Telescopes Styles:There are three basic telescope styles.  In the refracting telescope (a) light is collected by a 2-element objective lens and brought to a focus at F. By contrast the reflecting telescope (b) uses a concave mirror for this purpose. The mirror-lens, or catadioptric, telescope (c) employs a combination of both mirrors and lenses, resulting in a shorter, more portable optical tube assembly. All telescopes use an eyepiece (located behind the focal point, F) to magnify the image formed by the primary optical system.

Reflector: use a large objective lens as their primary light-collecting element. BCI refractors, in all models and apertures, include achromatic (2-element) objective lenses, in order to reduce or virtually eliminate the false color (chromatic aberration) that results in the telescopic image when light passes through a lens.

Refractor: use a concave primary mirror to collect light and form an image. In the Newtonian type of reflector, light is reflected by a small, flat secondary mirror to the side of the main tube for observation of the image.

Catadioptric: employ both mirrors and lenses, resulting in optical configurations that achieve remarkable image quality and resolution, while housing the optics in extremely short, highly portable optical tubes.

Astronomy Knowledge & Software

Most amateur first-time telescope users know little or nothing about the night sky, and you certainly do not need a course in astronomy to enjoy your telescope to the fullest. Begin with the objects easiest to find: the Moon, Jupiter, Saturn, Venus, Mars etc. which are bright objects even in the midst of a big-city environment and can be located by using star maps in popular monthly magazines. Analogous to the Earth's longitude and latitude, the celestial sphere is divided by a grid of lines that are used to define the positions of every object in the sky. Just as the location of, say, Paris, is defined on Earth by its longitude and latitude, so the position of the Orion Nebula in the sky is defined by its Right Ascension and Declination. Right Ascension is the celestial analog to the Earth's longitude, and Declination is the celestial analog to the Earth's latitude.

For more advanced celestial listings, use BCI’s Starexplorer™ sky software because—

l        Fun the whole family can enjoy! Explore the heavens on your personal computer with Starexplorer™---vividly displays over 10,000 astronomical objectives on screen.

l        Print detailed star charts to guide you on your journey through space.

l        Locate planets, galaxies, nebulae, and star clusters quickly and easily in the night sky.

l        Easy-to-use Microsoft ® Windows™ pull-down menus and on-line help.

Focal Length & Power: The distance between the point where incoming light meets the first optical element and the point where the image appears. The longer the focal length, the higher the magnification you can get. Focal length is how far the light travels inside the telescope.  The telescope objective lens has a focal length and the ocular lens (Eyepiece) has a focal length. These determine the magnification of what you see.
The power, or magnification is a function of the focal length of the telescope's main (objective) lens (or primary mirror) and the focal length of the eyepiece employed. The focal length of the objective lens is the distance between the lens and the point at which it brings light rays to a focus; this focal length (in millimeters, or mm) is printed on a label affixed to the optical tube of every telescope. The focal length of each eyepiece (which typically ranges from 4mm to about 40mm) is printed on the upper surface of the eyepiece. To calculate power, divide the focal length of the eyepiece into the focal length of the objective lens.

Telescope power value = Objective focal length F' Eyepiece
Focal Length F' x Barlow lens power

For example, RR70060E telescope has a focal length of 700mm. The 4mm eyepiece will produce a magnification of 175 (700mm divided by 4mm = 175 power). With 3x Barlow RR70060E can reach Max. Power 525x.
When buying a telescope one of the least important factors to consider is the power of the telescope. The key to observing fine detail, whether on the surface of the Moon or on a bird one mile in the distance, is not power, but aperture - i.e., the diameter of the telescope's main (objective) lens or primary mirror. The eyepiece employed determines the power and all telescopes include one or more eyepieces as standard equipment, and optional eyepieces are available for higher or lower powers. Most common mistake of the amateur observers is to "overpower" the telescope and to use magnification to which the telescope's aperture and typical atmospheric conditions cannot reasonably support. The result is an image s fuzzy, ill defined, and poorly resolved, through no fault of the telescope. Keep in mind that a smaller, lower-power, but brighter and well-resolved, image is far superior to a large, high-power, but dim and poorly resolved image.

Aperture:The aperture affects the brightness and the resolution of what you see. The aperture is the diameter of the objective lens (on refractor telescopes) or the diameter of the mirror (on reflective telescopes). The larger the aperture, the more light the telescope can gather and the sharper the resolution.

