|
|
|
|
 |
|
|
|
|
|
|
|
|
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!Thursday, June 30, 2011Another telescope observing tip for beginnersI remember how awed I was when I first started in astronomy. It was all so incredible. A source of much of that awe was how just much there was to see with astronomy binoculars and telescopes. Wow! It was almost overwhelming. If you are a beginner with a new telescope, the, I do understand how you feel. Where the heck do I begin? A common beginner mistake is to rush to see it all in the telescope eyepiece and before you know it, you find yourself wandering. This can be fun, of course, and there are times I still do it for kicks, but, as a beginner, wandering really doesn’t set you up to learn and accomplish much. In my first summer of observing, I did this far too often and, as a result, I was basically tripping over my own feet when it came to acquiring skills needed to successfully setup & use a telescope. So, here’s another observing tip to add to my A Dozen Telescope Observing Tips for Beginners: Have a plan before you observe. Now, there is no need to go overboard on this, though I know some, well, anal types that do carried away. Me, I like a little wiggle room when it comes to my observing plan. Either way, the idea is to try not to do too much in one observing session by observing with a plan in mind. It also gives me a sense of mission accomplished when I'm done. My observing plans are pretty informal, but they are specific. I may decide to just stay with one constellation or two and work on what I can see within those boundaries. At other times, I select a particular class of objects, say, globular clusters, and restrict myself to working those with the binoculars or telescope. This may seem a little restrictive to a beginner, but it’s quite the opposite, actually, especially if you own and use a large telescope with its potential to see so much. Then I may narrow it down a bit more, say, by combining the two and just working on globular clusters in the constellation Ophiuchus as an example. Of course, if I have the time, I may just move on to other areas of the sky or types of objects, but I always have a pretty good idea of exactly what I want to see before I setup & use a telescope. Summer telescope observing tip.It’s getting downright hot up here in northern Wisconsin in terms of temperature (and also politics), but, hey, this is summer, after all. If you are an astronomer, you already know that summer does present some challenges when it comes time to setup & use a telescope or astronomy binoculars, but if you are just getting started in astronomy, here’s another tip to add to my Dozen Telescope Observing Tips For Beginners: your best observing in terms of seeing conditions in the summer is typically well after midnight. The other night was a good example. The sky was clear prior to midnight and, of course, I just had to take advantage of that, despite the fact that I was dog tired from working outside all day. Then, too, rather than wait, I still wanted to get to bed at a reasonable time, so out came the telescopes and binoculars as soon as it was dark enough to use them. Sad to say, observing conditions were poor. Unfortunately, that “first dark” in the summer is often a less than prime time for observing because the heat from the earth is still rising into the air and the atmosphere is a little murky and unstable as that air mixes with cooling night air. That’s why I’ve noticed on some summer nights that seeing conditions just keep getting better as the night progresses. In fact, those last couple hours before first light creeps into the eastern sky are often much, much better than what I had prior to midnight. Of course, you have to get out of bed to take advantage of this. Hey, take an afternoon nap or something. Wednesday, June 29, 2011Galaxies in large telescopesI’ve had a couple of good nights behind the telescope eyepiece, recently, but I’ve never left the constellations of Ursa Major and Canes Venatici. Using large telescopes is like that. The number of objects visible in large telescopes can be almost overwhelming. As a result, it takes a long, long time to see all there is to see in even a small part of the sky and, in fact, it is questionable to say you can ever see it all when using truly large telescopes. At some point in telescope size, sky conditions, not your telescope, become the limiting factor on how much there is to see. It's a nice position to be in with a telescope. Of course, when tracking down small faint galaxies, as I have been doing for a couple of nights in the above constellations, the game is all about determining which ones you are seeing in the telescope eyepiece coincide with the ones on your star chart. It does take patience, yes, and some hard-acquired skill, too, but it is a fun game. I love it and it is why I take the extra effort and time required to setup & use a telescope that I have to wheel around the yard with wheelbarrow handles and wheels, but that’s the only way this gal can comfortably manage large Dobsonian telescopes like my 12.5” Obsessions. When trying to choose the right telescope for "Name that Galaxy", though, there are only big or bigger telescopes to consider. This is not a game for small telescopes. Keep in mind that this game of “Name that Galaxy” is not going to impress the heck out of guests you invite to have a look through the telescope eyepiece. (My husband will vouch for that, though he is too polite to say otherwise). After all, with only a couple of exceptions, galaxies are little gray fuzz balls when viewed through telescopes, some brighter and larger than others and some even show a hint of detail and structure, but all are basically fuzz balls. Spectacular objects they are not in the eyepiece, not compared to some other deep-sky objects, anyway. Still, the very fact that