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

From: Shady Wheaton (swheaton_at_austin.rr.com)
Date: 09/05/04 

Date: Sun, 05 Sep 2004 01:54:31 GMT

Congratulatons Rat. Sounds like a great scope. My wife always tells me
to get what I want for my hobbies as I wouldn't enjoy them as much if I
kept putting thingds off. I like what I keep hearing about the TEC's as
well as the 24 PAN's. I've been using sets Nagler T-6's, & a set of
Celstron 30mm Ultimas in my binos with my different scopes and have
thought of a set of 24 Pan;s also. I have a pretty servere astigmatism
in my left eye to contend with and tend to get differing spike patterns
on stars also. I realy like my Vixen LVW's in cyclops mode too. At my
age the ER is just another feature to be enjoyed. I just had an eye
appt. a few weeks ago and discussed a lot of specifics about my eyes and
hobbies, as you alluded t,o with my optometrist, and she made me a set
of glasses specifically for using with scopes and other activities I
would do at infinity and they really seem to have helped. I even enjoy
my binoculars more now. Can't wait to hear your Jupiter reports. It's
one of my favorte targets. I like the variability and changes in the
shorter period of time. Excellent report. Thanks.

Shady in Ausitn, TX

Ratboy99 wrote:

>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 ***) 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
>
>

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