RAT NOTES - TEC 200 F9 Triplet Apochromat - 09/01/04

RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

Well, it's been a long journey to get all the way from my first 8" SCT, to the
Televue Ranger, through three Dobs, and another 2 (8" - again, and 11") SCT's,
of course interspersed with three (or four) more refractors, and finally here
- my very own 8" APO refractor.

Why don't I just save the suspense and say it up front:

Holy Cow!

I first inquired about this scope with TEC 23 months ago. Received it last
Monday, not bad actually, given the apparent dynamics of creating such an
instrument.

The outer box looked more as if it had been kicked by UPS all the way from
Colorado rather than being driven here by truck, but the scope was well packed
in bubble wrap in an inner box with another outer layer of peanuts, which
protected it completely. Once opened it appeared to be unharmed.

Some time ago, I received the mount; a Losmandy Titan. I had a few weeks
playing around with it using my 6" Tak as a guinea pig. It is a nice big mount
and I figured that it would be adequate to the task. As it turns out, there are
some idiosyncrasies (as well as something of a learning curve) to it. I am
still waiting to get a pair of stainless steel worm covers, as the supplied
aluminum ones are subject to expansion / contraction when the scope is
subjected to changes in temperature. It is a nice fit for visual use with the
big OTA.

Here's a good place for a side note: One thing I realized when it came time to
set up this monster, is that I am damned glad that I have already owned and
become well acquainted with 2-3 EQ mounted refractors. I still remember the
time I took a dive in the snow to catch the AP Traveler as it accidentally slid
out of the dovetail plate. This is not one of those scopes that I am going to
be taking a dive for; I can barely lift it. The listed weight of the OTA is in
the ~50 lb range. I've been consistently eating my Wheaties and lifting weights
so that I would be up to the task when it came time to hoist it onto the mount
(I'm 6'3" 205 lbs, and I bench 3 sets of 8 @ 165 lb, and curl 3 sets of 10 @ 40
lb each arm - 3x week).

Anyway, after I got the box opened and the rings in place on the mount, I went
about the matter of lifting the OTA into the rings. I'm glad it is only 50 lbs,
because it feels like 70. I am able to carry it up the step ladder into the
heavens and lift it gingerly into the rings, and have so far done so twice, but
I will probably try to rig up some sort of hoist for moving it between the
mount and the case, because it is a bit too precarious to balance for my taste.
I fully intend to NOT damage the scope, so I need to come up with procedures
that do not take 90% of my strength to execute.

After the scope was on the mount, I commenced to worry.

I must have tightened every knob 3 times. I was particularly concerned (read
paranoid) that the dove plate was not properly set in the dovetail assembly. I
worried about this until the day before yesterday, when I was mounting the
scope for the second time (even though that first night, I visually confirmed
using a flashlight that it was properly seated). I also immediately ordered a
case for the OTA from Scopeguard. But I still don't know which is worse,
leaving it on the mount or moving back and forth to the case all the time.

Another good side note: Why would it be necessary to have mounted it twice in a
few days? I'll tell you why: The doorway for rolling the mount out had an
opening that was 74" high . I say "was" because after that first night of
sitting on the ground (on my butt) to observe the Zenith, I decided that I
would be needing to enlarge the door again (for the second time). I spent two
days brushing up on my rudimentary carpentry skills by adding a third, top door
opening on hinges that gave an additional 10" of available height (87" total).
Now I have to climb even higher to get the thing on the mount.

So I took the scope down, mount and all, and reassembled it with the legs
further extended. Now at the Zenith, a 7 mm Pentax hangs about 33" off the
ground at focus. Not bad, I can pretty much look in while seated on a low bench
(read inverted milk crate). Closer to the Horizon, I pretty much need to be
standing, unless I am willing to crank my neck, or better still, stand my Air
Chair precariously "on top" of the milk crate. Not a bad solution, as I have
decent balance, and if I were to fall off at least the scope would not be in
much peril, as the mount would surely be capable of receiving my form in motion
without the OTA so much as moving from its target.

Appearance:

I don't have all the measurements in front of me, but it is around 5.5 feet
long with the dew shield retracted. The paint is white with a durable, rough
texture. This will be very effective in hiding finger prints and also makes the
tube less slippery when it has dew on it (I handle the tube using "rubber dot"
type photo gloves for grip and to keep oils off of the assembly). It
incorporates a black anodized, high quality Feathertouch dual-speed focuser.
The lens cell is nicely appointed with the technical specifications of the lens
(F=200 mm, F/L=1800 mm, etc, etc) laser-engraved thereupon. Very Nice.

The lens itself is pretty amazing. I wish I knew more about how a lens cell is
designed to compensate for temperature changes. I am also curious to see at
just how cold of an ambient temperature that this telescope can be used and
still maintain its figure. We typically see substantial periods where the
thermometer at night appears to be perpetually stuck at 5 degrees F. It would
be nice if the scope would be able to handle such a cold temp, but there was no
guarantee given that it would at the time I placed my order.

Speaking of which, I would have, for the sake of long term maintenance,
preferred to have ordered an air-spaced unit, as being non-technical, I am
superstitiously distrustful of the long term utility of an oil spaced
objective. Just the same I have been assured to my satisfaction that it is a
non-issue. It was also the only option available to me at the time that I could
afford, so it is what it is.

