Monday, June 1, 2009

A users opinion (review): Tele Vue Pronto Part Two

Observing with the Pronto: Functions

With the correct mounting plates for whichever mount I am using it mounted on the clamshell, it’s time to look at the operating aspects of the Tele Vue Pronto. Focus is typical Tele Vue, butterly smooth. However I have noticed that this particular focuser may have a bit of image shift. This could be age or something is out of adjustment. A trip to Uncle Al (Nagler) of Tele Vue might be in store or is it something I can fix myself. Not sure yet. But it’s there at moderate to high power. Not really a big issue, not like older SCT’s. Clamshell adjustment to balance the tube is straightforward with one little twist of the wing nut. Not a lot of room to move the tube though because it is short. It remains somewhat bottom heavy on the SP mount because of the limitations of the adapter plate which cannot be adjusted. I might be able to adapt the balance plate with the SP plate adapter to alleviate that. Just haven’t tried that. The sliding dew shield/light shade is smooth without any issues. The Quikpoint is OK but nowhere near what a StarBeam could do. It’s a little small and can be hard to aim when the tube reaches an awkward position. On the SP mount the OTA looks over-mounted but it is quite the stable platform. The legs do not need to be raised too high as the OTA is short enough to keep the tripod lower. At only 480mm, this is quite the little tube compared to the 1000mm SP-C102.

Observing with the Pronto: Looking at stuff

I’ll get this over with now. It has false colour (chromatic aberration). Okay, I said it. Now here’s where it always go south. People tend to *demonize* a very well built refractor on this one big hiccup. Really, it’s not a big deal the actual false colour; but, if you are looking for virtually colour free or any aberration free system, be prepared to spend a mint on that refractor. No matter how you look at it, there are very few “essentially perfect” telescopes. I think, collimation, spherical aberration and surface roughness are less forgiving than colour correction. But it always seems to end up on this ONE thing. If it has a hint of blue out of focus, it isn’t “good”. That’s bunk. Personally, I don’t care.

Indications so far are that the scope is very well collimated with stars at high power being well rounded with concentric rings being circular when seeing permits. I have yet to have a really steady night to test real high power with this Pronto (my old one hit 600X one night). I did not detect the rough images that the C102 suffers at higher power. The entire image of a star at high power is smooth. Everything snaps into focus as it should. As noted there is a bit of image shift at powers greater than 75X but not pronounced enough to shift the field of view out of the eyepiece. Did I say it had false colour? Shhhhhh! Enough of that!
Lunar detail is always easy so I won’t spend much time on that. In fact, I’m done. But I did enjoy a nice view of the Appenine Mountains last night.

Planetary detail: Well we have only had Saturn to look at so far and the Pronto has delivered although I find the image a tad dim. Not a surprise given that the rings aren’t tilted the way we want it. I have seen at least two moons in the Pronto. Not bad. I have detected minimal false colour on Saturn...wait a minute, we’ve talked about that already...shut up you chromatic aberration demon!

Double Stars: The Pronto is stellar on doubles...hehehehehe...stellar, that was not intended now wasn’t it? I have enjoyed many doubles mainly because the optics are quite stable. Problems inherent in the C102 sometimes diminish my enjoyment of double stars, not that it isn’t enjoyable in it, but the Pronto being sharper adds to that although the aperture and thus, the resolving power is less. Porrima shows as a slight figure-8 and from what I have heard MIGHT be able to be split in it at super-high power during a stable night. Alpha Herculis has been glorious showing the components colour although some false colour is shown on the companion...BUT WHO CARES! Trickier doubles like Algeiba still split although with some measure of difficulty. Again, the smooth, sharp optics help. Easy doubles like Alberio and the cats eyes in Draco are a total pleasure with the Pronto and fun to share with people.

Deep Sky: It’s small. It’s not really a deep sky scope. But I can see where the 480mm focal length will come in handy (M31, M81+82 etc). It’s just that the scope has yet to enjoy a dark sky, so I haven’t got a whole lot to say about deep sky observing. However, seeing M44 and IC 4665 really look like open clusters. With the field of view of the Pronto at low power, this has been the case. But again, apart from this I can only remember deep sky objects from my old Pronto, which I won’t comment on.

Small Refractor Renaissance

Mini-meets: It seems that the arrival of the new-used Pronto triggered more city meets than previous most likely because we are all starved for observing but are not able to drive the hour long distance to a dark sky. Seems that a few of us have been more than willing to put up with the sky glow and just observe in local parks. It has also triggered a large following of small refractors ranging from 66mm to 102mm. Most of us have been checking out doubles, had a few "Galileo Moments" like finding Mercury or just sitting back enjoying the odd bright open cluster. But for some reason or another, more local observing has taken place since the arrival of this Pronto. Others blame it for all the clouds! I won't take credit for this surge in interest but it is possible that with smaller, more portable instruments, more observing will take place. The old *portability question*.

Daytime Use:
Thats another story, stay tuned for Part Three.

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