Explore Scientific 208mm f/3.9 CF Newtonian EXOS2-GT

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Explore Scientific 208mm f/3.9 CF Newtonian EXOS2-GT

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Carbon Fiber 208mm Newtonian
Includes FL-EXOS2GT mount
f/3.9 812mm focal length
2" Two-Speed Focuser
Cradle Rings w/ Handle and Vixen-Style Dovetail

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Item # 54035

Mfg Model # N208CFEXOS2GT

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PACKAGE: Explore Scientific Newtonian 208mm f/3.9 with Carbon Fiber Tube and White EXOS2-GT GoTo Computerized German Equatorial Mount.

Warranty

This product is serviced and supported by its manufacturer according to the terms and conditions included in the packaged product. Orion's limited warranty does not apply. Please contact the manufacturer directly for technical support.

Warning

Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

Specs

Best for viewing

Brighter deep sky
Best for imaging

Solar, lunar, planetary & Messier objects
User level

User level

Beginner Level - Suited for a wide range of uses, these products are simple to operate and set up. Some initial assembly may be required depending on the type of product. Optical instruments with this rating will have very good optical and mechanical quality. Great for families, young people, and folks who don't want to mess with equipment and complexity. Beginning level telescopes will show you countless lunar craters, Saturn's rings and a myriad of star clusters and nebulae! Referring to the manual is recommended.

Intermediate Level - These products offer higher performance and more advanced features than Level 1: Beginner models. They typically take a bit longer to learn and need some set-up or adjustments. But anyone with the slightest technical bent will have no problem getting familiar with these models. Referring to the manual is recommended.

Advanced Level - These products provide the best performance but may require more skill to master and appreciate. Optical instruments with this rating have exceptionally fine optics and mechanics. Some are easy to use but might be on the large or heavy side. Some are intended for specialized uses. These products will appeal to the more technically inclined. Referring to the manual is highly recommended.

Intermediate
Optical design

Optical design

Reflector telescopes use a pair of large and small mirrors to direct incoming light to the eyepiece. Refractor telescopes refract, or "bend" incoming light to a focus by means of an objective lens. Cassegrain telescopes, such as Maksutov-Cassegrains, "fold" incoming light using two mirrors and a front "corrector" lens.

Reflector
Optical diameter

Optical diameter

For telescopes, the optical diameter (also known as aperture) is the size of a telescope's main light-collecting lens or primary mirror, measured in millimeters or inches. Telescopes with larger optical diameters collect more light, which leads to an increase in brightness and image resolution compared to smaller instruments.

For binoculars, the optical diameter (also known as objective lens diameter) is the size of each of the front-facing objective lenses of a binocular measured in millimeters. Binoculars with larger objective lenses collect more light, which increases image resolution and brightness. Binoculars with larger objective lenses are recommended for low light situations, and binoculars with at least 50mm or larger objective lenses are recommended for pleasing astronomical observations at night.

208mm
Focal length

Focal length

The distance from the center of a curved mirror or lens at which parallel light rays converge to a single point. The focal length is an inherent specification of a mirror or lens and is one of the factors in determining resultant magnification for a telescope (along with the focal length of the eyepiece being used).

812mm
Focal ratio

Focal ratio

The focal ratio of an optical system is the ratio of a telescope's focal length to its aperture. Short focal ratios (f/5, f/4.5) produce wide fields of view and small image scales, while long focal lengths produce narrower fields of views and larger image scales.

f/3.9
Resolving power

Resolving power

The theoretical resolving power of a telescope can be calculated with the following formula: Resolving power (in arc seconds) = 4.56 divided by aperture of telescope (in inches). In metric units, this is: Resolving power (in arc seconds) = 116 divided by aperture of telescope (in millimeters). Note that the formula is independent of the telescope type or model, and is based only upon the aperture of the telescope. So the larger the telescope's aperture, the more it is capable of resolving. This is important to keep in mind when observing astronomical objects which require high resolution for best viewing, such as planets and double stars. However, it is usually atmospheric seeing conditions (not the telescope) which limits the actual resolving power on a given night; rarely is resolution less than one arc-second possible from even the best viewing locations on Earth.

