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light curve; ingress; totality
As the light curve wiggles.
As the light of the primary star continues to wane, discussions of the time of "first contact" have arisen - that's when the dark disk began to encroach on the F star photosphere. Pre-eclipse predictions indicated the date could be JD 2,455,055 = 2009 Aug.11 (Hopkins & Stencel, 2008 Epsilon Aurigae - book - p.97). Different observers point to slightly different times to represent the start of ingress.
Jeff Hopkins (Hopkins Phoenix Observatory) has analyzed light curve data and concluded the eclipse began (V band) on JD 2,455,072 = Aug 28.
See his webpage at http://www.hposoft.com/Plots09/FirstContact.JPG .
Italian observer, M.M.M.Santangelo (Osservatorio Astronomico di Capannori) has published statistical results of his independent photometry in issue 2224 of the Astronomer's Telegram and states that the eclipse "did not still take place until at least August 17th" = JD 2,455,060. Read more
Success! However, it's not over til it's over...
Greetings again from historic Mount Wilson Observatory, perched in the Angeles National Forest mountains, above Los Angeles. As previously mentioned, we're here using the Center for High Angular Resolution Astronomy (CHARA) telescope array of 6 one-meter telescopes, operated by Georgia State University. The light from 4 of these telescopes at a time can be merged in the Michigan IR Combiner, or MIRC. Each pair of telescopes is capable of producing interference fringes. Measuring the fringe contrast and knowing the wavelength and telescope separation for each pair over the course of an evening, provides pieces of information that can be used to construct an image.Read more
Looking ahead, the year of totality
Did you observe the palindromic date this weekend, 01- 02- 20 10 ?
If you have been observing the steady decline of the light of epsilon Aurigae this autumn, you might wonder if it too will be palindromic - that is, the brightness symmetricaly rising during egress early in 2011, as steadily as it declined during ingress autumn 2009. Short answer, probably not. Among the many wonderful conundrums surrounding epsilon Aurigae is that the eclipse is asymmetrical - egress tending to be fast than ingress.
This difference is thought to be due to asymmetries in the disk - somewhat less well defined on the trailing edge that we'll see later in 2010 and during early 2011 as eclipse ends, relative to the leading edge this past few months.Read more
