The Uncluttered Telescope Buyer’s Guide

• Author: admin
• Filed under: Buyer's Tips
• Date: Oct 16,2008

By Matthew Kriebel

There are several telescope buyers guides available on the Internet, some good, some not so good. Many of them carry far too much information that a beginner doesn’t need. This guide is from our experience with telescope customers and hope it is simple and helpful in helping you choose a telescope!

Towards that end, the first and in some ways only rule of telescopes is:

Aperture is King!

Aperture is the diameter of the main lens or mirror of the telescope. The bigger it is, the more light the telescope gathers. Do not judge a telescope by its magnification, and stay away from any brand of telescope that sells itself on excess magnification claims (300x!, 600x!, etc.). This is sure sign of poor quality.

More light gathering means better, brighter images, assuming all other things being equal. Decent commercially sold telescopes usually start about 60mm in size (about 2.3″) and go to 20″ diameter or more. Roughly speaking, every 2 extra inches of aperture doubles the light gathering capacity of the telescope.

The big problem with getting more aperture is that it increases the size and weight of the telescope. Having a huge, giant telescope with lots of light gathering power has little benefit if it is so heavy you never want to take it out and use it! A minor, but critical caveat to the ‘Aperture is King’ rule is that the small, portable telescope that gets used all the time is more powerful than the giant telescope that never gets moved out of the garage.

What Kind of Telescope?

There are three types of telescope: Reflector, Refractor, and Cassegrain. For beginners purposes, only the first two should be seriously considered. Cassegrain telescope are very nice, but are a bit advanced for first time scope buyers.

Reflector: telescopes use parabolic or spherical curved mirrors to gather and Reflector Telescopeconcentrate light. The advantage of reflector telescopes is that they are the most economical for larger sizes. The disadvantages are: in inverted image (meaning a reflector telescope cannot be used for looking down the street) and a need for occasional maintenance: the mirror must occasionally be aligned, or collimated to ensure the telescope is working at its best.

Refractor: telescopes use two or more lenses to gather and bend (or refract) light. The Refractor Telescopeadvantage for refractors is that, at equal sizes, they provide a more crisp image of the object being view versus a reflector telescope, refractors also can be used for terrestrial viewing (i.e. Looking down the street again), and they do not need to be collimated like reflector telescopes. The disadvantages to refractor telescopes is that as refractor telescopes get larger, they increase in price at a much faster rate than reflectors. At smaller sizes, say 2-3″ in diameter, the prices are roughly equal for reflectors and refractors. But by the time you reach a 5″ aperture, the price of the refractor will be at least double that of the reflector.

Due to the difficulty of grinding larger lenses, the weight of those lenses, and an optical effect called chromatic aberration (where the light is broken up as it travels through the refractors lens in a manner similar to prisms) refractors generally are not made larger than 5-6″ in diameter.

What Kind of Mount?

Any telescope is going to need a mount! There are three different mount designs to consider: altazimuth, equatorial, and dobsonian. Whatever mount you decide on, it should be strong enough to hold the optical tube without wobbling. Nothing is more annoying than trying to view an object in the sky, only to have it bounce around and be unwatchable because of a poor mount.

Altazimuth Mounts: Altazimuth mounts are simple mounts designed to help aim the Altazimuth Mounted Telescopetelescope in simple up/down (altitude) and left/right (azimuth). Altazimuth mounts are simple and intuitive, and work well for beginners. They are also useful if you wish to use your telescope for terrestrial viewing. The problem with altazimuth mounts is this: objects in the sky do not move in convenient up/down, left/right motion. They move through the sky in an arc (or at least it seems that way to us!). This means that trying to track celestial objects using an altazimuth mount can be like drawing a curve with an etch-a-sketch! For most beginner viewing, this is not an issue, and one can always reacquire an object that moves out of the field of view. But it does mean that if you find a nice object with your telescope, and leave to go let your friends know, it will likely move out of the eyepiece view by the time you come back!

Equatorial Mounts: Sometimes called German equatorial mounts, are distinguished by Equatorially Mounted Telescopetheir counterweights that are needed to keep the telescope properly balanced. Equatorial mounts require more setup than altazimuth mounts as they must be adjusted to your latitude and aimed North. They are also not as intuitive to aim as altazimuth mounts as they do not follow left/right up/down motions but instead move along declination and right ascension. This follows the path of stars, planets, and deep space objects, but takes some getting used to. The advantages of equatorial mounts are that they can track objects with a turn of a knob, or they can even be motorized. The other advantage is that with some study, the equatorial mount’s setting circles can be used to actually find objects in the night sky! Equatorial mounts are also required for any type of astrophotography, but for beginners this should not be a great concern.

