Imagination plus zoom eyepiece equals awesome observing

I've added the final piece to my ideal star-gazing equipment, a Vixen 8mm-24mm zoom eyepiece - and in the process come across a wonderful piece by Chet Raymo that sums up what I think observing should be. But more on that later. I bought the Vixen zoom used on Astromart to complete the approach to observing begun with using a small refractor on a parallelogram mount (instead of binoculars) and sitting in a revolving beach chair with an adjustable back. What I've learned technically in the past 24 hours is primarily about the zoom lens, but Raymo has confirmed and expanded my view that this is a good approach to observing. To sum up:

• Astronomical observing is - or should be - 10 percent visual and 90 percent imagination.
• The zoom is a delight in this straight through observing mode.
• Zoom quality is impressive. Though the view isn't quite that of a good eyepiece of fixed focal length, I am hardpressed to prove the difference.
• The zoom is par-focal, but it's important to focus first at the highest power.
• The zoom is also helpful when letting visitors use a DOB. st it on highpower, let them look and when they inevitably fail to move the scope properly and lose the view, just zoom out to recapture and center the object once more, then zoom in. Nice! (That's led me to order an inexpensive Celestron zoom that looks just like this one - we'll see!)
• I can just barely squeeze this whole rig into my tiny, domed observatory and while it's worth getting out of the cold wind, it takes some doing to find the ideal position of chair, telescope, and dome slit-opening for the specific object you want to observe. If I can be out in the open with this rig, that's what I would prefer. But last night that would have been impossible with wind gusts up around 20 mph.

• The zoom also worked fine in the ShortTube 80 and the 80 ED and it did a nice job in daylight birdwatching, although it delivered a little more power (at the highest setting) than daylight conditions really allow.
  

I think the 80 ED is a tad better, as I said before, than the Celestron 102 F5 - as it should be, given the price and the fact that the Celestron is a simpler achromatic. But for this kind of deep sky observing at relatively low powers (21X - 62X), I am perfectly content with the Celestron 102. If my main goal is splitting double stars and looking at the planets and moon - or having a completely versatile, one-scope-does-all, I would choose the 80 ED. But my main goal is to simply get enough stimulation from telescope and eye for my brain to begin to deeply appreciate what I am seeing.

The zoom lens is so convenient and so intriguing to use, that I can forgive a slight loss in contrast and sharpness. This is particularly true when the telescope is delicately balanced above me, as in this arrangement with the p-mount. The balance is sensitive to eyepiece weight and changing eyepieces is a little more involved once you are comfortably settled in the chair. So having the zoom is definitely the way to go for this particular observing system. And I do like looking up with both eyes open, but only one for the scope. Bottom line - I've sold my big binoculars and don't regret it for a moment. Using a small refractor this way gives me the best of both worlds - the looking up in comfort view I got with binoculars, and the higher power views the small refractors can deliver.

Does that mean this is all I want to do? Certainly not. I intend to use everything I have - reflectors, catadioptrics, and refractors with diagonals and computer controlled drives and video camera, as the situation and my whims demand. What's more, each approach complements - and supplements - the other. I never would have tried a zoom lens if I had not seen it as useful for this kind of observing where changing eyepieces is awkward. But now that I've tried it, I'm looking forward to using the zoom in other situations. At the very least it will give you a quick look that will help you decide which fixed eyepiece is best for a certain object.

But beyond that, I found using the zoom intriguing. I loved going smoothly and continuously from wide-field, low power views to the smaller, high-power field. This first struck me as I looked at M37. It's a wonderful open cluster, but seeing it go from a few stars with blurry background, to a host of fine, tiny stars was a special delight and one of the high spots in about five hours of observing under clear - but not steady - skies in two sessions, one in the evening, one in the morning. here's a simulation, done in Starry Nights software, of the view of M37 at 24mm (low power) and 8mm (high power). But you need to imagine sliding effortlessly from one to the other. (Click on images for larger views in separate window.)

I actually started before then, testing the zoom in daylight. A couple white-throated sparrows cooperated by pecking at the lawn just 20-feet away from where the scope was set on a tripod. To my surprise the Celestron 102 easily focused that close - so suddenly I was looking a sparrow in the eye, the nice sharp image of his little body totally filling the field of view.

Satisfied with my daylight test, I tried the zoom on all three scopes starting shortly after sunset when a thin crescent moon hung in the twilight about 10 degrees below brilliant Venus. I used the two F5 scopes on these two objects and to no surprise was rewarded with a purple halo - particularly noticeable around Venus. The 80 ED would have been better for both the moon and the planets. But I wanted to see how the zoom performed compared to a fixed eyepiece - and again, the fixed eyepiece did better, but not by a whole lot.

I liked giving the moon some breathing space - as Leslie Peltier suggested. That is, not using such high power that all you see is moon - but instead leaving a significant amount of sky around it. I gain a better appreciation in terms of the total reality when seeing another planet - the moon - this way.

As it became darker - and the trees came up to grab the moon in their bare branches - I left the ST80 and went to using the Celestron 102 almost exclusively, though I did make one quick comparison on the Pleiades with the 80 ED. I was not overwhelmed. Better - yep, but barely. With the 102 and the zoom on low power I was getting the entire cluster. This was similar to the slightly higher power view I could get with a 20mm Televue Plossl. But while I felt the Plossl was a tad better, it was a subjective opinion and I was perfectly content to use the zoom. As near as I could tell there were no stars revealed by the Plossl that were not also revealed by the zoom - when at the same power.

