minute of arc

Austin JM, Gallant JC, Van Niel T (2013) Mean monthly radiation surfaces for Australia at I arcsecond resolution.

On that night it will have an apparent equatorial diameter of 46.8 arcseconds and will culminate a few minutes after midnight at an altitude of just under 61.5[degrees].

A small telescope splits Mizar itself into a beautiful pair of stars (separation 14 arcseconds), with Alcor far off to one side.

This implies, mainly for the inner (and faster) satellites, an angular indeterminacy of many arcseconds. For the 'critical' observations, near to the resolution limit, the angular positions must also be calculated 15 minutes before and 15 minutes after the time reported by Galileo, in order to obtain, instead of a point, a more correct angular interval.

In small telescopes M76 materializes as a rectangular object 80 arcseconds long--about the size of the famous Ring Nebula in Lyra.

Although just 7 arcseconds wide when it's most favorably placed this month, the planet's disk is in the shape of a miniature first-quarter Moon.

From Hubble data, they determined that the ring has an angular diameter of 1.66 arcseconds -- comparable to the separation of two auto headlights viewed from 100 miles away.

The 1100GTO comes with a guaranteed peak-to-peak periodic error of 7 arcseconds or better.

On a high-inclination orbit relative to our Galaxy's spiral arms, it is just passing through our neighbourhood, heading southwestwards by an apparent 2.3 arcseconds per year; in 500,000 years it will have retreated too far to be visible to the naked eye!

Its slightly gibbous disk is 18 arcseconds wide and growing as the distance between Venus and Earth steadily shrinks.

Wilson observatory in Pasadena, Calif., has succesfully measured the positions of five stars to an accuracy of 3 arcseconds and tracked them over wide angles (greater than 20|) as the earth rotated.

Its resolving power of 0.9 arcseconds is perfect for sampling the typical seeing of 2 to 3 arcseconds common at most amateur observing locations and is well-matched for high-resolution solar imaging in the daytime.

Viewed through a telescope in mid-July, Venus sports a 23% sunlit disk that measures 40 arcseconds from tip to tip.

Its gibbous disk is nearly 10 arcseconds wide--big enough to warrant attention from telescopic observers.

This apochromatic refractor's 101-mm aperture can capture 10th-magnitude stars with 1-second exposures, and its diffraction limit is only 1.3 arcseconds at a red-light wavelength of 630 nm--much smaller than the 2 1/2-arcsecond daytime seeing I expect to encounter.