Dobsonian Mounts: Some consider the Dobsonian to be just variant of the altazimuth Dobsonian Telescopemount, and they are not completely wrong. Dobsonians have the same advantages and disadvantages of altazimuth mounts: intuitive movement, no tracking, etc. But the difference is that a Dobsonian mount uses a lazy-susan style platform to move in azimuth and usually some form of hubs to move in altitude. The result is that a Dobsonian mount can handle much, much heavier optical tubes than most altazimuth tripod mounts are capable of handling. Thanks to several improvements in design, Dobsonian mounts have become more and more popular as they are one of the most economical telescope designs on the market today.

Other Considerations:

The optical tube and mount are major concerns, but they are not the only things one should consider when buying a telescope:

Eyepieces: Eyepieces are often overlooked when buying a telescope, but they should be considered seriously by the beginner as they are 50% of the overall optical system. Almost all telescopes include 1 or 2 eyepieces, but by no means are all eyepieces created equal. Cheap telescopes usually include old, cheap eyepiece designs such as Ramsden or Huygenian designs that actually can make the image worse. The telescope you buy should come with eyepieces that, at a minimum, are Kellner or preferably Plossl design. These eyepiece designs are considered the standard for decent eyepieces.

Finder Scope: Every telescope needs a finder scope, a small telescope that sits on top of your main optical tube and aids in aiming the telescope. Most lower end telescopes these days use a reflex finder which projects a red dot onto an optical window to show where the telescope is pointing. These reflex finders are actually easier to use than a cheap finder scope would be. However, for larger telescopes a 6×30 (which stands for: 6 magnification, 30mm aperture) finder scope is much more appropriate. Larger telescopes may also have even larger finder scopes. Avoid telescopes with old 5x finder scopes, or at least be willing to try and attach some sort of reflex finder in its place.

Optional Accessories: Not everything you need for observing the night sky will come with your telescope (and if it does, beware, some companies gussy up cheap scopes with cheap accessories!). There are some things that should be in any astronomer’s ‘kit’. Such as:

1. A Planisphere: Make certain this is one you can read easily at night with your red flashlight!
2. A Red Light Flashlight: A red flashlight prevents you from losing your night vision the way a regular (white) flashlight would.
3. A Barlow Lens: A Barlow lens is a lens you slip your eyepieces into that then doubles or triples their magnification. Having a barlow is like doubling the number of eyepieces you have. Make sure you have a barlow before you go buying additional eyepieces.
4. A decent Astronomy book: Don’t just buy a book with pretty pictures. Make certain it is a useful book that gives helpful instructions and advice on how to use your telescope, find& observe night-sky objects and other hints. Make certain to read it fully before you go observing, then refer to it during your observation session.
5. Time and good weather: Make certain that you have time for your new hobby. It takes some commitment for even casual viewing. Also, make certain that before you go observing that the weather is decent for viewing. There’s no point in going observing on a night where haze clouds everything in view.
6. Warm clothing: OK, you should really have this stuff already. But it is important to know. Even in warm summer months the temperature can get surprisingly cool at night. Be certain that you are ready for the weather, wherever you are and whenever you observe.

Other accessories you should consider, but are not as crucial as the above items are:

1. Filters: There are a lot of filters available, and they all help with viewing certain objects. Moon filters cut down on the bright moon (which can actually be painful to view through a large telescope!). Color filters help bring out features of the planets. Sky Pollution filters reduce (but do not eliminate) the effects of light pollution. Read up on their effects and decide if any of these filters are right for your needs.
2. A Carrying Case (for accessories): Eyepieces, barlows, filters, books, & planispheres! All these little parts can be hard to carry and just shoving them into a bag isn’t a very good idea. Consider buying an accessory case to put your eyepieces, etc in for easy transportation. The time to consider getting a carrying case is when moving the accessories is starting to get in the way of your night sky enjoym
3. Binoculars! :If you haven’t already gotten a full sized pair, you should. Binoculars make for easy viewing, help find night sky objects. And are great for quick viewing. These need not be specifically astronomy binoculars, just a decent pair of full-sized binoculars will work fine.