That's one thing a zoom lens does for you - it helps you appreciate the fact that higher power, up to a point, reveals more stars. But when I put the zoom - it is continuous, not a click-stop one - at about the power of the 20mm, it delivered the same faint stars,

By 8:15 pm I had decently dark skies and so decided to go for M1. I thought this would be somewhat of a challenge for the 4-inch, but found it easily since it fits in the same FOV (at 24mm on the zoom) as Zeta Tauri, one of the bull's "horn tips" - the fainter of the two. I love this little puff of smoke from an explosion nearly 1,000 years ago. It looks like someone put a dot on a clean blackboard, then tried to erase it with their thumb.

But when I went in the house about 10:30 and started to read Raymo's book, "The Soul of the NIght," I found the first chapter focused on M1 - the "Crab Nebula," and that Raymo has some things to teach me about using my brain while observing. (This book had just arrived, having been purchased used on Astromart. The paragraph on M1 alone was wortht he $5!) Chet Raymo says "seeing through a telescope is 50 percent vision and 50 percent imagination." I think he's too generous on the "vision" side of the ledger. I would say its 10 percent vision and 90 percent imagination - if by imagination we mean bringing to the experience at the eyepiece your accumulated knowledge. And that's the tricky part.

But Raymo goes on to give a wonderful accounting of what's happening in his imagination as he see this little smudge in the sky through a telescope. Please note he's not simply talking about what he thought - or about what he knows - but about what he "feels."

In the blur of light I could easily imagine the outrushing shockwave, the expanding envelope of high-energy radiation, the torn filaments of gas, the crushed and pulsing remnant of the skeletal star. I stood for a quarter of an hour with my eye glued to the eyepiece of the scope. I felt a powerful sensation of energy unleashed, of an old building collapsing onto its foundations in a roar of dust at the precise direction of a demolition expert. As I wacthed the Crab nebula I felt as if I should be wearing earplugs, like an artilleryman, or the fellow who operates a jackhammer. But there was no sound.

Oh my! That is what observing is all about. I wish I could be half as eloquent - not simply in what I write here, but in what I bring to the telescope in terms of imagination. That's the critical ingredient. Not the equipment, not our eyes - but what our minds can add to the stimulation of photons we receive through scope and eyes. And that's the goal of my experimenting with this approach to observing in a comfortable chair, while looking up.

But last night I didn't do enough of that. I still was in testing mode. And having found M1, I moved on to M37, M36, M38 and M35 - that wonder full collection of open clusters now high in the evening sky. They are all very familiar to me, but each view through different scopes on different nights is like peeling an onion. The view through the 15-inch isn't better or worse than the view through the 4-inch - it's just peeling the onion deeper - lookingi into layers I couldn't see before. But in looking into those deeper layers we lose some of the big picture - some of the "surface" effect I catch in the 4-inch which can't go as deep.

From a mechanical standpoint what was really useful was being able to point the scope with the red dot finder to the rough area of sky, then scan around in low-power, wide-field mode. This is roughly equivalent to what you see in 20X80 binoculars. When you spot your target you simply center it and zoom in - and if you have already preset the focus in high-power mode, everything holds together. In fact, I did very little focusing as I changed targets, except when I was trying to split close doubles.

That's what came next. I decided to give Gamma Leo a try and in the end what this proved to me was I could go to something like 125X by using a Barlow in front of the zoom. I could not split this fine double - though transparency was good, seeing was poor - with lower power. I even tried a 6mm Plossl - 83X - with no luck. But with the Barlow on and zoomed in to the highest power, I could split it, though not real well. Besides the poor seeing, at that power this mount doesn't work well. It takes about 10 seconds for the image to steady down

It was a short hope from Gamma to the two, neat galaxies in Leo's haunch. I just placed the red dot halfway between Theta and Iona Leonis and there were M65 and M66! These are so close together that they still are both in the eyepiece when zoomed in – of course that's only around 60X ;-)

I didn’t see NGC3628 which also should be in the same field and more importantly, I really didn't appreciate in any deep fashion the mind-boggling experience of seeing three huge galaxies – hundreds of billions of stars – all swimming the same eyepiece field.

I was thrilled to see them so easily, but I quickly moved on – I was getting tired and cold – to M51, the "Whirlpool." Well, I could see both components, but it took a lot of imagination to see this for the two colliding galaxies that they are.

Much easier were M81 and M82 – the "ear mites" in the Great Bear, Ursa Major. At about 8-12 million light years these two are much closer than the Leo pair which are around 35 million light years away.

I went in, read some, and slept some – then after tending to the puppies – what a wonderful treat that always is – they went back to sleep and I went out again about 4:15 am. If anything, the sky was more transparent by about half a magnitude and I had fun touring my favorite objects in the morning sky these days – the double double (did not split), Albireo, M57, M25 and the Coathanger. But I spent most of my time with the globular cluster M13 and it charming neighbor, M92. These two star cities, holding hundreds of thousands of the oldest stars in our galaxies, are the best sights in Hercules. I was in a slightly more meditative mood, as well, and so I think got more out of this experience.

But the bottom line is this – on the mechanical side, I'm sold on the benefits of a zoom lens. I'm sure earlier models did not perform nearly as well as the current crop. They are still not perfect – but the little quality they give up is compensated for by the ease of use and the simple pleasure of being able to zoom in without fumbling in the dark and cold with eyepieces and set screws,

Far more important, however, is Chet Raymo's approach to observing and I look forward to learning more from his book and eemtually eviewing it here.