they are galaxies - "island universes" made of billion of stars and incredible distances - fires up my imagination like no other objects that can be seen with telescopes. If the sky is clear, again, tonight, I will be back to pointing my scope at Ursa Major and Canes Venatici. I still have a lot left to see, there. Monday, June 27, 2011Great opticsJust what is it about the spectacular images delivered by great binoculars, spotting scopes, telescopes or even microscopes that drive otherwise sensible people to spend more than they should to get the best of these instruments? I can understand if someone is using one of these instruments, professionally, and needs to see the utmost detail for the sake of research or a career, but that accounts for only a few percent of sales every year. Let’s face it, most of us who pay big bucks for premium birding binoculars, a superb birding spotting scope or exquisitely corrected APO refractor telescopes are doing it because we are addicted to great image quality, not because we actually need such image quality, though, as always, we tend to stretch the word need a bit to justify spending what we do. I can’t really say when I became such a lover (addict) of great optics. I suspect it just developed as I gradually worked my way up from cheap binoculars, spotting scopes and telescopes into ever better and more expensive models. Then there came a day when I was so addicted to the good stuff that I could no longer be satisfied with merely good optics. That day was not good news for my checkbook, of course, but my eyes continue to thank me to this day. If you gotta be hooked on something, nothing beats great optics. Small telescopes or big telescopes?So is there really that much difference between what small telescopes can do compared to large telescopes? That is a good question, since, as a rule, large telescopes are certainly more expensive than smaller telescopes, not to mention that when it comes time to setup & use a telescope, large telescopes have issues that you don’t get with small telescopes. So if I am going to spend the big bucks on that large telescope, what am I getting for my money? To test this, I spent a few hours observing this last Saturday night with both my small 80 mm refractor telescope and my much larger 12.5” Dobsonian telescope. I have basically light-pollution free, dark skies in my back yard, but sky transparency was only fair. For my test object, I chose one of those objects that are much sought by amateur astronomers, but nonetheless a potentially tough object to spot, especially in small telescopes, namely the Veil Nebula. The results? The Veil was not visible in my 80 mm refractor, despite its excellent APO optics, not at first, anyway. It was only visible when I added a Televue Bandmate O-III filter to my Televue 17.0 mm Nagler eyepiece that I could see this super nova remnant. Even then, it was only visible because I knew exactly what I was looking for and how to observe tough objects. So, without the filter, no Veil; with the filter, just detectable, but by no means an awe inspiring object. Overall, I was pleased, though, because it was the first time I spotted the Veil in such a small telescope. In my 12.5” Dobsonian, things could not have been more different. The Veil was easily spotted without a filter, though still not what this object could be on a night of better seeing conditions. With the O-III filter, though, even under only fair conditions, it got big smiles from me and my husband, who I invited to take a look through the telescope eyepiece. So, is it worth the money to go with a larger telescope? Only you can answer that, of course, but remember, I saw the Veil in both telescopes. Just a matter of how much of a view you want and how much you are willing to spend to get it. Friday, June 24, 2011Digiscoping for birds So you just bought a new birding spotting scope and want to maybe use it for some bird photography? Go for it. Thanks to digiscoping – taking pic through the eyepiece of a spotting scope with small digital cameras – bird photography has never been easier. Okay, note that I said “easier”. I did not say easy. This is still bird photography, after all, and bird photography is always a very challenging type of photography, not to be confused with taking pics of the family on a picnic. There are some things you can do as a beginner bird photographer, though, to make things “easier”. First, digiscoping or, in fact, any type of photography using spotting scopes, is going to be limited to fairly bright conditions. Both spotting scopes and small digital cameras are relatively slow in photo lingo, meaning that it takes a fairly long time to capture and process that image and time is the enemy of sharp pics. Why? Birds are not especially cooperative subjects for the camera – they are constantly moving or twitching. Give them even a fraction of a second too long and your odds of getting a sharp pic go out the window. Make it easier on yourself and confine your shooting to good light. Second, be a bit selective with your avian subjects until you get some experience under your belt. For instance, there is a huge difference between trying to photograph wading birds, which tend to remain motionless as they hunt and fish and songbirds, which can be frustratingly twitchy and active. Then, when it comes time do try your hand at song birds, try digiscoping birds at the feeder, first, where they are more likely to stay put for a bit. Third, develop a good trigger finger when digiscoping. This is a skill that only comes with experience, but it is a big part of getting a sharp bird pic. A good trigger finger is all about recognizing that exact moment when you need to click the shutter and then doing it, quickly, but smoothly as not to vibrate the camera or spotting scope. Your pics will tell you when you got it right. Lastly, keep shooting