"LIVE FROM THE STRATOSPHERE" P R O J E CT U P D A T E #19 PART 1: NASA TV schedule for this week PART 2: Teachers from Utah and central Arkansas wanted PART 3: Live data from the Kuiper as it flies! PART 4: Correction to Activity 3C PART 5: Virtual Kuiper: a student led project on MicroMUSE PART 6: Star Census activity PART 7: Ben Burress describes how the telescope is pointed _______________________________________________________________________ Alas, the upcoming Space Shuttle mission has been postponed until after the live KAO flights this coming Thursday and Friday. As a result, "The Preflight Briefing" will be played over NASA TV on Wednesday at 1PM, 4PM, 7PM, 10PM Eastern and on Thursday at 1AM Eastern. On Thursday, "The Jupiter Mission" will begin live coverage at 2:30PM Eastern. At 3:00PM a short break for the Video File will occur, and then the LFS program will resume until the conclusion at 5:00PM Eastern On Friday, "The Night Flight to the Stars" will be carried in its entirety _______________________________________________________________________ We would like to identify certain Live From the Stratosphere participants. If you are a teacher in Utah or in central Arkansas, please send a brief Email note to firstname.lastname@example.org and be sure to include a phone number Thanks so much _______________________________________________________________________ During the upcoming live KAO missions, data from the plane will transmitted over the Internet to the LFS Web archives For Webbers, use http://passporttoknowledge.com/lfs/livedata.html This data will be sent every 5 minutes and will enable you to track various aspects of the mission's status. The following ten parameters will be sent: time ground speed outside temperature longitude air speed cabin temperature latitude altitude cabin pressure heading A sample set of lessons in using this data is also available. For those without Internet access, the latitude and longitude readings will be displayed during the television program. This will enable your students to track the progress of the aircraft across the country. Get your large wall maps ready! _______________________________________________________________________ In final editing, an error was made in activity sheet 3C (on the back of the poster). The sheet states, "Albedo is an index of how bright or dark a surface is in visible light (the lower the number, the brighter). This should have read: the higher the albedo number, the more visible light is reflected and thus the brighter the surface appears in visible light. _______________________________________________________________________ A virtual Kuiper is under construction in cyberspace. This student- led project may have special appeal for computer-oriented students, particularly those familiar with MUDs, MOOs and MUSEs. If you'd like to take a look at what is happening, telnet to micro.musenet.org. Then @tel to room #2074. Look for edwardo online. For more information about this activity, visit the "Kids Stuff" area online or send Email to David at email@example.com. _______________________________________________________________________ A reminder about the Star Census collaboration. The quick look data is due to firstname.lastname@example.org by this Friday at 10:00 AM Pacific in order to be included in the Friday night broadcast. You are also strongly encouraged to participate in the longer-term collaboration effort described fully on line or in LFS #18 _______________________________________________________________________ POINTING THE TELESCOPE By Ben Burress, Tracker Operator It's 4:00 a.m., we're at 41,000 feet somewhere over Nevada looking at the variable star GG Tau, in Taurus. I just glanced out the little port hole next to the Tracker station and saw a single light in a plain of blackness. We often fly over lightly populated areas. The flight has taken us from Ames to the skies of Oregon, Idaho, and Montana, and we're now heading back toward home. The flight has gone very well so far, although someone in the back of the plane acquired some air sickness--that happens from time to time. It's too bad we fly at night most of the time: the views out the windows would be awesome with a little daylight to see it by.... The hours of a KAO flier are pretty bad, as you might imagine. It may sound exciting, but it can get downright tedious. I don't think that anyone LIKES working all night under these conditions, even the astronomers. The worst part is that we'll be landing around 6:00 a.m., just in time to get into morning commuter traffic! There are basically four levels of Operator/telescope control which aid in pointing at the correct object. First is a specialized computer called "TIPS", the Telescope Inertial Pointing System. TIPS uses the aircraft's heading, roll, pitch, latitude, longitude, the telescope's orientation within the plane, and current time to "dead reckon" where the telescope is pointing, calculating from only this batch of information the celestial coordinates that the telescope is pointing at. When the additional information of the desired object's celestial coordinates is thrown into the calculation, the telescope's pointing coordinates and the object's actual coordinates are displayed together in a graphic representing the telescope boresight and the object. Initial acquisition of the object field then is a boring video game of joy-sticking the telescope until the cursor for the object lines up with the spot for the boresight. At this point, the telescope should be pointing well within the object's neighborhood, within maybe half a degree--which is pretty good considering that this was all done in the dark, without actually observing the outside universe. Now, I turn my attention to the wide field acquisition camera, which when zoomed in has a field of view of about 2 by 3 degrees. I locate the position of the object in the acquisition field by comparing that field with the acquisition chart for the object. Perhaps a little more joy-sticking of the telescope is required now, and by this time the object resides within the field of view of the tracker telescope, where most of my work is done. Usually I have determined the star I will use for tracking far in advance, and once I recognize that star in the tracker telescope field I place an "AOI" on the star and activate the tracker. The AOI is a small video box which defines the region of the camera field that the tracker computer sees. If the tracker sees a star in the window, it calculates the position of the star's center and keeps that star at a specified location in the field. It does this is by determining if the star's center is on or off of the specified tracking location; if it is off, the tracker calculates how far and in what direction, then sends a correction signal to the telescope compensation system, which in turn sends an appropriate jolt of electrical current to the telescope's magnetic torquer motors, which moves the telescope in the right direction by the right amount to place the track star on the tracking location again. This measurement/correction cycle takes place thirty times per second, so the telescope doesn't drift very far before being torqued back onto position; in the camera fields the stars look virtually motionless. Once the tracker is set to tracking a star, I move the telescope around in small motions by "tweaking": using a hand paddle with buttons that instruct the tracker to move the specified tracking location about. In this way, I place the object of interest on the investigator's instrument boresight. One other aspect of KAO telescope pointing peculiar to infrared astronomy involves the technique of "chopping" and "nodding", which you may have heard described elsewhere. I won't belabor my point by describing the reasons for doing these things, other than to say that by chopping, the investigators can separate from their object's infrared signal the component contributed by our own warm atmosphere, and by nodding they can separate out heat emissions from our own telescope. The chopping motion of the Oscillating Secondary Mirror (OSM) creates two images of everything in the focal plane field of view: stars, planets, and optically invisible infrared objects alike. As part of the technique, the investigators must observe both chopped images, which is where nodding comes in: I set up the tracker to track in one of two locations, each of which places one of the object's chopped images on the instrument boresight. At this point, after setting the tracker to track on either of the two "beam" locations, the investigators are set up to start taking data. If I do my job right, then the time point when they can take data is two minutes or less--some objects take more time, some less. And that's what the main part of my job boils down to. Simplicity at its best: I point the telescope wherever the astronomers want it. The details of knowledge, the skills, and the experience which allow me to do this job efficiently and reliably add up to more than that, but that is true of many straightforward-on-the-surface occupations. In fact, I do more around the KAO than flying as a crew member. When they don't have me flying, I can be found at my computer working on various writing projects, from procedures to newsletter articles to manuals. I also keep in contact with the various investigator teams, by email and phone, to anticipate their needs on their next flight series: everything from lab equipment to cryogenic liquid supplies to serving as liaison between them and the KAO staff.