Takahashi FSQ 106
is amazing how whenever you buy a nice new astronomical toy the first time
you look through it you'd swear it gave the best views you've ever seen. Well,
that is how I felt last night after setting up my new FSQ-106 on my balcony.
Even though it was a full moon and I haven't got a good mounting system worked
out yet, I couldn't resist the temptation to bring out the new toy.
the moon was full, and the roof on my balcony seriously restricts the amount of
sky available for viewing, I focused on the moon. The back focus on the scope
is unusually short, so much so in fact that you cannot use a standard diagonal
on the telescope, you have to purchase one designed by Takahashi it you want to
use one. For this test I looked straight though much of the time. I also used
my Televue 2" apo 2x Powermate for part of the test. This extended the
back focus far enough back so that I could attach a 1-1/4" diagonal.
I really was amazed at the views this scope gave. When the image of the full
moon snapped into focus I was mesmerized. Detail on the moon seemed cry out
for attention, keeping my eyes glued to the eyepiece. I was able to see minute
features inside of small craters that I can't recall seeing with my 8"
SCT. What really knocked my socks off though were the jet black shadows. On
the edge of the moon near Tycho there are many mountains that, even at full or
near full moon, cast shadows. Well, in the FSQ those shadows were incredibly
black. It was stunning to see the mountains in the foreground and their inky
shadows silhouetted behind them—it was like there were holes in the moon that
let you look through the surface and out beyond it into deep space. I got so
excited about the view that grabbed my lunar 100 card and started to ID craters.
It was great fun.
always liked going out observing bright objects during a full moon, but the
views never seemed to be this good with my other scopes. Don't get me wrong, I
love my other scopes. I own an 8" SCT, a 120mm achromat, an 80mm semi-apo,
and a 60 mm achromat, but these views with the FSQ just seemed so much better.
for flatness of field, the FSQ did great. I tested the optics with a few
setups. I started with a straight through look using a 26mm Orion eyepiece,
then moved to the Televue 2" apo 2x Powermate with the same 26mm eyepiece
and an Orion 1-1/4" diagonal, then used the Powermate with a Televue 7mm
Type 6 eyepiece and the diagonal. With each optical train I centered Betelgeuse
and then ran it around the FOV to check for flatness. The star remained the
same shape everywhere in the FOV--I tried it while wearing my glasses (they
correct for my astigmatism) and without the glasses. In all instances the star
did not distort from its original starting focus point at the center of the FOV.
Of course without the glasses on the star was slightly distorted by my
astigmatism, but even then the distortion did not change as I moved the star
around in the FOV. With the glasses on, the star came to sharp crisp focus and
stayed that way no matter where I placed it.
correction on the scope was flawless. This was true even at high power. The
reason I wanted first light to be under the full moon was to specifically test
this aspect of the scope. Looking at a full moon makes things about as bad as
they can get for inducing chromatic aberration. The color correction test was
conducted by pointing the FSQ at the full moon using the same setups as above
(straight through with a 26mm eyepiece / Powermate with the 26mm and diagonal /
Powermate with a 7mm eyepiece and diagonal). There was no chromatic aberration
in the images that I can attribute to the FSQ. Surprisingly, the inexpensive
Orion eyepiece faired better than the Televue. In part this is because the
Orion 26mm eyepiece produced a much lower magnification than the Televue 7mm
Type 6 eyepiece. The Televue eyepiece, however, had a brown fringe around the
outer edge of the FOV. This fringe was there even if I took the eyepiece out
of the scope and held it up to a lamp, so it is caused by the way the lens is
secured within the barrel of the eyepiece. With the Televue eyepiece in the
FSQ, as I moved the moon to the edge of this brown fringe the moon would start
to show slight fringe color. It was a brownish color and not red, green or
violet. I attribute this completely to the Televue eyepiece and not the FSQ.
Even at the highest magnification (the Powermate and 7mm eyepiece brought the
magnification up to 151 power) there was absolutely no chromatic aberration
caused by the FSQ.
last test conducted was photographic. I mounted my Nikon 35mm FM-10 film
camera on the scope and shot the moon with some hypered techpan film. Focusing
for the camera was accomplished with a Stellar Technologies International
Series IV Stiletto focuser. The moon was photographed both with and without
the Televue Powermate to compare the quality of the FSQ’s images at its native
f/5 and at f/10. It will be several more weeks at best before I finish the
roll of Tech Pan, but when it gets developed the photos will be posted.
scope does have its shortcomings. First, it is very heavy. The OTA alone
weights 14 pounds. After adding the Powermate and camera, I could not get it
to balance in the dec axis. This test was conducted using an Orion Astroview
equatorial mount that is designed for lightweight scopes. Balance would not be
a problem on a heavier mount. I'll be putting it piggyback on my Meade 8"
LX200GPS, so balance shouldn't be an issue. Were you going to use this on an
equatorial platform, even just for visual use, you'd have to invest in at least
a mid-range mount that would allow better balancing in declination.
second problem I noted was that the FSQ has an extremely short back-focus. I
was able to do everything I wanted, but the focuser was racked virtually all
the way in when I photographed the moon without the Powermate. With the
Powermate back focus is not an issue. Use of the Takahashi Extender Q would
probably eliminate the back focus problem as well, but that was not tested.
Also, a standard 1-¼ diagonal will not work on the scope due to the
short back focus. Takahashi does sell special adapters for astrophotography
and special diagonals. These are designed to work on the FSQ and will
eliminate all back focus shortcomings. I've ordered them.
I am very excited to add the FSQ to my slowly growing collection or telescopes.
all I have to do is work out a good way to mount this on the LX200 and I'll be