HOW TO OBSERVE STARSHINE TO HELP CONTRIBUTE TIME AND POSITION ESTIMATES (LAST UPDATED 6/25/99)
by Paul. D. Maley, NASA Johnson Space Center Astronomical Society, Houston,Texas, USA
[If you only want to watch STARSHINE and not measure positions in the sky of its flashes to help improve its orbit, then go back to the main menu and click on A BEGINNERS GUIDE ON HOW TO TRACK STARSHINE.] As of June 24, 1999 the prime objective is to obtain information on flashes from the STARSHINE satellite; our secondary objective is to get positional data. You do not need optical aid for either of these efforts since the satellite is visible only when it flashes. The BEGIINNERS GUIDE will instruct you on how to spot the flashes.
Now if you want to measure positions, here are the detailed steps that you will need to familiarize yourself with in order to succeed. After reading this, if you have any questions, please submit them on this site through the QUESTIONS AND COMMENTS area.
-EQUIPMENT YOU NEED
1.compass with both the directions and degree scale annotated around the circumference of the compass. You will need this type of compass since predictions of where to look for STARSHINE will be listed in terms of elevation and azimuth. Both of these angles are specified in degrees.
2.flashlight (if you can, place red cellophane over the front in order to help keep you from losing your night vision when the light is turned on)
3.lawn chair or similar for the observer to sit in.
4.shortwave radio (multi-band radio which can pick up time signals on 5.0, 10.0 or 15.0 MHz, generally available from companies like Radio Shack). You will need a source of time signals to record during theobservation of STARSHINE. If you do not have one available, there are alternate methods which can be used for timing described later.
5.portable battery powered tape recorder with cassette. This will be used to record the time signals from the radio and the observer's voice.
6. engineering scale ruler. This will be used later to measure the position of STARSHINE that you will plot on a star chart.
7. stopwatch. This should be a digital watch that can be held and operated in one hand. If you do not have a time signal radio, the stopwatch will be used to start up when you see the STARSHINE in your binoculars. If you have a time signal radio, the watch will be used later to determine the time at the position you plotted when you play back your tape recorder..8.clipboard. This will be used to hold your star charts.
9.calculator. This will be used to help you during the time you plot the position of STARSHINE.
10.star charts. Available here through this web site by clicking GSOC SATELLITE PREDICTIONS.
11.STARSHINE visibility predictions. Available here through this web site by clicking GSOC SATELLITE PREDICTIONS.
12.Access to the internet. The internet will be your source of viewing predictions and charts that will guide you to where you need to look in the sky and tell you when to look.
13. Digital watch which displays hours/minutes/seconds. This can be an inexpensive quartz watch available from such places as Target, Wal-Mart, K-Mart, etc.
-THE OBSERVING SITE
You also need an observing site. You may have more than one site as long as each site is identified clearly when reporting the observation. The site should be away from lights, but be a safe, secure location. If youcannot get away from lights, at least shield your location from lights using buildings or other obstructions to block specifically bright light fixtures.
The site must be located accurately using one of the following:
1. county map which shows latitude/longitude coordinates (inexpensive and generally easy to locate)
2. topographic map (from the United States Geological Survey) of the map scale 1:24,000 which shows latitude/longitude/elevation. These maps may be a little harder to find and more expensive than county maps, but they are available in some libraries and map stores. They are the best maps to use.
3. Global Positioning System receiver (accurate to 100 meters)
To determine your location from the map, you will need the engineering scale and calculator. See the section on HOW TO DETERMINE THE POSITION OF THE OBSERVATION and use the same scheme for interpolation to determine the latitude and longitude. Elevation above sea level is usually expressed in feet and can be found from the topographic map only. Do not use the elevation values from the GPS receiver as they tend to be very inaccurate.
4. MAPBLAST Web Site
On this web site, go to RESOURCES and click on MAPBLAST. Check out this site and see if your observing location can be clearly found. If it can be located, the coordinates you derive by following the step by step procedure should be quite accurate. If you cannot clearly locate the site, use one of the previous methods for determining your location.
