2020 Astro P1 Flashcards
(18 cards)
Does a higher or a lower declination mean a star is closer to the north pole
higher
If MST ahead of GMT, is your longitude east or west?
East
If MST is behind GMT, is your longitude east or west?
West
What measurement must be taken in the lunar distance method
angular distance between moon and other celestial bodies (moon). compared with tables in a nautical almanac to determine local time and hence longitude
State how meteor showers get their names
named after constellation which radiant lies in
[6 MARKS]
Descrube a naked eye experiment to determine the position of a meteor showers’s radiant
-Dark adapted eyes
-Observe meteor
-Plot meteor trail on a star chart
-Repeat observation to plot lots of trails
-Extrapolate meteor trails to a common origin (radiant)
-Thus identify radiant and constellation in which it lies
3 differences between appearance of aircraft in sky and appearance of an artificial satellite to a naked eye observer at night
-aircraft has flashing lights
-aircraft’s light is coloured
-satellites disappear before reaching horizon
State 2 differences between seeing conditions and weather
-seeing conditions are a measure of atmospheric stability
-weather affects the sky’s transparency
Define averted vision
Place object at edge of fov
-look slightly to the side of object so light falls on rods instead of cones
[6 MARKS]
Describe plan to measure the level of light pollution in garden to determine the effect of light pollution.
Identify reference stars
-with a range of known magnitudes
-compare which of these stars can / can’t be observed
-know magnitude which under ideal seeing conditions should be visible
-determine affect of light pollution
State rhe effect that lunar libration has on the amount of the Moon’s surface that is visible from Earth over a period of one month
We can see over 50% of its surface
(59%)
Explain what would happed to the tides of earth if the moon orbited much closer to earth
-greater range between high and low tide
-because gravitational force of the moon is greater
Suggest one reason why ancient civilisations may have alligned their stone circles with stars such as sirius
Any one from:
-religious association with the star
-association with an event/significant time of year eg harvest, flooding of the nile etc
State 2 days of the year when the rising or setting sun can be used to find the exact direction of east or west
equinoxes
define azimuth
direction of a celestial object from the observer (ncp’s azimuth points north)
Give two reasons why a total solar eclipse can only be observed for a short period of time by an observer standing on earth’s surface
-because area of shadow on eath is small
-because the moon covers sun for a small amount of time (moon is same size as sun in sky)
What is the position of the moon when an annular eclipse is most likely visible from earth
apogee
Define annular eclipse
An annular solar eclipse takes place when the Moon’s apparent size is smaller than the Sun’s, causing the Sun to look like a bright ring, or annulus, surrounding the dark disk of the Moon.