There is plenty to consider when buying your first telescope, but some things should not be worried about. These include:

1. Astrophotography: Astrophotography, even in the age of digital cameras, is pretty advanced stuff that requires a lot of time and equipment. Trying to jump into it, or making your telescope buying decisions based on it, is like learning to swim by jumping into a the deep end of the pool. First make certain that you enjoy astronomy, and can commit the time for basic viewing before you even consider taking up astrophotography. Remember that if you need a different mount than what you initially buy as your first telescope that you can usually sell the old telescope at a reasonable price.
2. Ultra-High End GPS Super GoTo Computer Guidance Systems: These systems, while great, can actually be problematic. They are expensive, aren’t the ‘idiot-proof’ systems some folks make them out to be, they limit you from learning about the night sky, and many designs actually require that you aim with the computer. This means if the computer’s motors run out of battery power, you can’t even aim the telescope yourself! Basic guidance systems, such as the Orion Intelliscope line are useful for finding objects in the night sky without taking the experience away from you! Consider these instead of completely controlled systems.
3. Color! If one were to look through a book of astronomy picture you would think that every view of the night sky through a telescope is awash in bright, pretty colors. Sadly, this is not the case. Most of these photos are taken with long exposure photography and show colors that, while there, are not apparent to the human eye. Be realistic about what you see, and make certain that the telescope you buy doesn’t have tons of unrealistic photos on its box (which were usually taken by the Hubble Space Telescope or the Viking and Voyager probes!).

With this guide we hope that you will have the ability to make a much more informed decision about what sort of telescope you want. Whatever telescope you buy or where ever you buy it, happy observing!

About the author

Matt Kriebel is the owner of the telescope & science store Spectrum Scientifics. Spectrum Scientifics is your source for telescopes, microscopes, binoculars, science toys, weather instruments, robots, and fun and useful science items.

Be sure to read the Spectrum Scientifics Store Blog: blog.spectrum-scientifics.com!

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http://EzineArticles.com/?The-Uncluttered-Telescope-Buyers-Guide&id=1468252

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Binoculars For Astronomy - How To Purchase Binoculars For Viewing The Night Stars In All Their Glory

• Author: admin
• Filed under: Astronomy, binoculars
• Date: Jul 1,2008

By Paul Maxey

Whether you’re a beginning amateur astronomer or a seasoned veteran, if you’re not using binoculars for astronomy you’re most certainly missing out. I’ve enjoyed stargazing with binoculars for many years and, during that time, have evaluated many different types of binoculars. While being an amateur astronomer can bring with it a high cost of entry, it doesn’t have to if you approach your new hobby appropriately from the beginning.

The truth is, many phenomena in the night sky can be seen with minimal equipment and even with the naked eye. In fact, a good pair of binoculars can take you a long way before you even begin to consider buying a telescope. One of the main advantages I’ve found over the years with binocular astronomy, as opposed to the traditional telescope, is the sharpness and clarity. By viewing with both eyes simultaneously, you can see as much as 35-40% more detail than you can with a telescope.

When it comes to astronomy, binoculars can be used primarily for locating objects in the night sky, for viewing them, or both. Each application requires a different set of priorities when determining the binocular specifications. That said, here are several factors you should consider:

* 1) Mounting: Your first priority for viewing the night sky is whether you will hold them or mount them on a tripod. Binoculars that will primarily be hand held should be lighter. This generally means they will have less magnification, but they will also have a larger field of view, allowing you to view more of the sky at one time. Mounted binoculars can have a much larger objective lenses, meaning much higher magnification. But, this naturally means a smaller field of view. Another consideration is that binoculars mounted on a tripod will provide greater image detail than binoculars that are wobbly and constantly trying to maintain focus on distant objects.

* 2) Aperture: You can use virtually any binoculars for an occasional look at the night sky. But, binoculars with large objectives (50mm and larger) are much better suited for more serious astronomical purposes than their smaller and more compact relatives due to their greater light-gathering ability. Nothing quite compares to viewing celestial objects through a pair of giant astronomy binoculars. The view is much wider than that of a telescope allowing large objects, such as nebulas and entire galaxies, to fit in their field of view. Keep in mind also that the older you are, the less likely it is that your eye pupils will be able to open to larger exit pupils. Hence, 7×50 binoculars (7 mm exit pupil) may not be appropriate for you. Your best bet may be to try 10×50 (5 mm exit pupil).

* 3) Magnification: Once you begin looking at binoculars with a magnification of 10x and higher, they can get heavy very quickly, making for an incredibly shaky image. Again, consider mounting them on a tripod so you can go for a larger magnification.