It is possible to see something of how the cell is constructed, but as I said,
being non-technical, it is difficult, even looking through clear glass, to see
clearly what is going on there.

Did I mention the glass? 200 mm of clear aperture…aaah!

It is a big lens to an amateur such as myself. Perhaps I shall dispense with
waxing poetic about the coatings rendering the glass "invisible." I will only
say that the coatings are considerably lighter than on the 6" Tak (which has a
very dark coating), they are more like the coatings on the Traveler, if I were
going to pick an equivalent.

As eluded to before, the dew shield is of the sliding variety, it is nice and
snug and I assume that it will move smoothly after it has been operated a few
more times. The lens cap is of aluminum and attaches directly (as opposed to
"screwing on", and is held in place with foam spacers - very nice, actually).
The interior of the tube is flat black and supports 4 baffles. The inside of
the focuser tube is lined with black felt. The 2" focuser cap is laser engraved
with the TEC logo and the logo also appears on the focuser. There are two decal
lettering type labels on opposite sides of the baffle reading "TEC APO 200 ED."
With the baffle extended and the focuser engaged the overall length is in
excess of 6 feet, it is a most imposing instrument sitting up on top of the
Titan mount.

At any rate, I still need to pinch myself, as I must surely be dreaming.

First Light:

So after a couple days, I had it together enough (and the weather had cleared
enough) for me to take it out for first light. First light ended up being
Polaris, using a 31 mm Nagler. The view consisted of a bright star with bright,
undulating spikes; on bright stars at low power my eyes are crap, highly
astigmatic. It was apparent as being a double star, something the scope would
see a lot of over the next few nights. I used the opportunity to attach a new
Telrad, and get it aligned. I was in business. I had a look around; M13 -
washed out by the near Full Moon, the near Full Moon - way too low to the
horizon and stuck in the muck -seeing was horrible, and then Vega for false
color (still having a hard time really being able to see any at all "in
focus").

And then of course the double-double. Well, at 257x, that thing was incredible.
(Don't ask me what the hell I was doing at 257x, I don't think I've used less
than that practically the whole time I've used it - except to locate objects!)
I had never quite noticed how apparent the magnitude difference was with the
one pair - the pair that is parallel in line with the larger grouping of all
four stars. The Airy Disks were quite apparent and surrounded by 1-2 faint and
symmetrical diffraction rings. The outer one was fainter, and came and went
with the seeing.

By this time I have recognized the folly of trying to scrutinize "out of focus"
star patterns with APO refractors. I'm no expert, but I do know that the
phenomenon of bringing all of the colors together to the same focus, but never
being able to quite do it completely is known as spherochromatism, and that
these colors interfere with each other when out of focus, and that I can
basically throw out Suiter's star testing book of pretty fresnel patterns when
it comes to evaluating Spherical Aberration in such an animal. Except, perhaps,
for the "in focus" images in the book.

I have become something of a backyard expert at evaluating optics via the star
test method by simply leaving the stars "in focus"(!). It doesn't take a rocket
scientist to know that if the energy is properly concentrated in the Airy Disk,
and the seeing is good that the remaining diffraction rings will be few and
faint. Through experience, I have seen otherwise, so it is pretty easy to
evaluate SA in an optic using such a method, once it is based on personal
experience.

Spherical Aberration? Coma? Astigmatism? What are those? We'll have none of
that here. This lens is one (or is that 12?) of a kind…

Another side note: I have spent a great deal of time trying to determine what
would be the perfect aperture for my location. A good part of this has been
conjecture along with testing my eyes, to see exactly what it takes to see all
a given aperture has to offer. There is much information, as well as
disinformation on the Internet regarding maximum and minimum useful powers. I
like the oft repeated maxim that for low power it is best to use the highest
power possible that frames the object being observed. That is why I finally
ponied up for the 31 mm Nagler, and especially the pair of 24 mm Pans for my
Binoviewer, which will not yield much of a wider fov than my 32 mm Plossls, but
are certain to give a darker sky background with its attendant increase in
contrast, and hence, fainter objects visible.

As for high power, I don't know why it is, but I am coming to the conclusion
that I can see all that an objective has to deliver to the image plane at 30x
per inch of aperture. I have revisited this rule of thumb over and over, in one
telescope after another. That (30 x per inch) is where the Airy Disk becomes
visible to my eye in the scope, and that is where I can see the full resolution
of the instrument.

This is an important point. My eyes have some floaters (flotsam and jetsam
floating in the vitreous humor), the larger exit pupil I can use, the more
clearly I can see. Also, contrast decreases with increased magnification. Being
a Jupiter watcher, using the lowest magnification that will reveal all the
detail that an instrument can resolve, will also maintain the highest level of
low contrast detail visible in that fully resolved image. Seeing, also, may
limit the high power utility of an aperture, and by matching the aperture and
its full resolution to the environment, care may be taken to insure that the
instrument is well suited for its purpose. In a nutshell, the largest aperture
that can get under the local seeing.

