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eclipsing binary section

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EB Photometry

Photometry of Eclipsing Binaries

New "Otero+" EBs

New EBs identified by Sebastian Otero and his colleagues:

Software Resources

  • The AAVSO facility VPHOT is available to members for processing CCD images and performing photometry.
  • AIP4WIN, astronomical image processing software that accompanies the book The Handbook of Astronomical Image Processing, by Berry and Burnell.  Many observers find this software inexpensive, functional, and easy to use.


If purchasing books, please consider purchasing from, accessed via the menu bar of the AAVSO website -- this provides financial support to the AAVSO.  Some books are only available secondhand, e.g. at

The following are useful books regarding eclipsing binary stars:


"An observation in a drawer is no observation at all."  I've lost the reference to who said that, but it is worth repeating.  Your observations must be put in to the public record to be useful.

Determining the Time of Minimum

This is one step that is unique to observing eclipsing binaries.  Once you're taken images of the star field through an eclipse, and produced a time series of V-C magnitudes (and C-K to ensure quality), you must now determine the mid-time of the eclipse.  If your data is of good quality, and the star is not badly spotted, the time series will be symmetric around the midpoint of the eclipse.  Most algorithms for determining the ToM assume this is so.  They numerically "fold" the time series around a hypothesized midpoint, and compute how well the ingress and egress legs match.  The algorithm

How to Observe EBs

This page will assume you are an amateur astronomer with some experience taking and processing CCD images.  The procedures for doing this are described in the AAVSO CCD Observing Manual, except that it is not essential that you be able to perform transformations.  Also, see our Bibliography, and Software Resources pages.


The Future

Neils Bohr is reputed to have said, "Prediction is very difficult, especially if it's about the future", but we can say a few things based on what is already on the market, and on the drawing boards.


EB:  In this website, and in informal conversation, "EB" is short for "eclipsing binary" -- of any kind!  Not to be confused with "EB" in the GCVS or VSX, which means an eclipsing binary with a beta Lyrae light-curve morphology, as opposed to eclipsing binaries with EA or EW light curve morphologies.  Both of the general variable star books listed in the bibliography (i.e. Percy, or Hoffmeister et al.) explain the differences between the different types of EBs.


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