Once you have your coordinates identified, go to the area on this web site called SET UP AN OBSERVING ACCOUNT. Enter the appropriate information. There will also be an option to allow you to enter the method by which you determined your coordinates. Once this is complete, you will be able to report your observations of STARSHINE.
-ORGANIZING THE OBSERVING TEAM
Observing STARSHINE will normally be done with a team. It will consist of
1.observer-This is the person who will need to locate the area in the sky where STARSHINE is to pass, will point the binoculars at it, makes the timing, plots the observation, and reduces its position. Because it is important that we are able to identify the observer especially if there is more than one observer, the final task of the observer is to report the observation. If there is more than one observer, each should report his/her own observation by logging on separately to the web site and entering the data.
2.time keeper- This individual keeps track of time for the observer, handles the time signal radio and the tape recorder during the observation. Also, reads the time every 30 seconds during the observing so the observer does not have to look at a watch.
3.data analyst- This person gets the prediction data from the web, plans the observing session, and keeps the log book. The data analyst should also work out the star charts and coordinate with any other teams toset up unique star pairs for each observing team.
4.advisor-Responsible for picking the rest of the team, monitoring the effort, keeping order at the observing session and assures all resources are available. The advisor can construct the team or teams any way that
seems appropriate. Because STARSHINE can flash at any place in its sky track (a sky track is the path across the sky on a particular fly over), it is best to assign one team to cover the ascending part of the pass, another to cover the point of maximum elevation, and a third to cover the descending part of the pass.
Team members should be team players, willing to learn, willing to stick with it, able to use common sense, able to follow direction. Observers in particular should have: a) good vision [glasses and contacts are OK), b) quick reaction time, and c) good memory. The observer is the key to making the timing fast and accurate and pinning down the exact sky position relative to stars.
It is best not to invite onlookers or others who have no role in the observation. People should be quiet during the observation period until after the tape recorder has been stopped. The only voice that shouldappear on the tape is that of the observer.
It is even possible for the entire process to be accomplished by one student from home, should such an individual's capabilities reach that level, and all resources become available to that student. It is also possible to have more than one observer at a site, provided that each observer is looking at a different section of the sky. It is also recommended that another timekeeper be present and that this 2 memberteam have a time signal receiver and tape recorder, flashlight, star charts and predictions.
-LEARNING ABOUT RADIO TIME SIGNALS
The time signal radio is a very important part of the operation. You can tune in to several possible frequencies and hear the monotones from the broadcast of radio station WWV. Each minute of time has a repetitive pattern associated with it. There are 60 seconds in every minute; some times you hear double clicks on certain individual second points. Don't let this confuse you. The repeating pattern you will hear is:
0th second: beep sound1th - 28th second: you hear at least one tick for each second29th second: this is empty. There is no tick heard.52nd second: a voice begins "at the tone, xx hours yy minutescoordinated universal time" where xx and yy are the actual hours and minutes announced
Then the pattern begins all over again. Sometimes there will be special weather announcements or other things that do not pertain to the time. Ignore that information.
The most important tick to listen for and use is the 01th second tick. The 00th tick is actually a beep. The first tick after that is a tick. This is the one that you should always use in stopping your stopwatch.(Note: you may decide that the 5th or 10th second may be easier to use after getting familiar with the repetitive pattern of signals. It is up to your discretion. We have set the 01th second as a standard in thisprocedure).
-THINGS TO LEARN BEFORE OBSERVING STARSHINE
1.How to find directions at night. Take the compass and flashlight. Place the compass on the ground and turn it until the floating arrow lines up with the North point. It will take a short time for the compass to settle down. Once you have completed this alignment, you can see which direction is north. Also note that the direction about the horizon is called azimuth. It is an angular measure in degrees that begins at 0 and ends at 360 degrees. Azimuth is defined as follows: 0 degrees =north, 45=northeast, 90=east, 135 = south east, 180=south, 215=southwest, 270=west, 315=north west, 360=north again. 0 and 360 are both north.
Elevation is the distance from the horizon to the overhead point (called the zenith) measured in degrees. The range of elevation is from 0 to 90 degrees. If you face northeast, for example, and look directly at the horizon, your azimuth is 45 degrees and your elevation is 0 degrees. If you tilt your head and look up 1/3 of the way from the horizon to the overhead point, your azimuth is still 45 degrees, but your elevation iscurrently 30 degrees. If you continue to tilt your head up until you are looking straight overhead, your elevation is no 90 degrees.