when you have an opportunity for a great bird pic. Digiscoping for birds is a numbers game and a huge percentage of what you shoot is going to get deleted when you get home and start editing with your photo software. Beat the odds and take as many shots as your subject will allow. Don’t even trust what you see on the review screen on your camera when out in the field. You’re going to need the larger scale provided by your computer screen to really judge what you have. About the pic: Green Herons, with their tendency to remain motionless, deserve an award for being such perfect digiscoping subjects Thursday, June 23, 2011Astronomy locationsI’ve lived in some excellent locations for using astronomy binoculars or telescopes to do astronomy. These places have offered very dark skies and lots of clear nights – so many, in fact, that there were times I spent more waking hours at night than by day. On the other hand, I have also lived in some truly pathetic places for astronomy where I suffered week after week of cloudy skies and seemingly only a few precious nights at the telescope eyepiece a year. Still, my enthusiasm and love for astronomy has never waned, not even when I found myself living in some less than great locations for astronomy. The question, then, is how can someone possibly maintain an interest in astronomy when the opportunities to setup & use a telescope are few and far between? How do you maintain an interest in astronomy if you live in one of those not so great places to actually get out and use telescopes or binoculars? Isn’t astronomy only for folks who live in areas with lots of clear skies? Not at all. I know many astronomers that live in some of the worst possible places for using telescopes, but they are still very active astronomers, simply because there is so much else to do in astronomy than looking through a telescope eyepiece. If you are the social type, as a good many astronomers are, there are local and national astronomy clubs and organizations such as the Astronomical League. When the clouds roll in, meetings just move indoors with guest speakers and programs. In fact, I’d rate joining an astronomy club as the single best thing a beginner with a new telescope can do for the sake of learning. If you have a computer, online resources for astronomy are staggering. You can get interactive star maps, discussion forums on telescopes and online equivalents of long standing astronomy magazines. Indeed, there is a whole world of astronomy just a mouse click, away. I do use online resources – quite a bit, in fact – but I am still old school enough to prefer the printed medium, in other words, books. I love to read anything about astronomy and I have the books to prove it. Believe it or not, there are actually nights when I don’t want the sky to clear so that I can keep reading! All in all, there is so much more to astronomy than just astronomy binoculars and telescopes, so don’t fret not living in a great location to use this equipment. Astronomy is for everyone and anyone with a curious mind and a spark of imagination, no matter where they live. Wednesday, June 22, 2011Telescope size issuesYou reach a point with telescopes where increasing size and practicality have a head-on collision with each other. That point depends on you and your situation, of course, but I’ve always claimed that when the sky clears and you start looking for an excuse not to go out and look through a telescope eyepiece because you don’t want to deal with the hassles involved with large telescopes, you’re in trouble. You bought too large a telescope. As always, when wondering how to choose the right telescope, the best telescope for you is the telescope you will use the most and that may not be the largest telescope. Here's an example. For me, the practical size limit on telescopes is has been reached with my 12.5” Dobsonian reflector, mostly because of how I am storing it between uses. Right now, this telescope sits in the house in a closet, disassembled when not in use, because that's the only way I can get it into the closet and also negotiate the stairs leading to the closet. This is not a good way to store a telescope of this size and I knew it when I bought it, so this is only temporary until I work on a solution, but a solution I have, already, make no mistake. I’ll be darned if I am ever going to let myself find an excuse not to use this superb telescope. Large telescopes stored in a house cause problems even if you only plan to setup & use a telescope in the back yard. First, you have to take the telescope apart into several manageable sections and then make several trips out into the yard. You then put the telescope back together. When you’re done for the night, of course, you have to reverse the process. All this setup and those trips in and out of the house are the main reason so may large telescope owners begin to look for an excuse not to observe when the sky clears. It is not just a matter of inconvenience and work, either. All that setup and take down time eats into valuable observing time. An even more serious problem with keeping large telescopes in the house is cool down time. Cool down time is what we refer to as the time needed for the telescope optics to “cool down” to whatever the temperature is outside when you decide to observe. Since this is often a temperature that is lower than house temperature, we call it cool down time, but in truth, it could be called heat up time if you are taking your telescope out into warmer temperatures. The problem, either way, is that your telescope mirror or objective lens changes its shape through contraction or expansion until it is at the same temperature as the surrounding air. Anytime you have mirrors or lenses changing shape, of course, you have horrible optics. Your telescope will be pretty worthless until its optics are at the same temperature as