That said, I have often had some difficulty pushing much past 225x on Jupiter
(my favorite object) at my house in the Rockies, and I have come to theorize
that I can fully resolve a 7.5" aperture at that magnification, so going much
beyond 8" is going to yield diminishing returns for observing Planets.
Diminishing returns on various respects: Cost, portability, seeing limitations
(BTW, I do use an 18" Newt for DSO's so please don't get the wrong idea). Now
8" is not generally considered an overwhelming amount of aperture for Planets,
so this explains why, for my purposes, I decided to go with a refractor.

Being limited as to maximum aperture useful for the application I could then
concentrate on getting everything possible from that 8" of aperture. At 8"
aperture, I can see resolve what the scope has to show at 250x, as will be
demonstrated later. By keeping it down to 250x, I can theoretically squeeze
more low contrast out of the system than running at a higher magnification.

Did I mention yet? This is a nice scope, it's a keeper.

Second light:

So, I go out a couple of nights ago and think I'll try for a couple of test
objects. I spent some bedtime reading looking over close doubles in the Night
Sky Observer's Guide (nice books by the way), and came up with a couple of
appropriate candidates in Cygnus.

Siegfried and Bob were both over (Siegfried is caretaker for a 9" Clark
Refractor, Bob has the second 8"er that is coming to this state (!), pretty
amazing when you consider that out of the 12, several of which are shipping out
of the country, that two would be coming here.

We were looking at stars and splitting a lot of doubles with the new TEC APO.

Needless to say, the Gemini GOTO was giving me fits, and a motor stalled. So I
finally decided to just push it to the objects and save for later trying to
figure out whether my problems were the mount or just my inexperience with it.
Sidereal tracking was still working fine throughout the evening. Glad I still
know how to star hop.

Ended up with Otto Struve 403 at .8 arcsec, and Otto Struve 410 at .6 arcsec
(according to The Night Sky Observer's Guide, both around mag 7, both are in
Cygnus).

Both split **clean** (no figure 8's or any of that crap), for all three of us
(so I do have witnesses), at both 257x and 450x.

Unbelievable! That .6 arcsec double is the closest double that I myself have
ever seen, and starting to push the theoretical limit for an 8"er, if I have my
facts straight.

Even more amazing is that they both split clean for me at the 257x, there we
are again at that magic ~30x per inch of aperture. Even at 450x, I could not
see them much better, if anything they were a bit more disturbed by the seeing
conditions at that extreme high power.

Another side note:

One thing that I have noticed is that it has taken me an inordinate amount of
time to get my facts straight regarding optics. For one thing, I think the
reason I was finally successful with the .6 arcsec double is that I chose one
that wasn't so bright that it's diffraction pattern would overwhelm the
separation of the Airy Disks. This and the fact that the stars were quite equal
in brightness, which helped them to split clean. What a stroke of luck that I
get a new scope, and sometime in the first week I am given the gift of sub-arc
second seeing. I mean this thing split .6 mm like it was butter. It never even
occurred to me, after all the hundreds of observations that I have now made,
that this might be the exception, and not the rule. It just seemed
so…natural.

Third Light:

Well, I had a lot of other questions still remaining, how about stray light,
sky background darkness, contrast, etc? I brought out my old faithful 10" F6
Zambuto Dob (Protostar 3 vane diagonal and quartz mirror, flocked tube), to do
a side by side. I let both instruments cool down for two hours. By some freak
of nature, the seeing cooperated for one more night. Not quite as good as last
night, but still pretty damn good. Let's have a look at that Otto Struve 410 at
..6 arcsec again. In the 8"er, there it was again, plain as day. Two tiny Airy
disks, the outside surrounded by the faintest diffraction ring, absolutely
beautiful.

Now to try it with the Dob. Got collimated, Found the star with a 22 mm Nagler,
switched to the 6 mm Radian (255x), holy cow, there it is; split!

I spent the better part of an hour carefully comparing one scope to the other.
I have come to the same conclusion as many others regarding diminishing returns
as more money is spent on a telescope. In a nutshell, in my case, was it worth
it?

Absolutely, emphatically, Yes.

There was perhaps a (WAG) 20% improvement in the aesthetic quality of the split
double star. While in the 8" the stars were tiny, hard Airy disks, in the Newt
they had something of a TV screen appearance to them. The diffraction rings
were interrupting in such a way as to appear to make fine lines in the image.
The star was still split clean, but it didn't have quite the same quality at
all as the image in the refractor.

Attempts to dsitinguish differences in background skyglow, contrast, light
grasp, etc., quickly became an exercise in futility. Simple matters like trying
to match magnifications and eyepiece designs became burdensome.

Then, my 45 year old bones began to make a further observation. The Dob ain't
that comfortable to use, it wobbles a bit at 255x, the objects fly across the
fov (I have a tracking platform, but really…), "go find that star again",
"yuck, that focuser", balance is an issue…

I sat at the EQ mount and operated the hand paddle on the mount and the 10:1
focuser. What a joy, what comfort, what a view! And that focuser!

IF I lived at a better location (again we are concurring with conventional
wisdom on the subject, and this is a big IF), I could perhaps see the utility
of going for a large Cat type scope on an EQ for observing the Planets.
Something like a 12" Mak would be great.

As to using a Newt such as my 10" F6 on an EQ mount, I somehow doubt that it
would work very well for myself, being awkward and uncomfortable. Sorry to say,
I am even starting to like my couch more these days (but it ain't over yet!)

