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SV90TBV SV90TF - Customer Comments
Yesterday I received my eagerly anticipated SV90TBV. So in the evening time after fulfilling my family obligations, I set up the SV90 €¦.
Let me preface this by saying I am in no way an optical expert. Nor do I purport to have extensive knowledge with star testing. I just want to post my own thoughts and experiences. They are my personal
opinions and observations only.
Vega was almost directly overhead so was an ideal target for the star test. Incidentally, I just love to compare telescopes! This is the first time that I've spent more than 30 minutes star testing a single
telescope - the SV90T. AP Maxbrite and Tak 2.8 were used to achieve 225x. Conditions were excellent for testing. I'm not going to bore everyone with details such as concentric fresnel rings on both sides
of focus, clear and defined, etc - it's just so played out. Let me just say this: I cannot detect any difference inside/outside of focus. My eyes cannot detect differences when the optics are better than 1/10th wave, so I am going to say that the SV90T's optics are better than 1/10th wave. How much better? I don't know and would not dare to venture a guess. Rimming the outermost ring can be found the barest hint of violet inside of focus and a touch of green outside of focus. In focus at 225x on the brilliant white Vega - no false color. Not the "false color comes and goes with seeing" usually attributed to apo doublets...but ZERO chromatic aberration. The reason I spent 30 minutes just testing the SV90T is because I REFUSED to not be able to assess the level of correction for this optic. Usually I want to know if it's under/over corrected. If forced to, I'd say undercorrected, better than 1/10 wave. But I wouldn't be my
life on it. The optic is that good. I would really love to see an interferogram for this objective. I've never been so enthralled while doing a simple star test!
Truly...thank you Vic Maris!!!!
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> For a couple of months, I have had a 90TBV blem reserved. Since my
> partner has another telescope on order, I figured we would drive to Auburn
> and get them when both were ready. Well, I got impatient. Last Wednesday
> (Feb 3), I contacted Stellarvue to verify that the 90mm was indeed ready and,
> since we would be in Sacramento on the 5th anyway, that we could stop by
> Auburn to pick-up the telescope.
>
> The new-telescope curse must have been in full force, as Thursday's
> weather forecast indicated clouds, rain, and possible thunderstorms for the
> following several days. However, the curse seemed to extend beyond simple
> meteorological phenomena. While preparing for the trip my mind seemed to "go
> blank" whenever I tried to figure-out what I wanted/needed to take.
>
> Friday morning was mercifully dry as we loaded our van for the trip. It
> seemed a good omen, as the forecast had promised a whole day of rain. Into
> the van went our Nighthawk Aplanat and F50 finder, about which I had a couple
> of questions. Some suitcases, an ice-box for refreshments, and
> other "mundane" objects accompanied the telescopes. The van's oil was a
> quart low, so I topped it off for the trip; then I filled the
> windshield-washer tank with water. So far, so good.
>
> The first sign of the new-telescope curse was a rumble deep down in my
> stomach, shortly before our departure. I figured it for nerves, and went out
> to the van. The second sign was that the van would not start. We tried
> turning the key a few more times, with no luck. This meant that we had to
> pile everything in the Jeep. The Jeep was almost out of gas, surely the
> third sign of the curse.
>
> The next sign was my feeling queasy as we approached Sacramento for a
> brief stop. As we exited the highway I suddenly felt very car-sick. The
> swooping off-ramp made the sensation worse. Continuing to Auburn I again got
> car-sick on the exit ramp.
>
> Entering the Stellarvue offices, the earlier indignities were quickly
> forgotten. Vic's greeting was, "You can't get that thing to focus, right?
> We have an adapter to fix that." He had noticed me carrying the F50 in a
> home-made holder with a camera in place of the eyepiece. Vic retrieved a
> small brown box from the back room. Out came what looked like a newborn
> Barlow, it was so tiny. The adapter, Stellarvue #BVA, screwed into the
> filter threads on the camera. It remains untested because of the weather.
>
> Next came the main event- the TBV90-- What a beauty! It's black, so it
> goes with the rest of my equipment. Vic asked me if I had any questions
> about it. My questions were answered thoroughly and quite patiently.
>
> Our discussion was interrupted by a nearby train, signalling for a bridge
> crossing. I wanted to go to the windows to take a look but could not see
> anything for the herd of telescopes and tripods that "blocked" the view. It
> turned out that the woman assembling F50 finder-scopes at the corner desk was
> also something of a rail-fan, having grown-up near a railroad track as had I.