* 4) Lens coatings: Lenses are coated to improve light transmission through the lenses. Binoculars that are not coated can lose as much as 50 percent of the light that enters them. Frankly, there’s no excuse for anything less than “fully multi-coated” (FMC) for astronomy. This simply means that all air-to-glass surfaces are coated multiple times. With multi-coating now featured on very low-grade binoculars it is very inexpensive.

* 5) Eye relief: If you wear eyeglasses, you’ll want to find binoculars with the proper eye relief. Many models provide long eye relief, allowing you to see the complete field of view with or without eyeglasses.

* 6) Field of view: This is how much of the sky you can see through the binoculars at any one time. Most that offer extremely wide views do so by compromising the quality of the image. A wider field of view can also be obtained with more expensive eyepieces.

As is evident from the above, not all binoculars are suitable for stargazing. As with anything, you must find the right balance of features and price for you. But knowing your options in advance will greatly aide you in finding the best pair of binoculars for you or the budding astronomer in your family to enjoy the wonders of space and science.

If you want to read more, see our quick review of binoculars for astronomy by visiting http://www.buydiscountbinoculars.com, a popular binoculars website that provides tips, advice and resources to include information on Apogee binoculars, Leupold binoculars and more.

Article Source: http://EzineArticles.com/?expert=Paul_Maxey
http://EzineArticles.com/?Binoculars-For-Astronomy—How-To-Purchase-Binoculars-For-Viewing-The-Night-Stars-In-All-Their-Glory&id=1117289

Zhumell 20×80 SuperGiant Astronomical Binoculars - Bestseller!

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A Beginner’s Guide to Telescopes

• Author: admin
• Filed under: binoculars
• Date: Jul 1,2008

By Angelo Valenti

For a backyard astronomer you have many options on what type of telescope to use in your endeavor. With all types of pricing, you may decide to go cheap on your first telescope, which is not advised. A cheap telescope may hinder you enjoyment of star gazing. Telescopes come in a wide variety of prices, starting with the cheap knockoffs, to the professional models that may cost thousands of dollars. If you are a beginner, you may first want to do some research to find the right starter telescope that fits your needs and budget, you should be able to find a decent starter telescope for just a few hundred dollars.

The telescopes we are going to concentrate on are Reflector, Refractor, and the Schmidt-Cassegrain class. Descriptions of each follow below.

Refractor Telescopes

The first telescope a beginner may think of are reflectors. That is the style that we are most accustomed to seeing, and cheap ones can be found plentiful in department and discount stores. But with a quality refractor telescope, This is where the comparison ends. A refractor telescope is usually a long, thin tube, mounted on a tripod. Because of this design, Refractor telescopes are portable and easy to move, and are simple to use. Refractor telescope are generally used for viewing the moon, sun, and planets.

The aperture of a refractor telescope is an important consideration for optimum viewing. This is the light gathering lens diameter. Generally, you would want have an aperture of 70mm, but you may prefer a larger diameter for a larger view.

Reflector Telescopes

If you are interested in viewing far away galaxies, distant star clusters or nebula, theReflector Telescopeis the one for you. Reflectorsuse mirrors in the base of large tubes for gathering light. An addition of a mount, or Dobsonian moves up and down to adjust for altitude, and it also pivots, a very easy design to use.

6″ and 8″ are popular sizes, but larger sizes are available. Price per inch, reflector telescopes are an inexpensive option for viewing deep sky objects.

Schmidt-Cassegrain

A telescope that brings together the technologies of both reflector and refractor telescopes is called a Schmidt-Cassegraintelescope.

These are the telescopes that you would use in astrophotography. A camera can be easily mounted to the eyepiece allowing breathtaking shots of the cosmos. Use of a computer and software allows you to program objects and coordinates for easy viewing. The Schmidt-Cassegrain pricing is about midway between refractor and reflector.

Angelo Valenti

This guide is designed to help the beginner astronomer make the right decision on what type of telescope may serve there needs. We make no claims to the superiority of any brand of telescope.
For more information, telescopes and accessories, please visit http://telescopefanatic.com

Article Source: http://EzineArticles.com/?expert=Angelo_Valenti
http://EzineArticles.com/?A-Beginners-Guide-to-Telescopes&id=1171471

Best Beginner’s Telescope

Celestron AstroMaster 114 EQ Reflector Telescope

Top Recommended Telescope

Celestron 11 Inch CPC Schmidt-Cassegrain Telescope

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Useful Article from EzineArticles: Resolving Power of Telescopes

• Author: admin
• Filed under: Buyer's Tips, telescopes
• Date: Jun 16,2008

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How to choose a telescope: Magnification revisited…