Altazimuth Mount: Once an object, whether terrestrial or astronomical, is located and centered in the telescope's field of view, the telescope's mechanical mounting permits the observer to track, or follow, the object as it moves across the landscape or sky. The objective’s motion is magnified by telescope. To the point where astronomical objects appear to move through the telescope's field of view in 10 to 30 seconds. It is therefore important for the observer to be able to follow, or track, objects as they move through the field. The simplest type of telescope mount allows the telescope to be moved up-and-down (in vertical, or altitude) and left-to-right (in horizontal, or azimuth). The altitude-azimuth (altazimuth) mounting thus permits the observer to follow objects by simple motions of the telescope in vertical and horizontal. Slow-motion controls, sometimes operated through flexible cables, can facilitate these motions. The altazimuth mount, owing to its simplicity and relatively lower cost, is widely used with telescopes in both land-viewing and astronomical applications.

Equatorial Mount: Can be adjusted 360 degrees for the following objects through the night sky. Although celestial objects are essentially fixed in their positions in the sky (on the celestial sphere, the imaginary spherical surface on which all astronomical objects are located), they appear to move in an arc across the sky, as the earth rotates underneath the sky once every 24 hours. From an astronomical point of view, therefore, the task of the telescope mounting is to compensate for the Earth's rotation and allow the observer to track the Moon, Jupiter, Taurus etc. planets, and stars. This task is made vastly easier by the equatorial mounting, the type of mounting incorporated into larger or more advanced telescopes. By aligning one axis of the equatorial mount to the Earth's rotational axis (a simple process which involves pointing one telescope axis to the North Star), the observer can track astronomical objects by turning one flexible control cable, instead of the two simultaneous motions required with the altazimuth mount. If a small motor (clock drive) is attached to the equatorial mount, this tracking can be performed automatically. These motor drives are available for most BCI equatorially mounted telescopes.

Barlow Lens:  Inserted into the telescope in front of the eyepiece, the Barlow lens effectively multiplies the focal length of the main telescope. A 2x Barlow lens doubles the main telescope's effective focal length, thereby doubling the power of each eyepiece used with the Barlow.  2x Barlow doubles, 3x triplets, and so on. 

Clock Drive: Used with equatorial mounts, it is a special motor, which drives the mounts gearing so that the telescope will be synchronized with celestial motion at the earth¹s rotation.

Erecting Eyepiece: Astronomical telescopes image objects in an upside-down and reversed-left-for-right orientation. This orientation is of no consequence in astronomical observing, but for terrestrial observing a normal right-side-up image orientation is highly desirable.  It is an erecting prism or lens system inserted between the objective and eyepiece lenses to invert upside-down images for terrestrial viewing. 

The diagonal mirror (a) diverts light to a 90-degree angle for comfortable observing; the wide-field finderscope (b) facilitates object - location.

Finderscope: A small, low power scope (e.g. 5x24, 6x30, 8x50) attached to the telescope and aligned to its optical axis. Facilitates locating specific celestial objects.  Most telescopes have rather narrow fields of view. As a result, finding and centering an object in the telescopic field can be difficult unless a Finderscope is used. The finderscope is a small, low-power, wide-field telescope, usually equipped with internal crosshairs for easy object sighting. With the finderscope aligned parallel to the main telescope, objects first located in the finderscope are then also in the main telescope's field.  To align your finderscope, take your scope outside in the daylight and find an object at least half mile away as far away as possible. Center this object (e.g. a tree) in your main telescope using your lowest power eyepiece. Now look through your finderscope. Using the three adjustment screws that secure the finderscope into its bracket, tighten or loosen them as needed to bring the cross hairs onto the same target as is centered in your main telescope. Your telescope is now ready to be aimed at any object in the sky and it will easily be located through the main optics of your telescope.

Eyepiece or Ocular Lens: The lens closet to the eye. The eyepiece forms the light transmitted form the objective lens into a visible image. With the telescope's primary optics (objective lens, primary mirror, or a combination of lenses and mirrors) having formed an image at the telescope's focus, the purpose of the eyepiece (consisting of two or more small lenses mounted in a metal barrel) is to magnify this image. Eyepieces are available in a wide range of optical configurations, barrel diameters, and focal lengths. It is the focal length of the eyepiece, in conjunction with the focal length of the main telescope, which determines the operating power of the eyepiece.  Eyepieces are typically available in focal lengths between 4mm (high-power) and 40mm (low-power). Please note that an eyepiece's optical type (e.g. PL: Plössl) has no effect on power, but does affect such characteristics as the field diameter seen through the telescope, color correction of the image, as well as image sharpness.

