Tele Vue Genesis Review
I never intended to buy a TeleVue Genesis. In fact I had seen this one languishing in the classifieds for months before my mate Ian bought it at a knockdown price. At that time I was happy with my TV-76 as a grab-and-go scope. Then one thing led to another and I took a chance to buy my dream telescope – a TMB 175 – and traded my FS-128 to friend Ian in a deal that included the Genesis. Now Ian was very sorry to see the Genesis go and I should have been warned ...
Design and Build
Well four of them, actually, because of course the TV Genesis is a Petzval. I have written about Petzvals at length in the NP101 review. The Genesis is basically the same design, with a long focal length (probably natively about F10) doublet up front and a second doublet reducer-flattener just in front of the focuser to make four elements in total.
The rear Petzval lens reduces the focal length by about half (down to a very fast 500mm, F5 in the Genesis) and reduces the OTA length as well, but not by quite as much. This design allows greater freedom to correct field curvature and coma then most other designs, but it doesn’t correct chromatic aberration. The CA level of a Petzval is determined by the doublet at the front. Now the Genesis is labelled “fluorite”, but here that is a little disingenuous. In a Takahashi, the fluorite allows the doublet to be apochromatic, but in the Genesis the magic mineral is in the Petzval element, so the doublet up front is an ordinary achromat.
The punch line to this is that the Genesis is an achromat, albeit one with a fast flat field and reduced aberrations like a slower achromat might have.
The overall appearance of the Genesis is only subtly different from an early NP101. I actually prefer the appearance of the Genesis, but perhaps that’s just me. The tube is finished in ordinary gloss white, rather than the now usual Tele Vue textured powder coat and the sliding dewshield is white too, rather than satin anodised like the later ones, though it slides over a black anodised lens cell; oh and you get solid chromed focuser knobs instead of the trademark “Mag’ wheels”. Otherwise it’s a familiar formula to Tele Vue owners – short, slim OTA, chrome focuser tube running by smooth rack and pinion, screw-fit metal lens cap, textured interior without baffles, clamshell.
Genesis with dew-shield extended.
The focuser is nicely smooth and free from play, just like the one on my TV-76. More modern Tele Vues have beefier focusers adapted to take heavy cameras for imaging and with dual speed pinions. But as single speed rack and pinions for visual use go, the classical TV unit on the Genesis is about as good as it gets.
The Genesis has a clamshell more or less identical to a modern Tele Vue, with two ¼-20 threads on the base to fit Tele Vue mounts. So it bolted straight onto my Tele Vue Panoramic mount (and looked great). There’s a lot to be said for this type of consistency and compatibility. Using Tele Vue’s own dovetail, the Genesis can be quickly and easily swapped between a Panoramic or Gibraltar and a Vixen or Sky-Watcher mount, because the dovetail replicates the ¼-20 threads of the clamshell base; i.e. you don’t have to remove the dovetail to swap.
The TV-Vixen dovetail replicates the TV ¼-20 threads of the clamshell, so it goes straight on a Gibraltar head.
The genesis is a 4” refractor, but is short and light enough to go on just about any lightweight mount from an EQ5 up.
The genesis comes in a hard case, not dissimilar to the one for a modern Tele Vue, except that it’s brown.
Genesis in case: a very compact 4” refractor.
The doublet design of the Genesis means it cools quickly when you put it outside and is ready to use after just a short cool-down period. That makes it a handy quick-look scope.
I vividly recall the time I first popped a Nagler into the Genesis and looked at the Orion Nebula. Given the large number of times, before and since, that I have looked at M42 that’s surprising. The view was just amazing – so flat and wide with such pinpoint diamond stars right to the field stop; at last that space walk they talk about. I was hooked. The Genesis is a telescope for sweeping star fields, for brighter DSOs and clusters. The Pleiades has never looked better and Andromeda is particularly detailed with that wide field.
Consider that very few 4” refractors have focal lengths of 500mm or less and even fewer combine it with a flat field. Takahashi’s FSQ matches it and the only scope with less is the rare Pentax SDUF F4, but that is purely for imaging and very compromised for visual use, I have heard. So 25 years on, the Genesis is still a rare visual instrument – supremely fast bright and wide.
Moon and Planets
If star sweeping and cluster gazing are the Genesis’ glory (I always reckon that’s what Al’ Nagler must like doing best himself), the planets and Moon are its Achilles’ heel. The optics on the Genesis are first rate – very sharp, very contrasty, perfect collimation and snap-to-focus. The problem of course is chromatic aberration.
According to the theory I have read, Petzvals generally have objective doublets with about double their corrected focal length. That would mean that the Genesis should display chromatic aberration like a 4” F10 achromat. Now the rule about chromatic aberration in achromats is that to display “acceptable” CA levels, their focal length should be longer than about 1.22x their aperture in cm, which in this case would be about F12. So you might expect that the Genesis suffers from quite noticeable CA at higher powers; it does.
Above about 70x the Moon is surrounded by a pretty purple halo, whilst above that even crater shadows are washed in purple, though everything is otherwise very sharp and detailed. Repeat after me “it’s an achromat”.
Don’t imagine that the Genesis is unusable on the Moon, far from it. Whilst it’s not an NP101, it’s not a ST102 either.
High power planetary viewing is a very colourful experience with the Genesis, though in other ways the optics hold up under high powers. Unfortunately, used as I am to APOs, I find a lot of CA rather hard to take and seeing Jupiter embedded in Imperial Purple isn’t the way I like it.
I loved the Genesis on deep sky, but I like observing the Moon and planets too, so the NP101, which does both, was a natural upgrade path. I used to be very sceptical of TeleVue’s Petzval designs – thinking all that glass a pointless complexity - we live and learn. All Tele Vue’s Petzvals give peerless deep sky views, but unlike the NP101 the Genesis is pretty much a specialist visual deep sky scope. Someone recently said to me of the NP101 (and I quote) “Oh the sharpness. Open clusters are mind blowing through those things.” Exactly the same could be said of the Genesis.
After perhaps a quarter of a century of, I would say, very regular use, the Genesis still performed flawlessly. The focuser was smooth and precise, the optics pin sharp with collimation spot on. And it still looked great. Tele Vues are solidly built. People talk about a “legacy telescope” and I suspect that Genesis will still be delivering lovely views long after both Al Nagler and I have gone. True, it’s not an APO and the NP101 is vastly better in that respect, but for low to medium power wide-field viewing the Genesis is unequalled.
Confession time: on an emotional-attachment level, I think I liked the Genesis even better than the NP101, for reasons that I find hard to explain. I preferred its looks and I think it was slightly shorter; perhaps it was even flatter and more stunning on deep sky. Its quirky single mindedness gave it character. Interestingly, the friend I bought it from still regrets selling it and reckons it gave him his finest views of extended DSOs like M31.
If you mainly like sweeping star fields, then it’s highly recommended, just remember it’s not an APO, so price accordingly.