HST’s ACS Camera Back In Service

In a little reported story, the Advanced Camera for Surveys (ACS) onboard the Hubble Space Telescope (HST) went offline on Sept. 23, 2006.

After an initial analysis, the Board determined that the ACS anomaly is confined to only one of the three channels – the High Resolution Channel (HRC), which performs about 18% of ACS science.

The unaffected channels are the Wide Field Channel (WFC), that provides nearly 72% of all ACS observations, and the Solar Blind Channel (SBC), which is used only about 10% of the time.

Hubble engineers were able to successfully bring the Wide Field Channel back on line September 30, and resumed normal WFC science observations on October 1. Among its many major scientific accomplishments, the WFC enabled the famous Hubble Ultra Deep Field (HUDF) discovery – a stunning view of more than 10,000 galaxies that assisted astronomers in determining how galaxies originally formed in the early universe.

Engineers are examining strategies for potentially returning the HRC to service. They report that all other subsystems on the telescope are functioning nominally.

So some of the ACS was brought back online on Oct. 1, 2006.

As you may or may not know, HST’s spectrograph, the Space Telescope Imaging Spectrograph or STIS, is offline permanently, which is a huge blow to astronomy. STIS was the only high-resolution spectrograph capable of ultra-violet observations, something you can’t do from the ground.

I agree with the many astronomers who believe that HST is too valuable to let decay. We should proceed with the scheduled servicing mission as soon as possible.

Want to know it? Teach it!

As many of you know, I’m in the first year of a PhD program in Math, Science, Technology and Engineering Education with my focus on astronomy education. Education is a new realm for me so there will be many stories coming forth. The first stems from a literature review I’m doing for a class.

I learned 10 times more about astronomy by teaching Intro to Astronomy adult education courses the last few years and by writing most of the 63 SA episodes than by getting my BS in astronomy. The degree gave me a foundation, but BS’s in astronomy are not designed to teach you about astronomy in general. They are designed (unfortunately) to 1. weed out those who can’t make it in grad school and 2. focus the survivors’ efforts into a few tiny astro subtopics.

So I ran across a paper in an education which said that – on average – people remember 10% of what they read, 20% of what they hear, 30% of what they read…80% of what they do and 90% of what they teach. That is clearly a rhetorical approximation, but one based on truth. If you want to really know some astronomy, teach it to someone else.

If you are one of those who wants to know more about astronomy, but feel overwhelmed by it all, then I have advice for you. Choose your favorite topic, and give a talk about to it to your local astronomy club. If you don’t have one, or are too nervous, then present it to your family during your next dinner/long car ride/etc. or try to explain it to co-workers over lunch. Try to teach it to someone. If you want, post your talk idea in our forums and we’l be happy to give some ideas and advice.

Quickly you’ll realize that suddenly you know quite a bit about something. That will usually lead to learning more about things associated with it. For example, you may give a talk about quasars – then decide that their jets are really cool – then want to learn more about radio astronomy – which is used to observe the jets – which leads to interest in SETI – which leads to UFOs and craziness.

But, hey, at least you learned a lot about astronomy before you went nuts.

SG Interview: Doug Welch on MACHO

Slackerpedia Galactica Interview: Doug Welch and the MACHO project. (MP3 audio file, 13:28, 6.2M)

MACHO, and its sequel, SuperMACHO, are projects that have directly detected dark matter. Dark matter is dark, yet we can observe it through a variety of clever techniques. One such technique involves measuring the brightness of stars and looking for the effects of gravitational microlenses — stars which get brighter for a brief time, once and only once, as the dark matter passes in front of it.

Dark matter is a funny term because it encompasses all the matter we can’t see. Dark matter is not one thing, it is all the things we can’t see but can detect due to their gravity. The dark matter detected by MACHO is likely things like planets, brown dwarfs, white dwarfs or low-mass black holes, if such things exist.

Dr. Doug Welch is one of the researchers involved with the MACHO project. In this podcast interview with Michael Koppelman, Doug talks about all things MACHO.

If you haven’t already subscribe to the podcast or just listen now.

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Harbinger

I was at my modest observatory on Saturday night. Beautiful, cool and clear night. While my telescope clicks away, taking image after image of my current target (which right now is GSC 3196-641) I get to stand outside and look at the night sky with the most ancient detector of all — my eyes!

I enjoy watching the seasons change. In the spring I anxiously look for the rise of Scorpius and Sagittarius. In the autumn I dread the rise of the Pleiades, Taurus and, the ultimate harbinger of winter, Orion.

They say Orion is the most recognizable asterism. An asterism is a recognizable group of stars, like the Big Dipper. We are used to saying “constellation” but technically that means ALL the stars in the constellation. The Big Dipper is a subset of stars from Ursa Major just like most of what we recognize as Orion is a subset of all the stars in Orion.

Anyway, if you stay up until midnight or so, you can see Orion rising. It’s always a beautiful sight, even though, for us in the Northern Hemisphere, it means the inevitable start of winter.