Diagonal Mirrors: When observing objects nearly overhead through refracting or mirror-lens telescopes, the diagonal mirror (or in some cases, diagonal prism) permits a comfortable observing position. The diagonal mirror diverts light out to a right angle to the telescope's main tube. All BCI refractors and mirror-lens telescopes include a diagonal mirror or prism for this purpose.

Fixed: Permanently attached and not intended to be removed (also occurs in microscopes).

Interchangeable: Refers to multiple eyepieces that attach to the telescope and provide varying magnifications.

 Moon Filter: Enhances contrast and removes glare when observing the moon.

Objective Lens: The primary light-gathering element of a telescope, located at the opposite end of the eyepiece. May be a mirror or a lens.

Solar Projection Screen: Because observing the sun can be harmful to the eye, a white screen, positioned directly in line with the eyepiece, is used to capture the projected image of the sun for solar observation

Astronomical & Terrestrial Observing: Since the distance of a celestial object generally corresponds to its brightness, telescope with the large aperture will not only allow you to see the faintest objects but also the most distant objects. For example, through a 60mm refracting telescope (e.g. RR70060E) you can see the bright center of the Andromeda galaxy, which is more than 2 million light years away. With an 8" (203mm) telescope or larger (e.g. RL800S), you can see the spiral arms of the much fainter Whirlpool galaxy, which is 35 million light years away from the earth.

All telescopes can be equally well applied for land-view applications as well as for astronomy, and in these cases the astronomical-quality optics generally outperform most telescopes designed exclusively for terrestrial use. You can recognize the faces of people from more than one mile; study the feather structure of a bird from 50 yards; observe insects on a flower from 25 feet.  When using a telescope for daytime, terrestrial observing, the distance you can see is limited by the condition of the atmosphere through which you are viewing. High amounts of moisture in the air or heat waves radiating from the ground will give you a blurry image over great distances.

UNDERSTANDING RIFLESCOPE

BCI has been manufacturing high quality military Riflescopes (pistol, Colt and AK family and heavy machine gun etc.) for more than 50 years. With experienced staff and state-of-art advanced Germany & Japanese optics machines, BCI Riflescopes are built to for most demanding conditions and best sports hunters. World famous sports optics companies are our long-term customers. 

BCI manufacture 1" and 30mm riflescopes. Each is tested to withstand the recoil of a powerful .458 magnum, obtain maximum point-of-impact accuracy and resist scratches with a special anodized finish. Each BCI riflescope features fully coated optics, waterproofing, fog proofing, shock proofing, non-removable eye-bell, non-removable windage and elevation screws, and haze filter caps.

Power

BCI riflescope model numbers identifying particular models are shorthand for two key measurements: power (magnification) and objective lens diameter. For example, a 440MT is a 4-power riflescope with a 40mm objective lens diameter. Consequently, this scope brings you four times closer to your target. The 40mm objective is relatively large, providing increased light-transmission. Under poor lighting conditions or with high-power scopes, larger objectives are preferable. Perhaps most important is the fact that the larger the objective diameter is, the larger the exit pupil and the easier it is to sight your target. Hold the scope at arm¹s length. The small circle of light you see in the eyepiece is known as the exit pupil. If you divide the size of the objective diameter by the magnification power, then you have the size of the exit pupil (in our example, 40mm divided by 4X = 10mm). The eye cannot actually utilize any more light than what is obtained by an exit pupil of 7mm, even at night. However, an oversized exit pupil does make target acquisition faster and easier, a feature of great benefit especially with moving targets.

The higher the power of magnification, the less bright the image and the less field of view. High power, as much as 36x, serves a very useful purpose, but only in the right circumstances. In general, use high magnification when some or all of the following apply:

1. For target and silhouette shooting.
2. With a bench rest or other support.
3. For small game (varmints).
4. When the target is motionless.

With lower magnification, you enjoy a brighter image and a wider field of view. Use low powers when some or all of these conditions apply:

1. In dense foliage where a wider field of view is preferable.
2. In low light conditions.
3. For moving targets.
4. At short range, especially with dangerous game.

Variable power scopes, or zooms, offer the benefits of high, medium and low powers, all in one scope. Zooms are particularly advantageous in changing light, weather, environmental conditions or geographic locations and when you're hunting different types of game. In short, variables enable the hunter to use the scope under various circumstances - from close-in brush hunting to open range hunting.  Fixed, low power scopes are recommended for hunting dangerous game, especially at close range or in dense foliage where a wide field of view is required and where a mistake in distance estimation could have dire consequences. Fixed power scopes are also preferable for still hunting, where the game comes to you. They are ideal for the hunter who hunts the same terrain and the same types of targets all the time.

