PART 1: Challenge Questions: last week's answer and a new puzzle
PART 2: Time change for the CU-SeeMe session
PART 3: San Francisco Bay Area teachers wanted
PART 4: Email HST experts your questions
PART 5: Skiing and software
Last week we asked:
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:
ANSWER from Karla Petersen:
A target that has a declination near 62 or -62 degrees can be viewed
for many days at a time. (Declination is sort of the celestial
equivalent of latitude on the earth, but it doesn't turn with the
earth.) This is because the earth does not block HST's view of the
target. We call this the "continuous viewing zone" or CVZ.
How to use the props to see this:
Challenge Question for this week:
There are many telescopes much larger than Hubble. The Hubble Space Telescope has a 2.4-meter mirror. At Mauna Kea Observatory alone, there are four telescopes with mirrors more than 3 meters across, including the world's largest telescope, the 10-meter Keck Telescope (more than 4 times bigger than Hubble!).
Why is the Hubble Space Telescope so special?
LAST-MINUTE TIME CHANGE FOR THE CU-SEEME SESSION
Today's CU-SeeMe session (April 17) occurred at 4:00PM Eastern time. This was different then the time originally announced. News about this time change was not shared widely due to some problems internal to the LHST team. We really regret any resulting problems we've caused teachers who planned around the original time.
We would very much like to identify several classrooms in the San Francisco/Silicon Valley area who plan to watch the April 23 program live. Please identify yourselves by sending a brief note to Geoff Haines-Stiles at ghs@passporttoknowledge.com. Please include your telephone number in your reply. Thank you.
As a reminder, we have arranged for HST experts to answer Email questions from classrooms. The folks at the NASA Goddard Space Flight Center (Greenbelt, MD), the Space Telescope Science Institute (Baltimore) and elsewhere are anxious to handle tough questions from your students. We are particularly encouraging questions about the Hubble itself and what it takes to keep it working properly. We'd prefer to receive questions whose answers are not easily found elsewhere.
Jeane Ryan
April 10, l996
The Ryans are a HUBBLE family as both Joe and I work on the Hubble
Space Telescope project at Goddard Space Flight Center in Greenbelt,
Maryland. Also our children Kelly, Susan and Andrew have grown up
with Hubble exposure for the last twenty years as Joe worked first
on individual instrument development, then on the integration of
instruments, mirror, solar arrays and all other parts to actually
build the telescope and now on the Servicing Missions.
Hubble took us as a family to California in 1985 when only Joe worked on the project. He was assigned to Lockheed Missiles and Space Incorporated, Sunnyvale, California as the Government On-Site Director. We lived in California for almost three years. While in California we became more avid skiers and fell in love with the Lake Tahoe ski areas.
Early in 1996 we decided to take our holiday break from Hubble to ski. As both Kelly and Susan live out in the San Francisco Bay area and Andrew had lived out in the Lake Tahoe area last spring, Lake Tahoe seemed to be the perfect choice.
We were really lucky that our ski trip coincided with Comet Hyakutake's closest approach to Earth. It would be missing Earth by ONLY 9 million miles. It was discovered by and named for the Japanese amateur astronomer, Yuji Hyakutake (pronounced "yah-koo- tah-kay".
We drove up the Mt. Rose road from the rented Mountain Shadows condo to a scenic overlook at about 7,500 feet altitude. We parked the car and got out to stare up at the night sky.
We knew the comet was to be very near the Big Dipper, an easily spotted constellation. There were so many stars in the sky that it was difficult to find the Big Dipper! It was, however, not difficult at all to find the comet. Hyakutake and its tail were easily spotted as it was the next largest item in the sky besides the moon. The comet appeared brighter and the tail longer when we saw it from the corner of our eyes rather than from straight on. The main head of the comet was thumb size and the tail about six inches long. It was a spectacular sight to behold.
Here we were many miles from the HUBBLE project, on a ski vacation in the mountains and our thoughts turned to HUBBLE. We thought of ourselves here on Earth almost on top of a mountain looking at the comet and wondered what HUBBLE was seeing actually being up there amongst the stars itself.
Seeing this comet prompted many questions:
- Why were there so many more stars in the sky when we looked at
the sky from the top of the mountain rather than from our
home in Arnold, MD?
Why could we see the comet and its tail so easily?
How large is the comet?
How long is the comet's tail?
How often are comets like this discovered?
We are back at work now and looking forward to learning about what Hubble saw looking at Hyakutake and seeing the pictures that are sent back. But let me tell you about my job in the Systems Verification Group
The Systems Verification Group is on stand-by to run the Servicing Mission Ground Tests (SMGTs) as soon as the hardware is delivered and tested. We handle the work on these tests for Al Vernacchio who is the Servicing Mission System Engineer (SMSE) Manager for the Government. When a problem occurs during the test it is documented as a Test or Simulation Anomaly Report (TSAR).
Another SVG member, Francine Crum, has been working on creating a World Wide Web (WWW) Online TSAR creation and tracking system. A user that has discovered a problem during the test is able to enter the problem into this system. Al, the SMSE is able to assign it to a System Engineer to figure out why the problem occurred and determine what needs to be done to correct the problem.
At the present time I am working on diagramming the process flow for the WWW Online TSAR System. When software is designed, the different steps taken must be very detailed and explicit. The list of these steps and what must be done in each are called software "requirements".
To make the flowchart, I am using a program called MacDraw Pro to make diamonds (decision boxes) and rectangles (actions taken boxes) which are connected by arrows. The boxes are annotated with the YES/NO decisions being made and the actions being taken. It is a challenging task as you have to think very logically, step-by-step to make sure that the software system is designed to handle everything and once created actually does what it was designed to do.
Try your hand at making a flowchart. Make your flowchart illustrate the making and eating of an ice cream sundae. Use a rectangular box for an action taken and a diamond box for a decision box. For example, to get ready to make the sundae, you might use an action box to indicate opening the cupboard, finding a dish and spoon, and various other tasks that require taking an action. You might use a decision box to determine what flavor ice cream or syrup you want. For example, one decision box might read "Do you want Chocolate Ice Cream?" Draw an arrow from one point of the diamond and state YES; then draw an action box that lists the actions if chocolate is selected. Also draw an arrow with NO and list what would happen if chocolate wasn't selected.
The flow diagrams that I have produced will be reviewed by other people who will be using the system and the SVG person who is doing the system programming. Ask a friend of yours to review your Ice Cream Sundae Making flow diagram. Of course you could apply this to any task that might interest you. This is often done for a variety of tasks, like programming a computerized robot Just remember that the computer program must describe "EVERYTHING" that must be done. Your flow chart should reflect "EVERYTHING" as well.
In addition I am reviewing, editing and expanding on the User Guide that is being written to tell a new user how to use the TSAR system. Clarifying the requirements, creating flow diagrams, actually testing the software program (trying to break it) and writing the User Guide are what I do in my job working with the SVG group.
I think it is BIG time FUN.