2. How to find the constellations. This is probably the most difficult part of the program. A constellation is a pattern of stars in the sky that seem to form some short of shape. To learn the constellations you will need to get familiar with the standard shapes and designs created long ago. These designs may be found in a number of books such as THE STARS by H.A.Rey.
To best begin the process, check out a book on the constellations from a local library. The internet access you have will also aid in locating a chart of the sky for the current month. It is accessed from this web site (go to RESOURCES, click NORTHERN SKY CHART, click on the month and print out the chart). The chart is circular and the directions in the sky are shown on the edges. You simply hold the chart up above your head aligning the chart directions to those you know from your compass. If you do this in the early evening, while lying on the ground or sitting in a chair using your flashlight, you should be able to pick out some of the brighter stars that form one or two constellations. This will take considerable practice.
Another aid will come in the form of star charts that you will get from the GSOC SATELLITE PREDICTIONS (see the section called THE SATELLITE PREDICTIONS AND HOW TO READ THEM). There are two types of charts. Both have the path of the satellite drawn against the background of stars. The first chart is called the wide angle chart. It contains several constellations with a grid system thatallows you to locate a particular point in the sky. The grid system is like the grid on world map. If you were to use a world map to locate New York City, for example, you would locate it using a set of coordinates. Coordinates are like direction, where one side of the map has a scale showing latitude (up and down scale), and the other side has a scale showing longitude (right to left scale). The range of latitude is from 0 to +90 degrees and 0 to -90 degrees, where longitude ranges from 0 to 360 degrees, or from 0 to 180 degrees and from 0 to -180 degrees.
The star chart is just like that except that the up and down scale is called Declination and right to left scale is called Right Ascension. On a map latitude is measured in degrees, and so is longitude. In the sky,Declination is measured in degrees (exactly like latitude), but Right Ascension is measured in hours, minutes, and seconds (and sometimes even in degrees). Declination has a range from 0 to +90 degrees and also 0 to -90 degrees. Right Ascension ranges from 0 hours to 24 hours like a clock. You need to get familiar with the use of the world map and then the star charts.
Time of sunrise and sunset may be also found from the web or from local news papers or television. It does not get dark enough to find star pairs until perhaps one hour after sunset. Because it also takes time tolocate the stars, choosing a pass that occurs too early may make it impossible to find the satellite in time. In some cases you may not have a choice. There is an advantage in observing in the early morning hourssince the sky will always be dark prior to the pass, whereas this is not always the case for evening passes.
-WHAT YOU NEED TO KNOW ABOUT TIME
The time in Los Angeles, for example, is not the same as time in New York City. You need to know about Standard and Daylight time. In spring, the USA goes on Daylight time where clocks are set ahead one hour, and in the fall, it returns to Standard time, where clocks are set back one hour. But when planning your STARSHINE observation you need to know about Universal Time. This is the time in England. There are four time zones in the continental USA: eastern, central, mountain, pacific. When it is 7:00 pm Eastern Standard Time (EST), it is 6:00 pm CST, 5:00 pm MST, 4:00 pm PST. When it is this time in the USA, in England it is actually midnight (0 hours) on the following day. In England we call their time Universal Time(UT) which is also called Greenwich Mean Time (GMT). GMT and UT are the same thing.
As you can see, as you go farther to the east in the USA the time is later; consequently since England is much farther east, it is much later there. The time in England (UT) is always 5 hours later than EST, 6hours later than CST, 7 hours later than MST, and 8 hours later than PST. But when we switch to Daylight Time, this difference becomes 4 hours for EDT, 5 hours for CDT, 6 hours for MDT, and 7 hours for PDT.
