Friday, July 01, 2005

Review: Astronomy Hacks

O'Reilly stretches the envelope once more with "Astronomy Hacks", part of their popular series of Hacks books, this time looking at tips and tools for observing celestial objects. The book is written in an engaging manner, and in a form comprehensible to both the novice and the seasoned amateur astronomer.

The book begins with a section on some basic Getting Started hacks. These address basic safety tips, etiquette, and selection criteria for amateur astronomers' tools like binoculars, scopes and accessories. It goes into some detail on the different kinds of scopes, and ruminates on the Scope Wars that rage between aficionados of the SCT versus Dob-bigots. Basic aspects of night-time viewing such as dark adaptation and dress, security, etc. are explored.

The next section deals with Observing Hacks, exploring night vision, identification of stars, star catalogs, constellations and celestial coordinate systems. The horizontal coordinate system, or the altitude-azimuth system is the way of treating the horizon as an equatorial line and measuring any object using it's altitude (height) and azimuth (angle relative to north). These are initutive because they are relative to the observer's position. Unfortunately, because the earth still moves, these are not absolute, and require the observer's location and time of observation to gauge the actual position of an object. The alternative method projects the Earth's equator onto the celestial sphere and the earth's frame of reference from the north and south poles to the zenith and nadir. This treats the Earth as a fixed point of reference, and is expressed using Declination(δ) and Right Ascension(α). Declination is similar to latitude - the angle north or south of the celestial equator. Right Ascension is similar to longitude - the angle east of the vernal equinox. The book also addresses the challenge of compensating for the earth's precession. The Observing Hacks section then looks at specific techniques for locating celestial objects - using tools like the Telrad unit-power finder and star hopping. Very cool hacks for observing DSOs (Deep Space Objects) like nebulae, galaxies, etc., and Shallow Space Objects like comets, asteroids, and meteorites. This extensive section wraps up with hacks for recording and logging observations, including how to plan and run a Messier Marathon.The photography section could have been more extensive. The challenges of night-time long-range photography could fill a whole book.

The next section delves into the time honored tradition of scope hacking for astronomers. Galileo set the pace with his hand-ground lenses, and most young astronomers have tried their hand at building a scope from the ground up, or at least from hacked together mirror kits, discarded tubes and pipe fittings. The convenience of the low priced and very good Chinese scopes makes the hobby all too easy nowadays, but one can and should still ensure optimal efficiency from one's scopes. The hacks described herein provide some such techniques. The first and most critical technique is that of collimation or alignment of the lenses and mirrors to share a common optical axis. Additional hacks include the elimination of astigmatism, diffraction spikes and contrast enhancements for better image quality.

The final section deals with accessory hacks such as dark adapting your laptop and your vehicle. Useful accessories like a Barlow lens (increases the magnification of the scope) and a finder eyepiece are discussed. The book wraps up with notes on planetarium software for PCs, Macs and PDAs. The popular and free Cartes Du Ciel or Sky Charts is described. Software for the Mac OS/Linux includes XEphem and KStars.

Astronomy can be an interesting hobby, or obsession for some. It enables us to briefly fathom the vastness of this universe, while providing much educational value. Astro-babes may be an added bonus, but I wouldn't know about that really;)

Astronomy Hacks/Barbara Fritchman Thompson Mapping Hacks/Jo Walsh Astronomy: A Self-Teaching Guide, Sixth Edition/Dinah L. Moche Turn Left at Orion: A Hundred Night Sky Objects to See in a Small Telescope--and How to Find Them/Mary Lynn Skirvin Meade ETX125EC Telescope w/ UHTC, Autostar Controller (497) and Tripod (884) Celestron Firstscope 114EQ 114mm Reflector Telescope

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