IOAA 2013, Наблюдения, нощен тур — Задача 3
7th International Olympiad on Astronomy & Astrophysics, 27 July – 5 August 2013, Volos Greece — Observational test · 27 юли 2013 г.
Указания
When you arrive at the telescope, you will be provided with suitable equipment and shown how to use it. You will also be given the answer form. Fill in your student code number before starting the questions.
Условие
At 14 o’clock local time at day time of the spring equinox a rare transit of Mercury is going to take place. A team of astronomers reaches a mountain top, early in the morning, in order to align his telescope and then observe the transit. The site is new and they do not know the geographical coordinates. Unfortunately the sky is covered with clouds. No stars are visible. The telescope cannot be aligned. The sky is overcast until 11 o’clock. The Sun becomes visible. An experienced astronomer manages to roughly align the telescope in less than 2 minutes! He only uses a water bubble.
You are given the telescope of the 7th IOAA and a water level. Assume that it is vernal equinox and that the (simulated) Sun is at its maximum elevation. Align the telescope.
(Note: Obviously for this exercise, a telescope tube is not necessary, therefore, for the sake of convenience, the telescope will be equipped with a rough paper-tube and without counter weights.
Решение
Answer: First the student levels the tripod with the help of the water bubble. Then he/she adapts the equatorial mount on the tripod. Because it is spring equinox, the declination of the Sun is 0°. At this point the student should immediately set the Declination circle of the telescope at 0° and secures the locking knob. The declination axis is calibrated. Then he/she rotates the Hour Angle axis and, by using the water bubble, makes the tube of the telescope horizontal. Then he/she rotates again by 90° the Hour Angle axis. Obviously, if the azimuth axis had been correctly set, at this point the telescope should be pointing somewhere on the local meridian. Then, as he/she knows that the sun crosses the meridian, he turns the azimuthal axis of the telescope until he observes the Sun above or below the direction where the telescope is pointing. Now the telescope is pointing toward the local meridian. Finally he turns the latitude (altitude) axis of the telescope, up or down, until he/she aims the sun. The polar axis of the telescope is immediately aligned!
(Note: This is an indoors exercise). [Maximum allowed time 16 minutes]
Оригинал в Архива: Observational_night.doc