When using your satellite predictions you will see the time expressed in 24 hour local time, which you will later have to convert to UT (or GMT). Here 0000 hours is midnight, 0600 is 6:00 am, 1200 is noon, 1800 is 6:00 pm and 2300 is 11:00 pm. Example 1. We are in Denver Colorado in June (when we are on Daylight Time) and the prediction is for a pass occurring at 8:24:22 pm MDT on June 11, 1999. Note that the time of prediction will be expressed in hours/minutes/seconds. We must also be aware that this is also 2:24:22 am UT (in England) on June 12. Why do we care about this? Observations of STARSHINE will be made from all over the world. There are 24 such time zones and each has a different time than your. Ithelps to have a time standard by which all observations can be reported. This has been chosen to be UT. All observations must be converted to and reported in UT. It is very easy to do.
When you tune in your short-wave radio to 5.0, 10.0 or 15.0 you will receive time signals from the National Bureau of Standards radio station WWV in Fort Collins, Colorado USA and they will be expressed each minute of the day, 24 hours a day, 365 days a year in 'coordinated Universal
Time". This is the same as UT.
- WHAT YOU NEED TO KNOW TO PLAN YOUR OBSERVATION
When you access the satellite predictions (described below), you will be able to see in advance when the next possible observing opportunities will be for your area for the next 10 days. The times of observation will be within either the two hours period following the time it gets dark after sunset or in the 2 hour period before the sky begins to get light before sunrise. The orbit of STARSHINE will be such that you may only get one or two good passes in the evening sky per month. Therefore, you might want toseriously consider the possibility of an early morning observing session in addition to the more convenient evening time. It is always possible that weather could ruin the one or two evening opportunities per monthin your area. If an evening opportunity occurs on any night of the week or weekend, you should attempt to take advantage of it.
Consult the local weather forecast. If the sky is predicted to be clear to partly cloudy, you have an excellent chance to spot your satellite. If the moon is in the sky, it may make the task harder, but you should still make the attempt.
-THE SATELLITE PREDICTIONS AND HOW TO READ THEM
From this web site, click on GSOC SATELLITE PREDICTIONS, click on SPECIFY YOUR LOCATION MANUALLY. Here is where you will enter your observing site coordinates: latitude (+for USA), longitude (- for USA) and time zone. Pick from the pulldown menu of time zones the one that is closest to your region. Once this has been entered, click SUBMIT. [If you have more than one site, you will have to perform this operation from scratch repeatedly]. Once your site is entered into the database, you can bookmark the GSOC SATELLITE VISIBILITY HOME PAGE and return there through the web when you next access the site. You can then call up predictions for your location and you don't have to reenter your location again.
Once STARSHINE is in orbit, the GSOC SATELLITE PREDICTIONS page has a special STARSHINE predictions area. [You can also locate predictions for the Russian Mir space station , the International Space Station (ISS) and other satellites.] The predictions will be contain the following information.
1. Local Time: This specifies your time zone and the number of hours from Greenwich, England. This is the difference between your time zone and UT or GMT. Example, If in Texas and on Central Daylight Time, the offset is -5 hours, meaning it is 5 hours later in Greenwich England than in Texas.
2.SATELLITE NAME: common name used to identify the satellite.
3.MAG: brightness of the satellite. The smaller the number, the brighter the satellite (e.g. 2.5 = brightness of the North Star, 0 = brightness of a relatively bright star, 4.0 definitely requires binoculars)
2.TIME-this is the local time in the 24 hour system in the format of hours (HH), minutes (MM), seconds (SS) which is expressed at three points in the satellite orbit as seen from your location. The first is called START which is the part of the sky that the satellite can first be seen if conditions are clear enough. The second is MAX. ELEVATION. This is the point in the sky which is the highest point in the sky reached by the satellite during the pass. The last point is called ENDS and it is the point in the sky where the satellite can last be seen before either disappearing into the shadow of the earth.
The time is expressed in your own local time. If in the evening you might see a pass time of 20:57:04, for example which is 20 hours in the 24 hour time scale. This means it is really 8:57pm local time. To convert to UT simply add 5 hours in this example and you get 1:57am on the following day.
