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.
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
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.
The Hopkins Phoenix Observatory will be presenting two workshops on Friday, August 7. One will be on spectroscopy of epsilon Aurigae and the other on Digital Single Lens Reflex (DSLR) camera photometry of epsilon Aurigae.
The spectroscopy workshop will provide an introduction to spectroscopy. There will be a discussion on what spectroscopy can be done with a minimum amount of equipment and expense. For those people wishing more, a review of the Lhires III spectrograph and its use for high resolution spectroscopy with some tips and tricks will be presented. Spectroscopy is exciting and easier than you may think.
While there has been some discussion about using a DSLR camera for photometry, and there will be a Workshop devoted to it, those with DSLR cameras may also find using them for spectroscopy an interesting and rewarding challenge.
During the first Workshop in Chicago, part of the Workshop will be devoted to low resolution spectroscopy using a DSLR camera with a Star Analyser spectrograph ($200). As with DSLR photometry, no modifications are needed for the camera, save a means of attaching the Star Analyser (easy). You can even do it on a tripod without a telescope.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).
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
What is meant by first contact?
Basically it's the start of the eclipse. The point where the eclipsing body first touches the primary star's image and starts a decrease in the primary star's brightness as seen from Earth. But it's not so simple. With epsilon Aurigae, first contact appears to be wavelength dependent. This means that the longer (red and visual bands) wavelengths will start to show an eclipse before the shorter (blue and ultraviolet bands) wavelengths. 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!