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OpticsBlog – Thoughts and reviews of binoculars, telescopes, scopes, sights, and much more - birdwatching, astronomy, target shooting - pretty much anything related to optics, nature, and life!Friday, August 31, 2007How to choose a telescope
Might be a little early for some folks to be thinking of the Christmas shopping season, but not for us in the retail business. In that regard, I have been thinking of more articles on telescopes, since that is one of our hottest product categories during the holiday shopping season. I've done four, so far, but I will add more if needed. Be sure to read How to choose the right telescope if you are a first-time telescope buyer and you should also read Telescope FAQs and A Dozen Telescope Observing Tips For Beginners if you want help on how to use a telescope. Lastly, if you are thinking of adding a camera to a telescope, Astrophotography in a nutshell is a must read, since not all telescopes and not all cameras can be used for astrophotography.
Best advice I can give, though, to someone shopping for a telescope is to shop early. By December, the selection is only a fraction of what it is during October. Thursday, August 30, 2007Telescope eyepieces
It's often hard for a beginner to understand why anyone would pay more for a single telescope eyepiece than they paid for their beginner's telescope, telescope, mount, eyepieces and all. It must seem stranger, still, for a beginner to see how some of us astronomy nuts stay up late at night arguing the merits and pitfalls of various telescope eyepiece designs and telescope eyepiece brands. What's all the fuss?
On a telescope eyepiece, you are paying for two things. First, how sharp and bright, not only in the center, but at the edge of the field and second, how wide a field. Telescope eypieces which offer the best of both are very expensive and, despite some fabulous telescope eyepieces such as the Televue Nagler and the Pentax XW (just a couple of my favorites), the perfect eyepiece has yet to be made. Of course, the best and quickest way to understand the lure of premium telescope eyepieces is to look through one. It's addictive. Wednesday, August 29, 2007Telescope magnification
Hardly a day passes that a beginner does not ask me about the maximum magnification possible with this model of telescope or that model of telescope. I patiently explain all the basics and variables of observing and point out that the quest to know the maximum magnification of any telescope is pointless.
Being more of a positive person than a negative one, I'd just like to make a sales pitch for low magnification in a telescope. Listen up, you beginners! Life as an observer is easier and more enjoyable at low magnifications. Images are brighter and sharper - image quality is better at low power. Your telescope is also easier to control and use at low magnifications - it's simpler to locate objects, because you have a wider field of view and, for the same reason, large objects, such as star clusters and nebulae, look better at low power because you see more of them. Then, too, an object stays visible in the eyepiece longer at low power and low power is also less demanding in the way of mount stability and quality. Okay, if you still don't believe, I invite you to go to an astronomy club outing, sometime, and see what magnification some folks are using in their really large telescopes. Better yet, take the opportunity to see what a big telescope can do at low power. The view, I promise, will take your breath away. Magnification is such a small part of astronomy. Tuesday, August 28, 2007New Leica spotting scope
I bought my first Leica spotting scope back in the year 2000. It was something of a miracle to me, both in the fact that I managed to find the money to buy it (I actually worked a second job to get the money for it) and also because it was such an incredible optic. It was an angled Leica Televid and an APO Televid at that. I was later forced to sell it, but, fortunately it went to a friend who, to this day, has given it all the loving care it deserves.
Naturally, then, when Leica announced a new version of the Leica Televid in the Televid 65 and Televid 85, I was more than a bit interested. Both models will offer the option of an HD (high definition version) and an APO version. In addition to the slightly larger objectives, the new Leica Televid spotting scopes will also support rubber armoring - a feature I always wish I had on my old Televid. To add even more interest, Leica has developed a new 25-50x aspheric zoom eyepiece, which Leica claims will be the first premium zoom to offer a wide filed of view, the only thing lacking on premium grade zooms these days. Will I report back when these new Leica Televid spotting scopes are available, later this fall? If a product has that little red ball on it, does it make Joanie drool? Oh, yeah. Monday, August 27, 2007Permium spotting scope
Perhaps in no other type of optic is performance more related to price than in a spotting scope. Why? Higher magnifications put greater demands on an optical system. However, there are always good buys at every price point, even in premium grade spotting scopes. Although most people would not conclude that $1400 is a bargain for a spotting scope, the Nikon Fieldscope 82mm ED is just that. In my tests, it scored right up there in terms of resolution, contrast and, especially image brightness, with all the more expensive European brands. Not to say that the Fieldscope is perfect, but if you can't afford to spend another $1000 on a spotting scope, you'll find the Nikon Fieldscope 82ED will do anything you can reasonably expect a spotting scope to do. I've used one for years, out in the field, for birding and it did a great job on the shorebird flats. Plus, no other spotting scope gives you the option of 75x.
