Posted by: T. Boyd | August 21, 2009

Galaxy Zoo and Watching Moons of Jupiter

Hanny's Voorwerp

Blue-green object found by Hanny Van Arkel

He delivers and rescues;
He works signs and wonders
in heaven and on earth, (Daniel 6:27 ESV)

I finally jumped in. I found out about the Galaxy Zoo web site some time ago, but never participated till today. I did the 20 minute tutorial with hands-on practice, and then enjoyed classifying about 10 galaxies in my first session.

This site has a huge deposit of deep sky photographs taken by the 2.5-meter telescope at Apache Point Observatory, New Mexico. The photographs were posted on the site and they asked for volunteers to go through the pictures one by one and answer a series of questions about how the galaxy appears to them. Then the project scientists analyze the answers statistically to classify each galaxy.

The creators of the site expected a few thousand volunteers, but they had a huge response, with some 70000 galaxies being classified every hour within one day of the announcement. Last summer one of the volunteers, a Dutch teacher, Ms. Hanny Van Arkel, 25, discovered a one-of-a-kind sight now appropriately called Hanny’s Voorwerp’ (object). It is still awaiting identification. It is a large bright greenish-blue “blob” near a huge galaxy.

You can join in on the fun for free at and contribute to a worthwhile project.

The other heavenly sight which I hope to be able to see (the August skies in Caroline County, VA, permitting) is to watch the activity of Jupiter’s moons. Every 6 years, we have a period of time when the plane of the orbits of the moons going around Jupiter is edge-on with Earth bound observers. And we are in that period now and for the next three or four months.

During that time, the moons will periodically eclipse one another, blocking the sunlight illuminating a moon. These are called eclipses just as when our Earth blocks the sunlight reaching our moon. Also the other periodic class of events is occultations when one moon blocks our view of one of the other moons. A table of times that these can be seen in North America is given by SkyAndTelescope.Com.

I will watch the weather prediction to try to see as many of these that I can. If I could rig up a light meter (photometer) to my telescope, I could contribute to the compilation of data that helps the team of astronomers to learn more about each moon. But even if I can’t do that, it will be a fun effort. I enjoy just seeing the moons anyway, and to see these eclipses and occultations will be very exciting to me.

Some of the upcoming better events of these Jupiter events are (times in EDT):

Aug. 31, 10:04 p.m. – an 81% occultation

Sep. 15, 10:12 p.m. – an 86% eclipse

Sep. 23, 12:41 a.m. – a 96% eclipse

If you would like to join me in these viewings, you can write me at


  1. via e-mail:

    I just started playinng with this. Wow! Thanks so much for sending this link. I dont typically have time for internet activities, but I think this one could replace our TV time for a long time. I think we will try some family cataloging there. Thanks again.

    Charles C.

  2. […] So Bright Exploring the heavens « Galaxy Zoo and Watching Moons of Jupiter Number of Galaxies and Stars August 24, 2009 Here is an expanded version of the first […]

  3. Originally I had “sometime” in the first sentence and today wondered about that. Is it sometime or some time? And my wife helped correct me. 🙂

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