Which resource lists star positions and time data to guide calculations?

Which resource lists star positions and time data to guide calculations?

• A. Astrolabe
• B. Sextant
• C. Log tables and ephemerides
• D. Magnetic compass

Answer: (C)

When you’re doing calculations that involve where a star will be in the sky at a specific time, you need a source that provides known positions tied to times. An ephemeris is exactly that kind of resource: it lists the calculated positions of celestial objects, including stars, for given moments. Having those time-stamped positions lets you compute where to look or how to convert observations into coordinates. Log tables complement this by giving quick, reliable ways to do the arithmetic needed to translate those positions into practical measurements. The other tools don’t provide this data. An astrolabe measures altitude and helps estimate time or latitude from a celestial sight, but it doesn’t list star positions. A sextant measures the angle between objects, which you then use with data, but it isn’t a data table itself. A magnetic compass gives direction, not star positions or times. So the resource that lists star positions and time data to guide calculations is the combination of log tables and ephemerides.

When you’re doing calculations that involve where a star will be in the sky at a specific time, you need a source that provides known positions tied to times. An ephemeris is exactly that kind of resource: it lists the calculated positions of celestial objects, including stars, for given moments. Having those time-stamped positions lets you compute where to look or how to convert observations into coordinates. Log tables complement this by giving quick, reliable ways to do the arithmetic needed to translate those positions into practical measurements.

The other tools don’t provide this data. An astrolabe measures altitude and helps estimate time or latitude from a celestial sight, but it doesn’t list star positions. A sextant measures the angle between objects, which you then use with data, but it isn’t a data table itself. A magnetic compass gives direction, not star positions or times. So the resource that lists star positions and time data to guide calculations is the combination of log tables and ephemerides.