Telescope Reviews, Page 5!
By Ed Ting
Updated: 9/18/00

You Know You're Really an Equipment Freak When...

 Less than 2 months after taking the photo at the top of "Page 4," you
 now have a room that looks like this...




Click on a Scope Below:
 Astro-Physics 155 EDFS
 Intes-Micro 8" f/6 Maksutov-Newtonian
 Astro-Physics Traveler
 Questar 7 (Brief Impression)
 Orion 80 mm EQ Ultra
 Celestron G5 (Brief Impression)
 TeleVue Renaissance (non-sdf)
 Starmaster 7" f/5.6 Oak Classic



1) Astro-Physics 155 EDFS
(155 mm f/7 apochromatic triplet, OTA only, w/case, $5400)
(Note: See related article)

Another masterpiece from the pen of Roland Christen, this 6" refractor boasted
perfect optics like the AP 130 EDT - no spherical aberrations, no false color.


The AP155, on the AP900 mount

When you first see this telescope, it looks surprisingly compact for a 6"
refractor.  The case doesn't look any larger than the 130 EDT's, and indeed
the 130 and the 155 (and the Star 12, for that matter) all have focal lengths
between 1,000 mm and 1,100 mm.  This was perhaps done on purpose.

Once you lift the OTA, however, you realize it is one serious chunk of metal
and glass.  For such a stubby tube, the OTA weighs in at 23 lbs, and will
just barely work for visual use on a GM-8 (for photography, get something
bigger.)  There is some major baffling going on inside the tube.  I counted
three "big" baffles, surrounded by as many as twenty other minor baffling 
ridges.

All of that glass means a longish cool-down time.  In mid-September here
in NH, it took the lens about an hour to stabilize.  We experienced first light
with the scope's new owner, alongside the big Meade 178ED, the 12.5"
Portaball, and my C102HD, which I am still testing.

The optics are simply first-rate.  In times of steady seeing, I could make
out tremendous detail on Jupiter's cloud belts.  The scope seemed to know
no limits in terms of magnification; it soaked up shorter and shorter focal
length eyepieces until the atmosphere and the GM8 began to give out.

Compared to the Meade 178ED, the AP 155 was slightly sharper.  The Meade
does throw up a minor purple halo around bright objects, while the AP was
completely (and impressively) color-free.  The Portaball saw deeper (in 
the Veil, for instance) but didn't quite have the resolution of the AP on 
planets.  Finally, my poor C102HD, which I still consider to be a major 
bargain, was simply outclassed in this exclusive field, and I wound up 
capping it up in mid-evening.

So, should you buy an AP155, or the 178ED?  With the AP on a GM8,
the two scopes are nearly the same price (you really need at least a G11
mount, however.)  The Astro-Physics has better optics, but the Meade
gives you a lot for your $6800, including Goto drives.  AP does have their
own Goto system, which is the best in the business, but it's expensive.
AP refractors have virtually perfect QC, while the Meades tend to vary.
Then there is the portability issue.  The AP handles like a 4" refractor,
only heavier and fatter.  The Meade is a Really Big Telescope.  There is
something like a 3:1 bulk differential between the two scopes (176 lbs
for the Meade, 60-something lbs for the AP/GM8 combo).  

Those with deep pockets can consider the AP 155 EDF, which is the
same scope with a 4" focuser and field flattener, and weighing in at 27 lbs,
for $6800.  Be warned, there is currently a long wait (a year or longer)
for this, or any other Astro-Physics telescope.

This scope is as good as it gets.  If you can't afford one, at least make it
a point to look through one someday.


2) Intes-Micro 8" f/6 Maksutov-Newtonian
(8.3" f/5.8 Mak-Newt, OTA only, $4300)

Another specialty item, this limited-production scope boasts superb optics.
I detected only a trace of undercorrection; the scope's images were razor-
sharp.  The term "refractor-like" kept coming up during our observations.
In fact, it is better than some highly-touted refractors I have known.

Again, if you're not familiar with the design, a Maksutov-Newtonian works
similarly to a conventional Newtonian, except there's a Maksutov corrrector
plate in front.  If you didn't look down the front of the tube, you'd think it was
a normal Newtonian.