3.EL. - elevation angle above the horizon specified in degrees (ranges between 0 and 90 degrees, where 0 is facing toward the horizon, and 90is looking straight overhead)
4.AZ.- azimuth direction around the horizon originating from the north and moving clockwise. The direction is abbreviated. Example: SSW = south southwest
-USING STAR CHARTS
There are three types of charts you will need. They are all available free from the GSOC site. The first is the ALL SKY CHART which depicts the entire sky from your site. When you are viewing the satellite prediction list, go ahead and click on the TIME under MAX. ELEVATION. You will then see a large star chart called the WIDE ANGLE CHART (see next paragraph). Just below this is the ALL SKY CHART [You will also find the chart on this web site by going to RESOURCES, click on NORTHERN SKY CHART, click on the month and print the current chart.] This is the one you first use by holding it above your head and aligning the chart with the direction you want to face. You should be able to make out some key bright stars of the major constellations in different parts of the sky. This is more of a learning tool to help you navigate around the sky with the unaided eye. The satellite path is drawn on the ALL SKY CHART as an arc with an arrow indicating the satellite direction of flight. But there are no time markers on this chart. Get familiar with the constellation patterns as they appear on both types of charts. These patterns may not be exactly the same as you might find in some astronomy books. Remember, the
darker the sky, the easier you will spot these patterns.
The WIDE ANGLE CHART is a large view of the sky with grid lines and the path of the satellite plotted over it; this includes time markers. The ordering of the time markers lets you see in which direction on the chart that the STARSHINE is coming from and moving toward. Print out the chart and note the satellite path as it is marked against the stars. Time ticks are annotated every so many seconds. In order to get charts of the entire pass on this scale, click on the right or left margins of this chart and keep to bring
up a new WIDE ANGLE CHART until you have such charts for the whole pass printed out.
You can create a CLOSEUP CHART by using your computer mouse to click on any portion of the sky track of the WIDE ANGLE CHART. The CLOSEUP CHART gives you a more magnified view of the stars as if you were using binoculars. You can change the size of the CLOSEUP CHART by clicking on the CHANGE CHART SIZE button. This will give you a larger scale chart but will not add any more stars.
You use the WIDE ANGLE by first holding it so you can see the chart and with both hands be sure it is directly in front of you (not over your head). It does not contain as big an area or as many stars as the ALLSKY CHART. The prediction AZIMUTH is used to help you locate the direction you face when holding the chart. The chart has an indicator on it to show which direction is UP and which is DOWN. Still holding the chart, tilt it upward to the angle of the ELEVATION of the prediction. You should now be able to spot key bright stars with your naked eye. To make this easier, you may want to attach this chart to theclipboard.
Since STARSHINE may flash along any part of the sky track, give a different WIDE ANGLE CHART to each observer to cover each portion of the pass. If your horizon is unobstructed it is possible to see flashes
as low as 10 degrees elevation in the descending portion of the pass.
Plan your observation so there is enough time to locate the stars where the satellite is expected to pass. The plan should include enough time for all team members to get there at least 30 minutes before the pass (depending on the experience level of team members). The timekeeper must set the digital watch to the time signal radio. About 15 minutes before the pass, the team should check out the observer's voice, time signal radio and the recorder in a test to see that everything is positioned properly and is working. If theradio/recorder do not work, be sure to have extra batteries on hand. You may have to switch radio frequencies if reception on one frequency is poor.
At 3 minutes before the predicted pass, the radio is turned on and the recorder activated. Both will not be turned off until 3 minutes after the pass. Your goal is to record at least 5 to 6 full minutes of time signals and the voice of the observer when the satellite flashes. If the voice announcements on the radio are hard to hear, the timekeeper should plan to announce the time in hours and minutes based on the readout of the digital watch.
Observing for the satellite flashes should begin in earnest about 60 seconds before the predicted pass time if you are using predictions made on the day of the pass. If your predictions have not been updated in a few days to a week, expect that the satellite could appear as much as two minutes early or late.
August 10: GSOC predictions show a pass predicted for 8:01:59 pm CDT on August 17 (01:01UT on August 18). It is known that sunset is 6:24 pm.
August 17: during the day, run a new set of predictions with new sets of WIDE ANGLE CHARTS for the whole pass and sets of CLOSEUP CHARTS for the whole pass. This might seem like a lot of paper but if a flash is seen, the observer must have immediate access to the right charts to plot the flash point. It is learned that the prediction is now for 8:01:45 pm. Also during the day, the timekeeper verifies digital watch set to the time signal radio.
