Takahashi
FC-65 Review
When I reviewed
Takahashi’s classic small fluorite doublets, the FC-50 and FC-60, I was
surprised to find they had differences beyond aperture. The reason is that the
FC-50’s true contemporary was actually the FC-65, not the FC-60 which arrived
later.
I love classic small Takahashis and I’ve
already reviewed many of their scopes in the 50-80mm aperture range, so I
wanted to try an FC-65. Problem is, the FC-65 is quite rare in Europe; it also
suffers problems from hazing of the objective. So first I had to first import
one and then get it fixed. Read on to find out how that turned out!
At
A Glance
|
Telescope |
Takahashi FC-65 |
|
Aperture |
65mm |
|
Focal Length |
500mm |
|
Focal Ratio |
F7.7 |
|
Length |
460mm minimum,
500mm incl visual back |
|
Weight |
1.5Kg w/o ring or
finder |
Data from me.
Takahashi FC-65 and FC-50.
Takahashi FC-65 and FC-60.
Takahashi FC-65 and FC-60.
Design
and Build
The FC-65 is a bridge between the TS-65
and the FC-60. Superficially it looks exactly like a 1970s TS-65, with similar
tube and identical optical specs, but crucially the earlier scope was a
triplet whilst the FC-65 is a fluorite doublet like the FC-60 (and FC-50
too).
It can be hard to track down exact
production dates for Takahashi scopes, but the TS-65 was still listed in 1979,
whilst the FC-60 was introduced in mid-1990, so the FC-65 was Takahashi’s
general-purpose small scope for the 1980s and so the true larger sibling to
the FC-50.
From its serial number, the FC-65 on
review was likely made in 1984.
The FC-65 pre-dates the cost-cutting -
plastic focuser wheels, cheapo dew cap and fixed cell - seen in later small
Takahashis like the FC-60, so the FC-65 is built and finished like the FC-50,
but with a larger focuser.
Optics
The main
difference between the last TS-65 (earlier ones were quite different again) and
this FC-65 is the objective. In both cases, aperture is 65mm and focal length
500mm giving a focal ratio of F7.7. However, the TS-65 was a triplet, whereas
this FC-65 is an air-spaced doublet with a fluorite crown at the rear in the
Steinheil configuration like other scopes in the FC series.
So the FC-65
objective is just like the later FC-60 then? Sadly, not quite. For one thing,
that green writing around the lens does not include ‘MC’, in other words it
wasn’t multi-coated.
More
importantly, Takahashi probably used a flint of the KZFS group – a ‘Special Short
Flint’ – some of which, such as KZFS4, are sensitive to hazing in contact with
water vapour (poor ‘climatic resistance’ in Schott’s terminology – KZFS4 is 3.0
on a scale of 1 to 4, where 1 is good and 4 is bad).
Consequently, almost all FC-65s suffer from hazing of the
flint, whereas FC-60s and FC-50s do not. Is this down to a different flint,
or just the protection of multi-coating in the later scopes? I suspect both,
but it seems possible Tak’ increased the focal ratio from F7.7 (for the FC-65) to
F8.3 (FC-60) because they had to use a different flint - one with poorer
optical performance, but better resistance to hazing.
So can you
fix it? Some owners with very light hazing have successfully polished it off,
but in this case deeper etching had occurred and attempts to polish it had
damaged the spacers. it needed professional intervention. So I sent it off to
Es Reid, renowned UK optician and telescope guru, who re-polished the flint
with a lap and re-spaced it too. The lens is now in good shape, but is
completely uncoated.
Tube
The OTA is a different (earlier) style from the FC-50 and
FC-60: much more like the TS-65 (see note above). Just about the only thing it
shares with the other small FC scopes are the 68mm diameter of the main tube
and the dew-shield graphics.
Compared
with the FC-50 and FC-60, the dew-shield is much larger, the lens ring wider
and different in profile to accommodate the collimation screws for the cell
that the FC-60 lacks.
The focuser
is heftier (see below) but lacks holes for a finder mount, so the finder mounts
on a separate narrow ring.
These
differences mean that the bare OTA at 1.5Kg is about 300g heavier than the
FC-60, but that increases to ~1.725Kg with the finder and ring.
The enamel
colour is different too: typical of 1980s Taks, including my own FC-50, it is a
dark blue grey with a shinier finish than the later lime green. One way to
distinguish the similar late TS-65 is the enamel colour, which was black (if
you want to know more about Takahashi colours, I have written an article, here).
Another
small difference is the dew cap. The FC-60 makes do with a basic polythene
push-on cap, but the FC-65’s has a solar port and slides in on felt. It’s like the
‘manhole cover’ from an FS-102, but made from hard plastic that has a metallic
grey finish to match the enamel.
Build quality
and finish are very high. Both the lens ring and focuser thread on, secured
with tiny grub screws. I have seen later small Takahashis with slightly rough
castings, but not here. As always with Takahashi, a serial number plate graces
the focuser.
Internal
finish is high too, with flawless blacking and a knife-edge baffle.
Focuser
The focuser
is different from the one on a standard FC-60, with a longer, wider, heftier body. The
drawtube is wider too, with a diameter of 55mm (vs 45mm for the FC-60) and
shorter travel of 73mm (vs 83mm).
These
differences give greater stability and less vignetting (if more weight). So this
focuser was re-used on the later FC-60NZ imaging variant (below), but with a
finder bracket mount.
Another
difference is that this focuser has the heavy cast and silver anodised knobs
from larger Taks. By comparison, the FC-60 (and more recent budget Taks,
including the FS-60C and FC-100DC) have hollow plastic wheels that look much
the same but are much lighter and flimsier too.