Basic reticule (*OEM reticule welcome):

30/30: Four picket-shaped posts are set at 90 degrees from one another. The center point is created by the crossing of fine crosshairs that connect the opposing pickets. This pattern can be used to measure distance. Using the 30/30 reticules, the crosshair lines represent an area 30" across at 4x from 100 yards away. (30" is the distance from chest to rump of an average size adult deer). If the same 30" target fills only half the crosshair area, it means it is 200 yards away.

30/30TV: As above but with a television-type, rectangular view.

Crosshair: A simple pattern consisting of thin horizontal and vertical lines that cross, forming a center aiming point.

Crosshair with 1/8 Minute Dot: A single dot placed in the center of the field of view. The dot measures 1/8 minute across at 24x. When aimed at a target 100 yards away, it represents 1/8" diameter; at 200 yards, _" diameter, etc.

Illuminated: A preferred scope for low light conditions. Feature a 30/30 reticule with illuminated crosshairs.

Red Dot: A single red electronic dot placed in the center of the field of view. *Green Dot available

4-min. Dot: Covers a 4" area at 100 yards.

5-min. (Small Dot): Covers a 5" area at 100 yards.

8-min. Dot: Covers an 8" area at 100 yards.

10-min. (Big Dot): Covers a 10" area at 100 yards.

12-min. Dot: Covers a 12" area at 100 yards.

16-min. Dot: Covers a 16" area at 100 yards.

Construction of Riflescope:

1. Eye Piece
2. Eye-Bell
3. Locking Ring (not on some series)
4. Power Ring (on zoom models only)
5. Elevation Adjustment
6. Windage Adjustment
7. Objective Bell
8. Adjustable Objective (on some models)

Parallax

A condition that exists when the image being viewed through a rifle or pistol scope doesn't fall squarely on the reticule. Parallax can be detected by moving your eye left and right, up and down, as you look at the target through the scope. If the image seems to move in relation to the reticule, you have parallax. A fuzzy, out-of-focus image does not indicate parallax, but simply points to improper focusing of the eyepiece for the user's eye. Most BCI big-game hunting scopes are set parallax-free at 100 yards, and parallax present at longer and shorter distances causes such a slight sighting error that it's of no concern to the shooter. However, on target and varmint scopes that are used for shooting very small targets often at long range, parallax can be the difference between a hit and a miss. Varmint and target scopes should be equipped with an adjustable objective lens (e.g. 83242VAR) so that parallax can be removed at various distances. By moving the objective lens axially, the image is focused on the reticule plane and sighting error is eliminated. 

BCI standard Parallax setting:  Riflescope: 100 yds. Pistol scope: 50 yds. Shotgun Scope: 50 yds. Black powder Scope: 75 yds.

Eye relief

This refers to the distance at which you must place your eye behind the eyepiece of a rifle or pistol scope in order to see the entire field of view. Although the optimum distance is quoted in specifications, there is usually some latitude so that your eye need not be placed at exactly the same place each time in order to see the whole field of view.

BCI Pistol scopes have very long eye relief because they are held at arm's length. Because shooter's arms vary in length, pistol scopes have considerable latitude where eye relief is concerned. Pistol scopes with 4x magnification have a maximum eye relief of 22 or 23 inches. However, pistol scopes of high power have what is called intermediate eye relief, a distance of around 16 to 18 inches.

These instructions apply to all BCI riflescopes, including handgun scopes.  Be sure the mounting system is compatible with your gun-scope combination. In some cases it may be necessary to use extra high rings or extension rings.  Before beginning the mounting procedures, be sure the gun action is open, clip or magazine is removed and a round is not in the chamber. Do not attempt any work until the gun has been cleared and determined to be safe.

BCI Riflescope needs to be focused for your eyes. If someone else uses your scope, it must be refocused for his eyes. The following steps will assist in proper focusing of your riflescope with a traditional style focus ring. If you have a scope with a fast focus eyepiece, skip steps 1, 2 and 9.

1. Grasp the knurled eyepiece lock ring and loosen by turning the eyepiece counter clockwise.
2. Turn the lock ring clockwise about five turns.
3. Hold scope about three inches from your eye. Quickly glance through the scope at a bright featureless area, such as a wall, tree or the sky. (Never look at the sun!) Focusing is easier with the scope mounted on a rifle or some firm object.
4. Turn the eyepiece, counter clockwise, until the reticule appears slightly blurred.
5. Turn the eyepiece, clockwise, until the reticule comes into focus.
6. Look away from the scope for a few seconds. Then look back quickly through the scope. If the reticule appears sharp and clear the instant you place your eye to the scope, the focus has been properly set for your eyes. Try this several times.
7. If the reticule appears fuzzy, or requires a little time to come into sharp focus, further adjustment is needed. Turn the eyepiece clockwise another full turn and repeat STEP
8. Keep doing this until the reticule is sharp the instant you put your eye to the scope.
9. When satisfied with your focus, tighten the lock ring against the eyepiece firmly.