7:25 pm: the team arrives at the site7:30 pm: each observer sets up and gets familiar with his/her assigned portion of the sky track using the WIDE ANGLE and CLOSEUP CHARTS. Each observer also knows the expected times when STARSHINE will pass through the charts for the assigned part of the sky and will listen to the timekeeper later when the time is being called out. 7:45 pm: team checks out the operation of the observer's voice, time signals and recorder to be sure the placement is correct. Replay the tape to verify. 7:58 pm: timekeeper starts radio, then starts recorder7:58:30 pm: timekeeper calls out 7:58:30 when the 30th second appears on digital watch7:59:00 pm: " 7:59:00 when the 00th second appears7:59:30 pm: time is called out each 30 seconds8:00:00 pm: "8:00:30 pm: "8:01:00 pm: "8:01:30 pm: "8:01:?? pm: observer sees the satellite flash. Observer calls out "MARK" the moment it flashes. If there is a reaction time, try to estimate it and correct the time appropriately. Immediately the observer plots the position of the flash on the WIDE ANGLE CHART as best he/she can. Then the observer must find the correct CLOSEUP CHART on which to more accurately plot the flash position.
8:04:30 pm: timekeeper stops the tape recorder8:05:00 pm: everyone goes inside.
Observer now plots the position on a clean copy of the CLOSEUP CHART using a sharp pencil. If there is not much time, it is OK to wait to the following day to listen to the tape recorder and determine the actual time of the observation and measure the true position on the chart. But do not wait more than 24 hours.
-WHAT WILL STARSHINE SATELLITE LOOK LIKE?
If you see a bright object moving across the sky it is not STARHINE. If you see a rapidly flashing light, it is likely to be an airplane and not STARSHINE. If you see a bright isolated flash at some point along the sky track, this is likely to be from STARSHINE.
The observer must study the star charts to know near which specific stars it is expected to pass and at which angle and times. At rare intervals, you may witness another satellite pass along the same track, but then the isolated quick flash of STARSHINE should be the clue to help you in your identification. It is possible that you may see anywhere from 0 to 7 flashes on a particular pass. If none are seen, do not despair as the angle between the sun, satellite and you is not favorable on this particular night. Try again!
-HOW TO DETERMINE THE TIME OF THE OBSERVATION
a. TAPE RECORDER METHOD (method 1): the best method!!
The data analyst (or any other designated member) now is instrumental in determining the time of actual observation. To do this properly, everyone should be familiar with the time signal pattern that repeatsevery minute.
The tape is played back and the appropriate minute is found where the "MARK" is called out. The tape is replayed and then as "MARK" is heard, a stopwatch is started. Depending on how close to the top of the next minute, the stopwatch will normally be stopped at the 01th second in the minute following. (NOTE: You may decide that the 5th or even 10th second might be more appropriate once you get used to hearing the pattern of ticks. This choice is up to you. But you should be consistent. In these directions we will continually refer to stopping the watch at the 01th second)
Example: it was found that "MARK" was heard at about 8:01:44 pm. The watch is started when "MARK" is heard, then it is stopped 17 seconds later when the 01th second of the next minute is heard. At the 52ndsecond during the 8:01 minute period, a voice will state "at the tone 01hours 02minutes coordinated universal time". The first tone you hear will be that of the 00th second. The next tone is where you stop thewatch. Then write down the resulting reading: example 17.38 seconds. Repeat this process 4 more times and you get 17.40, 17.55, 17.42, and 17.33 seconds. Add these five numbers and divide by 5. This will be the average elapsed time. Let us say this is 17.40. Now subtract 17.40 seconds from 8:02:01.00 and this will be the true local time of the observation: 8:01:43.60 pm CDT. Convert this to UT by adding 5 hours=01:01:43.60 UT. Record both of these times in your log.
b. WHEN A TAPE RECORDER IS NOT USED
This method is not preferred because it means that the observer must hold a stopwatch in one hand, while concentrating on the flash from the satellite. Because there is no tape recorder used, the observer does notneed to call out "MARK". Instead, when the flash is seen, the observer must activate the stopwatch as accurately as possible. The observer must also remember the relationship of the flash point to key stars in the sky in order to pin down the precise position.
