the TMB.
For all of these reasons, using
the TMB eyepieces for my Saturn observations makes me feel like I am seeing
the planet in a whole new way, despite the fact that I have been observing
it for many years.
Deep Sky Objects, Double
Stars, and Bright Stars
To see how well the TMB performed
on different deep-sky objects (DSOs) a variety of objects were observed that
are visible in the summer, fall, winter, and spring night time skies. This
included supernova remnant M1; globular clusters M13 and M22; planetary nebulae
M27 and M57; emission nebulae M17 and M42; diffuse nebula M78; spiral galaxies
M31, M33, and M81; elliptical galaxies M32 and M110; irregular galaxy M82;
open clusters M11 and M41; double stars including Alberio, the Double Double,
Izar, and Rigel; and bright stars including Sirius and Vega. The limiting
magnitude during most of the tests ranges from 5.0 to 5.4, and the seeing
During my tests I noted that the
sky background was darker in the TMB than the Zeiss and Pentax Orthoscopics
or TV Plossls. This, in combination with the higher contrast, sharpness, and
light transmission in the TMB, helps them to bring out the faintest detail
visible in DSOs. The same held true for observing and splitting double stars.
M1 - The internal structure and
irregular shape of the Crab Nebula was better defined in the TMB than the
Pentax eyepieces in my friend's AP 92mm. In addition a nearby double star
was easier to split in the TMB.
M11 - The darker sky background,
better definition, and tighter star images made it easier resolve the stars
in this open cluster when using the TMB than the Zeiss or Pentax eyepieces
in the AP 5.1".
M13 - The stars were resolved better
at the core and around the edges in the TMB than the Zeiss or Pentax in the
AP 7.1". It was even more pronounced when comparing the TMB 8mm and TV
M17 - In the AP 5.1" the detail
in the Swan Nebula, including the darker and lighter portions within the nebula,
as well as faint nebula behind its neck and tail, was easier to see in the
TMB than the Zeiss or Pentax eyepieces.
M22 - As with M13, M22 was also
better resolved at the core and around the edges in the TMB than the Zeiss
or Pentax eyepieces in the AP 5.1".
M27 - The hour glass shape of the
Dumbbell Nebula, as well as the foot ball shaped extensions on each side,
were easier to see in the AP 7.1" when using the TMB than in the Zeiss,
as was the mottling within the nebula. The same was true for the fainter stars
embedded within the nebula.
M31 - When observing the Andromeda
Galaxy in the AP 5.1" the TMB eyepieces made it easier to see two dust
lanes than the Zeiss or Pentax eyepieces. In addition detail in and around
the core of M31, such as the dark nebulae off to the side of the nucleus,
and NGC 206, a star cloud in the south end of the galaxy, were easier to denote
in the TMB.
M32 - In the AP 5.1" the oval
shape and starlike core were brighter and resolved better in the TMB than
Zeiss or Pentax.
M33 - The TMB eyepieces showed
more mottling in the central region of the Pinwheel Galaxy in the AP 5.1"
than the Zeiss eyepieces, and the higher contrast of the TMB made it easier
to see the spiral arms.
M41 - The TMB 8mm eyepiece did
a better job resolving the stars in this cluster than the Pentax 7mm in my
friend's AP 92mm, and the color of the red star near the center of this open
cluster was more pronounced.
M42 - The Orion Nebula appeared
brighter and showed more mottling and fine detail in the TMB than the Zeiss
and Pentax in the AP 5.1" and 7.1". The star images appeared sharper
and brighter as well, so the fifth and sixth star of the Trapezium were easier
to denote. Also the light blue color of the Orion Nebula was easier to see
in the TMB.
M57 - The Ring Nebula through the
TMB eyepieces was brighter, better defined, and showed more variation in tone
than the Zeiss eyepieces in the AP 7.1". This was particularly true at
the rims of the nebula at each end, which appeared more elongated. In addition
the central region of M57 appeared brighter, and nearby stars were easier
M78 - The two 10th magnitude stars
in this nebula and the somewhat mottled and elongated appearance to it appeared
brighter in TMB than the Pentax eyepieces in my friend's AP 92mm.
M81 and M82 - In my friend's AP
92mm the oval shape of M81 was easier to see in the TMB than the Pentax, as
were the dust lanes between the center of the galaxy and the arms. M82's elongated
spindle shape that seemed to curve up at one end was defined better in the
TMB eyepieces than the Pentax.
M110 - In the AP 5.1" it was
easier to denote the stellar core of M110 with its brighter central area that
faded out to a less bright outer area in the TMB than in the Zeiss or Pentax
Albireo - This is one of my favorite
double stars and the TMB provided the most beautiful view of this double star
I have ever had. The reason they performed better than the Zeiss was a combination
of higher contrast, sharper star images, the colors being brighter and more
pronounced, and darker sky background in the AP 5.1". After completing
the eyepiece comparisons I observed Alberio for another hour and just enjoyed
the view through all of the TMB eyepieces including the 10mm, 8mm, 6mm, 5mm
The Double Double - These double
stars were easier to split in the TMB than the Zeiss, showing cleaner and
brighter star images as well as a darker sky background between the stars
in the AP 7.1".
Izar - The primary star of this
double star is a light yellow or golden color, while its smaller companion
star is light blue. When comparing the view through the AP 5.1" the colors
were brighter, more pronounced, and it was easier to split in the TMB than
the Pentax eyepieces.
Rigel - Although this double star
is not difficult to split (separation of 9.5") the difference in magnitude
between the primary and secondary stars (6.5) can make it more challenging
to see the dimmer secondary. The lower light scatter and darker sky background
in the TMB made it easier to see the companion star than in the Pentax eyepieces
in my friend's AP 92mm.
Sirius - The sky background around
Sirius appeared darker in the TMB than the Pentax in my friend's AP 92mm,
and there was less light scatter, so it was easier to see fainter nearby stars.
Also Sirius appeared whiter in the TMB.
Vega - As with Sirius, the sky
background around Vega appeared darker in the TMB in the AP 7.1", and
there was less light scatter, so it was easier to see fainter nearby stars.
Also Vega appeared whiter in the TMB.
Overall I have been very impressed
by these eyepieces. They bring a new level of performance to my observing,
in many cases showing me detail I have never seen before in over 30 years
of observing. I find that I want to go back and observe celestial objects
I have observed many times before in order to see what new detail they will
show me. While I have seen improvements in other eyepieces over the years,
the combination of the better sharpness, light transmission and contrast,
as well as lower light scatter and a darker sky background in the TMB provide
a new way of observing celestial objects. In addition I did not find their
smaller field of view to be an issue when I used them with my telescopes on
homemade Dobsonian-style alt-az mounts.
I think other observers will find
these eyepieces useful as well. For example, solar, lunar, and planetary observers
will find these eyepieces help to bring out finer detail, as well as providing
a more natural view of these objects. Double star observers will find these
eyepieces make it easier to split double stars, in particular ones that have
a brighter primary star, as well as enhance the colors of the stars. Deep-sky
observers will find them useful in bringing out the faintest detail visible
Many years ago Al Nagler revolutionized
wide field deep sky eyepiece designs when he introduced the Nagler and Panoptic
eyepieces. In many ways I feel Thomas Back has done the same thing by revolutionizing
narrow field planetary eyepieces with his TMB Super Monocentrics.