the air and the bigger the telescope, obviously, the longer this cool down takes. Just how long, though? Got an hour to observe? From experience I know that on a 12.5” telescope like mine, taking it from the house out into the backyard on a cold zero degrees winter night, I’ll need at least an hour and often more. That’s just for cool down time and we still have to throw in setup and take down time. As you can see, that makes for a long night of observing. My solution? We will be building a large shed to keep the telescope permanently housed outdoors. I’ll still have to roll it in and out of the shed to observe (I have wheels for it), but I won’t have to take it apart to negotiate stairs and, especially, I won’t have to deal with cool down time. It converts my 12.5” telescope into a grab and go telescope and I’ll never have an excuse not to use it when the sky clears. That’s the idea. Tuesday, June 21, 2011Digiscoping birds My friend’s favorite bird is the Red-winged Blackbird and I have been promising her more pics of her favorite bird for some time, now. I just haven’t gotten around to it with all the other birdwatching projects I have been doing. Fortunately, the Red-winged Blackbird is not an especially challenging bird to photograph, especially if you use digiscoping – taking pics of birds with small digital cameras behind the eyepiece of a spotting scope. Most places you can stop your vehicle along a marsh road and take a pic right from your vehicle with conventional digital SLR cameras and long telephoto lenses, but digiscoping provides a better chance to fill the frame with a subject because of its greater magnification potential. I won’t have to hop in the car and drive to a marsh, however, because we live right on a rather marshy lake. In fact, because of our proximity to the lake and bog, we actually have Red-wings visiting our bird feeder. These are not your usual suburban bird feeder visitors, of course, but, compared to some other members of the blackbird family, Red-wings are relatively well-behaved as far as squabbling and bullying other birds. They are more than welcome at my feeders. Now, if I can only get one to pose for a nice pic! Sunday, June 19, 2011Astronomy bugI’m not sure if having the astronomy bug qualifies as an actual addiction, but if an addiction is something you can’t shake, well, I’ve been in love with astronomy for over forty years, now, and looking through my astronomy binoculars or a telescope eyepiece is still as much a thrill as ever, even after all these years. I’m hooked and I’ hooked bad. So, I am sometimes asked what about astronomy, specifically, hooked me so completely. Was it a certain category of object to be seen in telescopes or binoculars? Was it a particular type of equipment? Do I prefer refractor telescopes or reflector telescopes or would I just as soon use binoculars as telescopes? Fact is, I’m a well rounded amateur astronomer compared to some astronomers I know. I don’t specialize in one type of astronomy or another and I own and use both telescopes and binoculars. Two things, though, got me hooked in my first summer of astronomy over forty years, ago. One was seeing Jupiter and Saturn in my first telescope. No surprise there, as planets are the first thing beginners want to see in telescopes. The other was seeing the lunar landscape through the telescope. That, probably more than anything else, drove home the fact that I was truly looking at something other worldly. There really is nothing here on earth that resembles what you see on the moon, even when seen through a small telescope. It may be “our moon”, but it is a world as alien from our own as any. Friday, June 17, 2011Telescope accessories: star atlas I love star atlases and star charts -the printed type that is - and, in fact, I have a modest collection of these hands on telescope accessories, some dating back to my first days as an astronomer. Oh sure, online digital star charts and CDs are amazing, especially the interactive types, and I do use them for various observing projects, but I guess I am old-fashioned enough to feel uncomfortable unless I have a printed star chart with me when I setup & use a telescope or uncase the astronomy binoculars. In fact, I’ve been known to just pull a star atlas out of my astronomy library and just browse through it for fun and, in my opinion, a good star chart can be a work of art. Will Tirion is a genius, in my book. Printed star charts are a necessity, of course, if you still navigate without the help of a computer, as I do, but I think every astronomer, even the most hardcore computer geek, should have something in printed form as a backup, even something as basic as the Celestron Sky Maps Chart. Computers on telescopes are, after all, still computers and that means you can sometimes find yourself without a functioning computer on a night you want to do some astronomy. I’ve seen it happen to friends and the language floating around their computerized telescope as they try to solve a computer glitch is not always pretty. Meanwhile, an hour later, they have still not looked through the telescope eyepiece for the sake of seeing what’s out, but I’ve already had an hour of wonderful observing. My favorite star atlas at the telescope is the Pocket Sky Atlas because of its convenient size. As for sitting down at the table and planning a night of observing with telescopes or binoculars, I more often pull out my old tried and true Star Atlas 2000.0, first edition, though, of course, I also own the second edition as well. Hey, if there is a new star atlas out there, I have to have it. Thursday, June 16, 2011Spotting scope size and weightIs spotting scope size and weight really that big a deal? I sometimes get this question from customers about spotting scopes, so the first thing I do is ask them some questions right back. Why? Because you need more information