Sussex, England.I’m not sure if I am qualified
to conduct this review since I only became involved in astronomy as
a hobby in 1999. At that time £600 seemed an extortionate amount
of money to spend on a telescope to look at the stars that I could
already see with my naked eyes. I remember with clarity my brother
taking only one look and saying, “For the price of that thing
you could have a nice holiday!” At the time I did somewhat agree.
In this review I wanted to compare two telescopes of
different designs to see, if nothing else, whether an expensive purebred
can better a Maksutov crossbred.
It may also be that there are people finding it difficult
to justify spending a lot of money on a telescope based purely on
guesswork. Hopefully this review can make someone’s decision
easier. Since I have purchased both of these telescopes and conducted
fairly extensive tests, I feel that I can at least talk about them
honestly and with no undisclosed outside interest.
I like to image, using both film and CCD, but stick
primarily to CCD. I have come a long way since I started three years
ago. This is mainly due to the fact that I have invested in the right
tools, such as autoguiders, to make imaging easier. Over the last
year I have improved so much that Astronomy Now, our national magazine,
has used my images in the Readers Submissions section and two were
even chosen Picture of the Month! Wow!
I hope you enjoy my first review.
Takahashi TOA 130S
Lens shade shown nearly retracted. Note the stop ring.
Here is a close up of the TOA 130 lens assembly.
STF MIRAGE 180mm Rumak Maksutov Cassegrain (deluxe)
Here is the STF Mirage with its fixed lens shade and
fixed cooling fan on top.
Here is a close up of the STF lens assembly. You
can clearly see this is of the Rumak type because, like Schmidt Cassegrain
telescopes, this also has a separate secondary mirror rather than
reflective spot on the inside of the front corrector.
As you can clearly see they are both superb looking instruments. The
Takahashi has a more showy appearance with its high gloss paint and
lustre that the STF lacks. Having said that, the STF has a different
look and feel to it, one that is more centred on performance rather
than sheer aesthetics.
The review is broken down into the important criteria
of specification, optics and my conclusion. (Bearing in mind that
the editor’s decision isn’t final!)
Specification
The Takahashi TOA 130 is an air-spaced triplet refractor
APO with the central lens being ED glass. The focal length is 1000mm
and the focal ratio is f7.7. The tube weighs in at 10kg/22lbs and
feels slightly nose heavy (it’s a big lens cell with lots of
glass). This is one reason why Takahashi ships the OTA with a tube
weight/counterbalance similar to the tube rings made of cast iron.
It does work well but adds even more weight (nearly 1kg/2.2lbs). The
OTA is 1120mm long with the retractable dew shield extended and 980mm
with shield retracted. When you buy the TOA 130 it only comes standard
with the visual adapters, so be ready to spend more money on finders,
rings, etc.
The STF 180 is a Rumak-Maksutov Cassegrain variation
of the Maksutov design. Simply put, this means it has a separate secondary
mirror instead of a reflective spot on the rear of the corrector lens.
This, I’m told, affords the telescope designer more freedom
to alter f-ratios, enables better field correction and corrects for
coma. But, this all this comes at a price premium as compared to standard
Maksutov Cassegrains.
Still, the STF is only just a third of the price of
the TOA 130, which makes it in my view very affordable!
The STF has an aperture of 180mm and, being f10, gives
a very usable 1800mm focal length. This is great if you’re looking
for a high resolution imaging scope. Strangely, the STF weighs nearly
the same as the TOA (8.5kg) but without all the heavy rings it feels
a bit lighter. It still however makes you feel that it is a quality
telescope (heavy is quality right?).
My STF is the deluxe version. This means it comes standard
with 1/8th wave optics and a cooling fan. More will be said about
this later.
The tube is a compact 765mm in length with the integral
dew shield attached and only 500mm when removed, although you would
never need to remove it except for cleaning
The STF Deluxe comes with a safe wooden shipping crate
and an extremely well made canvas padded bag. It is also supplied
with a very good 7x50 finder, a nice camera holder that attaches the
same way the finder does and an integral cooling fan. There is also
a separate auxiliary fan that screws onto the rear cell (one pushes
air from the eyepiece end while the top pulls air through the OTA).