Don't get me wrong, I am all for bang for the buck. And I like ALL telescopes,
but I did want to drop this note and express just how pleased I am with this
latest acquisition. Like I said before, I still can't believe that it is really
here. It is safe to say that for 1/10 of the price a person, willing to accept
some minor disadvantages and inconveniences, can get 90% to where it is
(however, to my own consternation, 90% doesn't always cut it for me when it
comes to eking out that final 5% of subtle detail in Jupiter's belts that I am
Always Looking For). And like I said, if I lived elsewhere, it might be a
different story).

By all means, it is very easy to enjoy this hobby to a very high level with
very modest means. But for me, with my years long quest for the perfect Jupiter
scope (well OK, I like the Moon, Saturn and Mars, too), I think I may have
finally found Telescope Heaven. This may very well be the closest thing to a
perfect 8" aperture that I have ever seen.

I can understand now what S&T meant, when they worked my patience over a while
back while I was waiting, by saying the only thing they didn't like about the
140 was that they had to send it back after the testing was done. Fortunately
for me, I don't have to send this one back.

Yet another side note:

Going through this latest comparison has put me in a bit of a sticky situation.
For one thing, seeing the .6 arcsec star for the first time in my 10" right
beside the 8" forced me to accept that I have to constantly remain open to
learning about how these things work. Picking the fainter double (not buying
the 8" refractor) was what really did the trick. I am seeing how different
eyepieces affect background sky glow (and there are some differences out there,
even among premium makes), I am further realizing that unless I properly clean
the diagonal, it might be adding some scatter to the image. I am realizing that
there are intangibles, such as comfort at the eyepiece, stability of the mount,
the ability for a scope to stay put while changing eyepieces and remain
balanced, the ability for the mount to track and keep a star centered for when
I wander away and then come back later, that all have a bearing on what one is
able to see.

For the longest time I was content to simply nudge my Dob slowly across the
sky. Now I just see aberrations wherever I look, even in my own eyes. So this
is where the road to becoming a critical observer leads…

I went through the same kind of thing one other time, when I was first getting
started. I originally was so taken by the stars that I would just lie out in
the yard and look up. Once I became obsessed with learning the constellations
and my way around the sky, for a time, it became a burden. I didn't want to
know anymore, I wanted to go back to ignorance, and just enjoy the sky for its
beauty. I passed through the other side of that dilemma and now am quite
comfortable both with the beauty, and knowing just a speck of what it is that I
am enjoying.

I feel the same way about telescopes now. As most of you here likely already
know, this is not a new thing for me. I have obsessed over telescopes for
years. I think (at least I hope) that I am finally reaching the point where I
can see the 8" APO and the 10" Dob for the apple and orange that they truly
are.

I have done countless side by sides between all of my scopes, especially the 6"
APO and the 10" Dob.

I truly feel that this time between the 8" APO and the 10" Newt, there will be
just the one night of comparison, I give up.

A friend asked me if it was "worth the wait." Yes, it was worth the wait. This
scope is finally good enough for me just the way it is, and I feel no
compulsion to put it (or myself) through any more rigorous and ridiculous
comparisons, or to spend another moment going over it with a fine toothed comb.
It has passed its side by side, and its first nights out under the stars with
flying colors. IOW, so far, so good and "good enough," for that matter.

I even think I might have got more than I paid for, as odd as that may sound.

Last side note:

I think that sometimes it is possible to create an instrument that performs
well on the bench, but the mechanics handicap its performance in the field.
Based on what I have seen with this instrument so far under the night sky, I
must say that it appears to be fully performing as well in the field, as it
must have done on TEC's optical testing bench. The specs to which it was
reportedly manufactured were exceedingly high, and for these specs to translate
so well to my eye under the night sky at 40 degrees F and dropping, is a
profound accomplishment; my hat is off to TEC.

As far as this humble test pilot can ascertain so far, this telescope appears
to be essentially a perfect instrument.

Did I already say it? I'll say it again; I think I have finally found Telescope
Heaven.

Very impressive, TEC guys,

I can hardly wait for Jupiter...
rat
~( );

email: remove 'et' from .com(et) in above email address

t (Ratboy99) wrote in message ...
RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

Well, it's been a long journey.
This telescope appears
to be essentially a perfect instrument.
Very impressive, TEC guys,
I can hardly wait for Jupiter...

rat
~( );

Excellent post.
Congratulations.
I don't think you'll need a drip tray.
Though I might. ;-)

Be careful out there!
Chris.B

t (Ratboy99) wrote in message ...
RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

Hi Rat ,

Nice report , thanks for sharing with us . Boy that TEC
,they are fast becoming the place to go for that very fine instrument
of distinction .
Please keep the reports coming , with much focus on your
observations of Jupiter this year .
Top of the day , Leonard






Well, it's been a long journey to get all the way from my first 8" SCT, to the
Televue Ranger, through three Dobs, and another 2 (8" - again, and 11") SCT's,
of course interspersed with three (or four) more refractors, and finally here
- my very own 8" APO refractor.

Why don't I just save the suspense and say it up front:

Holy Cow!