to answer such a question, correctly. It’s how you plan to use a spotting scope that counts for this question, sometimes right down to the specific technique you will be using within a given application. Birdwatching and birding is a good example. There is a huge difference between carrying a birding spotting scope and tripod over your shoulder and hitting the trail all day versus doing your birding out of a vehicle with a car window mount or just setting the spotting scope up on a tripod and birding from a single location all day. I’ve done it both ways. Oh yeah, you might think twice about choosing that big 85mm spotting scope if you plan to carry a spotting scope and tripod over your shoulder all day, especially us gals. I learned that the hard way, carrying big scopes all day and I still have the grooves left by the tripod in my shoulder to prove it. Finally, I had the good sense to drop down to the excellent Kowa 663 spotting scope and have never regretted it. The loss of performance compared to the big scopes I had been carrying didn’t amount to a darn thing when it came to identifying birds and going smaller on the spotting scope also meant I could get by with a lighter tripod for even more weight reduction. No more big spotting scope and heavy tripods over my shoulder for this gal. Never. Now, on the other hand, why not a big birding spotting scope and heavy tripod when you don’t have to carry the spotting scope and tripod very far? I used to drive from one prairie marsh to the next, all day long, setting up my spotting scope along the road where I parked. Big scopes posed no problem at all and, believe me, birds will look even more spectacular in some of those big scopes. The Wow! factor went right off the scale when I’ve used a TV-85 or Kowa 883 this way. Okay, so maybe some of us should have two spotting scopes to cover all the bases, one small and one large, but if you can only afford one good spotting scope and will be doing some of your birding over the shoulder, so to speak, I’d have no hesitation using a small birding spotting scope do it all. Wednesday, June 15, 2011Spotting scopes for astronomy Yes, you can use conventional spotting scopes for astronomy. A spotting scope is nothing more than a small telescope designed to be used by day, but it is still a telescope, after all. I’ve used my spotting scopes as grab and go telescopes for astronomy for many years and I can tell you that, as far as the grab and go feature, nothing beats a spotting scope; spotting scopes are wonderfully light and portable. Own a spotting scope? Want to get started in astronomy? You got it covered. Go buy a star atlas and you’re set. Of course there are limitations to using a conventional spotting scope in lieu of a dedicated astronomy telescope. The first is magnification. Spotting scopes are designed to be used by day and, by day, the atmosphere severely limits how much magnification you can use effectively. That’s why most spotting scopes only go up to about 60x on the average. 60x is enough, though, to do all kinds of astronomy. It’s plenty for observing the moon and seeing brighter star clusters, nebulae and even some galaxies. 60x is a bit light, though, for the planets, but it is still enough to see cloud belts on Jupiter and the rings of Saturn. Images of these two planets will not be large, however, but you will be able to spot some detail on them on a night of good seeing. Mars, though, is too small to be more than a tiny red disc at 60x. The second issue with using spotting scopes for astronomy is the mount or, should we say, the tripod. Spotting scopes use standard photo tripods and these do have some limitations for astronomy. The biggest shortcoming of photo tripods for astronomy is that they do not allow you to observe objects directly overhead because the tripod head just won’t angle back that far. That means the best you can do is observe object somewhat short of being directly overhead. Don’t let that stop you, though, because that still leaves a lot of sky to see. The moon is full this week and it makes a great first astronomy target for a spotting scope. Give it a try. Tuesday, June 14, 2011Spotting scopes, telescopes, prairieYou can take the girl out of the prairie, but you can’t take the prairie out of the girl. Funny how the prairie imprints itself in your psyche when you’ve spent most of your life there. Now that I live deep in the north woods of Wisconsin and a long, long way from a prairie or even a farm, you’d think that I would forget about those wide open places, but I can’t. I still find myself making comparisons between these beautiful north woods and the prairies of my youth. Every time I look through my birding spotting scope, for instance, I still form mental pictures of a prairie marsh and all the incredible days I spent there. For me, well, spotting scopes and prairie marshes just go together like peanut butter and jelly. It seems very strange to use a spotting scope and not see a prairie marsh all around me. When I setup & use a telescope, I am reminded of how good I had it out on the prairie where I could see horizon to horizon, for miles in any direction, not a tree in sight. Now, of course, it is a battle to see down to the horizon in any direction with all these trees. That’s why I have my hubby making our dock on the lake a bit wider as we speak. At least over the lake I will be able to see a bit more of the sky than in the yard. A local astronomer I met, says she even purchased a small plot of cleared land specifically to make better use of her telescopes. That has to be one of the most expensive telescope accessories, ever. I’m not in the position to do that for the sake of seeing more in the telescope eyepiece, but it shows how we astronomers, up here in the north woods, value a little bit of open country. Now don’t get me wrong. I wouldn’t trade what I have in