The Pole Star’s Substellar Point is fixed almost over the North Pole. Thus the angle from this star can be converted to produce the aircraft’s latitude, since the circle drawn from the Substellar Point located almost at the North Pole equates to a latitude reading as latitude is a circle based on the Pole. [James P.162]
The sun, moon and planets are much closer than the stars. This resulted in extra calculations to allow for the orbit of the moon around the earth and the planet’s orbits of the sun.
A highly skilled astro navigator could produce very accurate nav fixes. PG Taylor, later Sir Gordon Taylor, flying the Catalina PB2B-2
VH-ASA "Frigate Bird11", pioneered the Australian / Chile air route in 1951. At one point approaching Easter Island, the astro fix resulted in the position S26 05 W115 32 that was only 6 miles north of track. [Taylor P.250]
Taylor's Catalina VH-ASA is held today by the Powerhouse Museum, Sydney.
Later DC6 era pressurised planes could not use the perspex astrodome bubble fitted in the roof as in the DC4 / Catalina era planes, as the pressurisation would not allow the bubble window. Instead they had a special window frame built into the roof near the rear of the flight deck through which a periscope sextant was used. [DC-6B Illustrated Parts Catalog Vol 1, P. 20-432]