The scope is extremely well-built, and almost overbuilt.  A glance down the
front of the tube reveals some serious baffling (it almost looks over-baffled.)
The secondary has full tilt controls.  The focuser is a low-profile unit, with 
course/fine knobs, and there's a cooling fan at the back end of the tube. The
OTA is heavy, and you will need something on the order of a GM11 to hold
it (forget about the GM8.)

On Jupiter and Saturn, the Mak-Newt was still sharp at around 300X with
a binoviewer.  It takes magnification well, and the only reason we stopped
at 300X was due to atmospheric conditions, which were not ideal.  It held
up very well against the Meade 178ED and the AP155EDF.  Depending on
the magnification used, and who you asked, any one of the three could be 
considered the "best."

Maksutov-based designs have something of a cult following, even today
when they are entering the mainstream.  There is nothing inherently special
or superior about the Maksutov concept, it's just that all of those spherical 
surfaces are easier to figure to precise tolerances.

You already know if you want one of these.  The Intes is an outstanding
example of the Maksutov art.


3) Astro-Physics Traveler
(105 mm f/5.8 oil-spaced triplet apochromat, OTA only, $2900)


The Object of Your Desire:  The AP Traveler

Everyone seems to want an Astro-Physics Traveler these days, and it's not
hard to see why.  The scope boasts outstanding performance in an incredibly
compact package.  If you haven't seen one, it is hard to describe just how
small the scope really is.  The soft-sided carry bag (included) is about 21"
long, and has about the same dimensions as the Pronto's case.  Thus, it is
an ideal travel scope.

However, the Traveler's optics are in a whole other league, compared to the 
Ranger/Pronto duo.  The scope shows no chromatic aberration, and the sam-
ples I've seen were either perfect or had very slight undercorrection.  The scope 
is overbuilt and sculpted like a work of art.  My only minor quibble is with the 
focusing knobs.  As beautifully-made as they are, they're slippery and slightly 
less functional than the ones found on Takahashis.

If you love to look at wide-field deep sky vistas, the Traveler is for you.  The
North America nebula is nicely framed, and with a 35 mm Panoptic and
a 2" OIII filter, all sections of the Veil are easily visible.  One look at M8
and M20 in the same field with a UHC filter will make all your cares about
its cost go away.

As well as it performs on deep sky, the Traveler's planetary performance is
usually underrated.  The little 105 mm scope takes magnification quite well.
The only disadvantage is that with only 610 mm of focal length to work with,
you wind up resorting to short-short eyepieces and barlows pretty quickly to
boost the image scale.  Still, the atmosphere usually gives out before the 
optics do.

This scope gives images rivalling (and some say exceeding) that of the Taka-
hashi FS102.  Propective buyers should be aware that your $2400 buys you
the OTA only -- the finder and diagonal are extra.  Also, there is a two year
or longer wait to get one.  Prices for used units are currently running higher
than the MSRP, so pay your money and take your choice.

If you have been considering the purchase of a Traveler, here's my advice: Get
in line, do it and be happy.  You're not getting any younger.

Update, 6/00:  I took delivery of my own Traveler recently, having waited over 
2 years on AP's waiting list.


4) Questar 7 (Brief Impression)
(7" f/14 Maksutov-Cassegrain, OTA only $5,255-$10,870, depending on options)
 
"Ed, there's a public star party at the school observatory tonight.  We need
someone to run the Questar 7.  Can you be there?"

Questions like this don't have to be asked more than once.  I was there an
hour early.  This particular Questar 7 was purchased used by the school,
and appeared to be about 20 years old.  An adequate mount, using most
of an old undriven Edmund Scientific pedestal, had been fashioned for it.

I wound up tracking the scope by hand, which, with a nearly 2,500 mm focal
length, got to be a bit annoying.  It did, however, give me lots of excuses
to look through the scope ("Here, let me center that for you - ah, um...what
a nice view.")

I spent several hours with this Questar 7, showing it to the public.  There 
were puffy clouds and a light haze up above, so I spent most of the time
looking at Jupiter and Saturn.  I also had time to run a quick star test.

