Astronomy | Astrophysics Answers

Calculate the Sun’s hour angle for an observer in longitude 103◦ 40` W, keeping the mean solar time of zone +7, who has made an observation of the Sun at approximate zone time 16h 30m, June 1st. The chronometer time was 23h 31m 20s, the chronometer error being 1m 10s slow on GMT. The ephemeris transit of the Sun for June 1st was 11h 57m 41s (taken from The Astronomical Almanac).

A passenger on a cruise liner celebrates his birthday one evening with a party. It is June 18th. The ship is in zone −12 and at zone time 23h 36m, June 18th, it crosses the date line. Show that the passenger may legitimately have another birthday party for the same birthday.

A star of declination 42◦ 21` N is observed when its hour angle is 8h 16m 42s. If the observer’s latitude is 60◦ N, calculate the star’s azimuth and altitude at the time of observation.

The zenith distances of a star at upper culmination (south of the zenith) and lower culmination are 24◦ and 74◦ respectively. Calculate the latitude of the observer and the declination of the star.

A plane, moving with a speed of 500 knots, flies the great circle route from Prestwick (4◦ 36` W, 55◦ 30` N) to Gander (54◦ 24` W, 48◦ 34` N).What distance does it cover and how long does the flight take?

A distant quasar is observed to have a redshift v/c = 0.15, where v is the
recession velocity of the quasar, and c = 300, 000 km/s is the speed of light.
(a) What is the recession velocity v of the quasar in units of km/s? (2 points)

A. 7.47 × 10−5 km/s
B. 45,000 km/s
C. 0.059 km/s
D. 1.43 km/s
E. 1.97 × 106 km/s

(b) What is the luminosity L of Altair in units of the solar luminosity L⊙? (4 points)

An astronomer observes a bright star (Altair) that has a parallax angle of
p = 0.20 arcseconds. The flux f from Altair is approximately 9.4 × 10−12 times the flux
from the Sun. The distance d from the Earth to the Sun is (1/206265) pc.
(a) What is the distance d to Altair star in units of parsecs (pc)? (2 points)


A. 0.20 pc
B. 2.06 pc
C. 3.14 pc
D. 5 pc
E. 50 pc

Problem: 3. Our neighbor galaxy, Andromeda, has a luminosity (intrinsic brightness)
3 times as bright as the Luminosity of our Milky Way galaxy, LAndromeda = 3LMW, and
is at a distance of dAndromeda = 0.7 Mpc. The flux we observe from the Andromeda
galaxy (apparent brightness) is 10,000 times brighter than the flux observed from a distant
quasar, fAndromeda = 104fquasar. This quasar has a luminosity that is 1000 times the
luminosity of our Milky Way galaxy, Lquasar = 103LMW. What is the distance d to the
quasar? (4 points)

A. 1.28 × 10−1Mpc
B. 3.85Mpc
C. 1.28 × 103Mpc
D. 2.36 × 106Mpc
E. 3.85 × 1012Mpc

(ii) Assuming the energy released during core bounce and supernova phase of this neutron
star was 2 MeV per neutron, calculate the total energy output of the supernova in
ergs. Note that 1 MeV = 1.6 × 10−6 ergs. (2 points)

A. 1.5 × 1063 ergs
B. 3.8 × 1051 ergs
C. 7.7 × 1051 ergs
D. 7.7 × 1057 ergs
E. 4.8 × 1057 ergs