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Blog

Citizen Sky is now officially permanent part of the AAVSO. In the coming weeks we will be moving additional content to the AAVSO site and freezing this site as an archive of the 1st three years of the project. Please visit the new landing page for future updates.

The after-mid-eclipse slide!

Although we won't be able to confirm until later, that mid-eclipse occurred as predicted during the end of July - beginning of August, all the evidence strongly suggests it's so. 


  • Despite solar conjunction at the start of summer, photometric monitoring continued, but little evidence for Mid-Eclipse Brightening has been produced thus far.  In fact, a first minimum during totality was reached near RJD 55250 (V ~ 3.8), then slowly rising toward mid-eclipse values close to V ~ 3.6Read more

Posted by Dr.Bob on August 8, 2010 - 12:48am

Mid-eclipse time!

How the time flies.  Seems like yesterday (actually 2005) when the first observing proposals* for monitoring epsilon Aurigae were being submitted - and suddenly we have arrived at predicted mid-eclipse.  According to Jeff Hopkins, who has made a study of the light curves, he expected mid-eclipse to occur August 4th, 2010 = JD 2,455,413.

The light curve shows no strong evidence for "mid-eclipse brightening" thus far.  Now that epsilon Aurigae is getting well separated from the sun, airmass corrections are less a problem, so more accurate photometry is possible.  From Mt.Evans this week, we had an exceptional morning for J& H band work, very good signal to noise, but found the brightness was close to that reported during spring 2010 - well into totality.Read more

Posted by Dr.Bob on July 29, 2010 - 1:45pm

New Planetarium Show & Video w/Timothy Ferris!

We are excited to announce the debut of a 7-minute Citizen Sky planetarium show narrated by Timothy Ferris. Please help us share the word and distribute this video far and wide!

Posted by Aaron Price on July 16, 2010 - 10:29pm

Newsletter #6 is Now Online!

The sixth issue of the Citizen Sky Newsletter has been released!

Note: It seems as though the email notification of the Newsletter is going into many people's SPAM folders - especially those who use Gmail.  Please take a moment to go into your spam folder and mark the message as "not spam" in order to prevent missing the notification email in the future.

Thanks and take care!
~RRead more

Posted by Rebecca on July 16, 2010 - 4:22pm

Updated version of VStar is now available!

An updated version of the multi-platform, easy-to-use variable star data visualization and analysis tool, VStar, is now available! (To download the new version simply visit the VStar page and click on "Download VStar Now.")

Check out the recent posts by David Benn and Doc Kinne on the VStar Team page for more details on the new release.

If you are unfamiliar with VStar please visit the VStar page for a basic introduction.  There you can find out how to download, launch, and use this powerful tool.  Happy VStaring!!Read more

Posted by Rebecca on July 7, 2010 - 12:00pm

Cosmic fireworks...

...or not. 
We are entering into a very special 2 month interval centered on predicted mid-eclipse, 4 August 2010 (JD 2,455,413 +/- 2 weeks).  Some expect a "mid-eclipse brightening" - as much as several tenths of a magnitude - which would demonstrate a substantial central clearing in the dark disk. 

Based on what we know from the initial round of interferometric imaging, the disk is so close to edge on, that seeing the "hole in the doughnut" is improbable.  However, there are some clues that surprises may await the persistent observer:

- the B star at the center of the disk is a significant source of ultraviolet photons, capable of vaporizing dust, possibly enlarging the central opening;Read more

Posted by Dr.Bob on July 2, 2010 - 10:10am

Independence Day Eclipsing Binary Marathon

It's a 3-day weekend for those in the USA. So here is a list of some eclipsing binary stars with expected eclipses this weekend. They are mostly bright so can be seen with the naked eye or binoculars. If you are out this weekend, look up, make a few obs and report them!

For you morning folk, our friend Algol (Beta Per - the Demon Star) will be in eclipse the evening of July 3-4. Mid eclipse is around 4:30am eastern, but it should start dimming around 12:30am or so. You don't have to stay up all night to get the whole eclipse. Just getting the start or end would be fun enough. Algol's chart is in our 10-Star Tutorial. It's brighter then epsilon Aurigae so can easily be seen from the city. Read more

Posted by Aaron Price on July 1, 2010 - 10:52pm

Your Local Observatory

The last few weeks I've heard from several observers that they haven't been able to do any observing due to poor weather and I got to thinking: if we can't talk about our observations, why not talk about our observatories? So I've created a thread in the forums so that you can tell us about your local observatory and discussed the Sachtleben Observatory of Hastings College, my home-town observatory.Read more

Posted by bkloppenborg on June 20, 2010 - 12:46am

No sign of mid-eclipse brightening, so far...

Despite a spring blizzard, we made it to our 28 inch f/21 RC telescope at Mt.Evans Observatory in Colorado (14,148 ft elev) and visually inspected epsilon, zeta and eta at low airmass mid-day Tues 6/15/2010.  Brian K and I agreed that eps and zeta were of comparable brightness, after several iterations.  I think eps is slightly fainter than zeta when color differences are taken into account, but that gets subjective under bright sky conditions.  Thus, we report no indication that epsilon Aur is brighter than zeta Aur at this time.  Hence, no evidence for mid-eclipse brightening at this time, but further reports to follow.

With mid-eclipse forecast for early August 2010 and mid-eclipse brightening supposedly lasting +/- 30 to 45 days around that point, we should either begin to see evidence for it soon, or redefine the mid-eclipse light curve.Read more

Posted by Dr.Bob on June 15, 2010 - 6:45pm

Last day to apply for the 1st round of selection for the upcoming Citizen Sky Workshop!

The deadline to apply for the 1st round of selection is midnight (Eastern) tonight Monday, June 14th!

The second Citizen Sky Workshop will be held Friday-Sunday, September 3-5, 2010 at the California Academy of Sciences in San Francisco.  We will kick-off the 3-day workshop with an opening reception and tour on the evening of September 2.  The focus of this workshop will be data analysis and scientific paper writing. We will have sessions updating us on the science of epsilon Aurigae, how to use VStar for basic data analysis, how to write papers for peer review, how to choose good research questions, doing literature reviews and much more. We also will have a free showing of the new Citizen Sky planetarium trailer on the California Academy of Science's brand-new planetarium dome.

Travel grants are available.
 Read more

Posted by Rebecca on June 10, 2010 - 11:57am

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