This particular Questar 7 had worked itself slightly out of collimation.
Since there are no apparent adjustments available (Questar's brochures
state that the instrument is permanently collimated) there was no way to
remedy this.  Also, there appeared to be some light throughput issues;
the 7's images seemed a little dimmer than they should have been.
Perhaps the surfaces are due for recoating.

If you've never used any of the scopes from New Hope, PA, there are a
few quirks.  There is a flip-in prism that directs light out of the bottom
of the OTA and serves as a 1X finder.  It's sharp, but susceptible to sky
glow.  Also, you are stuck with the screw-in Brandon eyepieces that have
the strange "pointers" spaced 90 degrees apart.  The Brandons are nice,
but it would have been nice to have the use of other eyepieces (no, I
didn't have one of the TeleVue adapters handy.)

In typical Questar weirdness, the eyepieces I had were labeled "40X-80X,"
and "80X-160X."  The two-magnification scheme is apparently for users
of the Questar 3.5, some of which have built-in barlows.  I could be mis-
taken, but none of the stated powers seemed to be close to the actual
magnification.
 
In spite of the above, this is an astonishing telescope.  The level of detail
visible (especially in the "80X-160X" eyepiece, when conditions allowed)
was nothing short of stunning.  During the course of the evening, some 
200 people stopped by for a look.  On more than one occasion, I had
someone remark to me that the Questar was giving the best images in
the field.  The other scopes available included the AP Star 12, the Orion 
(UK) 8" Europa, a 10" f/10 Cave, and an old C10.  When a member of
the public can tell the difference, that says something.  

A quick star test revealed no significant aberrations, although it did
confirm the scope's mis-collimation.

I had no idea that any catadioptric could be this good.  If you didn't tell
me what kind of scope I was looking through, I would have told you it was
an apochromatic refractor in the 6" range.  Moreover, it is scary to think 
how well this telescope might perform if someone were to attend to some
of its needs.


5) Orion 80 mm EQ Ultra
(80 mm f/11.3 air-spaced doublet refractor, 6X30 finder, manual EQ mount,
diagonal, 9 mm and 25 mm Kellners, NLA)

I've seen a couple of these now.  While one was OK, the other one had some 
problems.  The design of the whole scope looks as if it was pieced together
from surplus parts.  The mount is shaky, and really more suitable for a 60 
mm - class refractor.  The 80 mm is a bit too much for it.

Also, the focuser is fitted into a drawtube that is not lockable.  If you put a 
Nagler or Panoptic, etc. in it, the whole drawtube could come sliding out on
you.  Be careful!  The focuser itself is not terribly smooth, and the eyepieces,
while acceptable, should be replaced in short order. 

The one OK unit I saw had passable optics.  There's some chromatic aberra-
tion, as you might expect.  The other unit I saw seemed as if the lenses weren't
quite squared on, and was severely overcorrected.  Also, images in both units
seemed a little dim for an 80 mm aperture.

Approach with caution.  Note: scope is NLA, get the Skywatcher 90 ($359) or 
the Explorer 90 ($339) instead.


6) Celestron G5 (Brief Impression)
(5" f/10 Schmidt-Cassegrain, EQ mount, 6X30 finder, 25 mm SMA, CD ROM
$689, $749 with drives - street)

Celestron turned heads again this year with the introduction of its G5,
which houses C5 optics in a newer, less-expensive OTA on a German 
equatorial mount.  The biggest surprise was the price, which represented
a 25%-35% drop over the older fork-mounted version.  Keeping in mind
that many C5 owners bought tripods for their scopes anyway, the price
difference is closer to 50%.

As a result of all this, the G5 is getting a lot of attention.  But how
good is it?  I have only seen two of them briefly, and both in daylight.
There's very little image shift, and the view seems sharp across the
field.  As soon as I can get one of these under the stars, I'll report
back.

Update: 11/22/98 Finally had a chance to use the G5 under dark skies!
The scope is very cute, about the size of a thermos bottle, only fatter.
The optics were slightly overcorrected, nothing serious.  The images of
Saturn and Jupiter were sharp and showed good detail.  It took a while
- about an hour and a half - to cool down, which is more than you might
expect for such a tiny scope.  The supplied motor drive works well.