1. Remove ring caps from mount, place scope in cradle formed by uncapped rings.
2. Slide scope fore or aft to position scope at the proper eye point (full field of view can be seen).
3. Rotate scope to align the reticule horizontally and vertically.
4. Replace ring caps and tighten firmly.

FOR THOSE WHO DO NOT HAVE A BORE-SIGHTER:

1. Mount your scope on your rifle and tighten all screws.
2. Set the target at 25 yards.
3. From bench rest, aim at the center of your target and shoot 2 or 3 rounds.
4. Examine your target; check how far your Point of Impact (POI) is from your Point of Aim (POA).
5. If the bullet hits were more than 3 inches (12 inches/100 yards) apart from where you aimed at, you have problem(s) with your mounting system.

Do not use W/E adjustment screw. Adjust the mounting system first.

FOR THOSE WHO ARE USING A BORE-SIGHTER:

1. With the top portion of your mounting rings open, put your riflescope on your rings, determine how far the center of your crosshairs is from the center of your Bore Sighter grid.
2. If they are more than 3 squares (12 inches/100 yards) apart from each other, you have problem(s) with your mounting system.

Do not use W/E adjustment screw. Adjust the mounting system first.

Pre-Zeroing

If available, use a BCI bore-Sighter collimator to pre-zero your rifle. At an approved range, or other safe area, bench rest the rifle. Remove the windage and elevation caps. If you have a bolt-action rifle, remove bolt. If you have a lever, pump or semi-auto loading rifle, use a mirror type bore sighting device. If you have a zoom power scope, turn the power change ring to the highest setting. If your scope model is equipped with an adjustable objective lens mount for a parallax correction, rotate the focusing ring to the appropriate standard-parallax setting.

At first you shall sight through the bore at a target of 100 yards. Move the rifle about to center the target in the bore.

Sight through the scope and adjust the windage and elevation screws to center the target on the reticule.

NOTE: Never force the windage and elevation screws past their natural stop. Internal damage can result rendering the scope inoperative. The most common occurrence with "over-adjusting" includes: power change system jamming, broken lenses, poor image quality, insufficient grouping of shots, and limited or irregular movement of Point of Impact alignment.

Final Zeroing:

Since final zeroing involves live fire, check bore to be sure it is free of any obstructions before loading. Use eye and ear protection. Fire three rounds at your target. Note impact on target. Measure the distance from group center to target center. Adjust the windage and elevation screws accordingly. Each click adjustment will move the bullet impact by the amount shown on the dials (type C or D) at 100 yards.

NOTE: Never force the windage and elevation screws past their natural stop. Internal damage can result rendering the scope inoperative. The most common occurrence with "over-adjusting" includes: power change system jamming, broken lenses, poor image quality, insufficient grouping of shots, and limited or irregular movement of Point of Impact alignment. If the bullet hits were more than 3 inches (12 inches/100 yards) apart from where you aimed at, you have problems with your mounting system. Replace windage and elevation caps when zeroing is completed.

	One Click=1/4" at 100 Yards	50 YDS. 100 YDS. 200 YDS. TYPE C 1/8" 1/4" 1/2" TYPE D 1/4" 1/2" 1"
	One Click=1/2" at 100 Yards

Each click of adjustment will move the bullet impact by the amount shown at the distance indicated.

Care and Clearing

BCI riflescope is shockproof and waterproof. With proper care, your scope should last you a lifetime. Due to the unique internal seals and special lubricants your scope can maintain a dry gas atmosphere to prevent fogging of the lenses in any conditions. No lubricants or solvents are required to preserve mechanical function. You should never try to take it apart or clean it internally by yourself. If your scope does need repair or adjustments, it should be returned to the BCI’s distributors. Your scope will perform it's best if occasionally wiped clean with a lens cloth or an optical lens paper like that for eyeglasses and camera lenses. When cleaning the lenses, reasonable precautions are necessary. Dry dirt and dust can be removed by air blast or with a soft brush. Fingerprints and lubricants can be wiped off with an eyeglass tissue or a cotton swab and a mild soap solution. Use the lens covers supplied with your scope whenever convenient. Keep protective lens covers in place when the scope is not being used. Maintain the metal surfaces of your scope by removing any dirt or sand with a soft brush to avoid scratching the finish. Wipe the scope with a damp cloth and follow with a dry cloth. Finally, wipe with a silicone treated cloth to restore luster and protect the scope against corrosion. Be careful not to touch the lenses with the silicone cloth. As convenient as vehicle storage may be, it can also be detrimental to your scope. Closed vehicles retain very high levels of heat. This intense heat could adversely affect the lubricants and sealants in your scope. Another danger comes from the constant vibration of a traveling vehicle as it can loosen your mounts and affect the zero point of your rifle.  The following tips can help even the best hunters odds.