my north woods for anything, but once in awhile I do fondly remember some places where the wind could blow for a hundred miles and never touch a tree. Monday, June 13, 2011Most important telescope accessory?When it comes to accessories used and needed, telescopes rank right up there with film and digital SLR cameras. The list of telescope accessories used by astronomers is often a long one. You have telescope eyepieces, usually three and often more, then on to filters of various types, finder scopes, red lens flashlights, star atlases, books, computer programs and on and on. Oh yeah, if you love marketing, you gotta love telescopes. Astronomers tend to be telescope accessory addicts. Let’s get out the credit card and have some fun. There is one accessory, though, that you need at the telescope in a big way and it can’t be bought. In fact, you can’t even see it or hold it in your hands, but without it, don't bother to setup & use a telescope and look through a telescope eyepiece. It’s called imagination or, maybe a better word is, appreciation. So, what, you thought that scientific types were all just dull, unimaginative fact spewing, techno geeks? Wrong! Okay, some of us are fact spewing techno geeks, but we are anything but dull when it comes to the imagination and appreciation department. In fact, if anything, we astronomers, including amateur astronomers, are more at the hyper end of things when it comes to imagination and appreciation of what we see. Spending our nights looking at things and places that no human can ever visit or even completely understand does that to you. The lure and the benefit of astronomy is mostly about what astronomy does for our minds. Here’s an example. Recently, a supernova has been sighted in the Whirlpool galaxy, otherwise known as M51. I’ve seen this distant jewel of a galaxy in my telescopes and even my astronomy binoculars, many, many times. Now, with a little luck and a clear dark sky, I might actually be able to look through my telescope and view a truly cataclysmic event – a supernova - that would vaporize Earth if we were unfortunate enough to be in the path of such a thing, but even more astounding is the fact that I will be seeing an event that is taking place in another galaxy, separate from our own. Oh, did I mention that we are actually viewing something that happened roughly 20 million years ago because it has taken the light and image from this galaxy and supernova that long to reach us? If that doesn't spark your imagination then you don't have a pulse. Friday, June 10, 2011Moon telescopes We’ve hit a string of cloudy nights up here in northern Wisconsin, so not much of an opportunity to put my new large telescope to work and, now that we are approaching full moon, I really won’t be able to stretch this telescope to its limits, for awhile yet, as far as seeing the faint stuff. Hunting deep-sky objects, especially faint deep-sky objects, is what large Dobsonian telescopes are all about and even a little light from the moon makes this type of work more difficult. That darn moon, anyway! That’s what I used to say (and worse), years ago, when I first started hunting faint deep-sky objects – star clusters, nebulae and galaxies – with large telescopes. I have a much different attitude toward the moon, these days, compliments of spending years trapped in a big city with severe light pollution that made it all but impossible to get serious about faint deep-sky objects. That left the moon and planets as the only practical objects to observe when it came time to setup & use a telescope. On some nights, it was the moon or nothing at all if I wanted to use a telescope, so you might say my situation forced me to see the moon in a new light, so to speak. I’m glad it did. I now have a deep appreciation for the moon as a serious target for astronomy and I even have a separate moon telescope to view the moon. My small, but optically excellent, 80 APO mm refractor telescope see the pic) makes an excellent moon telescope - images are sharp, contrasty and brilliant. One thing I learned in the big city is that you don’t need a big telescope to seriously study the moon; you can observe the moon with just about any size telescope and small telescopes are easier to setup and use than big telescopes. They’re also easier on the eyes – the moon can be painfully bright in large telescopes unless you use a filter. Even better, small telescopes are cheaper and that makes moon telescopes available to everyone. So, okay, the approaching new moon means that my big telescope won’t see much action, but my small telescope is ready and waiting. Now all I need are some clear skies. Thursday, June 09, 2011Spotting scope eyepiecesOne of the questions I’m asked, from time to time, concerns the differences between telescope eyepieces and spotting scope eyepieces. More specifically, why are telescope eyepieces universal – able to be used in just about any type of telescope of any brand – whereas spotting scope eyepieces are typically brand and even model specific within a brand and anything but universal? Is it all an evil plot by spotting scope manufacturers to lock you into using and buying only their spotting scope eyepieces? In the first place, most low priced and mid-priced spotting scopes don’t even give you the option of changing eyepieces. You’re stuck with the eyepiece that comes with the spotting scope and that is nearly always a zoom eyepiece with enough of a magnification range for typical daytime use. This is enough. Most users won’t need or be able to use more than this, anyway, due to limits imposed by the atmosphere during the heat of the day. Astronomy is a different ball game. In astronomy, you need access to a much wider range of magnifications and you switch telescope eyepieces constantly. You need more than one eyepiece to do astronomy. Only when you get to expensive spotting