Ronan, Colin A. (1991). "Leonard and Thomas Digges". Journal of the British Astronomical Association. 101 (6) . Retrieved 25 January 2012.

FirstScope Telescope | Celestron FirstScope Telescope | Celestron

A 32mm super wide angle eyepiece, mirror-cooling fan, battery box and a red dot finder complete the system. Uncle Bob and Aunt Mary were our favourite relatives. Bob and Mary would make the trek from Vancouver to our orchard two or three times a year, occasions anticipated with much excitement. Maybe it was because Mary and Bob had no children of their own, but they were always very generous with me and my siblings. Bob could always make me laugh too. He had a tremendous sense of humour and was always ready with a joke.

With this basic separation into groups established, we can review the benefits and compromises of each. I still have the telescope. I’m thankful for that. Any time I want, I can relive childhood triumphs, but mostly it’s nice to have an old friend to casually poke around the sky with. I can also assess the scope’s performance without relying on memories tinted with the golden patina of nostalgia. And you know what? Luna is actually a pretty good scope. The quality of the optics in the telescope, determined predominantly by their cost, will have a significant bearing on the quality of the views, and the cheap refractors that tend to be popular at electrical goods and camera shops are often disappointing. Although some detail and moons may be seen when observing Jupiter and Saturn, in either case the planet itself will appear quite small and very bright in the view.

My first telescope - Getting Started Equipment Help and My first telescope - Getting Started Equipment Help and

Not compatible with #93648 Off-Axis Guider, not compatible with #93519 2" Mirror Diagonal (discontinued) The first scope you linked to has a spherical primary, which means that this scope is what is generally referred to as a Bird-Jones telescope. That means that it has a correcting lens at the bottom of the focuser tube. It also means that it is very difficult to collimate. Reflecting telescopes: Newtonian, two- and three-mirror systems". Telescope-optics.net . Retrieved 2013-08-01.

a b Paul Schlyter. "Largest optical telescopes of the world". Stjarnhimlen.se . Retrieved 2013-08-01. Dobsonians may be elegantly simple affairs - no wires, no batteries, you just point it at what you want to see - or they may include a full ‘Go-To’ control, which can automatically point the telescope at hundreds of sky objects. Galileo set himself to improving the telescope, producing telescopes of increased power. His first telescope had a 3x magnification, but he soon made instruments which magnified 8x and finally, one nearly a meter long with a 37mm objective (which he would stop down to 16mm or 12mm) and a 23x magnification. [40] With this last instrument he began a series of astronomical observations in October or November 1609, observing the satellites of Jupiter, hills and valleys on the Moon, the phases of Venus [41] and spots on the sun (using the projection method rather than direct observation). Galileo noted that the revolution of the satellites of Jupiter, the phases of Venus, rotation of the Sun and the tilted path its spots followed for part of the year pointed to the validity of the sun-centered Copernican system over other Earth-centered systems such as the one proposed by Ptolemy. Unlike most of my astronomy friends, I never had a big “Aha!” moment when I found myself suddenly fascinated with the wonders of the universe. That’s not to say there weren’t some important episodes that remain fresh in memory many decades later — there were plenty. And one memory that stands out with crystalline clarity, even now, is my very first look at the Moon through my first telescope. Albert Van Helden; Sven Dupré; Rob van Gent (2010). The Origins of the Telescope. Amsterdam University Press. pp.32–36, 43. ISBN 978-90-6984-615-6.

How to choose your first telescope - BBC Sky at Night Magazine

Comparatively heavy, they tend to be shorter lengthwise, and this compactness makes them ideal where storage space is limited.There are compromises, as reflectors need their mirrors adjusting from time to time, although this shouldn’t put you off. Refracting telescopes available to the amateur today therefore tend to be available in apertures between 60 – 150mm. Reflecting telescopes have an open tube at the front and a round mirror inside the bottom of the tube, called the primary mirror. In 1754, Euler sent to the Berlin Academy a further paper in which starting from the hypothesis that light consists of vibrations excited in an elastic fluid by luminous bodies—and that the difference of color of light is due to the greater or lesser frequency of these vibrations in a given time— he deduced his previous results. He did not doubt the accuracy of Newton's experiments quoted by Dollond. [64] No further practical advance appears to have been made in the design or construction of the reflecting telescopes for another 50 years until John Hadley (best known as the inventor of the octant) developed ways to make precision aspheric and parabolic speculum metal mirrors. In 1721 he showed the first parabolic Newtonian reflector to the Royal Society. [60] It had a 6-inch (15cm) diameter, 62 + 3⁄ 4-inch (159cm) focal length speculum metal objective mirror. The instrument was examined by James Pound and James Bradley. [61] After remarking that Newton's telescope had lain neglected for fifty years, they stated that Hadley had sufficiently shown that the invention did not consist in bare theory. They compared its performance with that of a 7.5 inches (190mm) diameter aerial telescope originally presented to the Royal Society by Constantijn Huygens, Jr. and found that Hadley's reflector, "will bear such a charge as to make it magnify the object as many times as the latter with its due charge", and that it represents objects as distinct, though not altogether so clear and bright. [62]