Tuesday, July 24, 2012

Carnival of Space #259

Welcome aboard to another fine issue of Carnival of space, a collection of the best the astronomy community has to offer.
Fasten your belts and we are starting....

"Gaming for real science!" Want to participate? Technology is making it possible for the public to participate in exploration as they never have before. Because Mars exploration is fundamentally a shared human endeavor, we want everyone around the globe to have the most immersive experience possible. Read more on Links Through Space"

Long-time readers of Dear Astronomer know that I am a pretty hard-core dark sky advocate. As a fan of science fiction and dark skies, I couldn’t resist passing along this video from 2001. From what I’ve heard the footage was archived VHS footage that was recently digitized by Scott Kardel (International Dark Sky Association).

Nextbigfuture - a novel architecture is proposed that would allow for an unmanned interstellar rendezvous and return mission. The approach utilized for the Vacuum to Antimatter-Rocket Interstellar Explorer System (VARIES) would lead to system components and mission approaches that could be utilized for autonomous operation of other deep-space probes. Engineering solutions for such a mission will have a significant impact on future exploration and sample return missions for the outer planets. This paper introduces the general concept, with a mostly qualitative analysis. However, a full research program is introduced, and as this program progresses, more quantitative papers will be released.

Simostronomy - His introduction to the night sky occurred at age five when his mother introduced him to the Pleiades on a crisp, clear, winter night. A book from a kindly librarian brought the rest of the universe into focus and Leslie's quest for knowledge of the night sky took off. As a teen Leslie earned $18 for a mail order telescope by picking 900 quarts of strawberries on his father's farm, earning two cents per quart. The 2-inch refractor arrived a few weeks later and 64 continuous years of night time observing began.

Simostronomy - If you are a visual observer, the eyepieces in your arsenal are as important as the optical tube or mount. One of my goals has always been to find the perfect combination of the fewest number of eyepieces to be able to handle all my typical observing requirements. I don't like to spend time changing eyepieces and refocusing. I want to observe, not focus and fiddle around. My search for the perfect combination of eyepieces for variable star observing has had episodes of experimentation and expense followed by long periods of satisfaction and observing action.

A Cheap Astronomy podcast talks through the OBAFGKM classification of stars and finds there's more to it than just getting fine girls to kiss you.

Land Ho! Riding with robots, using NASA's "Eyes on the Solar Sytem" site to see what the spacecraft carrying Mars Curiosity sees as it approaches the Red Planet over the next few days.

Supernova Condensate - The Frost Line in circumstellar disks marks the point where volatile molecules start to condense into ices. But is it the only such line? Perhaps, as some astronomers have proposed, there might also be a Soot Line to consider...

Astroblog - Views of the Aurora Australis form the recent solar storm of 15 July

The Meridian Journal - The Spitzer space telescope has found a possible exoplanet which is smaller than Earth and may be covered in lava.

Astronomers at the dotAstronomy conference made good use of their video cameras to make two films: "Science: it's Universal" & "Sh*t Astronomer's Say"

Sunday, July 15, 2012

Jupiter occultation summary

Jupiter occultation stood up to my expectations. I didn't set up anything in advance due to the weather, I just got all the equipment ready and outside the house. I set up the alarm clock for 3am and tried to get in a few ours of sleep. When the alarm went off, I went out to see the moon which just rose in the north-east. Even with the naked eye the view was fascinating, and Jupiter was very near to the edge of the moon. I set up everything and then Venus rose as well. Venus showed a lovely crescent phase! Then all there was to do was to take pictures and wait. The weather was clear but humidity was very high. I used two telescopes: one for viewing (a small refractor with x100 magnification) and another one for photos and video (Bresser N130 with Philips SPC 900 Webcam).
The following pictures show the first part the disappearance. It happened so quickly that you can easily miss it. I just pressed the button to take the video and moved to the other telescope for visual observation. It took around 80 seconds and it seemed just like the moon swallowed Jupiter.
Jupiter occultation
Jupiter occultation
And the video (I was some seconds too late to start it, sorry)

But don't worry, it came back after an hour, you might even see the famous earth shine
Jupiter occultation
And as dawn arrived I took a photo of the general view of the sky with the moon, Jupiter and Venus just before sunrise. I followed Jupiter to see how long after sunrise I could see it with the naked eye. Since it was so close to the moon it was relatively easy to see it even 25 minutes AFTER sunrise.
The moon Jupiter and Venus
The moon Jupiter and Venus (bottom) after the occultation
And another bonus was that at 5:40am I saw the live launch of Soyuz for the ISS over the internet.

Thursday, July 5, 2012

Jupiter Occultation

An occultation is an event in which a celestial body covers another, farther away object.  Usually, the term is used to describe an event when the moon covers a star or a planet or when a planet or an asteroid covers a far away star. On July 15th there will be a marvelous Jupiter occultation. The moon will cover Jupiter for about an hour (the exact time and durtaion of the occultation is  dependent on the observer's location).

Occultations can also contribute to science. During the 80s Uranos occulated a distant star. Photos of the events showed that just before and after the occultation the star blinked several times. The theory was that Uranus has a set of rings (like Saturn). When Voyager 2 reached Uranus it detected and photographed the predicted rings.

Seeing Jupiter's occultation is possible with the naked eye, but the look through a telescope, even using a small magnification, is marvelous. At first, two of Jupiter's large moons (Io and Europa) will disappear behind the moon, then Jupiter will disappear and then the other two moons (Ganymede and Callisto). It is best to check your local almanch for the exact times. The times given here are appropriate for Israel. Unfortunately the event will not be seen in the United States at all, but US observers will have a Venus occultation in August!

Here are some tips for occultation observations:

  1. Start early - Even the view of Jupiter so close to the moon is great so start watching it as soon as possible (Which will be when the moon and Jupiter rise in the morning)
  2. Check the weather - If weather is bad its worthwhile to drive off to somewhere else. Check with other astronomers in different cities nearby
  3. The occultation itself is very very short - a few seconds only, so make sure you know exactly when it happens.
  4. If you have two telescope use both. If you want to try and photograph as well you might need help. It is difficult to handle both at the same time and you might need to choose between visual observation or astrophotography
  5. Check out when the end of the occultation occurs. You will need to be very accurate for this, and you can divide your attention between visual and photography to the start and end of the occultation
  6. Do not forget the moons! Watch carefully until all moons are occulted.

Jupiter occultation times for Israel (GMT+3)
Date: July 15th (The night between Saturday and Sunday)
Occultation start: 4:03
Occultation end: 5:06
Jupiter Occultation - Illustration
Jupiter Occultation - Illustration