The G5 is a good value in a small, portable scope.  Its optics are good,
and the aperture is more generous than many traditional travel scopes.
Recommended. 


7) TeleVue Renaissance (non-sdf)
(101 mm f/5.5 or f/5.4 brass refractor, OTA only, $1349-$3495 depending on
vintage and version, this model NLA)


A Real Looker: TeleVue's Renaissance

"Ed, you need another 4 inch refractor like you need a hole in the head."

"Some of those older Renaissances weren't so good."

"You're going to have to sell a bunch of scopes to pay for this."

Those comments echoed through my head as I wrote the check.  But,
like a teenager listening to his parents objecting to his latest girlfriend,
they only partially registered in the recesses of my mind.  I was in a
daze.

...That daze goes back to 1985.  At the time, I was a poor college student
flipping through astronomy magazines.  One day, I saw an ad for the Renai-
ssance, a beautiful 4" refractor in a brass tube.  I have thought about owning
one ever since.

The Renaissance uses the same four-element-in-two-groups configuration
on the Genesis.  The objective operates at around f/12, and the field flat-
tener near the focuser brings the optical train down to f/5.5.

Early versions from TeleVue's Pearl River Days were f/5.5.  Later versions
were f/5.4.  The move to the f/5.4 seems to coincide with TeleVue's move
to Suffern around 1993.  At that time, TeleVue added a sliding dew shield
and an easier-to-adjust tube ring drilled for the new 1X finders, which were
just becoming popular.  Also, these later "sdf" versions had a fluorite 
element in the field flattener, which increased in size from 60 mm to 66
mm.  The sdf versions have superior color correction and are more desir-
able as a result.

Mine arrived well-packed from the seller, and I placed it on the supplied
Super Polaris mount.  It's a real looker.  Just seeing it set up makes
you want to go observing.

I noticed a problem with the focuser almost immediately.  There was
way too much play in it, and in certain positions it would not rack in
or out at all.  I called TeleVue and discovered, after answering a few
questions, that three teflon spacers inside the drawtube were missing.
I cut my own teflon spacers, and the focuser seems good as new now.

There's some chromatic aberration on Jupiter, but it's not as bad as on
my Ranger.  The purple is a darker, more subdued shade than on the
Ranger.  Planetary detail is impressive, although you start resorting to
short focal length eyepieces and barlows pretty fast to boost the image 
scale.  The scope is fun on deep sky, with a 32 mm Plossl, which yields
a 2.9 degree FOV.  A 35 mm Panoptic will throw up a bright 4.25 degree
FOV.

Potential buyers of these older f/5.5 versions should be aware that Tele-
Vue has limited parts available for these units.  Also, the false color is
somewhat worse than the newer f/5.4 Genesis and Renaissance models. 
Finally, you are going to have to find a way to keep the brass tube clean
(it collects fingerprints.)

By the way, TeleVue warned me NOT to varnish the brass.  They have
never done so, and probably never will.  The varnish has the potential to
ruin the finish.  As a protective measure, they told me to clean the tube
with brass cleaner, and then wax the tube with car wax twice a year.
Potential Renaissance owner, take note.

These older units are good telescopes and are available second-hand at
reasonable prices.  However, I think unless you are a "telescope geek"
like I am, you are probably better off with any of the newer f/5.4 versions.

The Renaissance has a typical personality for a TeleVue telescope.
Even for its day, it was an excellent product, but perhaps a hair below
the exalted best from Astro-Physics and Takahashi.  However, the Tele-
Vue scopes make up for this by having a sense of "fun" that these more
"serious" scopes lack.  I find that I am a bit less serious, a bit more friendly
towards my fellow astronomers, and observe at a somewhat slower pace,
when using TeleVue telescopes.

And I think that's the way Al Nagler would want it.


Renaissance Close-Up

Update, 11/24/98 It's a good, but not great planetary scope.  Its optics are
about the level of my fine C102HD, and below that of the Takahashi.  However,
with a 13 mm Nagler or the 35 mm Panoptic, the Renaissance is a stunning
wide-field deep sky scope, and that's the way I think I'll use it.

