Star Measurements

a.) Briefly describe three ways that distances to stars can be measured. b.) Name an object, not man made , that emits light in pulsars similar to those from a pulsar. Any wavelegnth is okay. Could we detect these pulses if they came from Jupiter? From a nearby star? c.) Name a type of expansion (or expanding object) that does not obey Hubble's law.

Declination and right ascension

I'm stuck on this multiple choice question: Which of the following could be the equitorial co-ordinates of a star that rises to the south of east when viewed from 48 degrees north latitude, and 88 degrees west longitude? a declination 60, right ascension 13 hours b declination 30, right ascension 6 hours c declination -30, right ascension 1 hour d declination -60, right ascension 20 hours I was hoping that someone could tell me the answer and how to come up with it. I am very confused about right ascension!

Scientist

What does it mean when scientist said reality is rational?

Compute and find an answer

You have a powerful laser beam that you can use to measure distances to objects near earth. The laser beam is a short pulse. You aim the laser beam at a far away object and at time t=0 you trigger a pulse. You measure the arrival of the return pulse that reflects off the object about apoproximately 2.5 seconds later, t=2.5 seconds. How far away is the object? What could that object be?

Compute and find an answer

Two stars A and B have the same Luminosity and Surface Temperature which turn out to be 3 times the Luminosity of the Sun. Star A is 10 L-Y away from the Sun and Star B is 150 L-Y away from the Sun. Which star will appear brighter in the Night Sky, A or B? How many times brighter would the brighter star appear to be in comparison to the dimmer star?