scopes do find optional eyepieces offered, though a zoom eyepiece is still the most used and most popular eyepiece. Optional spotting scope eyepieces tend to be specialty eyepieces for digiscoping or scanning. Here’s where you are indeed usualy stuck staying within the brand. Yes, of course, spotting scope manufacturers want you to buy their optional eyepiece for the sake of another sale, but there is also an optical reason involved. Most spotting scopes are actually small telescopes, small refractor telescopes to be exact and very short focal length refractors at that. As a rule of thumb, short focal length instruments are fussy about eyepieces. Those expensive optional spotting scope eyepieces you see for sale are specifically designed for the manufacturer’s spotting scope and no one else’s. The manufacturer does not want to be responsible for any lack of performance that can occur when someone else’s brand of eyepiece is used in their spotting scope. Yes, there are some spotting scopes on the market that allow you to use telescope eyepieces. In the case of spotting scopes like the Celestron C90 which are actually small astronomical telescopes adapted for day use, focal lengths are quite long and, as a result, such scopes are not at all fussy about eyepieces. In the case of spotting scopes like the wonderful Pentax PF-80ED, you have a conventional spotting scope with a short 500 mm focal length. That means that you should either stay with specific Pentax eyepieces made for this spotting scope or exercise caution when choosing other brands of eyepieces to use in the PF80-ED. Wednesday, June 08, 2011Clear nights for the telescopeIf you are thinking of buying a telescope and trying astronomy, you no doubt have many telescope first questions and/or concerns. One of these is how often will I actually get to use those astronomy binoculars or setup & use a telescope at my location? Am I spending money for something I won’t be able to use that often? To actually predict the number of nights the sky will be clear in your area depends on your local climate, of course. If you are fortunate enough to live in a dry desert area, the number of clear nights at the telescope eyepiece will be much higher than in a wet and humid location. Proximity to a large body of water can also affect the number of clear nights you get, often to the negative. If you really want numbers to compare one location to another, there is plenty of data available on weather and climate websites for any given location. Okay, so maybe you live in an area where there are not a lot of clear nights. Don’t be in a hurry to pass on astronomy, not by a long shot. There is so much more to astronomy than the actual number of nights with the binoculars or telescopes. How can you put a number on something that is so enjoyable and fascinating as astronomy? I can’t and neither can the thousands of astronomers out there that live in less than ideal to downright lousy locations to do astronomy. Fact is, only a small percentage of amateur astronomers live in places with a high percentage of clear nights. Most of us aren't that lucky. I myself, for instance, have spent my entire life in places that rated only poor to fair in terms of numbers of clear nights and yet my love of astronomy has endured undiminished for over forty years. One good night with my astronomy binoculars or my telescopes will get me through sometimes months of cloudy nights. It’s not the number of nights at the telescope that counts. Go ahead and buy a telescope. Welcome to astronomy! Tuesday, June 07, 2011Summer nights and telescopesWhen I was young, I found it fascinating to learn that summer days in the north country were so incredibly long and, if I could someday live as far north as Alaska, there would even be enough daylight that I might not have to go to bed at night! That's every kid's dream summer. Now that I am older and an avid astronomer, though, with a lot of money invested in astronomy binoculars, telescopes and telescope accessories, I am not that crazy about such long summer days or, more to the point, such short summer nights. It’s not that I don’t love summer observing, it’s just that there is so little of it each night. Right now, as of early June, up here in northern Wisconsin, I am wasting my time looking through a telescope eyepiece much before 9:30 in the evening and, it will be after 10:00 in the evening in a couple of weeks before things are dark enough to setup & use a telescope. On the other end of the day night/cycle, it starts to get light around here at 4:30 in the morning this time of year. That makes for a rather narrow observing window when you want to get out and use your telescopes or binoculars. Of course, I get all that lost darkness back in our north country winters, but wouldn’t it be nice to have both long nights and warm temperatures when using my telescopes? Oh, you can also have the mosquitoes, too. They have a tendency to make my summer observing sessions even shorter. Friday, June 03, 2011Share a spotting scope or telescopeThose of us who use optics on a nearly daily basis, whether it be binoculars, spotting scopes, microscopes, telescopes, whatever, acquire certain skills in using our optical equipment that we come to take for granted. Then, when we invite someone else to look through a spotting scope or telescope eyepiece, we just assume they know what they are doing, same as us. Big mistake. I’ve learned the hard way to instruct people ahead of time when I invite them to look through my optics. I’ve had people topple over my spotting scope and knock telescope eyepieces out of the focuser, to name just a couple of instances where I paid the price for lack of prior instructions. At the very least, without prior instructions, you’ll get people touching lens surfaces or touching the wrong knobs. People just have a tendency to put their fingers