Believe it or not, I even found I could leave the gentle top fan running
and the visual impairment was next to nothing. No eyepiece adapters
are supplied but the cell threads are the same as Schmidt scopes so
take your choice!Both are very well built with the TOA taking the
lead at this point in the review just due to its sheer finesse and
attention to detail. They will both easily last a lifetime, just buy
a damn good case for the TOA! (Takahashi really should supply a case
considering the cost of the scope.) Both the Takahashi and the STF
will need a moderate mount, especially if you will be imaging and
using separate guide scopes. Mounts such as Astro-Physics (600, 900
and 1200), Losmandy G11, Vixen Atlux, etc, are needed at the minimum.Optical
and Field PerformanceWhen you first take these scopes from a warm
house to the outdoors you will notice that the TOA acclimates much
faster. Despite what some people say, I find it to be very good in
our British climate. It needs no more than 30 minutes.
The STF will require longer (I found often nearly an
hour) but using the cooling fan could often reduce this time to as
little as 10 minutes. I did find that as the temperature drops, the
STF would need the fan turned on for a moment to keep it on track
with dropping temperatures.
Both scopes have excellent dew shields that work well.
Both telescopes have excellent mechanics and show zero
image shift while focusing. Of course they operate entirely differently,
but from a visual and imaging point of view, they couldn’t be
any better. My TOA has the 2.7inch focuser, which, until they come
out with a CCD the size of 6x7, isn’t a problem. Also, as many
may be aware, the Takahashi focusers are legendary and with the addition
of the 10:1 micro adjustment accessory, they are still as good as
anything currently available.
The STF is fairly similar in layout to all the Meade
and Celestron Schmidt-Cassegrains in that the focuser and eyepiece
placement are the same. I find the focuser to be a useful size even
with gloves, however it can sometimes seem slow in it’s gearing
when making large alterations (for instance, changing to the f6.3
reducer) but it is extremely precise for fine focusing. The focuser
is fairly long and this can cause it to clash with the diagonal/ binoviewer
in certain positions.
One important aspect of visual astronomy for me is the
use of binoviewers. I have the Denkmeier standard refractor version
with the 2” f5 rich field Starsweeper. The STF worked extremely
well with and without the Starsweeper. The TOA 130 is fantastic with
the binoviewer but to my surprise didn’t have quite enough forward
travel to use without the 1 _ OCS. This is a shame because the TOA
should be fantastic for low power rich field views. At high power
(4x Powermate, binoviewer and 12.5mm Orthos resulting in a magnification
of 320x), the views are still incredibly sharp and full of contrast.
Planets / Moon
While viewing Saturn and Jupiter, I found I could never
see quite the same detail with the STF as I could with the TOA. By
detail, I mean low and high contrast areas. Both planets were noticeably
brighter in the STF, which can obviously be attributed to its larger
aperture. Often the views were more stable in the TOA. I found I would
spend nearly all my time looking at the planets through the TOA. One
key point to remember is I never knowingly had a night of exceptional
seeing, which may work in the favour of the STF with it’s larger
aperture.
Looking at Jupiter’s moons is another pleasing
past time with the TOA. With practice one can tell which is which
purely based on size, brightness and colour shade. This is not quite
the case with the STF although the difference between the scopes was
very subtle.
Using a Meade 18mm SWA in the binoviewer and 2x OCS
(110x magnification), the TOA would show nice detail quite clearly
and precisely. The STF with the same setup, minus the OCS, (giving
100 x magnification) seemed softer and slightly lacked low contrast
detail cutting edge contrast of the TOA.
In my opinion, the TOA is the better planetary scope.
With lunar observing, I believe contrast is more important
than overall brightness. Since the TOA is probably one of the finest
colour corrected refractors money can buy (my opinion) the issue of
colour didn’t even arise. Surprisingly though, the STF appeared
slightly warmer in colour than the stark views through the TOA. Looking
at the crater Plato, I could easily discern 4 or 5 craterlets but
with the STF, at times it was hard to see 2 or 3. While viewing Copernicus,
the TOA would show the central peaks as three main structures whereas
the STF could only manage two. Tyco showed a similar result with the
TOA clearly managing to show the crater walls with more definition.