• Author: admin
• Filed under: Buyer's Tips, telescopes
• Date: May 22,2008

We’ve realized that in all of our ‘how-to-choose’ articles, we make a concerted effort to warn prospective buyers of optical instruments against magnification hype. And for good reason too. We still see people around us falling for that trick and ending up with instruments that have either poor optics or insufficient aperture or both. Hopefully our readers do not fall prey to the marketing machine anymore. Just to be sure that our newer readers are aware of this trap, we will quickly revisit it here (and expand on it a bit):

While the hyped-up power ratings often seen are not necessarily fraudulent claims (the instrument will usually go to the stated magnification), there is a limit to usable magnification. The quality of the lens, mirrors, eyepieces, etc play a huge role in how much of that power one can actually use. At high magnification, the image and also imperfections in glass are also magnified.

The same goes for movement. At high magnification, movement is also magnified and the slightest movement renders the image completely unusable, and in the end all you can see is a blur! So this is where the usable magnification is clearly determined in part by the quality of the optics and also the quality of mounts and/or tripods.

Lens diameter is a key factor in the amount of usable power and the general rule of thumb, called the sixty rule, states that the upper limit of a telescope’s power is determined by its lens diameter (in inches) multiplied by 60. For example, a 4″ telescope has a maximum usable power rating of 240X. In our experience, if you take 15% off that, you have a more reliable maximum power rating that does not depend on perfect viewing conditions. that And this upper limit pretty much is assuming you have an extraordinarily calm and clear night sky.

So, if you’re after power, then choose a scope with largest diameter lens that you can afford. Large diameter lenses capture more light too, so you are able to view much dimmer objects (Note: a 4-inch scope has four times the light gathering power of a 2-inch scope, and not double).

Optical quality and mount stability are not even a consideration - never compromise on those - its all about usable power, remember? If the image is blurry, its blurry. And that’s that - your first date with your new scope (and maybe even a new hobby) is ruined before the romance could even really get started…

Note

Often a larger diameter scope in the same series is only slightly more expensive than the one below it. These Celestron scopes are a good example. If budget allows, we always recommend higher apertures…

Price: $599.00

Celestron NexStar 4 SE Telescope

Price: $799.00

Celestron NexStar 5 SE Telescope

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Why we recommend the binocular, telescope and night-vision vendors we do…

• Author: admin
• Filed under: Buyer's Tips
• Date: May 19,2008

We have been asked by a few of our readers why we always recommend the same vendors.

Well, the suppliers we recommend have excellent track records and reputations. That’s the most important consideration for us at the moment, since we have had (and heard of) some bad experiences with some fairly ‘big name’ vendors that trade via the Internet.

Also, telescopes.com, binoculars.com and thenightvisionstore.com consistently have the lowest prices (about 99% of the time) for the instruments we recommend. Add to that the fact that they often offer free or very low-cost shipping within continental US, and the savings to our readers are often quite dramatic. Stock availability and delivery times are also always excellent.

We also recommend the mighty Amazon.com (and Amazon.co.uk for our UK readers) because their dedication to customer satisfaction is world-famous. While they do not carry the variety of items that the abovementioned vendors do and their prices are slightly higher, our readers often save a bit of money when they purchase Amazon’s famous package deals.

So, until we can find a better deal for our readers, we are happy to endorse the vendors that we currently do.

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Stablized binoculars

• Author: admin
• Filed under: Buyer's Tips, binoculars
• Date: May 5,2008

Stabilized binoculars are becoming very popular because they have the ability to minimize the inevitable motion while viewing caused by movements such as shaking hands, moving vehicles, vibrations, etc. Not all stabilized binoculars are created equal though, and they differ in the mechanisms used in stabilizing the image.

One of the mechanisms includes the so-called active systems. In active systems, the movement in the binocular is determined using a sensor. With the help of the sensor, other areas of the binoculars’ system are changed to give the user a stable view. Passive systems require the user to manually set the stabilization of the binocular either by the help of a gyroscope or disengaging some parts of the binoculars’ casing.

There are actually three types of stabilized binoculars to choose from:

Gyro-stabilized

This battery powered stabilized binocular has a passive system and stabilizes at a very fast rate. It is, however, quite bulky and heavy.

Vary-angle Prismatic (VAP)

These stabilized binoculars have microprocessors that accept signals from special sensors. Whenever a signal is received by the microprocessor, it automatically stabilizes the image as its initial response. While it also requires batteries, it is more compact and weighs less than gyro-stabilized binocular.