The observer, quickly uses a sharp pencil to plot the point where the timing was made on the CLOSEUP CHART, then goes inside and attempts to use one of several possible methods to stop the watch. The methods are listed below in order of preference. When a tape recorder is not used, there is only one chance to properly stop the watch.
Method 2: Using a short-wave time signal radio, be sure you are familiar with the pattern of signals as described by the section called RADIO TIME SIGNALS. Wait until the 01th second of a minute to stop the watch. Write down the hours/minutes/seconds that you stopped the watch. Subtract the watch reading. Apply the watch systematic correction as described in the section called THE STOPWATCH. The result is the actual observation time.
Method 3: Using a speaker phone (or regular telephone), call the National Bureau of Standards time signal number at 710-567-6742 or 202-762-1401. These are long distance phone calls and are not free of charge. Use the same process as method 2 to obtain the observation time.
Method 4: On this web site, go to RESOURCES and click on USNO Real Time Master Clock. This method takes more time and you should become familiar with the clock in the days prior to attempting your observation. The clock has a 30 second countdown clock that is on the same page. The moment you access the page, the countdown clock starts to count down from 30 to 0. When it reaches 0, the UT clock freezes up. If you click the 'back' button on your browser and then click USNO Real Time Master Clock again, a new 30 second countdown begins. Once you see the pattern, it is best to click on USNO Real Time Master Clock around 35 to 40 seconds after the start of a minute. This will let you see the UT clock increment past the 01th second of the following minute. Use the same steps as in Method 2 to compute the observation time.
-HOW TO DETERMINE THE POSITION OF THE OBSERVATION
After making the observation, the observer will plot the position of the point using the WIDE ANGLE CHART if possible. In some cases the chart simply does not have enough resolution or is too cluttered and you have to then go to a CLOSEUP CHART. Since you will not know where in the sky the flash
can occur in advance, this will be a challenge to jump from one WIDE ANGLE CHART to a CLOSEUP CHART and will take some practice. You might wish to make several copies of the CLOSEUP CHART in case this chart is ruined. This must always accomplished as soon after observing the satellite as possible. Do not wait until the following day. Now, it is time to use the engineering scale to determine the Right Ascension and Declination on both sides of the chart. Find the declination lines closest to the point and draw a line between the right side and left side of the chart. Example: if the point is between +10 degrees and +11 degrees declination, you will interpolate between the two lines. Interpolation is the process of measuring a point between two reference lines. Find the +10 degree line on the right side and the same grid line on the left side and draw a line between the two with the sharp pencil. Repeat the process using the +11 degree line. Now you have two parallel horizontal lines drawn on the star chart with the point you plotted located in between.
Next find the grid lines in Right Ascension at the top and bottom of the chart between which the point you plotted lies. Example: The point you plotted lies between the 50m and 55m grid lines. Also you see the 15h appears to the left of these lines, meaning that the Right Ascension is between 14h and 15h. Remember also that Right Ascension is measured in hours/minutes/seconds. Find the 50m grid line at the top and the 50m grid line at the bottom and draw a line between the two. Repeat the same process for the 55m grid lines. Now there is a small rectangular box around the plotted point which is bounded by the 4 grid lines you drew. The box has four sides. As you look at it, the right side is along the declination axis between 10 and 11 degrees.
Using one of the small scales on the engineering scale, line it up so that 0 is lined up with the 10 degree line and the scale increases in number in the direction of the 11 degree line. Measure the number ofdivisions between 10 and 11 degrees (example: 57 divisions). Now measure the distance from the 10 degree line to the point in the direction of the 11 degree line so that this measurement is made with the scale lined up parallel to the declination grid (that is in the same direction in which you completed your first measurement). Let us say that the distance of the point from the 10 to 11 degree line is 8 divisions.
