Никола 2018, 1 октомври — Задача 3. The extinction in terrestrial atmosphere.

1 Октомври 2018г.

Условие

Extinction is a term used in astronomy to describe light attenuation due to its absorption and scattering.

A star was observed at different zenith distances during one night at the Engelgardt’s Astronomical Observatory in the program of atmospheric extinction study at blue. Astronomers use parameter X, air mass, as an extinction characteristic. This parameter corresponds to relative length of the ray’s way in the atmosphere. That means X = 1 for zenith, $X = 2/3^{1/2}$ for $z = 30^{\circ}$; X = 2 for $z = 60^{\circ}$ and so on.

The determination of the star’s brightness was performed with the method of photon counting. The 3$^{\mathrm{rd}}$ column includes number n – the quantity of photons which were detected during one second. A luminescent source was used for calibration the data of observations. It produces a stable flow of photons N = 9900 ± 100 per second, which is equal to magnitude mb = 9.64$^{\mathrm{m}}$ beyond the terrestrial atmosphere.

6.1. Draw the table (similar to that you see right) in your answer book. Calculate the air mass for given zenith distances in 1$^{\mathrm{st}}$ column, and write the result into the 2$^{\mathrm{nd}}$ column.

6.2. Calculate relative magnitude of the star Δmb (blue), and write the result into the 4$^{\mathrm{th}}$ column. Use the luminescent source as standard for the relative magnitudes.

6.3. Find functional relation between Δmb and X with a help of graphical method.

6.4. Determine the magnitude of this star as it was observed in zenith.

Решение

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Оригинал в Архива: 1102018.pdf