1, A variable power scope should be set to its lowest power for fast target acquisition. High powers should be reserved for long range, controlled shots.

2, Lens caps provide good protection in foul weather by should be removed when stalking or still shooting to save time in snap shooting situations. Take off transparent or tinted covers to avoid image distortion. The scopes are recessed to avoid lens contamination with lens covers removed.

3, Using a BCI Bore Sighter is recommended after any fall or mishap to assure the zero point of your rifle.

4, Storing your rifle and scope overnight in the outdoors will help avoid external fogging of optics. In extreme cold, cycle the action a few times to loosen it up prior to returning to the hunt.

UNDERSTANDING SPOTTING SCOPE

Magnification: The spotting scope is often named by two numbers separated by an "x". For example: 15-45x60. The first number is the power or magnification of the spotting scope. With a 15-45x60 variable power spotting scope, the object being viewed appears to be 15-45 times closer than you would see it with the unaided eye. The second number in the formula: (15-45x60) is the diameter of the objective or front lens. The larger the objective lens, the more light that enters the spotting scope, and the brighter the image.

The higher magnification of a spotting scope, of course, is a double-edged sword. As magnification increases, many other things decrease: field of view, image brightness, image steadiness, and sometimes image sharpness. And higher magnifications are much more sensitive to atmospheric turbulence and pollution. This is a big price to pay for a larger image, but in optics there are no free lunches.

The challenge in using a spotting scope is to make magnification work for you and not against you. The basic rule of thumb is to use magnification sparingly--never sacrifice image detail or steadiness for image size. Small, steady, and sharp beats big, wobbly, and fuzzy every time, especially on small subjects like birds. Too little magnification in a spotting scope is better than too much, especially with a scope that does not offer a choice of magnifications (after all, you may be able to get closer).  

Field of View
When using a scope, always begin at the lowest available magnification (widest field of view) and work up as needed. If you start at high magnification, a bird often flies away before you find it in the narrow field of the scope. Find that sparrow in the wider, more friendly field of 20x (20 power) first, then switch to 40x or higher if necessary. When you've finished, be sure to switch back to lower magnification to be ready for the next bird. The first skill to master with a scope is lining up the target -- finding a bird in the narrow field of scope. This can be frustrating at times, but there are ways to make it easier. As mentioned, a wide field of view is still the best solution. This invariably means low magnification, but special wide-field eyepieces can help. These eyepieces are available as options on many scopes and are usually 20x to 25x in magnification. They can offer as much as 40 percent more field than a conventional eyepiece of the same power, and nearly 100 percent more field in some cases than a zoom eyepiece at the same magnification. Add a standard eyepiece of 40x to 50x to one of these special eyepieces for a scope system that will handle nearly any situation. 

Eyepieces & Eyeglasses
If you wear glasses, pay particular attention to eye relief; this will be the single most important feature for determining the field of view. Look for eyepieces that offer at least 14 mm or 15 mm of eye relief if you expect to see a full field of view with glasses (remember more is better when measuring eye relief—18 mm is better than 14 mm). Favorite scope sports a 20x eyepiece with 20 mm of eye relief and a nice wide field of view. I don't miss too many birds with that combination. 

Angled or Straight?
Spotting scope eyepieces can be fit to a scope body at different angles, which also affects a scope's pointability and ease of use. Straight-through eyepiece scopes are the most common and feature an eyepiece that is in line with the scope body. Angled-eyepiece scopes, on the other hand, have the eyepiece mounted at 45 degrees or so to the scope body. Although some observers have a strong preference for one or the other, each configuration has its advantages.

Most people find the straight-through models to be the easiest to aim, at least at first. The straight-through scope is also the best choice for observing birds on the ground or at eye level. This is also the most convenient version to use when viewing from the tight quarters of a vehicle or a small blind, or when your scope is attached to a camera or a shoulder stock.