>
> We produced the Nighthawk Aplanat, about which we had a question. Last
> time the skies were clear, I do not remember when, I could not get any kind
> of image from my camera. Checking the "usual suspects", we verified that all
> lens caps were removed and that power was on. Then I tried the low-tech
> approach of actually Looking Through The Tube Without An Eyepiece. The
> normally circular view down the tube's axis was an oval, like the objective
> in a feline eyeball. After taking down the equipment, and one mood-swing
> later, we set the tube on our kitchen table to see if the problem was
> something simple that we could repair. The problem turned-out to be what
> looked like a baffle-ring that had come loose. My partner fished it out and,
> figuring it was in there "for a reason", we re-inserted the baffle-ring and
> pushed it in a ways. It was a relief to find a simple fix to the problem; in
> the future we could do the same thing it it happened again. My theory was
> that I have a Celestron variable-Barlow that is quite long, and that I may
> have dislodged the ring at some point. Over time the ring then migrated to
> the far end of the focuser-tube and then tilted, giving us the cat's eye view
> of the universe.
>
> Anyway, I asked Vic about the baffle-ring because I intended to just
> leave it out of the focuser if the telescope's performance would not be
> affected. Vic took out the baffle-ring and lined the focuser with black
> velvet while we waited! After installing the velvet Vic dubbed the
> long-unnamed Nighthawk "Elvis".
>
> The adventure was not yet over, nor were the telescope gods finished
> playing with us.
>
> We returned home on Saturday, with another round of car-sickness for me.
> After we unloaded the car I tried to start the van, figuring that, since we
> no longer needed it for the trip, it would likely start. It did not. The
> day had been cloudy and rainy all day, so I decided to sleep-off the
> car-sickness. I woke up just after sunset with the sky clearing. The
> humidity was the next best thing to actually being underwater but we decided
> to try looking at Mars, to test the 90mm.
>
> **** WHAT YOU HAVE ALL BEEN WAITING FOR *****
> THE FIRST/SECOND-LIGHT REPORT!
>
> We set-up the Orion Atlas on the front yard, with the clutches disengaged
> and no power so that we could just move the telescope or hold it in position.
> Mars showed as a tiny, brilliant, peach-colored disk in the eyepiece, using a
> Meade 26mm eyepiece that had come with our LX200. We had to use an
> extension-tube to get a good focus. With a 4X Barlow we could see some
> surface detail. I thought I could see a dark band near the "upper" (I guess
> it would be south) pole but my eyes do not seem very good at picking out
> these things. The disk was very steady and clear, without the "usual"
> fuzziness but the surface detail kept dancing in and out of my view. This is
> why I generally just use a camera on the telescope. My partner, with better
> eyes than mine, reported definite surface details and later showed me some
> Mars pictures in a magazine that resembled the telescopic view. The picture
> showed the brown band that I thought I saw, along with a mostly vertical
> patch below it that I also thought I saw. No ice cap showed in our view. Of
> course, the clouds rolled in before too long so we took the equipment back
> into the house.
>
> Sunday night started similar to Saturday night, with the clouds
> clearing-out as the Sun set. We set-up the Atlas in the back yard this time,
> laying down tarps and boards because of the mud. After doing a polar
> alignment we did a one-star alignment on Sirius, which showed as a brilliant
> pinpoint. Our first object was M42. The trapezium was tiny yet beautiful,
> outlined with four pin-point stars, and we could see a bit of the nebula,
> although it appeared to me a bit washed-out because of the sky brightness.
> For grins I dialed-up M1, M64, M67, and M74. I thought I could see the
> faintest of patchiness around M1, but the others were invisible, victims,
> presumably, of my astigmatisms and my area's Bortle 7(red) skies. Any
> visible stars near these objects were focused right down to pinpoints.
>
> When Mars finally cleared the house and trees we took a look at it. The
> planet appeared to me the same as the previous night, which makes sense
> because its day is similar in length to ours. Unfortunately, the mount
> stopped responding to commands from the hand-controller, so we had to
> power-cycle it and re-align. After that, Mars stayed in the field-of-view.