Scope Trivia: If you wear a wool coat while observing, this scope will give you
an electric shock.  Unfortunately, the shock is delivered to the part of the body
nearest the scope, which happens to be (usually) the nose or the part of the face
nearest the eye.  Ouch.  I watched this happen again and again at a recent star 
party.

Update, 12/7/98 By strange coincidence, a friend purchased another f/5.5
Renaissance less than one month after I got mine.  His version is a little
different.  Mine is the earliest version, with the tube ring split on one side
and the focuser held on by four allen bolts.  His version has the tube ring 
split on both sides and the focuser appears to be threaded on, like the
newer Genesis and Renaissance models.

I mention this because his "newer" f/5.5 Renaissance is slightly sharper, and
has less false color than mine.  Buyers should keep in mind the differences
between these models.  It seems as though I have become something of an
unwitting "expert" on these older scopes; e-mail me if you are confused.


8) Starmaster 7" f/5.6 Oak Classic
(7" f/5.6 Dobsonian reflector, Telrad, choice of focuser, $550-$950
depending on options, NLA)
(Note: see related article)

Extraordinary telescope.  At first glance it looks just like a typical 6"
Dobsonian, but it's not.  Both the optics and the mounting are far better
than your run-of-the-mill cheap Dob.  The mirror is a super-sharp Zambuto
unit mounted in a remarkably airy and open mirror cell (it almost looks 
like there isn't a mirror cell) with large plastic thumb screws that facil-
itate, even encourage collimation.  The rocker box is made of red oak,
and is well-finished like a fine piece of furniture.


A perfect little telescope - the 7"
Starmaster Oak Classic

The tube rests in a square wooden form.  This setup is more rigid than the 
typical plastic bearing-on-Sonotube configuration.  Also, it allows the use
of much larger altitude bearings.  As a result, the action is very smooth,
with just the right amount of "sticktion."  Large eyepieces do not affect the
balance, even when the scope is pointed down near the horizon.  The scope
is a pleasure to pan around the sky.

This unit had slightly undercorrected optics, and was slightly out of coll-
imation as well.  In spite of this, the mirror produced razor-sharp images.
If it wasn't for the diffraction spikes around brighter objects, you'd think
it was a refractor.

We looked at lots of stuff during a 5-hour observing session.  Also present
were a Ranger, a 3" 1950's era Unitron, and Meade's new 102ACHR/500.
As much as I like refractors, the Starmaster outclassed them all.  The 
scope split Zeta Aquarius, Alpha Pisces, Castor, Epsilon Lyra, etc.  On 
deep sky (the Veil, M57, NGC7331, M35/NGC2158, etc) there is impres-
sive contrast and very little of the edge-of-field aberrations found in typical
Newtonians.

It was only on the planets that the little Starmaster fell short.  The refrac-
tors showed a little more "snap" to their images, and the diffraction spikes
got annoying on Jupiter.  However, there was still impressive detail avail-
able, and the images are about as good as you can get from a Newtonian. 

Complaints?  A few minor ones.  The Sonotube is well-finished in a kind
of "starry" wallpaper, but it is Sonotube, which seems a little out of place
on a premium instrument.  Also, there are no end rings - neurotic owners 
might worry about fraying.  The scope is short, so you need a chair (but 
it's just right for small children.)  And it costs twice as much as your
typical 6"-8" Dob (but I think it's easily worth the extra money.)

There is nothing like a long observing session to bring out the personalities
of a scope and its users.  I'm into deep sky, while my friends like splitting
double stars.  As the night wore on, we literally begin speaking different
languages.  I start talking in four-digit numerals, while my friends start
using lots of Greek letters.  The Starmaster turned out to be just fine for
both applications.

If you run across one on the used market, grab it.  There were only about
150 of these made, and although only the last 40 or so had the stunning
Zambuto optics in them, all samples are worth acquiring and collecting.  

I'm very impressed.  Rick Singmaster has apparently stopped production
of these units, which is a shame.  For a portable scope (you can carry
the whole thing outside in one trip) I cannot think of a better choice.
I was on hand this night to watch the scope change hands, and if the
new owner hadn't bought the scope, I might have done so myself. Highly 
recommended if you can find one.



Home Page