115.80arc*sec
Lowest useful magnification

Lowest useful magnification

Lowest useful magnification is the power at which the exit pupil becomes 7mm in diameter. Powers below this can still be reached with the telescope to give wider fields of view, but the image no longer becomes brighter at a lower power. This is due to the fact that the exit pupil of the telescope (the beam of light exiting the eyepiece) is now larger than the average person's dark adapted pupil, and no more light can fit into the eye.

30x
Highest useful magnification

Highest useful magnification

The highest practical limit is different from the often used "highest theoretical magnification" specification. The "theoretical" limit generally is 50x the aperture of the scope in inches (2x the aperture in mm). So for example, an 80mm refractor is capable of 160x, and a 10" telescope is theoretically capable of 500x magnification. But after approximately 300x, theory breaks down and real world problems take over. The atmosphere above us is constantly in motion, and it will distort the image seen through the telescope. This effect may not be noticeable at lower powers, but at higher powers the atmosphere will dramatically blur the object, reducing the quality of the image. On a good night (a night where the air above is steady and the stars aren't twinkling), the practical upper limit of a large telescope is 300x, even thought the theoretical limit may be much higher. This doesn't mean the scope will never be able to reach those higher "theoretical" powers - there will be that rare night where the atmosphere is perfectly still and the scope can be pushed past it's practical limit, but those nights will be few and far between.

246x
Highest theoretical magnification

416x
Limiting stellar magnitude

Limiting stellar magnitude

The limiting stellar magnitude is a measure of the faintest star you can see through the telescope.

14.3
Finder scope

None
Focuser

2" Crayford
Secondary mirror obstruction

80mm
Mount type

Equatorial
Astro-imaging capability

Astro-imaging capability

The astro-photographic capability of the telescope is based on the style, stability, and accuracy of the mount and tripod. Telescopes on either very lightweight mounts or non tracking mounts (such as Dobsonians) are capable of only very short exposures such as lunar photographs. If a motor drive is attached to an equatorial mount, even a small lightweight mount is capable of capturing some planetary detail. Larger EQ mounts that utilize very precise tracking and excellent stability are capable of longer exposure deep-sky photography.

Lunar, planetary & long exposure
Dovetail bar system

Dovetail bar system

A universal attachment system for holding the optical tube onto the tripod. A dovetail bar is attached to the tube rings, then it slides onto the mount itself, making for quick assembly and disassembly.

Yes
Motor drive compatibility

Motor drive compatibility

A motor drive automatically moves the telescope in right ascension at the same rate as the east-west drift of the stars so stars can be continuously tracked in the eyepiece without manual adjustment. Motor drives are usually equipped with a hand control that allows the telescope's tracking speed to be slightly increased or decreased, which is particularly critical when taking long-exposure astro-images.

Clock drive included
Computerized compatibility

Computerized compatibility

Some mounts are compatible with a motorized Go-To system for fully automated computer finding of objects in the night sky. Others mounts are compatible with computer finding systems which require the user to manually move the mount to the object's position as indicated by the computer finder.

Go-To included
Alignment procedure

1,2, and 3 star alignment
Number of objects in database

272,994
Motor speeds

9 speeds
Power requirement

12-volt DC (tip positive)
Setting circles

Electronic, via the hand controller
Polar-axis scope

Sold separately
Tube material

Carbon graphite
Tripod material

Steel
Weight, optical tube

18.3 lbs.
Weight, mount/tripod

16.7 lbs.
Weight, fully assembled

35.0 lbs.
Other features

vixen style dovetail, camera mount
Warranty

Warranty

This warranty gives you specific legal rights. It is not intended to remove or restrict your other legal rights under applicable local consumer law; your state or national statutory consumer rights governing the sale of consumer goods remain fully applicable.

One year

Shipping Info

When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available.

SHIPPING RESTRICTIONS APPLY FOR THIS PRODUCT

This product is available to ship Standard delivery within the 50 US states. Delivery is not available to APO/DPO/FPO addresses, US territories/protectorates or Canada. 3 Day, 2nd Day and Next Day delivery is not available.

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