Friday, August 24, 2007Big telescope
If you are one of those fortunate to live in area without light pollution, you should think big when you think telescope. Take it from me, someone trapped under the city lights, a big telescope under light polluted skies will never reach its full potential and, to make matters worse, an area with a lot of light pollution is also an area that typically has a lot of other kinds of pollution. This means that sky transparency in the big city is never what it is in a rural area and sky transparency is almost as important for seeing the faint stuff as a dark sky. Bottom line - if you have a dark sky site, go for all the marbles. Get a big telescope.
On the other hand, if you live in an urban area, keep portability in mind. You will, sooner or later, want to take your telescope to a dark sky site and if the telescope doesn't fit in your car or if it requires a lot of dismantling to travel, you aren't going to get it done. That's a shame, because you'll never know what your telescope can really do until you get it under a truly dark sky. Thursday, August 23, 2007Solar filters
Had a customer ask me why he couldn't find one those solar filters that attach to an eyepiece of a telescope, like the one supplied with the telescope he had when he was a kid. I told him to count his blessings. It would be better if he did not find one.
A solar filter that attaches to an eyepiece is simply dangerous. Should the filter crack, the full brunt of solar light as well as the heat being "collected" by the telescope immediately enters the eye, instantly resulting in a burned retina and that awesome amount of heat also makes it likely that the filter will fail. Think back to the days when you played with a magnifier and tried to start a fire. A telescope concentrates many hundreds of times as much heat. A solar filter belongs on the front of the scope. Should it crack, only a very small amount of light enters the eyepiece and, furthermore, most of the heat from solar radiation is stopped before it ever enters the system. Better yet, buy a solar telescope designed specifically for observing the sun, such as the Coronado PST. Please, anyone who finds a solar filter that attaches to an eyepiece at a garage sale or flea market, throw it away. You may be preventing someone a real tragedy. Wednesday, August 22, 2007Good spotting scope
"Why is a good spotting scope so darn expensive? Why can't I get one that is tack sharp at 60x for under $500, even? "
These are questions that I get all the time on spotting scopes. The problem is magnification. As magnification goes up in any optical system, the demands on the optical system also go up rapidly and thus the more critical optical quality becomes. It is relatively simple to make an optic sharp at 8x and even with two optical systems, you can get a relatively sharp 8x binocular for under $200. 60x, on a spotting scope, however, is a different ball game, entirely. You don't get sharp at 60x with a poor lens, anywhere in the optical system, be it in the eyepiece or the objective. In fact, you don't get sharp at 60x with even an average quality optical system. If you want a spotting scope that is as sharp at 60x as it is at 20x, it is time to pull out the credit card and spend at least $1000. Sorry, there are no shortcuts, here. Tuesday, August 21, 2007Sptting scopes for astronomy
Had the Kowa 663 spotting scope out the other night under the stars to frame some open clusters and was once again impressed with how well a spotting scope can perform for these deep-sky objects. With the TSE-21WD 20x wide angle eyepiece, views of large open clusters were breathtaking and as good as I have seen in any telescope of any kind. And why not? The Kowa 663, is, in effect, an APO refractor telescope. It should do well in the same applications as any small refractor. With the Z9B 20-60 zoom eyepiece, I have even seen cloud belts on Jupiter on a good night and the views of the lunar landscape at 60x are astounding. Anyone who already owns a spotting scope, especially a premium spotting scope, owes it to themself to get that spotting scope out under the stars.
Monday, August 20, 2007Fun with stereo microscopes
As I bike along the trails during the summer months, I stop and collect interesting specimens that I might want to look at under my stereo microscope on a rainy day. This Sunday was definitely a rainy day, so I spent a couple of hours with my LOMO SF-100 stereo microscope.
I was surprised to discover just how much I have accumulated in the way of rocks, twigs, old wasp nests, mosses, dried seed heads and even a few dead insects this summer. All such specimens are fun under a stereo microscope. I upgraded this microscope by adding an aftermarket, LED ring light from and that has proven to be a wise purchase. I originally added the ring light to my microscope for photography, but I was pleasantly surprised to discover that the ring light also reveals more specimen detail than the standard LOMO reflected light. Friday, August 17, 2007Canon t-rings
Had a customer, yesterday, that ordered the wrong t-ring for his Canon Rebel camera and there have been others. Maybe a little history would help.
