Live from the Hubble Space Telescope

UPDATE # 20

PART 1: Challenge Questions: a new puzzle

PART 2: Another reminder about upcoming live interactions

PART 3: Collaborative weather activity

PART 4: Analysis of Pluto takes shape

PART 5: Quest for a Number

CHALLENGE QUESTIONS: A NEW PUZZLE

Last week we asked:
Pick two spots on Pluto (other than the poles) that are on opposite hemispheres. From these two vantage points, describe the phases of the moon, Charon, that you would see. (Hint: there are two periods of time to worry about, one long and one short.)

ANSWER:
Unfortunately, we don't yet have a clear answer available. We will share the result as soon as possible. We regret any inconvenience causes.

Challenge Question for this week from Karla Peterson:

During December 1995, HST observed a fairly blank patch of sky for many days without interruption. This incredible picture of very distant and faint objects has been named the "Hubble Deep Field" and was revealed to the public in January.

Question: What special property must a target have in order for HST to observe it for a long time without interruption?

Props to help work on the question:

globe 		(to represent the earth)
piece of wire 	(to represent the circular orbit of HST around earth -
		HST is in a very low orbit, only about 600 km
		off the earth)
bead 		(to represent HST in its orbit around earth)
protractor	(to help you make the orbit have an inclination
		of 28 degrees - inclination is the angle between
		the orbit and the earth's equator)

ANOTHER REMINDER ABOUT UPCOMING LIVE INTERACTIONS

This coming week will feature two opportunities for your students to interact with experts of the Hubble team. Please consider joining us in these activities.

On Wednesday, April 10, Alex Storrs and Tony Roman from the Space Telescope Science Institute will be available on WebChat. Their topic will be "How we prepared the HST to make your Pluto and Neptune observations". They will cover this topic in two separate sessions, from 9-10am Pacific (noon-1pm Eastern) and 11am-noon Pacific (2-3pm Eastern). To participate, point your Web browser here.

On Thursday, April 11, Chris Wilkinson and his colleagues from the team that operates the HST will be available on CU-SeeMe. They will discuss the Hubble as a spacecraft and will get into details about what it takes to keep the system operating safely. They will cover this topic in two separate sessions, from 9-10am Pacific (noon-1pm Eastern) and 11am-noon Pacific (2-3pm Eastern). The hour in between is reserved for classroom-classroom interactions. To join the fun, use the following CU-SeeMe reflector sites: 128.42.249.172 (first choice) and 198.64.198.250 (alternate if the primary experiences problems)

COLLABORATIVE WEATHER ACTIVITY

As announced in the previous LHST message, we are hoping that next week, many classrooms will participate in a data sharing activity involving weather. Students will be expected to collect local weather information each day next week and share it with us. National weather maps will be constructed from data submissions.

If you are planning to participate, please send a brief RSVP to Jan Wee as soon as possible. Include in your note to Jan the following information: name of school, teacher's name, grade, city/town, state, latitude (given in degrees N), longitude (given in degrees W):

ANALYSIS OF PLUTO TAKES SHAPE

Marc Buie is hard at work analyzing our Pluto images. As he goes, he is sharing his work online. Marc writes:

"I've begun digging into the LHST Pluto images. I'm basically working this data "live" on my WWW pages. You can get there from my Pluto page, or, jump straight to the analysis page, and watch the results grow there. I'm using the WWW as an electronic lab notebook so what I think of and work out as I go along will be written there as I proceed. If you want to know where things stand, just hop onto my page and check it out.

QUEST FOR A NUMBER

Wayne Baggett

March 22, 1996
I spent much of today searching for a number. Numbers are very important to the HST, partly because almost everything is done with computers, and computers love numbers! I am working on one of the new instruments which hopefully will be placed aboard HST next year, and I needed to know the value of a specific piece of information so that I can use it in the computer programs for which I'm responsible. Unfortunately, the only people who know what the number was are 2000 miles away , so I had to contact them in order to get it.

You see, I work in Baltimore, Maryland (try to find it on a map), but the instrument is being built in Boulder, Colorado (try to find Boulder, too), so getting the information I needed is not quite as simple as walking down the hallway to someone's office. Also, since the instrument is still being built, the number wasn't available in any books or papers that I can access. I basically had two options: use the telephone, or send electronic mail. Because the person I needed to "talk" to (let's call him Joe) is very busy himself, I decided to use email so that he could decide when to answer my question.

So, I sent Joe the question "What is the value of Read Delay?" ('Read Delay' is an important quantity for a certain use of this new instrument.) The time was 11:00 in the morning in Baltimore, but it's only 9:00 in the morning in Boulder (think about why this is so), so I figured I might have to wait a while for the answer and continued working on other things while I waited.

I checked my mailbox just after lunch, and I found a message from Joe: "It is 570 (175 for the readout & 395 for the delay)." Well, it was good for him to get back to me so quickly, but what he described wasn't what I thought I was asking about -- we had a problem with our definition of what 'Read Delay' meant! I had to ask him to clarify his answer, so I sent him another email (this is now the third email message to be sent across the Internet for this question!) telling him what I thought 'Read Delay' meant and asked him to clarify the definition for me. The time was now 1:20 in the afternoon, Baltimore time, and nearing lunchtime in Colorado.

While I waited for Joe's response, I worked on some other stuff I needed to finish: I reviewed a manual for the new instrument to make sure that it was written correctly, I answered some questions for another person here in Baltimore, and other such mundane things -- nothing as exciting as finding out just what that number was!

At about 2:15 I checked my mailbox again, and Joe had replied! Finally, I would learn just what value and meaning 'Read Delay' had. He told me that his description was correct, and that the source of my information for the definition of 'Read Delay' was wrong. In fact, 'Read Delay' does indeed have a value of 570, but I was only interested in the part that was 395! We were both right! Finally, I sent him a response to thank him for the information and to restate the value just to be sure that I had everything right. An hour later, at about 3:20pm Baltimore time, Joe sent the sixth email to confirm my newly-learned definition and the value of 'Read Delay'. Thus, the HST project has taken another tiny step toward the future.

Unfortunately, the number will probably change next week.