Astro Methods Index
The Astro Methods is a collection of worksheets that solve
problems of interest to the practicing amateur astronomer and serve as a
learning tool to better understand the underlying phenomena at work.
Several of the Methods employ the User Constants to create
data and graphs customized to the user's time and place of observation.
The Methods demonstrate the utility of the Astro Functions
as building blocks for complex astro-computing worksheets. For ease in
following the logic, calculations are compartmentalized into reference
worksheets inserted in the main worksheet. Interested users can open these
fully documented reference sheets to study the Astro Functions and
techniques employed. (Mathcad 8 Standard does not have the ability to hide
sections of equations, hence the use of references to accomplish this.)
You are invited to extend the Methods to meet your personal
needs by including them as reference sheets into your worksheets.
- Julian and Gregorian Calendars
Here are notes on the problem of setting up a calendar system that is
in synch with the position of the sun. The use of leap days to resolve
this problem in the Julian calendar and the reforms that led to the
Gregorian calendar are discussed. A practical example of -- and cautions
concerning -- conversion between Julian and Gregorian dates is examined.
- Sidereal Time for Civil Time
For any day this worksheet creates a handy chart to help the observer
determine what part of the night sky is visible at any hour and location.
- Polar Alignment with Polaris
This worksheet assists the observer in polar alignment of a telescope
using the simple method of offsetting from Polaris. Graphs of Polaris in
relation to the north celestial pole for the current and future times of
interest are generated for your particular location.
- Star and Planet Phenomena Charts
Get an idea of what is happening in the sky by using this sheet to
generate customized low-precision charts of rise, transit and set
phenomena of planetary bodies and stars for periods of a month to a year.
- Earth's Nutation Visualized
Nutation is a slight wobble of the Earth that is in addition to that
caused by precession. The slight affect this has on the location of the
vernal equinox is used to determine such quantities as true obliquity,
true equinox and apparent sidereal time. Various charts and a movie help
you visualize this important phenomenon.
Astro Utilities Electronic Book Copyright © 1999
Pietro Carboni. All rights reserved.