For lunar observing, I found the TOA more satisfying
to observe with, no matter what eyepiece set I used.
Stars and Deep Space
This is where the STF shows its aperture advantage.
To my surprise, the TOA still manages to compete. For objects like
globular clusters, planetary nebulas and other small, tight objects,
the STF was slightly better in terms of visibility and ease of viewing.
The TOA still manages to show objects such as M13, M3, M45 and the
Double Cluster in an almost magical way (remember the often mentioned
“diamonds on black velvet”). This is due to the sharp
definition of the stars, which somewhat makes up for the lack of aperture.
For objects such as M57, M27, M81 and M82, the STF clearly wins due
to aperture. One benefit that the TOA has is its ability to use widefield
eyepieces, allowing for a “wow” feeling more often than
the STF.
Stars snap to focus equally well in both telescopes,
though slightly tighter in the TOA, and reflect what one expects from
top drawer optics without a central obstruction!
CCD Imaging
I won’t delve too deeply here because I feel the
TOA justifies its own review specifically as an imaging instrument
(The STF has already been given a thorough review; see below). With
the f5.8 TOA reducer/flattener, I believe it’s capable of out
performing the Takahashi FSQ though it does come at a significant
cost increase. I intend on doing a comparative review soon.
The STF has already been very fairly reviewed by Dominique
Dierick on Cloudy Nights and it would be a good idea to read that
in conjunction with my review.
What I will add is that these two telescopes are both
first rate in their respective fields with the TOA well suited for
low-to-medium focal length and the STF for medium-to-long focal length
imaging and visual viewing. Using my Starlight Xpress SXVH9, I did
find the star images to be sharper and tighter using the TOA as compared
to the STF.
Before using the STF, I made sure I was meticulous with
collimation. Incredulous as it seems, the STF arrived from Germany
in perfect collimation! This is a good proof of its tremendous build
quality. I’ve collimated this scope only once in 6 months and
even that wasn’t really necessary. The STF has the standard
3 push pull screws on the secondary should it need adjustment. However
it is worth pointing out that the TOA also arrived in perfect collimation.
Should it ever need adjusting, which I doubt it would, there are 6
sets of push pull lens adjustment screws showing yet another indication
of quality!
Here you can just see the earlier mentioned collimation screws
This picture shows both scopes atop my AP 900 GTO mount.
The following images were taken at prime focus with
equal processing and similar total duration (10 minutes). The difference
in focal length is quite obvious, as is the sharpness. What can be
clearly seen is that they are both intended for totally different
jobs with reference again to image scale and focal length. Decide
for yourself what you think you will image more often and what your
requirements are.
Remember that tracking accuracy is very important when
imaging at longer focal lengths. If you feel your imaging skills and
mount may be pushed to and beyond the limits, the TOA may be the better
tool. Because of the British climate, the TOA may also get more use
visually and for imaging since longer focal length scopes require
more stable weather for imaging.
STF Mirage 180 (top image), Takahashi TOA 130
(bottom image)
Conclusion
I was hoping the conclusion would be incredibly obvious,
but it is not. This is in part because I really want the TOA’s
high price tag to be justified but also because I feel that the STF
is a worthy scope. The STF is the sort of trusty friend you grow to
really like, much like a pet. It also makes a wonderful package with
everything you really expect and more for the money.
However, the TOA is the kind of telescope you would
feel justified leaving to your children. It feels incredibly robust
and does everything so well. I feel that Takahashi should, considering
the cost of the TOA, supply a case to protect it.
In conclusion, the TOA is my favourite visual and imaging
scope but as an affordable package the STF is worthy of consideration.
As with many things, you do get what you pay for and the cost difference
between the two is easily a family holiday! But for the perfectionist,
the TOA is a fantastic performer that will never fail to please.
If you want both a great scope and a holiday, the STF
is a fine choice. For sheer perfection, it just doesn’t quite
compare to the TOA. Used together, both scopes actually compliment
each other well. I even mount the STF on top of the TOA on my AP900GTO! |