I first inquired about this scope with TEC 23 months ago. Received it last
Monday, not bad actually, given the apparent dynamics of creating such an
instrument.

The outer box looked more as if it had been kicked by UPS all the way from
Colorado rather than being driven here by truck, but the scope was well packed
in bubble wrap in an inner box with another outer layer of peanuts, which
protected it completely. Once opened it appeared to be unharmed.

Some time ago, I received the mount; a Losmandy Titan. I had a few weeks
playing around with it using my 6" Tak as a guinea pig. It is a nice big mount
and I figured that it would be adequate to the task. As it turns out, there are
some idiosyncrasies (as well as something of a learning curve) to it. I am
still waiting to get a pair of stainless steel worm covers, as the supplied
aluminum ones are subject to expansion / contraction when the scope is
subjected to changes in temperature. It is a nice fit for visual use with the
big OTA.

Here's a good place for a side note: One thing I realized when it came time to
set up this monster, is that I am damned glad that I have already owned and
become well acquainted with 2-3 EQ mounted refractors. I still remember the
time I took a dive in the snow to catch the AP Traveler as it accidentally slid
out of the dovetail plate. This is not one of those scopes that I am going to
be taking a dive for; I can barely lift it. The listed weight of the OTA is in
the ~50 lb range. I've been consistently eating my Wheaties and lifting weights
so that I would be up to the task when it came time to hoist it onto the mount
(I'm 6'3" 205 lbs, and I bench 3 sets of 8 @ 165 lb, and curl 3 sets of 10 @ 40
lb each arm - 3x week).

Anyway, after I got the box opened and the rings in place on the mount, I went
about the matter of lifting the OTA into the rings. I'm glad it is only 50 lbs,
because it feels like 70. I am able to carry it up the step ladder into the
heavens and lift it gingerly into the rings, and have so far done so twice, but
I will probably try to rig up some sort of hoist for moving it between the
mount and the case, because it is a bit too precarious to balance for my taste.
I fully intend to NOT damage the scope, so I need to come up with procedures
that do not take 90% of my strength to execute.

After the scope was on the mount, I commenced to worry.

I must have tightened every knob 3 times. I was particularly concerned (read
paranoid) that the dove plate was not properly set in the dovetail assembly. I
worried about this until the day before yesterday, when I was mounting the
scope for the second time (even though that first night, I visually confirmed
using a flashlight that it was properly seated). I also immediately ordered a
case for the OTA from Scopeguard. But I still don't know which is worse,
leaving it on the mount or moving back and forth to the case all the time.

Another good side note: Why would it be necessary to have mounted it twice in a
few days? I'll tell you why: The doorway for rolling the mount out had an
opening that was 74" high . I say "was" because after that first night of
sitting on the ground (on my butt) to observe the Zenith, I decided that I
would be needing to enlarge the door again (for the second time). I spent two
days brushing up on my rudimentary carpentry skills by adding a third, top door
opening on hinges that gave an additional 10" of available height (87" total).
Now I have to climb even higher to get the thing on the mount.

So I took the scope down, mount and all, and reassembled it with the legs
further extended. Now at the Zenith, a 7 mm Pentax hangs about 33" off the
ground at focus. Not bad, I can pretty much look in while seated on a low bench
(read inverted milk crate). Closer to the Horizon, I pretty much need to be
standing, unless I am willing to crank my neck, or better still, stand my Air
Chair precariously "on top" of the milk crate. Not a bad solution, as I have
decent balance, and if I were to fall off at least the scope would not be in
much peril, as the mount would surely be capable of receiving my form in motion
without the OTA so much as moving from its target.

Appearance:

I don't have all the measurements in front of me, but it is around 5.5 feet
long with the dew shield retracted. The paint is white with a durable, rough
texture. This will be very effective in hiding finger prints and also makes the
tube less slippery when it has dew on it (I handle the tube using "rubber dot"
type photo gloves for grip and to keep oils off of the assembly). It
incorporates a black anodized, high quality Feathertouch dual-speed focuser.
The lens cell is nicely appointed with the technical specifications of the lens
(F=200 mm, F/L=1800 mm, etc, etc) laser-engraved thereupon. Very Nice.

The lens itself is pretty amazing. I wish I knew more about how a lens cell is
designed to compensate for temperature changes. I am also curious to see at
just how cold of an ambient temperature that this telescope can be used and
still maintain its figure. We typically see substantial periods where the
thermometer at night appears to be perpetually stuck at 5 degrees F. It would
be nice if the scope would be able to handle such a cold temp, but there was no
guarantee given that it would at the time I placed my order.

Speaking of which, I would have, for the sake of long term maintenance,
preferred to have ordered an air-spaced unit, as being non-technical, I am
superstitiously distrustful of the long term utility of an oil spaced
objective. Just the same I have been assured to my satisfaction that it is a
non-issue. It was also the only option available to me at the time that I could
afford, so it is what it is.

It is possible to see something of how the cell is constructed, but as I said,
being non-technical, it is difficult, even looking through clear glass, to see
clearly what is going on there.

Did I mention the glass? 200 mm of clear aperture…aaah!

It is a big lens to an amateur such as myself. Perhaps I shall dispense with
waxing poetic about the coatings rendering the glass "invisible." I will only
say that the coatings are considerably lighter than on the 6" Tak (which has a
very dark coating), they are more like the coatings on the Traveler, if I were
going to pick an equivalent.