Back in the 90s, when camera makers were switching to autofocus lenses, some manufacturers used the same lens mount for their new autofocus lenses as they had been using for their manual focus lenses. Examples here include Nikon and Pentax. Some manufacturers, though, did not. Examples here include Minolta and Canon. A Canon manual lens is defined as a lens with no autofocus capability. Manual focus Canon lenses and cameras haven't been sold for years. If you want an all manual focus Canon lens or camera, you need to shop used. T-rings for this lens mount will be advertised variously as Canon FD or Canon T or, more often, just Canon. An example, here is the Meade 07370 and the Celestron 93413 A Canon autofocus lens is defined as a Canon lens with autofocus capability. The fact that Canon autofocus lenses can also be focused manually is irrelevant. Canon autofocus lenses and cameras all fall under the umbrella of the Canon EOS system. If you own any Rebel (digital or film), Elan or any D series Canon camera, it is autofocus and it takes an EOS t-ring. A t-ring for an autofocus Canon, whether it be a Rebel, an Elan or a D30 will always be labeled as an EOS. Examples here include the Celestron 93419 and the Vixen 3776 Hope this helps. Thursday, August 16, 2007High power magnifier
One of the toughest things for customers to understand in a magnifier is that, as magnification goes up, lens size goes down. Why can't someone make a 10x magnifier or even a 20x magnifier that is three or four inches wide? One that offers a wide field of view?
The problem in a magnifier is its very simplicity. There's only so much you can do with a single plane lens setup. If you want both a large magnifier and a lot of magnification, you have to use a very special magnifier. It's called a stereo microscope. That's right, a microscope. A stereo microscope, like a magnifier gives you an upright, correct right to left image and, like a magnifier, it allows you to use two eyes, so it provides depth perception as well as comfort. The only drawback, of course, is stereo microscope size - you can't fit one in your pocket. That doesn't mean you can't get a portable stereo microscope, though. For a microscope you can throw in a pack, even a fanny pack, try the little Nikon Mini Field microscope. It weighs about as much as a compact binocular and will give you a full 20x with a wide field of view. Think of it as a magnifier on steroids. Wednesday, August 15, 2007Pocket monocular or compact binocular?
"Never leave home without optics" is a rule I made for myself many years ago and it's one that has served me well. It never ceases to amaze me after all this time just how useful a monocular or small binocular can be, not just for activities requiring a small optic, but also for situations not normally associated with optics. Bottom line is you'll never know how handy a monocular or small binocular can be unless you carry one at all times.
Binocular or monocular? For taking a quick peek, nothing beats a monocular. It's the best backup optic you can carry and a monocular is so small, there is never an excuse for not carrying one. On the other hand, if you find yourself in a serious optical situation that calls for a lot of observing, you'll be happier with a binocular. A binocular is not only more comfortable to use, it is also easier to line up on target and to steady. I always carry a monocular and sometimes add a binocular, but, then, not everyone is an optics nut like me. At the very least, though, everyone should carry a monocular. Tuesday, August 14, 2007Perseids this year
It looks as if I will miss out on the Perseids this year. Every time I managed to sneak out of the apartment for a look to the northeast to see the famous meteor shower, the clouds literally got in the way. Some years you win and some years you don't. I'm not complaining, though - I've has some spectacular Perseid years. My best ever was back in the mid-70s, out in the Sandhills of Nebraska, hundreds of miles from any bright lights. As I sat on the tailgate of that pickup truck, barely a minute would pass before another Perseid meteor would streak across the sky. At times, I was treated to multiples and even a few that left a trail. Believe me, I never touched my astronomy binocular or telescope that night, even though both waited in the bed of the truck. It was the memory of that night that keeps me looking every year around August 12th. I'll be back next year.
Monday, August 13, 2007Concert camera
Part of my job is to steer a customer down the right path when it comes to picking the correct product for their application. Most of the time, there are plenty of reasonable options and a customer will have no problem picking the right product from the menu I offer. Sometimes, though, I have to gently let the customer know that the type of product they have chosen is inappropriate for the job and the only practical options are expensive ones. Picking a digital camera or digital binocular for a concert is a good example.
Digital binoculars are a very poor choice for concerts, especially night concerts. Why? Digital binoculars do not have flash and the tiny lenses used on digital binoculars are the worst choice for working in low light or trying to freeze the action on constantly moving performers. Take all the pics you want, but they will be blurred and dark. A conventional digital point and shoot camera will always take better pics than a digital binocular, but digital point and shoot cameras still suffer from small lenses and anemic flash units. So what do you really need for a concert camera? That application calls for a good SLR camera and accessory flash and a large telephoto lens. You'll also want a tripod or, as an option, an image stabilized lens. Of course, when you get to the concert, you'll likely discover that no one is going to let you in the door with that kind of equipment. Forget the photography and enjoy the concert. Thursday, August 09, 2007Pocket monocular
The Zeiss Miniquick 5x10 monocular has been a round a long time and has earned a well-deserved reputation for its excellent optics. Back when I was making a decision to purchase a monocular for my own use, this one was certainly on the list. I opted, instead for my Nikon 5x15HG, primarily because I don't own much in the way of blouses or tops that had a pocket and the Zeiss comes with a clip designed for pockets. Still a great choice, though, for those who prefer a pen style and pen sized monocular with great optics. Eye relief is a very comfortable 16mm for those who wear glasses, too. Just wish I had pockets.
