Rapid rise to end of eclipse
Well folks, the end is near: third contact arguably arrived 2 weeks earlier than predicted - sometime during late Feb, early March**. We've seen a rise from V ~ 3.75 then, to V ~3.55 last night according to several observers. At this rate, ~50 milli-mag per week (0.050 mag/week), we will climb to out of eclipse level, V ~ 3.0, during April and May.
**Caution: there is a chance, albeit small, that we are being fooled by one of those out of eclipse variations that can add/subtract up to 0.1 mag to brigthness trends, so careful watch is still needed.
Among the end of eclipse observations scheduled or accompished include the following. First, an attempt to obtain an egress image using the CHARA Array atop Mt.Wilson. However, weather and instrument challenges have limited success with this so far, but 4 dedicated evenings are scheduled for the first few days of April. Getting an egress image, showing the disk edge position, is critical to setting orbital parameters. Second, Hubble Space Telescope secured one final Cosmic Origins Spectrograph far UV spectrum of epsilon Aurigae on 17 March 2011. The spectra will help interpret the nature of the disk's central star. Third, the IRTF SpeX instrument is queued up for observations March 28-29, and fourth, the Spitzer Space Telescope IRAC camera is scheduled to obtained two more snapshots in its series during mid-April. Both SpeX and IRAC are providing essential information about the gas and dust that comprise the disk. Several of these facets will be reported at the Boston meeting of the American Astronomical Society in May, held jointly with AAVSO. Hope to see some of you there!
Finally, March brought joy and sadness: joy from all the observing reports, sadness from the beginning of the end of the long eclipse, and sadness because of the loss of longtime AAVSO observer and my astronomical mentor, Edward A. Halbach.