The Celestron 70mm AstroMaster LT altazimuth refractor is a surprisingly good, but surprisingly inexpensive, scope for the beginning astronomer who also has an eye for nature. This well-built refractor optical system is a good way to begin your journey into the night sky, as well as exploring nature during the day. It provides you with detailed high-contrast views of the Moon and planets in the heavens, as well as sharp views of birds and animals across a lake or across the back yard.
The construction of the optical system is first rate, as the AstroMaster has all-glass optical components, with high transmission optical coatings on every air-to-glass surface for enhanced image brightness and clarity. The mount has a convenient pan handle, like the control handle on a camera tripod, for guiding the scope around the skies or the landscape. A built-in clutch makes operating the well-balanced scope with the pan handle smooth and easy. The scope assembles in only a minute or two, with no tools required.
Once you have scanned your way through the solar system and the brighter Milky Way objects, you can use the AstroMaster to look at things closer to home. The altazimuth mount will let you easily track objects on the ground and allow you to get a closer look at nature and your surroundings.
The AstroMaster 70 has a light grasp 100 times that of the sharpest eye for nighttime and twilight use. It can also resolve details ten times smaller than you can see clearly with your unaided eye. Combine that light grasp and sharpness with its two eyepieces (a 20mm for 35x magnification and a 10mm for 70x), and you have the ability to see many, many celestial and terrestrial objects that are simply invisible to the unaided eye. Some chromatic aberration (a faint halo of violet light around the Moon and planets when observing at night) is visible in the AstroMaster 70 LT, as it is in all achromatic refractor telescopes.
This Telescope's Optical System . . .
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Refractor optical tube: 70mm (2.8") aperture. 700mm focal length f/10 achromatic doublet lens with all-glass optics. No plastic lenses.
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Coated optics: The two-element crown and flint glass objective lens has a layer of antireflection coatings on all air-to-glass surfaces for high light transmission and good contrast.
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Dovetail mount: A quick-release dovetail bar on the 28" long optical tube fits into a dovetail slot on the mount. The optical tube can be installed and locked firmly in place in seconds using a single no-tool knob on the mount.
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Dew shield: A dew shield (an extension of the optical tube that's threaded onto the front of the objective lens) slows the formation of dew on the lens in cold weather. This extends your undisturbed observing time. It also improves the contrast when observing objects on the ground during the day.
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Rack and pinion focuser: The 1.25" focuser has dual focusing knobs for precise image control with either hand. The good-sized focus knobs are easy to operate, even while wearing gloves or mittens in cold weather.
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Star diagonal: The 90° viewing angle 1.25" star diagonal (eyepiece holder) allows comfortable viewing when looking overhead at the sky. It provides erect mirror image views (objects are reversed left for right). This is not a problem when observing the stars and planets, but may be disconcerting during terrestrial observing, as printing (license plates, the names on boats, etc.) will be backwards. For most nature studies this isn't a problem, though, because a duck still looks like a duck whether he's facing left or right. An optional #6329 45° viewing angle image-erecting diagonal is available if right-reading images are essential. It gives you correctly oriented images and a more comfortable extended terrestrial observing position.
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Two eyepieces: You get a high power 1.25" 10mm (70x) eyepiece and a low power 1.25" 20mm (35x) with a wide 1.7° field of view (over three times the diameter of the full Moon). Both eyepieces have antireflection coatings on their lens surfaces for sharp images and good contrast.
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Red dot finder: A permanently mounted straight-through red dot illuminated finder allows easy non-magnified views of the sky and ground, with a red dot of light showing exactly where the scope is pointed at all times.
This Telescope's Mount . . .
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Altazimuth mount: The altazimuth mount with camera tripod-style pan handle provides right/left and up/down motions. This is suitable for casual astronomical observing, and will let you easily track objects on the ground to allow you to get a closer look at nature and your surroundings. An adjustable tension knob at the base of the mount allows you to lock the tube in place or to adjust the drag on the scope during right/left motions. This lets you control how smoothly the mount moves as you move the tube left or right to follow objects moving across the sky or on the land. A knob on the mount head locks the scope in place up and down, as well as letting you adjust the drag on the scope to set the travel smoothness when adjusting its position vertically using the pan handle. The optical tube is well balanced, but keeping your hand on the pan handle at all times when the clutches are unlocked would be a sensible safety precaution.
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Tripod: The lightweight pre-assembled tripod has 1" diameter stainless steel legs to provide a rigid and stable observing platform. It easily adjusts in height with no tools needed for standing or seated observations through the telescope. Spreader bars lock the legs firmly open when the tripod is set up. The tripod includes a convenient accessory tray that attaches to the spreader bars to hold your eyepieces and accessories close at hand and up out of the dew-soaked grass. The no-tool lock knobs that adjust the leg height of the tripod are on the inside of the legs so they won't snag on clothing in the dark, a thoughtful touch that's sure to be appreciated.
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Software: Comes with TheSky Level 1 sky-charting CD-ROM that has a database of 10,000 stars and objects it can plot and display on your Windows-based computer screen. That's enough solar system and deep space detail to keep you busy observing for years, yet not so much that you're overwhelmed by charts showing much more detail than your scope can usefully reveal. Custom sky chart printing lets you print out eyepiece finder charts to use with your telescope to help you locate and identify the planets and many famous and faint deep space nebulas, galaxies, and star clusters by star-hopping from object to object using your scope's pan handle control. There are 75 full color images of well-known celestial objects to help you identify them through your scope.
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Two year warranty: As an expression of Celestron's confidence in the quality of their products, the AstroMaster is protected by Celestron's two-year limited warranty against flaws in materials and workmanship.