Cardanic suspension

This is the latest innovation when it comes to stabilized binoculars. Cardanic suspension type of stabilized binocular has a prism system which is mechanically suspended that allows the image to be clear and stabilized once viewed by the user. These are quite a bit pricier than the first two types of stabilized binoculars, but they are quickly becoming the most popular due their light weight. They also do not require batteries or any external power.

Of the 3 types, we recommend the cardanic suspension models. They are rapidly becoming one of the fastest selling binoculars in the market today- and for good reason.

Our recommendation:

Canon 10×30 IS Image Stabilized Binoculars

This is a great informational video about the “Canon 10×30 IS” and provides

and excellent general introduction to how these instruments work:

Consistently the best deals on the Web…

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More on choosing a binocular

• Author: admin
• Filed under: Buyer's Tips, binoculars
• Date: May 5,2008

Shopping for a new pair of binoculars for you or yours can be very overwhelming, given the large variety available. Our article: Choosing a binoculars - beware the ‘power’ hype!, covers a lot of ground, but we felt that an additional article on the main types of binoculars would be helpful to our readers and would assist them in choosing a binocular that best suits their needs.

Astronomy binoculars

Perfect for novice astronomers, especially since they are much more portable than most good quality telescopes. Since these binoculars are usually of very high power and have large diameter lenses to capture as much light as possible, it is recommended that they be used with a tripod. Good optical quality is a must with these, and fully multi-coated lenses are essential.

See our review on Zhumell’s 20×80 SuperGiant Astronomical Binocular

Marine/Boating binoculars

Astronomy binoculars make work well for this application, but specialized boating binoculars have rubber armored housing and waterproof construction. Since sea spray is notorious for damaging sophisticated equipment, it is best to find a pair of marine binoculars that will be best protected. Power and lens diameter are also similar to astronomy binoculars, since they are often used under low-light conditions.

Hunting and Birdwatching binoculars

Nikon 8×42 Monarch ATB

Generally, low power and fairly large lens diameter is the order of the day here. The best powerXaperture for hunting and birding binoculars would be 7X50, 7X35, 8X30, 8X40, and 10X50. All of these choices are great for pinpointing the animals’ location and details due to the low power but high magnification and light transmission, without the need for a tripod. It is best to choose a binocular that has a specialized focusing feature,sicne the subjects’ details and tiny movements are of the utmost importance in both hunting and birding. Moreover, choose a pair of hunting or birding binoculars with an extended eye relief feature so you can comfortably view your subject for long periods of time. As with marine binoculars, it is best to choose a birding and hunting binoculars that has a rugged housing or rubber armor construction.

Sports binoculars

Nikon 8×40 Action Ultra-Wide-View Binoculars

These offer a spectator a much-needed close-up view of the sport when seats aren’t optimum. Typically, the best binoculars for outdoor sports events have lower power and medium lens diameter, e.g. 7X32, 7X35. Wide angle binoculars are the order of the day here, as they enable the viewer to follow a play without having to move their head too much. Remember, comfort is everything for sports applications.

General use binoculars

Zhumell FC Compact Binoculars

Many people want to purchase an instrument that they can use for more than one application. These general use binoculars aren’t perfect for all applications, but if you choose a quality brand, they are fine most of the time. For convenience and portability (there is nothing as frustration as wishing you had your binoculars with you), we recommend one of the compact models. Those you can bring along anywhere, just in case…

Consistently the best deals on the Web…

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How to choose a night vision device

• Author: admin
• Filed under: Buyer's Tips, Uncategorized, night vision
• Date: Apr 15,2008

It is very important to note that affordable night vision optical systems require some light to work. This can be moonlight, artificial ‘ambient’ light or artificial infra-red light.

Image intensifying night vision devices are by far the widely used. The other type is thermal imaging, which ’sees’ only areas of heat on a body, or which have been left behind by some event or thing. Image intensification is also referred to as gain multiplication.The ‘trick’ with night vision goggles, monoculars and binoculars is that they collect infrared and visible light with the objective lens and focuses it on a battery powered image intensifier, which amplifies the signal as follows:

• a photo-cathode inside the tube absorbs the light energy and converts it into electrons
• the ‘image’ formed by the energized electron strikes a phosphor screen
• the phosphor screen fluoresces, forming an image that the user sees through the eyepiece(s)
• Note: the phosphor screen is colored green because the human eye can differentiate more shades of green than other colors, thereby providing very a realistic ‘gray scale’-like image.

