“ Manufacturer: Tele Vue / Type: Telescopic Eyepiece „
Within the world of Telescopic Eyepieces there is one name that stands
tall on a pedestal of quality, it is the manufacturer of choice not
just for planetary and lunar viewing but Deep sky observation as well.
It is this versatility within the ranges of TV's available eyepieces as
well as a commitment to quality and finish that have got Televue to
where they are today, and if they keep producing EP's like this 11mm
Plossl I will certainly keep on coming back for more.
I do already own an extensive range of TV's but within my collection
there are a few eyepieces that shine above the rest. One such example
being the 11mm plossl.
Let's start with the look of the thing. It's a rather diminuitive 2 and
a half inches long and has the company name as well as the focal length
printed in vibrant green on the side. Two black dust caps cover either
end with the word Televue embossed on the lower dust cap. Of course
none of these facts affect the performance of the eyepiece but they do
give it a stylish quality that will look great amongst your collection.
The eyepiece comes in a small black box with a rough texture, Inside is
a shiny silver card with the company logo and brandname printed on it,
I can see no use for it except as a sort of a badge, to kind of welcome
you into the 'exclusive' club of Televue owners.
Now swiftly onto the important part, what I saw through it and how it
compared to other EP's of similar focal length I've tried, before
finally getting onto the technical stuff which while unfortunately not
exactly exciting it is vital stuff you will need to know if you're
considering purchasing this EP.
This EP fills a niche for me, it provides a good transition from low
power planetary viewing to higher power DSO viewing (Deep space
objects). Now just a little bit of geekiness as I'm afraid it's
unavoidable, the telescope I generally use the EP with has a focal
length of 1500mm, with this 11mm eyepiece that gives me a magnification
of 136x. This makes Saturn appear about the same size as a ball bearing
held at arms length (as a very rough approximation, about 6mm in
With this EP I was able to see not only the two equatorial bands I'm
used to seeing in saturn, but faint hints of the southern polar region
as well, I could even make out slight differences in hue on the planets
surface, a fantastic view.
Unfortunately Saturn is the only planet thats in a good enough position
to observe at the moment, so wwith that I went on to my last target in
the solar system, our closest neighbour...the moon.
With the moon being approximately half a degree in diameter this EP
frames it beautifully. The whole moon is visible in your FOV, the moon
is perhaps the best target to showcase Televues excellently defined
contrast, a feature thats noted throughout their extensive range. Along
the terminator (the boundary between light and shadow on the moon) I
could pick out shadowed craters, and rough rilles on the satellites
surface. Along the terminator is the best place to observe the moon,
it's where you can achieve the most detailed views. A wonderful view,
one of the most pleasing I have had to date, My favourite crater
'Tycho' near the moons southern pole was so detailed.
Leaving the solar system behind for Deep Space I tried the EP on three
distinct types of object. Firstly....
Planetary Nebula: These are stars who in reaching the end of their
lives have thrown out the outer shells of gas in their violent death
throws. The gases usually form spectacular and intricate shapes
corresponding to the stars magnetic differing fields.
The first PN I turned my sights on was ngc 6543 or the Cats eye nebula, under higher magnification the nebula displays a wealth of detail, on
any usual PN with a magnification of 136x not a huge amount of detail
would be present, but the cats eye is monster of a nebula, it takes up
a whopping 5 arc minutes and 48 arcsecond of sky (or to put it another
way around 8 times the size of jupiter). From my light polluted skies
only the inner core was visible, significantly smaller than 5 odd
arcminutes, but still visible. A crisp PN, the EP was able to resolve
small details within the shell but I think this particular
magnification is not enough for planetary nebulas.
I then went onto a PN I know well, M57. It appears as a nice round ring
of smoke. With the 11mm TV the nebula looked magnificent, a slight
darkening towards the centre of the nebula but unfortunately no sign of
the central star. A very sharp view the nebula stuck out like a sore
thumb. In summary, not quite enough magnification to really open up planetary nebs, but some nice low power views achieved.
Galaxies: Next up the search for some faint fuzzies to see what this EP
can really do. First up was m64 or the black eye galaxy nearly popped
out of the eyepiece. It's core was easily spotted with it's outer halo
just on the limits of averted vision. To put it into context, this was
the absolute best view of m64 I have ever had. It's times like this
that I wish I lived under darker skies but alas.
I then toured the Virgo Supercluster, a large area of sky that is
absolutely teaming with galaxies. M87 which is a galaxy with the most
amount of star forming material yet discovered (around a trillion suns
worth) was next on my list. The galaxy had a bright center and a
fainter halo. I viewed about 10 NGC galaxies as well as a handful of
Messier objects, so to summise the TV 11mm worked extremely well on all
of them, allowing me to go deeper and fainter than I had been before.
Not the very best EP out there for galaxies but certainly on up there
with the best.
Globular Clusters: Finally I turned this EP onto some of my favourite
Globular Clusters. A GC is a densely packed ball of stars that can
contain from a few thousand to a few million stars packed into a
relatively small area of sky.