> The Feather-Touch focuser with the speed-reduction made focusing a LOT easier
> while we were using the 2X Barlow with a 4mm Nagler eyepiece, compared to the
> Nighthawk with its rack-and-pinion focuser. Using Barlows had always been
> frustrating for me because it was so easy to miss the focus-point but the
> Feather-Touch made focusing even this combination pretty painless.
>
> We then moved on to the Beehive cluster since it was near Mars. I only
> saw a few stars until I removed the Barlow and replaced the 4mm Nagler with
> the 26mm Meade eyepiece. I could not discern the cluster; it just looked
> like a bunch of stars. My partner asked me how many stars were in the field;
> when the count passed twenty I was informed that this was indeed the Beehive.
>
> Next was the Pleiades. It was kind of overwhelming, not the nice little
> bunch of stars I was used to seeing in the Nighthawk. The view was packed
> with stars, bright and dim!
>
> For our last object we dialed-up M42 again, just to try the 4mm Nagler
> and Barlow on the Trapezium. Again, the two-speed Feather-Touch came in
> handy. The Trapezium appeared much larger (duh!) but was still pretty easy
> to focus. We put in a 31mm Nagler "hand-grenade" to look at the whole thing;
> once again, I was awe-struck!
>
> With clouds mounting an assault from east and west and everything getting
> wet, we decided to give-up. But it was a good night. As we brought the last
> pieces into the house I glanced at the clock; it read 9pm.
> While we were at the Stellarvue offices a gentleman was picking-up a
> 130mm telescope but the "right" case was out-of-stock so they padded-up
> another case to hold it. After reading the "Oh, Yeah!" messages it occurred
> to me that he may have been Mr. Jewell, who received the same fantastic
> service we did.
>
> I continue to be awe-struck at the thought of the owner/president of a
> company personally providing such service. The "other guys" talk about
> Kool-Aid and StellarZombies (my word) and such but I think it's just
> StellarEnvy.
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I have a 90TBV and the earlier Stellarvue BV1 binoviewer, and am quite
pleased with the performance of the system. I previously owned a 10"
Discovery Dob for several years, so I feel like I'm in a pretty good
position to offer comparitive reports. You won't see the detail in
the DSO's that you see in the Dob because aperture does rule,
especially when comparing 10" to 3.5". But you will be surprised at
what you do see. The contrast in the fluorite triplet is amazing, and
the background sky is totally inky black, both of which make even dim
DSO's pop out and become visible beyond my expectations. To really
take advantage of the high powers needed when viewing planets, you'll
probably want to stick to cyclops mode, but the moon and brighter
DSO's are outstanding with the binoviewer and medium powers. You'll
be amazed at the detail you'll see in Jupiter and Saturn at 150x to
200x in the 90TBV, and a leisurely scan down the terminator of the
moon in bino mode is a mind-boggling experience.
Oh yeah, my Dob? After my first Stellarvue apo (an SV85S), I sold it
because it was just gathering dust.
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I also have the 90TBV and you will have to pry this scope from my
dead fingers to ever get it away from me. It's just an incredible
scope. The sharpness and contrast are amazing, the best I've seen.
Jupiter and Saturn are excellent through it, even when sky conditions
are less than optimal. I've pushed the power on Saturn up to 250X on
good nights and the image holds up very well. As was also mentioned,
double stars are a treat through the scope, very sharp, lots of color
and very dark sky for a background. I spend some nights doing nothing
but doubles with it.
I guarantee you will love the scope, its a real winner and worth
whatever wait there is. A one of a kind scope IMO.
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Finally got the scope out of the city Sat. night, to a family stargazing event. Not quite dark skies, but still
managed to add M92, M81, M82, and M101 to my list with this scope. But the real
thrill was to see and hear the kids' excitement at viewing Saturn and,
especially, the moon at high power with spectacular resolution. That never gets
old.
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If you can swing the extra hit
on the budget, I think you will really appreciate the extra
features of the 3 inch FT focuser vs. the 2 inch. The FT 2 inch
is the finest of that size that you will find anywhere, but the
3 inch has the threaded endcap options available, camera rotation
collar, approx. 10 lb camera payload, extra drawtube braking
mechanisms top and bottom....just an exquisite focuser. Throw in the
fluorite lens element of the SV90TF with it's superior contrast and
SA/CA correction and you have the ultimate imaging or visual
instrument for just $200 bucks more.
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