Using your calculator divide 8 by 57=.14035; this is the fractional distance of the point between 10 and 11 degrees. We now multiply .14035 x 60 minutes because we know there is 60 minutes in one degree ofdeclination. The result is 8.4210 minutes. We need to know the value of declination in degrees/ minutes/ seconds. Now we multiply the fractional value of minutes .4210 x 60 since we know there is 60 seconds in each minute = 25.26 seconds. The value of the measured position in declination becomes 10 degrees + 8 minutes + 25 seconds. Ignore the fractional part of the seconds value when reporting the position.
Determine the Right Ascension using the same technique. Align the engineering scale to where it is parallel to the Right Ascension grid, but you are going to place it so that 0 mark on the scale is on the 50m
grid line near the point you marked. Now measure the number of divisions between the 50m and 55m grid lines. Let us say this is 28 divisions. Now measure the distance from the 0 mark on the scale to the point. Let us say it is 16.5 divisions as best you can tell. Just like before, take the fractional distance 16.5/28=.5893. Now multiply it by the distance between the grid lines (5m) = 2.9464. This says the point is 2.9464 minutes from the 50m line. Since we do not report fractions of a minute (only seconds) we multiply .9464 x 60 = 56.7857 seconds. We now have all the components from which to assemble the value in Right Ascension. We also know that Right Ascension is measured in hours/minutes/seconds and Right Ascension increases from the right side of the chart to the left side. This means that the value of Right Ascension of the plotted point is 14 hours (50m + 2m=) 52 minutes + 57 seconds. We truncate the fractional value of seconds and round up to the nearest second.
Keep the CLOSEUP CHART copy with the satellite position marked. File it away in your observing log.
-HOW DO YOU FILL OUT AN OBSERVING LOG?
Use a pen to fill out your log book with the following information as an example.
Site: Seabrook Intermediate School yardObserver: Jane S. SmithTimekeeper: Juan GonzalesData Analyst: Jay GreyDate: 14 April 1999 Thursday nightSatellite: STARSHINE
Time of predicted maximum elevation: 8:00:25 pm=01:00:25UT on 15 AprilPredicted Azimuth: 123 degrees
Time of flash: 8:01:43.6 CDT = 01:01:43.6 UTRight Ascension of flash: 14hours 52minutes 57 seconds
Declination of flash: +10 degrees 8 minutes 25 seconds
IF YOU ARE ALSO RECORDING THE TIMES OF FLASHES SEEN even if positions are not reported, add this information to your log and report flash times via the web site as described in the next section:
Time of flash 1 (to nearest second): 8:00:12 CDT = 01:00:12UT on 15 April
Estimated elevation of flash 1: 45 degrees
Estimated azimuth of flash 1: 225 degrees
Time of flash 2: 8:01:34 CDT = 01:01:34 UT
Estimated elevation of flash 2: 30 degrees
Estimated azimuth of flash 2: 60 degrees
[Estimated times and of any other flashes seen]
-HOW TO REPORT AN OBSERVATION
Your observation should be reported via this web site within 24 hours of the time you made it. First go to LOGIN TO REPORTING FORM and log in. Then click on STARSHINE SATELLITE OBSERVATION FORM and enter the UT of the observation and the position measured from the star chart. The options will also allow for selecting the method by which the observer made the timing. Then click SUBMIT OBSERVATION. You can also submit the observations times of any flashes seen.
-WAYS TO IMPROVE YOUR OBSERVATION
Practice learning about how to use WIDE ANGLE and CLOSEUP star charts is the key to improving the timing operation and the position determination operation. An observer will probably make significanterrors in both aspects for a while before becoming comfortable with the process. Awareness and readiness are important. So is reaction time. The observer must be quick to react when the satellite flashes and must
also have a good memory for plotting the point where it flashed . There will be some limitations to the accuracy of the computer based star charts, but the combination of position and time will be processedafter it is received.
Residuals are a measure of the observer's error. These will be determined and provided to the participant (method to be announced) so that the error in time and position can be studied. Usually one observer will tend to have larger or smaller errors than another person. This will assist the advisor in knowing which observers need improvements. If the data analyst is reducing the satellite position, it may also be helpful to have the observer participate just in case there is an inability on the part of the data analyst to properly conduct the measurement (which might tend to mistakenly indicate observer error).
Good luck, and thank you very much for your interest in this project.