Wednesday, August 08, 2007Spotting scope eyepieces
Now and then a customer asks why eyepieces on spotting scopes (see my article What is a spotting scope? ) don't typically interchange from one brand or even one model to the next. Is it because manufacturers want to make you spend more money for their spotting scope eyepieces?
It might seem that way, given the price of eyepieces for premium grade spotting scopes, but there is an optical reason for this. Spotting scopes are, for the most part, very short focal length optical systems. This is by design, since portability is important (spotting scopes are small telescopes designed to be used by day). The problem comes when we try to match an eyepiece to such short focal length systems. The shorter the focal length of an optical system, the fussier it gets about eyepieces. That spotting scope eyepiece on your scope was designed as an exact match. Using an eyepiece not made for that exact model of spotting scope is risky as far as performance. Manufacturers of premium grade spotting scopes are aware of this and are rightfully hesitant about allowing the use of some other brand of eyepiece in their spotting scopes. It might hurt the pocket book, but when you pay for an expensive eyepiece, you are assured of getting an eyepiece that is designed specifically for your spotting scope. Tuesday, August 07, 2007Bug Loupes
Insects are a vital and amazingly diverse part of our world, so it should come as no surprise that I enjoy studying them. (That's me, Joanie the nature girl.) Equipment needs are minimal. Just get a good field guide and a magnifier and head out to the field.
I've used small pocket magnifiers like the B&L Hastings, for many years, but lately I have been playing with loupes, specifically photographic loupes such as the Pentax 5.5x loupe. When I see an insect I wish to study, I simply slip an standard index card under it and place the loupe over the top for a better look. The insect is contained, momentarily, within the sides of the loupe (safer for both of us), then released, unharmed, back into the environment after a basic identification has been made. Now, don't get the idea that you need an expensive loupe like the Pentax. There are many less expensive models that will do a great job. A great choice, here, is the Carson Bug Loupe. It will cost you less than a field guide and get you started, nicely. Monday, August 06, 2007Wildflower calendar To those in tune with Nature's rhythms and cycles, the seasonal appearance of certain wildflowers is as reliable as a calendar and a lot more colorful. Last week, for instance, while riding the bike trail, I saw my first Goldenrod of the season. This weekend, I noticed that the Big Bluestem has formed its famous turkey foot heads and is getting ready to strut its stuff for fall.
Where has my summer gone? I have had so much fun this summer with my bike riding, birding, photography and astronomy that I have lost track of time. My binoculars, telescope and camera have all gotten quite a workout, not to mention my bicycle and, of course, me. My prayer of thanks to Earth Mother for all her wonderful treasures and her gift of life. I am truly blessed. Thursday, August 02, 2007Monopds versus tripods
From time to time, I've been asked to recommend a monopod for use with a spotting scope, both with and without a camera attached. Hey, I hate having to lug a tripod around out in the field as much as anyone, but after having tried every alternative to a tripod, including shoulder stocks (we don't carry) and monopods, I still carry a tripod. Why? Monopods and shoulder stocks don't offer the stability needed at these magnifications.
For casual viewing and scanning at relatively low magnifications, say 20x to 30x, monopods and shoulder stocks are better than nothing, but even at those magnifications, they leave a lot to be desired if you are trying to study fine detail. Forget monopods and shoulder stocks altogether at 60x. They're just dead weight at this end of a spotting scopes magnification. For a spotting scope with a camera attached, forget a monopod at any magnification. If you want sharp pics, you will need a tripod. Monopods with a 300mm, f2.8 lens (about 6x) camera lens are one thing, but 40x shots with a camera and spotting scope are another thing, entirely. It's tough enough to get good pics at this magnification, even with a good tripod. A monopod just doesn't get the job done if you want those keepers. Wednesday, August 01, 2007Homesick scope blues
Life in the big city has never appealed to me, but as I have done so often in my life, I adapt and make the best of what is offered. Truly, I am not in Kansas, anymore. Okay, not in Nebraska, anymore, but you get the idea. Regardless, I still shake my head in disbelief, even after three years, to find myself living the Chicago suburbs. What's a girl who wants nothing more than to sit in a smelly marsh all day with a spotting scope doing in a place like this? What's a girl who only wants to see the Milky Way arch across a dark sky doing in a place where she's lucky to even see a few bright stars? How can a gal live in a place where a telescope is little more than a piece of bedroom furniture? (That's right, I keep a telescope in my bedroom. Doesn't everyone?) So, what keeps me here?
Certainly, it's the job, which I love, and the people I work with, whom I love even more. When the last day of work comes, though (and I'm getting old enough to contemplate that), don't look for me the next day in the city. I'll be on may back out to the great wide open spaces, binocular around my neck, looking for the nearest smelly marsh and dark sky. With any luck at all, that's where I will breathe my last. |
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