Selection criteria 1: Light Amplification

As can be expected, the major difference between various ‘grades’ (and prices) of night vision devices is the quality and sophistication of the intensifier tube:

Generation 1

These instruments have medium gain values giving good images, and their intensifiers are made up of simple electrostatic tubes, which are able to amplify available light by 500-20,000 times. They work more or less as described above.

While Gen-1 night vision devices cost less and are almost always larger and heavier than instruments from the other categories, don’t turn your nose up at them because they’re ‘only’ Gen-1 (there was a generation 0 ). If you don’t have a big budget, and do not need to use your night vision device in very dark environments, then they make good financial sense. Note that Generation 1 night vision devices’ utility can be greatly expanded when infrared illuminators are used - even when there is ZERO ambient light present.

Generation 2

These are smaller, lighter and more energy efficient. are generally smaller in size and weight and use noticeably less current. These devices have microchannel plate added under the image intensifier, which ‘pre-amplifies’ the available light signal and thereby significantly improves light amplification - approximately 20,00-75,000 times amplification.

These are by far our most highly recommended grade if you can afford them - much harder to ‘outgrow’ than Gen-1.

Generation 3

These are very costly devices, and are naturally suited for those people whose lives (or livelihoods) depend on night vision, e.g. law enforcement, military, security personnel and even researchers.

As with anything, there are always enthusiasts that want to buy the ‘best’, and spend a lot of cash on Generation-4, which are full military-spec. We would only recommend those if money is not a problem

Selection criteria 2: Intended use

Night vision devices are frequently used for:

• spelunking
• scouting games
• camping and exploration
• observing wildlife
• hunting
• police surveillance
• nighttime security

Once you are sure about what you will be using your device for, and what the worst operational conditions would be, you will need to consider: gain, range and image quality. In our experience, the latter two are primarily determined by the former, which is determined by the Generation/grade. Another thing to consider is whether you will be able to use an infrared illuminator (built-in or accessory), since they drastically improve range and image quality. Infrared illuminators are probably well suited for cave exploration, while they may not be for law enforcement tactical operations. Its quite easy to decide, but you must give it some thought.

While tempting, it is quite difficult to suggest a hard and fast formula for selecting a night vision device, so we’ll offer an example instead:

Some friends of ours are ardent paintball enthusiasts. Recently, they discovered that practicing for their ‘war games’ competitions at night while wearing night vision goggles is not only great fun, but really improved their competitiveness during the day. These guys may actually be onto something and it sounds like great fun, but we cringe at the thought of paint getting all over such fine devices (they claim it does not)! Certainly more exciting than a “Dinner in the Dark Party”, where guests wear night vision goggles while dining!

How we used their needs to recommend a night version device:

• low light operation
• no infrared illuminators
• ‘hands-free’
• ± only 75m range needed
• very good clarity
• wide angle view

We recommended ATN NVG7 Generation 2 Night Vision Goggles, since a Generation 1 device would not work well on very dark nights. Given how well those are working for the paintballers, we would recommend the same for law enforcement and security/surveillance personnel that may have to use their night vision devices during a tactical operation. Of course, if there is a bigger budget, then Gen-3 would be better - not for paint-balling though! Too expensive and sacrilegious …

Note: less magnification generally results in brighter, clearer images. Choose the lowest magnification you can live with.

In ending, we would like to comment on monoculars. It is our opinion that while monoculars are quite a bit cheaper than binoculars, they are too tiring on the eyes when used for extended periods. If you’re going to buy a handheld device, then we recommend buying binoculars over monoculars.

Recommended night vision devices

Bushnell 2.5×42 Night Vision Binocular w/Built-In IR

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Rigel 3200 Pro Night Vision Goggle

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Night Owl Explorer Pro 5x Binocular

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ATN Night Shadow Generation 2+ Night Vision Bi-Ocular

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ATN Night Shadow Generation 3A Night Vision Bi-Ocular

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ATN NVG7 Generation 2+ Night Vision Goggle

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USNV-PVS-7 XD-4 Military Spec

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Choosing a Telescope

• Author: admin
• Filed under: Buyer's Tips, telescopes
• Date: Apr 8,2008

We’ve written this guide for a beginner, or someone who has been disappointed by his/her first purchase(s). Those with more experience will already have learned a lot in the field or from more experienced enthusiasts, and can make more informed choices.

Do you really need a telescope?

Many many times, people buy telescopes because they think its what they need. In many cases, a good binocular is a better tool for the job, and it is much more versatile and portable too!

