Notes from Under Sky

A Wocket in My Pocket

In which I review the Tele Vue Ranger

My birthday was earlier this month (September), and my wife Debby's gift to me was a trip to Woodland Hills, the local scope/camera store, with a budget of "a couple of hundred dollars." Very dangerous of you to leave that incompletely specified, my love…

I thought I might like an 80 mm short tube of some sort, so I gave Carlos a ring before going over to see what kinds he had. He told me he had the Celestron WA model, which sits on one of Celestron's light EQ mounts. I wasn't too sure about that.

As it so happens, I was looking at their ad in the October 2000 Sky and Telescope. They listed a Ranger/Pronto as "in stock," which I took to mean that they sell them at below MAP (minimum advertised price). I asked Carlos how much the Ranger was.

"Hmm, let me see. Oh, we also have a used one."

Ahh, the magic word, "used." We eventually settled on a price of $400, not to include the 20 mm Plossl (I have enough eyepieces, so this didn't bother me), but including TeleVue's travel bag, which apparently opens to allow the scope to be used in light rain. Debby had told me she finds the Ranger/Pronto duo "cute," which was a point in its favor…I think.

The Ranger and Pronto are optical clones, but the Pronto is higher up on the mechanical scale. The objective is a 70 mm doublet with the front element being the ED crown. Two other sites have already remarked on it being advertised as a semi-apochromatic, which I've never seen Tele Vue call it—perhaps they used to and have since withdrawn the claim.

My Ranger is a textured green tube that looks better in person than it does in the ads. As stripped down as it is from the Pronto (the Ranger OTA weighs just over half as much), it still feels well built. Looking into the objective end reveals an unbaffled spot from around the sliding focus tube, but it doesn't seem that any light from there will actually get into the image.

The first test I performed was on the sun's reflection off a fixture on a telephone pole. I would estimate it magnitude –8 or so; I bring it up only because the amount of purple in the image was, in my opinion, quite objectionable. I was concerned about how it would perform on the nearly full moon, which was at about magnitude –11.5 or so.

I needn't have worried. The telephone pole fixture, despite being dimmer than the moon overall, was much smaller and had a higher surface brightness. That night, with the moon nearly filling the field of view (6 mm Radian at 80x), the amount of purple was not enough to annoy any but the most discriminating of lunar observers (which I'm not). At the lunar limb, the amount of light scattering off the edge was minimal; the sky was nearly dark black at the edge, but not quite. There was surely enough detail for me to spend a couple of nights at. I suspect Venus might be a tad purpler than desirable, but the Goddess of Love wasn't far enough away from the sun sufficiently for me to test that out.

The planets were equally impressive in the Ranger. Saturn was up first, with Titan just about directly northward and easily visible, despite a magnitude 4.3 sky (my next-door neighbors, who I've invited over for a couple of looksees through Opus, my 5-inch SCT, were having a party). At 80x again, the rings showed quite sharply, with the Cassini division thin but rather easily seen nearly all the way around the planet. I think they could have been seen all the way around with higher power, and certainly the Ranger was loafing at 80x, but I couldn't seem to get the scope to focus with my Barlow and the 6 mm Radian. Perhaps I need another Barlow. Saturn's disc showed its mellow texturing, with a southern temperate darker zone separating the light cap from the lighter equatorial zone.

Jupiter was next, but it was too low in the sky. What to do? Simple: move the scope. One great advantage to the Ranger/photo tripod combo is that it's so light that moving it around to chase objects is actually an exciting and enjoyable activity, making hunting down objects a bit more like really hunting. I simply moved the whole assembly, which couldn't have weighed more than 8 pounds. It would have been possible with Opus, and in fact I have moved him around chasing gamma Virginis (and didn't capture it until the next night—another story in itself), but it's much more inconvenient.

Anyway, Jupiter was more impressive even than Saturn, showing the two dark equatorial belts and the NTB quite distinctly, and the southern polar zone could be seen to be textured (but what texture exactly I couldn't make out). I wasn't sure if I actually could see the GRS (which was past the CM by the time I was observing), but I suspected it toward the trailing limb. The four Galilean satellites were all visible on the preceding (celestial west) side, and though the discs the Ranger showed were nearly entirely due to diffraction, from the brightnesses I was able to identify them as (from nearest to furthest from Jupiter) Europa, Io, Callisto, and Ganymede.

Wide-field, low-power observing was just as good. The 32 mm Plossl I have yields 15x and the largest true FOV achievable with the 1.25-inch focuser that comes on the Ranger—a little over 3 degrees. At that power, the Double Cluster actually looked a little small. NGC 869 and 884 were not as impressive as they might be either from a dark site or through a larger scope (they seemed better in Opus from brighter skies) but with averted vision they still put on a good show. Even M31, the Great Andromeda Galaxy, could be seen handily in the Ranger; its wide true FOV underscores how small the nucleus of this spiral is. I thought I could see the larger central disc, but I wasn't sure of this. M15, a compact globular, showed up as a bright, fuzzy star at 15x. The Pleiades, of course, were brilliantly framed as in no other scope; I saw this particular view as perhaps the best advertisement this scope could have.

From a mechanical perspective, the focuser is my main complaint. The helical focuser is smooth and well-built, but can only be used for fine focusing; coarse focusing is done using a manual slide tube with a simple locking screw. This is awkward and I found myself running into the end of the helical focuser travel at the most inconvenient times. You can probably get better at this over time, but it is at least an initial stumbling block. I also wish the dust cap was a bit more robust—the Pronto has a nice metal screw-on cap—but at least the cap does lock on with springs.

The Ranger doesn't come with a finder; the argument is that a finder is superfluous on a scope with a potential true FOV of over 3 degrees. That's as may be, but it sure is a hassle to switch from long to short eyepiece as you move from target to target. The 8–24 mm zoom (sold by either Vixen or Tele Vue) is a big help in this regard. There is a screw hole pre-tapped for mounting a finder; Tele Vue suggests one of their red-LED finders.

Overall, I found the Ranger an excellent buy at $400; I think I would even have bought it at $500, if I were specifically looking for this scope. It's rugged and looks equally at home with terrestrial and astronomical viewing. And, of course, it's extraordinarily portable: I needed to give it a name, and at first I went hunting through my Bloom County compendiums for a suitable tag-along for Opus. In the end, though, I found my answer in one of my son's Dr. Seuss books, entitled There's a Wocket in my Pocket. It is practically pocket sized, it does have the power of a wocket—I mean, rocket—and best of all, it trips off the tongue perfectly. I'm sure prospective buyers will agree with me on that…well, two out of three ain't bad.

Copyright (c) 2000 Brian Tung