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Dr.Bob's blog posts
Samuel Beckett's play features characters who are simply hanging out, waiting for their friend Godot to show up. It may be beginning to feel this way with epsilon Aurigae too, as the slow phase of ingress grinds on. The current photometric V = 3.05 level suggests we are still within the range of normal out of eclipse light variation. However, the non-optical brightnesses are in decline, especially the I and J bands in the near-infrared.Read more
Several observers are reporting V = 3.00 in mid-August even though predictions that eclipse started in early August. Reviewing the past light curves indicates that ingress may have a slow and then a faster phase: in 1982 it took nearly 50 days to drop 0.2 mag, and then another 100 days to drop another 0.6 mags, visually. Translated to 2009, it may be late September before the star reaches eta Aur's brightness (~3.2). Patience.
Adler Planetarium - what a splendid astronomical facility - our compliments to Lucy, Larry, Rebecca, Aaron and the CS/Adler gang for hosting a marvelous first Citizen Sky workshop, Aug. 4-7, 2009. Among the many meeting highlights was a report that appears to clinch the evidence for the existence of a cold disk in the system, a chance to meet with many key participants like Arne Henden, the Citizen Sky senior staff and Jeff Hopkins, Gerry Samolyk, Mike Simonsen - veteran observers, as well as meet the newer participants to the project (Hi PJ, Rhonda, Alice, Barry, Bill, Brian, Mark, Niko...). Hopefully everyone who attended came away with new contacts and ideas that will carry us far.Read more
Robin Leadbeater just provided spectroscopic evidence that the eclipse is starting - and on the 40th anniversary of Apollo 11 moonlanding.
Leadbeater has been following the neutral potassium absorption line at 7699A in the far red, and reports a doubling of the equivalent width (area inside the curve). The new component has appeared about 1/3A longward of the longterm line, corresponding to a redshift of about 20 to 25 km/sec, which is consistent with radial velocity of ingress (see Lambert and Sawyer, 1986: http://adsabs.harvard.edu/abs/1986PASP...98..389L -- figure 2, attached.
Photometric confirmation is eagerly anticipated. Congrats Robin!
7/10/09 - we've entered a special time with THREE local eclipse events heralding the predicted start of eclipse for eps Aur: a partial lunar eclipse this week, a total solar eclipse on 7/22 and another lunar eclipse on 8/5 - same week as start of eps Aur eclipse and the Adler meeting!
We've been frustrated at the mountain due to access road repair by the state highway department and cloudy mornings - thus , no new SSP4 data this week. We plan to try again later next week. Read more
We were fortunate to have 3 relatively photometric mornings to study eps Aur and friends with the SSP4 photometer - J & H bands (1.2 and 1.6 microns). Visually, eps appears brighter than eta Aur (3.2) - in agreement with other reports coming in. What's odd is that eps appears to have stayed in bright phase since the last minimum of light in early March 2009. What will happen during these last 3 weeks prior to predicted start of blue color eclipse? Calibration work on our data is underway, and we plan to persist with these measurements during July - give or take highway department's plans to rebuild the access roadway! Full report at the Adler meeting in early August - including pictures of the baby mountain goats (Capella and her kids, literally).
Finally some real data! On 6/23/09 we were fortunate to get a photometric morning and could begin to measure J & H band fluxes of stars in broad daylight - including alpha Cet, alpha Tau, alpha Aur and epsilon Aur - marginally in the latter case at first pass, but we will try to improve on the statistics in the coming week. The high altitude location helps darken the daytime sky.
Our second week showed some progress. We put both the SSP4 near-IR photometer and the FLIR mid-IR camera on scope, but we frustrated by the continued unsettled weather - see image. It's hard to go much IR work with clouds constantly in the way. However, a drying trend is forecast for the coming week, and eps is starting to move away from the sun's glare, so fingers crossed. We're still hopeful to be among the first to obtain new season eps Aur data prior to eclipse.
At least we were able to point the telescope TOWARD eps Aur this afternoon - despite the snow flurries (yes, even in June). 40F high today. Now that classes are done, we've moved up to Denver University's high altitude observatory atop Mt.Read more
This weekend marks both the 65th anniversary of the Allied invasion of France that changed the course of World War II, and the time of the year when the Sun and epsilon Aurigae are at their closest approach (minimum angular separation, 21 degrees). Both were and are difficult periods, but for both, conditions gradually improved. So it will be for observing epsilon Aurigae as it becomes an increasingly prominent morning star just as eclipse begins in August. If you are fortunate to see Capella and the Kids rising in the next 2 months, memorize the brightness of epsilon relative to eta and zeta - it's about to change.Read more