In other
ways it is a typical Takahashi focuser, smooth and precise with an effective
lock mechanism via the silver wheel on top. This example originally had some
shift, but the visit to Es Reid saw that tightened up alongside the optical
work.
Internally,
the drawtube has machined ridge baffles and several knife-edge ones too for
maximum stray light protection.
FC-65 focuser detail with FC-60.
FC-65 focuser extended with period OEM 0.965” accessories.
Takahashi FC-60NZ imaging version uses the heftier
FC-65 focuser.
Takahashi focuser wheels L to R: 1990s plastic, recent
plastic, cast metal.
Mounting
The FC-65
has the same 68mm clamshell as both the FC-60 and FC-50 and even the one for
the recent FOA-60 fits fine. All have the Tak standard pair of M6 bolt holes at
35mm separation and a central ¼-20.
It may be a
little heavier than the FC-60, but the FC-65 goes fine on the PM-SP (below) and
would work on any mini equatorial, or on a heavy-duty photo head. The
period-correct mount would have been a P2Z (below) or an older EM1 or Sky
Patrol.
For many of
the shots here it’s mounted on a period-correct 1980s Takahashi table-top “Theodolite”
mount usually sold with the FC-50.
For fitment
to a Vixen dovetail (also found on Skywatcher and many other smaller mounts), Takahashi make a slim silver plate with the
correct M6 threads, intended for the Mewlon 180.
Alternatively, various 3rd parties make similar plates.
FC-65 on PM-SP mount.
Old-Skool Takahashi P2Z
mount.
Accessories
The FC-65
shipped with a clamshell, a ring mount for the 5x25 finder and a separate ring
for mounting accessories like the 40mm guide scope.
It likely originally
came with a 0.965” prism diagonal, 7mm and 18mm Takahashi MC Ortho eyepieces (see
below) to fit the original 0.965” eyepiece holder, but It’s possible to
thread-on a modern 1.25” eyepiece holder in place of the original 0.965” one to
take the full range of 1.25” accessories.
For use with
the modern multi flattener, Takahashi make an adapter ring that fits either the
FC-65 or FC-60.
Takahashi MC Orthoscopic eyepieces.
In
Use – Daytime
The FC-65
works perfectly fine as a daytime spotter – just about small enough to go on a
photo tripod (though it’s not weather proof of course).
In
Use – Astrophotography
The heftier focuser
with a its wider drawtube and the slightly shorter focal length, mean the FC-65
has more imaging potential than the FC-60. But imaging back in the day would
have meant a with a 35mm film SLR.
However, the
uncoated objective and lack of a 2” eyepiece holder mean this particular FC-65
isn’t well suited to deep sky imaging, but takes a very decent snap of the
Moon.
Unprocessed crop of the Moon with Fuji XM-1 APSC.
In
Use – Observing the Night Sky
General
Observing Notes
The focuser
is smooth and precise and largely free from image shift, but so is (generally)
the smaller FC-50 unit. The big difference is that you could fit a 2” visual
back, but I don’t have one.
Cool
Down
As you would
expect of a small air-spaced doublet in a proper cell, cooldown is very fast,
noticeably faster than a larger Takahashi doublet (an FS-102) on the same
night.
Star
Test
Post repair,
the star test is ok, but likely not as good as it originally was.
Interestingly, though, I couldn’t notice much degradation of the in-focus view
(see below).
The
Moon
The FC-65
gives an excellent lunar view. At 100x with a 5mm Nagler, the Moon fills the
field with lots of sharp detail and just a little extra flare around the limb
due to the lack of coatings and slight residual haze.
Highlights of a 12 day Moon included
some rille detail and in Gassendi; that inky black shadow of Promontorium
Laplace extending into bright Sinus Iridum; dawn over
the Aristarchus plateau picking out the depths of Vallis Schröteri.
Jupiter
At 100x with a Nagler Zoom set at 5mm and a TMB Monocentric, views of
Jupiter were excellent just minutes from a warm house. I
noted a very sharp planetary disk with good contrast revealing some features
(darker spots and differences in thickness) in the equatorial belts, further
fainter belts to north and south and the dark polar hoods.
The Galilean moons are
shown as perfect tiny disks of slightly varying colour and brightness.
The view was very similar to my (optically near perfect) FC-60 on the
same night, the main difference was the faintest hint of
out-of-focus false colour in the FC-65 that the FC-60 eliminates.
Deep
Sky
The lack of
coatings make this scope slightly dimmer than the FC-60, but still the Pleiades
through a 32mm Plossl were sparklingly glittery
pinpoints of dazzling blue white just as they should be in a fine small
apochromat.
Other
brighter DSOs, like the Orion Nebula and Andromeda Galaxy, were much as they
look through a typical quality multi-coated 55-60mm refractor.
Summary
Takahashi’s
1980s FC-65 is an interesting piece of Tak’s history, with the excellent
no-cost-cutting build of all Tak’s from that era.
A bigger
focuser with a wider drawtube and a faster optic mean it could have been a
better small imaging scope than the later FC-60.
Unfortunately,
hazing of the flint on almost all existing examples means it’s not going to be
as durable as an FC-60 and likely won’t perform quite as well even if you get
it fixed.
Takahashi’s
FC-65 is an interesting retro-scope with typical 1980s Tak’ quality, but a poor
choice of flint glass is its Achilles’ heel.
Takahashi
FC-65 on 1980s “Theodolite” table mount.