observing aids

any content that aids in observing practices

Charts and Sequences Update January 2012

There are over 100 new and revised charts and sequences since the last update in November. Many of these are for stars in the newly formed YSO Section Program, southern stars with new photometry from APASS and campaign targets. The rest are revisions based on issues reported to CHET and requests for new sequences from our observers.

Bob Nelson's Database of Eclipsing Binary O-C Files

Nelson Database of Eclipsing Binary O-C Files

Bob Nelson has developed over 5400 O-C (Observed - Computed) files of eclipsing binaries, all in Excel format, that we are hosting on our site. The purpose is to provide information on period variation for selected eclipsing binaries (for astronomers interested in a particular star) and to determine the best elements for predicting future eclipses.

SID Monitoring Group FAQ

When the ultraviolet rays from the Sun hit the Earths atmosphere the energy they possess work to knock electrons off of the atoms and molecules that the atmosphere is made up of. These free electrons make up a region of the atmosphere known as the Ionosphere. The region is strongest on the daytime side of the earth since it is dependant on the energy from the solar ultra violet rays.