Angled-eyepiece scopes are awkward to aim at first, but with a little practice they line up as quickly as straight-through models. This version eliminates much of the neck strain that occurs when observing birds perched high in a tree or on a mountainside. This is also the best scope to use on a tripod, since it can be kept lower, which adds to stability. There are two additional advantages of scopes with angled eyepieces. They are easier to share among birders of differing heights, and they are more comfortable to use for nighttime stargazing. Personally, I find angled eyepieces to be the most comfortable for extended viewing.

No matter what scope you choose, practice is the key. Take your scope out in the backyard and randomly line up on convenient objects until you build up speed. This will pay off in the field when that rare or accidental species makes a sudden appearance. Don't worry if you sometimes miss a bird when the action is hot -- even experts fumble at times. 

Easy on the Eyes
Eye fatigue is the second big obstacle to overcome in a spotting scope, and it is more of a problem than in binoculars. Two eyes are definitely more comfortable to use than one, especially if you don't learn to use the one properly. You can't use a spotting scope comfortably for long periods until you develop good observing techniques.

First, use your better eye if one is stronger or sharper than the other, as is the case for most people. This will help minimize eyestrain to some extent and will give you the sharpest possible view. If you have astigmatism, wear your glasses when you observe, for the same reason. If you are nearsighted or farsighted, this can be corrected by focusing the scope.

Next, keep both eyes open when you observe. This is by far the most difficult technique to learn when using a scope, but it is also the most essential. Contrary to what some experts might tell you, closing one eye when you observe is the worst thing you can do. This pulls the muscles of one eye more than the other, which quickly leads to tired eyes and blurry vision. You simply cannot use a scope for long periods if you observe with one eye squeezed shut.

Of course, leaving both eyes open is much easier said than done; it requires some practice. At first you will be distracted by the image from your off-eye (non-scope eye) as you try to concentrate on the image in the eyepiece. This is natural, and to be expected, so you will have to make a conscious effort to keep your off-eye open.

First, relax both eyes totally when you observe. Squinting in your scope eye quickly leads to squinting in the other eye, and squinting is a very difficult habit to break. To avoid squinting, use the focuser on the scope constantly to make fine adjustments -- that's why it's there. Relaxed eyes are the key to all-day observing in a spotting scope, or even with binoculars.

Second, use your master eye as your scope eye. This is your stronger eye, but not necessarily the right eye if you are right-handed or left eye if left-handed, since many people are cross dominant in this regard. At any rate, it is easier to ignore the image produced by your weaker eye when it, instead of your dominant eye, is used as your off-eye.

It also helps keep your scope eye as close to the eyepiece as possible. This will minimize the effect of the unwanted image from the off-eye and also keep unwanted lateral light from causing a glare in the eyepiece.

If you absolutely cannot manage the both-eyes-open technique, you can compromise by only partly closing the off-eye. This is still much better than squeezing it all the way shut. Another solution is to place a hand over the off-eye (but keep it open) as you observe, assuming you have one hand free to do so.

UNDERSTANDING NIGHT VISION

BCI has been manufacturing high quality military Night Vision (Gen. I, II, II Plus, III) for more than 20 years. With experienced staff and state-of-art advanced European and American techniques & machines, world famous sports optics companies are our long-term customers.  Our NV2003 produces images comparable to Generation 2 devices. The NV2003 does not contain a Micro Channel plate, but uses fiber optic bundles to eliminate distortion thus providing excellent resolution and a flat field of view. The result is superior image quality comparable to Generation 2 devices at half the cost

Recreational uses consist of camping, hiking, fishing, boating, and nature viewing. Other uses include surveillance, search and rescue, and property management. The key difference between the night vision generations is the intensifier technology. Gen. I devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain; Generation III devices further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen. II devices. Generation II and III devices offer greater light amplification but a price beyond the reach of most buyers. Generation I devices are high quality and provide light amplification adequate for most recreational activities and for many professional uses.  BCI Night Vision products collect and amplify existing light through the objective lens that is then focused on the image intensifier. Inside the intensifier, a photo cathode is "excited" by the light and converts the photon energy in to electrons. These electrons accelerate across an electrostatic field inside the intensifier and strike a phosphor screen (like a green monochrome TV screen), which emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image.  It varies anywhere from 1-1800 feet. The maximum viewing distance depends on the conditions of use and upon model chosen. Overcast conditions, fog, rain; etc. may reduce the effective distance of a night vision. An Infrared Illuminator will increase viewing range, especially in enclosed areas like a warehouse, cave, or thick brush. Normally BCI Night Vision has 1.5x and 2x, the more you magnify the more light you lose. 