As eluded to before, the dew shield is of the sliding variety, it is nice and
snug and I assume that it will move smoothly after it has been operated a few
more times. The lens cap is of aluminum and attaches directly (as opposed to
"screwing on", and is held in place with foam spacers - very nice, actually).
The interior of the tube is flat black and supports 4 baffles. The inside of
the focuser tube is lined with black felt. The 2" focuser cap is laser engraved
with the TEC logo and the logo also appears on the focuser. There are two decal
lettering type labels on opposite sides of the baffle reading "TEC APO 200 ED."
With the baffle extended and the focuser engaged the overall length is in
excess of 6 feet, it is a most imposing instrument sitting up on top of the
Titan mount.

At any rate, I still need to pinch myself, as I must surely be dreaming.

First Light:

So after a couple days, I had it together enough (and the weather had cleared
enough) for me to take it out for first light. First light ended up being
Polaris, using a 31 mm Nagler. The view consisted of a bright star with bright,
undulating spikes; on bright stars at low power my eyes are crap, highly
astigmatic. It was apparent as being a double star, something the scope would
see a lot of over the next few nights. I used the opportunity to attach a new
Telrad, and get it aligned. I was in business. I had a look around; M13 -
washed out by the near Full Moon, the near Full Moon - way too low to the
horizon and stuck in the muck -seeing was horrible, and then Vega for false
color (still having a hard time really being able to see any at all "in
focus").

And then of course the double-double. Well, at 257x, that thing was incredible.
(Don't ask me what the hell I was doing at 257x, I don't think I've used less
than that practically the whole time I've used it - except to locate objects!)
I had never quite noticed how apparent the magnitude difference was with the
one pair - the pair that is parallel in line with the larger grouping of all
four stars. The Airy Disks were quite apparent and surrounded by 1-2 faint and
symmetrical diffraction rings. The outer one was fainter, and came and went
with the seeing.

By this time I have recognized the folly of trying to scrutinize "out of focus"
star patterns with APO refractors. I'm no expert, but I do know that the
phenomenon of bringing all of the colors together to the same focus, but never
being able to quite do it completely is known as spherochromatism, and that
these colors interfere with each other when out of focus, and that I can
basically throw out Suiter's star testing book of pretty fresnel patterns when
it comes to evaluating Spherical Aberration in such an animal. Except, perhaps,
for the "in focus" images in the book.

I have become something of a backyard expert at evaluating optics via the star
test method by simply leaving the stars "in focus"(!). It doesn't take a rocket
scientist to know that if the energy is properly concentrated in the Airy Disk,
and the seeing is good that the remaining diffraction rings will be few and
faint. Through experience, I have seen otherwise, so it is pretty easy to
evaluate SA in an optic using such a method, once it is based on personal
experience.

Spherical Aberration? Coma? Astigmatism? What are those? We'll have none of
that here. This lens is one (or is that 12?) of a kind…

Another side note: I have spent a great deal of time trying to determine what
would be the perfect aperture for my location. A good part of this has been
conjecture along with testing my eyes, to see exactly what it takes to see all
a given aperture has to offer. There is much information, as well as
disinformation on the Internet regarding maximum and minimum useful powers. I
like the oft repeated maxim that for low power it is best to use the highest
power possible that frames the object being observed. That is why I finally
ponied up for the 31 mm Nagler, and especially the pair of 24 mm Pans for my
Binoviewer, which will not yield much of a wider fov than my 32 mm Plossls, but
are certain to give a darker sky background with its attendant increase in
contrast, and hence, fainter objects visible.

As for high power, I don't know why it is, but I am coming to the conclusion
that I can see all that an objective has to deliver to the image plane at 30x
per inch of aperture. I have revisited this rule of thumb over and over, in one
telescope after another. That (30 x per inch) is where the Airy Disk becomes
visible to my eye in the scope, and that is where I can see the full resolution
of the instrument.

This is an important point. My eyes have some floaters (flotsam and jetsam
floating in the vitreous humor), the larger exit pupil I can use, the more
clearly I can see. Also, contrast decreases with increased magnification. Being
a Jupiter watcher, using the lowest magnification that will reveal all the
detail that an instrument can resolve, will also maintain the highest level of
low contrast detail visible in that fully resolved image. Seeing, also, may
limit the high power utility of an aperture, and by matching the aperture and
its full resolution to the environment, care may be taken to insure that the
instrument is well suited for its purpose. In a nutshell, the largest aperture
that can get under the local seeing.

That said, I have often had some difficulty pushing much past 225x on Jupiter
(my favorite object) at my house in the Rockies, and I have come to theorize
that I can fully resolve a 7.5" aperture at that magnification, so going much
beyond 8" is going to yield diminishing returns for observing Planets.
Diminishing returns on various respects: Cost, portability, seeing limitations
(BTW, I do use an 18" Newt for DSO's so please don't get the wrong idea). Now
8" is not generally considered an overwhelming amount of aperture for Planets,
so this explains why, for my purposes, I decided to go with a refractor.