Do your research. Ask people who already do what you are planning to do. Save yourself some money and frustration. If budget is a limitation, then a good $100-150 binoculars is more often than not much better than a junky telescope - most times that same binoculars is a better bet even when you have a huge budget. Beginners and even intermediate amateurs do not need fancy telescopes!

Since you should get a high quality telescope that you won’t outgrow quickly or lose interest in, it will be hard to keep prices very low - but there are some good choices that are reasonably priced. Just remember - quality first! A bad choice for your telescope will lead to frustration and disappointment rather than enjoyable nights under the stars. Remember, good telescope can last a lifetime - even longer.

If you’re still convinced that you need a telescope, read on…

Types of Telescopes

There are three main classes of telescopes available to the amateur astronomer:

1. Refractor telescopes - classic “department store look” telescopes that use refracting lenses housed in a long, thin tube mounted on a tripod. OK for viewing the sun, moon and planets where magnification detail is more important than brightness.
2. Reflector telescopes - large instruments that use mirrors housed in large tubes. They really ‘grab’ lots of light and are great for viewing faint, deep-sky objects like galaxies, star clusters and nebula.
3. Compound telescopes - also called cadioptric telescopes, They use both refracting lenses and reflecting mirrors, which provides compactness. Designs include those of Schmidt, Cassegrain (Cass), Maksutov (Mak) and hybrids.

Buy from a reputable dealership

While this seems like just pure common sense, many a potential enthusiast has had their envisaged love-affair with optical systems destroyed very quickly because they paid good money for bad equipment from a ‘gadget supply store’. A telescope is not a gadget. It is a marvel of physics and should be seen as such. So buy from a reputable store, whether online or traditional ‘brick and mortar’.

Beware the power/magnification hype!

We say exactly the same thing in our guide to buying binoculars. Shrewd manufacturers and dealers use the promise of magnification to hypnotize and trap the unwary newcomer. The outrageous (for what is being sold) specifications of 400x, 1200x, etc magnification is just hype and has no relation to actual usable power.

Aperture rules, OK?

Just as with binoculars, what you should be after is aperture, which is determined by the objective lens. The more light it can capture, the clearer and brighter the image.

While many lower-end ‘budget’ telescopes perform OK on a bright day, they are almost useless at night. And trust us, even if it was not the originally intended use, most telescope owners eventually turn their instrument to the heavens on a cloudless night, hoping to see what they see in magazines and on the Internet. A large percentage of them end up very disappointed. So, forgo power for aperture (after you have identified a reputable dealer of course).

Both light gathering and resolving power increase as apertures increase, which means that you will be able to see dimmer objects. Note: a 4-inch scope has four times the light gathering power of a 2-inch scope, and not double. (2 x 2 =4).

As can be expected, manufacturers are starting to push larger lenses as ‘beginners’ do more research before they buy. The end result is the production of telescopes with reasonable power ratings, large apertures, and junk optical quality. And there is no substitute for optical quality. If everything is just a blur, then you may as well not even look at it. Trust us, its that disappointing!

Buy the smallest telescope for your needs

Of course the previously mentioned factors are most important, but the more portable and easily usable your scope is, the more likely it is that you will have it with you when a great viewing opportunity presents itself. The smaller sized scope coupled with a good mounting also means that you will be able to set up and focus much more quickly than with a huge scope.

Mount stability

Poor stability will turn working with even a very good telescope into a real nightmare. Be sure to budget with a nice solid tripod in mind, and remember that it can easily set you back more than $250 - but it is well worth it - we would even go so far as to say its essential.

Join a club or an online community!

There is not much to be said about this other than that you should learn from other’s experiences and/or mistakes. Ask questions, learn as much as you can. It’ll save you money, time and potential frustration. The advantage of joining an actual club is that you will be able to work with other members’ equipment, even if just for a quick look and feel. Its a great way to identify a short-list of scopes to make a selection from.

All of the telescopes that we strongly recommend below have also received excellent reviews from others like you, the buyer/enthusiast. You will do well with any of these, but the more sophisticated ones will be with you for a very long time, since its hard for even an experienced amateur to ‘outgrow’ those.

Recommended telescopes (in order of cost & ’sophistication’)

Meade ETX-80AT-TC Astro Telescope with AutoStar

Automatic finding and tracking of thousands of objects

AutoStar Suite Astronomer Edition Software

Instructional video

Compact and easy to use

Zhumell 8-Inch Dobsonian Reflector Telescope

Celestron NexStar 130 SLT Telescope

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