where they are not supposed to go or grab hold of something they should not touch. Sometimes they do this out of curiosity and sometimes they do this without being aware of it. It’s more than putting your equipment in harm’s way, too. It’s also a matter of helping people correctly place their eyes over eyepieces in order to see anything at all. In the past, I have been a tour guide on birdwatching expeditions and also at a local astronomy observatory. I love to show folks all the many things to be seen in the spotting scope or telescope, but I’ve learned there is right way to share a spotting scope or telescope and a wrong way. If you expect to invite others to look through your equipment, you need to provide instruction, first. That's the right way. Summer astronomyOne of the things I remember about my first taste of astronomy was how hot it was that summer. I also remember how anxious I was on some evenings that first summer for the sun to go down and the sky to get good and dark so I could setup & use a telescope or binoculars. I had the astronomy bug and I had it bad. (Still do, after forty years, too.) Summer, as a season to use telescopes and astronomy binoculars, has it disadvantages, but I love it all the same. Maybe it’s because it was the season when I first looked through a telescope eyepiece or maybe it’s because I also know what it is like to look through a telescope eyepiece and have my eyelashes freeze to the eyepiece. Oh, yeah, bring on summer. Of course, in those days I was a college student taking only a couple of summer classes, so I could afford to stay out late and that is important for summer astronomy, because the sky doesn’t get telescope usably dark until rather late on summer evenings. That makes things rough if you have to get up for work early the next morning. And what would summer astronomy be without mosquitoes? Still, there is something about summer nights under the stars with a good telescope or astronomy binoculars that just can’t be beat. At the very least, summer nights are often the most comfortable time of day when things get really hot. Summer also just happens to be a season when the sky is especially rich with treasures to be seen in telescopes or binoculars, but even without the help of telescopes or binoculars, summer is a great season just to grab a lawn chair and sit out under the stars and marvel at it all. Summer is my favorite season for astronomy. Thursday, June 02, 2011Astronomy magic, Dobsonian telescopesSometimes, you do get those nights with the telescope under the stars where everything just comes together and you experience a little astronomy magic. Those nights are all too rare, but I had one, last night. Yesterday sure didn’t seem to be leading up to a great night looking through the telescope eyepiece. We had gale force winds most of the day with some clouds, now and then. By nightfall, however, the clouds were gone and the wind was little more than a gentle breeze. Best of all, it was new moon, so skies were at their darkest. Oh, yeah, time to setup & use a telescope, especially if you own one of those large Dobsonian telescopes as I do. Truly dark skies deserve the largest telescopes you can find. My new Obsession 12.5” was just itching to get out under the stars and so was I. With my very narrow observing window above my yard in the forest, I really had very little to observe, other than Ursa Major and Canes Venatici, but with a high grade 12.5” telescope, those two constellations alone will supply you with hours of targets to see in the telescope eyepiece. I was not disappointed. The sky transparency was superb, so I managed to spot nearly every galaxy on my star chart for the area. With my Televue 22 mm Nagler eyepiece, I was able to get both M81 and M82 in the same field of view and they were about as bright as it gets for galaxies. That was a sight I will not soon forget. As for the Owl Nebula, M97, who needs an O-III filter? It’s been at least twenty years since I’ve seen this planetary so bright and obvious. Needless to say, I got to bed rather late, last night. That’s astronomy magic for you, compliments of a great sky and enough telescope to use it. Wednesday, June 01, 2011Telescope sizeTelescope size is a double-edged sword. On the one hand, the bigger the telescope, the greater the performance and potential to see more. For some kind of work in astronomy, there is just no substitute for telescope size. You can’t turn a small telescope into a big telescope, no matter how many telescope accessories you add to your small telescope. A small telescope, even the best small telescope, is still a small telescope. That's just a fact of life when it comes to telescopes. On the other hand, big telescopes are also a big pain in the butt to move from one location to another, not to mention more time consuming when you decide to setup & use a telescope for a night of observing. Little wonder, then, that you hear horror stories of folks buying large telescopes and never using them. Large telescopes can also be harder to operate and use, though much depends on the type of telescope, here. (I can operate my 12.5” Obsession with my pinky finger.) So, there comes a point with telescope size where you should seriously consider making a permanent home for your telescope, a la an observatory. I have always recommended 12” as the place to consider putting your telescope in an observatory, even if it is nothing more than a shed with a removable roof. It will save you of so much time and eliminate the headaches of dealing with large telescopes. An observatory means you will spend more time looking through the telescope eyepiece and less time on telescope setup and preparation. That's the idea. Now, where is my husband Bill? He love building things … |
|
|
|
|
© 1999- OpticsPlanet, Inc
- telescopes,
binoculars,
microscopes,
riflescopes,
rangefinders,
& more.