Being limited as to maximum aperture useful for the application I could then
concentrate on getting everything possible from that 8" of aperture. At 8"
aperture, I can see resolve what the scope has to show at 250x, as will be
demonstrated later. By keeping it down to 250x, I can theoretically squeeze
more low contrast out of the system than running at a higher magnification.

Did I mention yet? This is a nice scope, it's a keeper.

Second light:

So, I go out a couple of nights ago and think I'll try for a couple of test
objects. I spent some bedtime reading looking over close doubles in the Night
Sky Observer's Guide (nice books by the way), and came up with a couple of
appropriate candidates in Cygnus.

Siegfried and Bob were both over (Siegfried is caretaker for a 9" Clark
Refractor, Bob has the second 8"er that is coming to this state (!), pretty
amazing when you consider that out of the 12, several of which are shipping out
of the country, that two would be coming here.

We were looking at stars and splitting a lot of doubles with the new TEC APO.

Needless to say, the Gemini GOTO was giving me fits, and a motor stalled. So I
finally decided to just push it to the objects and save for later trying to
figure out whether my problems were the mount or just my inexperience with it.
Sidereal tracking was still working fine throughout the evening. Glad I still
know how to star hop.

Ended up with Otto Struve 403 at .8 arcsec, and Otto Struve 410 at .6 arcsec
(according to The Night Sky Observer's Guide, both around mag 7, both are in
Cygnus).

Both split **clean** (no figure 8's or any of that crap), for all three of us
(so I do have witnesses), at both 257x and 450x.

Unbelievable! That .6 arcsec double is the closest double that I myself have
ever seen, and starting to push the theoretical limit for an 8"er, if I have my
facts straight.

Even more amazing is that they both split clean for me at the 257x, there we
are again at that magic ~30x per inch of aperture. Even at 450x, I could not
see them much better, if anything they were a bit more disturbed by the seeing
conditions at that extreme high power.

Another side note:

One thing that I have noticed is that it has taken me an inordinate amount of
time to get my facts straight regarding optics. For one thing, I think the
reason I was finally successful with the .6 arcsec double is that I chose one
that wasn't so bright that it's diffraction pattern would overwhelm the
separation of the Airy Disks. This and the fact that the stars were quite equal
in brightness, which helped them to split clean. What a stroke of luck that I
get a new scope, and sometime in the first week I am given the gift of sub-arc
second seeing. I mean this thing split .6 mm like it was butter. It never even
occurred to me, after all the hundreds of observations that I have now made,
that this might be the exception, and not the rule. It just seemed
so…natural.

Third Light:

Well, I had a lot of other questions still remaining, how about stray light,
sky background darkness, contrast, etc? I brought out my old faithful 10" F6
Zambuto Dob (Protostar 3 vane diagonal and quartz mirror, flocked tube), to do
a side by side. I let both instruments cool down for two hours. By some freak
of nature, the seeing cooperated for one more night. Not quite as good as last
night, but still pretty damn good. Let's have a look at that Otto Struve 410 at
.6 arcsec again. In the 8"er, there it was again, plain as day. Two tiny Airy
disks, the outside surrounded by the faintest diffraction ring, absolutely
beautiful.

Now to try it with the Dob. Got collimated, Found the star with a 22 mm Nagler,
switched to the 6 mm Radian (255x), holy cow, there it is; split!

I spent the better part of an hour carefully comparing one scope to the other.
I have come to the same conclusion as many others regarding diminishing returns
as more money is spent on a telescope. In a nutshell, in my case, was it worth
it?

Absolutely, emphatically, Yes.

There was perhaps a (WAG) 20% improvement in the aesthetic quality of the split
double star. While in the 8" the stars were tiny, hard Airy disks, in the Newt
they had something of a TV screen appearance to them. The diffraction rings
were interrupting in such a way as to appear to make fine lines in the image.
The star was still split clean, but it didn't have quite the same quality at
all as the image in the refractor.

Attempts to dsitinguish differences in background skyglow, contrast, light
grasp, etc., quickly became an exercise in futility. Simple matters like trying
to match magnifications and eyepiece designs became burdensome.

Then, my 45 year old bones began to make a further observation. The Dob ain't
that comfortable to use, it wobbles a bit at 255x, the objects fly across the
fov (I have a tracking platform, but really…), "go find that star again",
"yuck, that focuser", balance is an issue…

I sat at the EQ mount and operated the hand paddle on the mount and the 10:1
focuser. What a joy, what comfort, what a view! And that focuser!

IF I lived at a better location (again we are concurring with conventional
wisdom on the subject, and this is a big IF), I could perhaps see the utility
of going for a large Cat type scope on an EQ for observing the Planets.
Something like a 12" Mak would be great.

As to using a Newt such as my 10" F6 on an EQ mount, I somehow doubt that it
would work very well for myself, being awkward and uncomfortable. Sorry to say,
I am even starting to like my couch more these days (but it ain't over yet!)

Don't get me wrong, I am all for bang for the buck. And I like ALL telescopes,
but I did want to drop this note and express just how pleased I am with this
latest acquisition. Like I said before, I still can't believe that it is really
here. It is safe to say that for 1/10 of the price a person, willing to accept
some minor disadvantages and inconveniences, can get 90% to where it is
(however, to my own consternation, 90% doesn't always cut it for me when it
comes to eking out that final 5% of subtle detail in Jupiter's belts that I am
Always Looking For). And like I said, if I lived elsewhere, it might be a
different story).