WMJ-1A---4.2x Gen II for riflecope & machine gun

NV2003---1.5x54 advanced Gen I

In fact you don't see through the night vision device, rather you see the phosphor screen on the back of the tube. The objective lens focuses the image on to the front of the intensifier tube. That image is then converted in to electron energy. It paints that picture on the back of the tube. You need to have a sharp image to start with. Then your eye needs to be focused onto the back of the tube where the image resides. Every eye is different and therefore the ocular focus is very important. Focus the ocular first and then move to the objective lens. You may have to adjust each lens several times before getting a sharp image. All night vision devices need some available light to work (e.g. moon light). It is possible to see a bright image in low light or no light conditions with the use of an Infrared Illuminator. An Infrared Illuminator is standard on all BCI Night vision devices. Night vision devices operate as a light amplifier for light in the "near visible" light range. Generally, this is in the 750-850 nanometer range. It cannot detect heat, which is at a much lower end of the light spectrum and requires thermal imaging technology (BCI also make such devices). Night Vision devices are designed for use in the dark. It may be harmful and can damage the device if you use it during the daytime or in other very bright situations. Keep in mind that strong direct light, such as projectors, car headlamps, strong flashlights, and so on, may be harmful to your night vision unit if you direct your device at the source of these intense lights.  Most advanced BCI Night Vision devices have electronic protection against such damage. Most of these are simple turn off overload circuits, but some have more sophisticated and separate light sensing mechanisms.

The number one damage factor is using the device in bright light. While most BCI Night Vision devices have a cut-off circuit when over exposed, exposure will shorten the life span of a night vision device. Exposure to rain, fog, or even extremely high humidity may damage night vision devices. Built for use at night, they can withstand short exposure to dampness or high humidity conditions. Night Vision devices have delicate vacuum intensifier tubes that are sensitive to impact and should be handled carefully. Clean lenses the same way you would your camera. The lenses are optically coated and may be scratch if abrasive material is used or if dirt is rubbed into the glass. Usually there is no need to remove the lenses and clean inside. Storage for long periods is best in a cool dry place with the batteries removed.

UNDERSTANDING MICROSCOPE

Biological microscopes share these basic features and components:

• The Stage: Specimens (i.e., objects to be observed) placed on a glass slide and ready for observing are positioned on the microscope's stage, a smooth, flat surface used to hold the glass slide. On most microscopes the specimen glass remains fixed while the microscope's objective lens and eyepiece move as a unit up or down to focus the image.
• Objective Lenses: A microscope's objective lens forms the image that is observed with the eyepiece. Different objective lens designs permit different magnifying powers. Most microscope includes three objective lenses mounted on a rotating turret for ease in switching powers.
• Eyepiece: The ocular, or eyepiece, consists of a series of lenses mounted in a barrel and placed in the eyepiece sleeve at the upper end of the microscope. Eyepieces of varying powers work with objective lenses of varying powers to yield a range of microscope magnifications.
• Magnification: The effective magnification of a microscope is determined by multiplying the eyepiece power by the objective lens power. Thus a 40x objective lens used with a 10x eyepiece presents an effective magnification of 400x to the observer. Lower magnifying powers allow for brighter, sharper images combined with a wide field of view; higher powers, often useful in specific observing situations, present larger but dimmer images with narrower fields of view. When observing a specimen, always begin at lower powers, progressively increasing to higher magnifications.
• Focusing: All microscope models include a focusing control for quick focusing of the image. More advanced models include both coarse and fine focusing controls; the fine focus is particularly advantageous in high-power applications.
• Light Source: Used to illuminate the specimen, some models include adjustable mirrors to reflect an external light source into the microscope's specimen observing area; some others utilize built-in light sources to provide direct and intense object illumination at high powers.
• Condensing Lens: Most microscope models include a sub-stage condensing lens that concentrates light on to the specimen. A rotary variable-aperture diaphragm permits varying illumination intensities. Some models include more sophisticated Abbe-type condensing lens systems and built-in color filter holders.
• Prepared Slide Set: Most microscope model is packed with a complimentary set of numrous ready-to observe prepared animal and vegetable slide specimens, plus some blank glass slides for your own specimens.

BCI microscopes have perfect optical and mechanical performance. Objective and eyepiece lenses are of optical glass, exclusively, providing images far sharper and higher in resolution than can be obtained with less expensive plastic lenses. Mechanical systems, including rotating turret assemblies, rack-and-pinion focusing mechanisms, and lens mountings are of machined brass and steel to permit years of quality performance.