and Chasing Jupiter from my Yard. 
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| National Geographic Telescopes are just low-end BRESSER telescopes. |
My 4 personal telescopes:
Ordered by Focal Length
Telescope #1 "Ned"
Model Number: iMeshbean F76700
Optical Design: Newton Reflector
Aperture: 76 mm
Focal Length 700 mm
Focal Ratio: f/9.2 ("slow")
Max Useful Magnification: 152x
Max Barlow Magnification: 525x
Max nonBarlow Magnification:175x
Purpose: Planet viewer / great Moon view(photo)
Eyepiece Diameter: 0.965"/24.5mm and 1.25"/31.75mm
Eyepiece 1: H 12.5mm 700/12.5 = 56x Magnification
Eyepiece 2: H 20.0mm 700/20 = 35x Magnification (105x with 3x barlow)
Eyepiece 3: K 20.0mm 700/20 = 35x Magnification (105x with 3x barlow)
Eyepiece 4: K 10.0mm 700/10 = 70x Magnification (210x with 3x barlow - Venus/Moon)
Eyepiece 5: SR 4.0mm 700/4 = 175x Magnification (only good for viewing moon)
Mount Type Altazimuth
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NOTE: A f/9.2 telescope is considered a "slow" focal ratio.
This optical design is well-suited for detailed views of the Moon, *very limited* planetary
surfaces like Jupiter and Saturn. My favorite Magnifications are 35x and 105x as the K20mm
lens works well with my phone camera.
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Telescope #2 "Bob"
Model Number: National Geographic NG114mm / NT114CF / 80-30114S
Optical Design Newton Reflector
Aperture: 114mm
Focal Length: 500mm
Focal Ratio: f/4.4 (fast)
Max Useful Magnification: 228x
Max Barlow Magnification: 375x
Max nonBarlow Magnification:125x
Purpose: Planet viewer / Deep Sky / Moon
Eyepiece 1: PL09.7mm 500/9.7 = 51.6x Magnification (154.8x with 3x barlow)
Eyepiece 2: K 10.0mm 500/10 = 50.0x Magnification (150x with 3x barlow)
Eyepiece 3: K 20.0mm 500/20 = 25.0x Magnification (75x with 3x barlow)
Eyepiece 4: PL26.0mm 500/26 = 19.2x Magnification
Mount Type: BRESSER 3point Pan Handle Mount
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NOTE: This telescope lacks focal length to match it's Aperture Useful Magnification, so not really good for planets.
But a short focal length makes a faster Focal Ratio. With it's wider Aperture and fast Focal Ration F-number,
it is my best Deep Sky I own.
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Telescope #3 "Jim"
Model Number: National Geographic 80-50070
Optical Design: Achromatic Refractor
Aperture: 70mm
Focal Length: 400mm
Focal Ratio: f/5.7 ("mid")
Max Useful Magnification: 140x
Purpose: Great Moon viewer / some nebulae capable / planet capable
Eyepiece Diameter: 0.965"/24.5mm and 1.25"/31.75mm
Eyepiece 1: SR 4.0mm 400/4 = 100x Magnification (only good for viewing moon)
Eyepiece 2: K 10.0mm 400/10 = 40x Magnification
Eyepiece 3: K 20.0mm 400/20 = 20x Magnification
Mount Type: AZ Pan Handle Mount (upgraded RCA)
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NOTE: A f/5.7 telescope is a versatile "mid-speed" focal ratio.
This optical design is ideal for wide-field visual observing of *non-detailed* views of nebulae and deep-sky.
Because of small aperture, great detailed views of the moon.
I have only used this telescope to look at Jupiter and it's moons, Venus, and the Moon.