By all means, it is very easy to enjoy this hobby to a very high level with
very modest means. But for me, with my years long quest for the perfect Jupiter
scope (well OK, I like the Moon, Saturn and Mars, too), I think I may have
finally found Telescope Heaven. This may very well be the closest thing to a
perfect 8" aperture that I have ever seen.

I can understand now what S&T meant, when they worked my patience over a while
back while I was waiting, by saying the only thing they didn't like about the
140 was that they had to send it back after the testing was done. Fortunately
for me, I don't have to send this one back.

Yet another side note:

Going through this latest comparison has put me in a bit of a sticky situation.
For one thing, seeing the .6 arcsec star for the first time in my 10" right
beside the 8" forced me to accept that I have to constantly remain open to
learning about how these things work. Picking the fainter double (not buying
the 8" refractor) was what really did the trick. I am seeing how different
eyepieces affect background sky glow (and there are some differences out there,
even among premium makes), I am further realizing that unless I properly clean
the diagonal, it might be adding some scatter to the image. I am realizing that
there are intangibles, such as comfort at the eyepiece, stability of the mount,
the ability for a scope to stay put while changing eyepieces and remain
balanced, the ability for the mount to track and keep a star centered for when
I wander away and then come back later, that all have a bearing on what one is
able to see.

For the longest time I was content to simply nudge my Dob slowly across the
sky. Now I just see aberrations wherever I look, even in my own eyes. So this
is where the road to becoming a critical observer leads…

I went through the same kind of thing one other time, when I was first getting
started. I originally was so taken by the stars that I would just lie out in

the yard and look up. Once I became obsessed with learning the constellations
and my way around the sky, for a time, it became a burden. I didn't want to
know anymore, I wanted to go back to ignorance, and just enjoy the sky for its
beauty. I passed through the other side of that dilemma and now am quite
comfortable both with the beauty, and knowing just a speck of what it is that I
am enjoying.

I feel the same way about telescopes now. As most of you here likely already
know, this is not a new thing for me. I have obsessed over telescopes for
years. I think (at least I hope) that I am finally reaching the point where I
can see the 8" APO and the 10" Dob for the apple and orange that they truly
are.

I have done countless side by sides between all of my scopes, especially the 6"
APO and the 10" Dob.

I truly feel that this time between the 8" APO and the 10" Newt, there will be
just the one night of comparison, I give up.

A friend asked me if it was "worth the wait." Yes, it was worth the wait. This
scope is finally good enough for me just the way it is, and I feel no
compulsion to put it (or myself) through any more rigorous and ridiculous
comparisons, or to spend another moment going over it with a fine toothed comb.
It has passed its side by side, and its first nights out under the stars with
flying colors. IOW, so far, so good and "good enough," for that matter.

I even think I might have got more than I paid for, as odd as that may sound.

Last side note:

I think that sometimes it is possible to create an instrument that performs
well on the bench, but the mechanics handicap its performance in the field.
Based on what I have seen with this instrument so far under the night sky, I
must say that it appears to be fully performing as well in the field, as it
must have done on TEC's optical testing bench. The specs to which it was
reportedly manufactured were exceedingly high, and for these specs to translate
so well to my eye under the night sky at 40 degrees F and dropping, is a
profound accomplishment; my hat is off to TEC.

As far as this humble test pilot can ascertain so far, this telescope appears
to be essentially a perfect instrument.

Did I already say it? I'll say it again; I think I have finally found Telescope
Heaven.

Very impressive, TEC guys,

I can hardly wait for Jupiter...
rat
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t (Ratboy99) wrote in message ...
RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

big snippo here

Beauty is in the eyes of the beholder... Expecially if he/she spent
mounds of greenbacks on the item of his/her love.

Andrea T.

Telescope Heaven..!!!

Thanks for sharing.

Edd Weninger

RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

Way to go, Rat! What'd I tell ya, you would love it?

Rolando

Way to go, Rat! What'd I tell ya, you would love it?

Rolando

Yes, you most certainly did steer me right.
rat
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Beauty is in the eyes of the beholder... Expecially if he/she spent
mounds of greenbacks on the item of his/her love.

Andrea T.

Thank you, Andrea, true to form as always.
rat
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t (Ratboy99) wrote in message ...
RAT NOTES - TEC 200 MM F9 TRIPLET APOCHROMAT - 09/01/04

Well, it's been a long journey to get all the way from my first 8" SCT, to the
Televue Ranger, through three Dobs, and another 2 (8" - again, and 11") SCT's,
of course interspersed with three (or four) more refractors, and finally here
- my very own 8" APO refractor.


An EIGHT INCH APO refractor?! Holy hawkdick!

Hey nice post... I'm a little jealous.

Have to ask though, how much did the OTA cost?

And do these TEC people have a website?

Happy observing, -Eric

Uh, just found the TEC website:

http://tec.idcomm.com:8888/tec_us/index.html

(as if you didn't know).

If I had $5K to spend I'd consider the APO 140. Looks like
the 200mm APO is ~$16K - less than the price of a new car
and money well spent.

-Eric