One of the brightest GC's in the northern hemisphere is the great
cluster in Hercules, m13. I had a feeling Globulars would be where this
eyepiece really shone out and I was right. Despite it's rather dense
core the EP allowed me to resolve individual stars right down to the
core, simply amazing. Likewise with M5, M5 has a much denser core than
most other northern globulars and yet I was able to see perfectly
defined stars to about three quarters of the way into the centre of the
glob. In short GC's are definately a strong point with this eyepiece.
Now that I've described the EP on performance, I'm afraid it's time to
get nerdy. This is the technical part I warned you about.
These plossls feature a 4 element design to cut down on light scatter,
and it does indeed accomplish this, almost none noticed on even the
brightest objects. The glass is multi coated, on turning the EP to the
light you can see that the coatings are evenly distributed with no
patchiness. The true field of view is 50 degrees, which is amongst the
smallest of my entire EP collection, while it can be a little annoying
you do get used to it. On my f5 telescope the exit pupil is 2.2mm so
right on the golden spot. The eye relief is 8mm, so a little close, but
there are a lot tighter EP's out there. The effective field stop
diameter is 9.1mm, not unusual for this focal length, again it falls
into a mid range in this respect, there are higher and lower field
stops for similar focal lengths, it comes down to whether you have the
cash to splash out on a ultra wide eypiece or not. Speaking of cash,
it's time to be bought down to earth with a bump, the Eyepiece costs
around £70 so it's not the cheapest plossl out there, I personally
would say it's worth every penny though.
The past couple of decades have seen an explosion of models in the amateur telescope market. As well as the profusion of types and sizes available, the quality has improved significantly.
Nowadays, with a decent scope and accessories, the amateur astronomer can obtain views and images that were the preserve of professional observatories only a few years ago.
In order to get the most out of any telescope, however, those 'accessories' make all the difference. To view the night sky, a range of 'eyepieces' are needed. These are small optical devices, which attach to the scope, through which, as the name suggests, the user looks through.
Eyepieces are sold in various focal lengths: the lower the focal length, the higher the magnification. Thus, the use of a range of different eyepieces can give the astronomer a variety of different magnifications to select from.
The quality and price of eyepieces varies dramatically: from around £20 to over £400 (i.e. the price of a small, high quality telescope!).
Use a cheap eyepiece on an expensive scope and the view will be severely degraded. I needed an eyepiece which would produce medium magnification views with my telescope. I decided to get one from the makers of the highest quality eyepieces in the world: TeleVue.
The Nagler 11mm (Type 6) eyepiece is (fortunately for me) one of TeleVue's cheapest models. Despite this it still cost a wallet draining £206 from Telescope House (Telescopehouse.com).
As well as being expensive, potential buyers should be aware that this is not a small eyepiece. The metal frame is packed with seven glass lenses making it a weighty package. At 190g, this is actually heavy enough to upset the balance of a small scope and may require adjustment of the telescope's counterweights to compensate.
Old style eyepieces had very narrow fields of view, typically 40-50 degrees (think looking down a toilet paper tube to get the idea). The Nagler, on the other hand, has a field of view of 82 degrees.
This is an amazingly wide angle, close to the human eye's 120 degrees, giving views almost like looking up at the night sky with the naked eye (looking through this range of eyepieces has been likened to going on a spacewalk!).
With a view this expansive, the user can move his or her eye around the view; when looking at extended objects such as large star clusters or nebulae, this can almost be like travelling in space: breathtaking!
My first use of this eyepiece was in viewing the moon. On my scope, the view was larger than the field of view meaning I had to navigate the telescope to see the whole of the moon! I found myself wandering from mountain range, to crater, to seas as new features caught my eye. The moon is over 200,000 miles away: I felt I could reach out and touch it.
The eye relief of the eyepiece is more than adequate, meaning that the user does not have to put his or her eye right to the lens. This means that spectacle wearers can view through the scope without taking off their glasses.
As expected from such an expensive eyepiece, the view through it is faultless. As well as the amazing field of view, all other aspects of the eyepiece are superb.
Chromatic aberration, the distracting coloured fringes seen in at areas of high contrast, evident with cheaper eyepieces, is completely absent.
Cheaper eyepieces usually give sharp views through the centre, with softer or distorted views near the edge. The Nagler 11mm gives 'tack' sharp views edge to edge.
Finally, the eyepiece produces views with excellent contrast. Muddy views are often the result of using a poor quality eyepiece. The Nagler 11mm is different. Bright areas are bright, and the night sky as dark as it should be. This has partly been achieved through blackening of the internal walls of the frame.
In summary then, this is a superb eyepiece. It gives sharp, high contrast, aberration free views of the night sky with a field of view that can literally take your breath away. If you can stomach the price, and cope with the weight for your telescope, there are no better eyepieces of this focal length on the market (well until Nagler introduces a type 7, of course!).