The Alexander Observatory

MATERIALS: red brick with white stone dressings and with a copper surfaced dome.

PLAN: The building is circular, 7m in diameter, with 11 brick panels and an entrance with a stone lintel.

EXTERIOR: The four step entrance is flanked by curving walls with a stone coping ending with a ball finial on each side. The dome rotation and dome opening, which is a triangular sector, are both operated by a pulley and rope. A commemorative plaque on the side of the building bears the legend ‘Presented to the Aldershot Army Corps by Patrick Y Alexander Esq 1906’.

INTERIOR: The telescope, an astronomical refracting telescope (Object Lens: 8-inch F:12 focal ratio) mounted on a gunmetal German-type equatorial mount, dates from 1891 and was constructed by Howard Grubb of Dublin. All the usual fittings associated with this type of professional instrument were provided. The clock drive (allowing the telescope to remain in sync with the rotation of the earth), which will run for about two hours without rewinding, has a facility to vary the drive rate. Declination and Right Ascension (the two co-ordinates on a celestial sphere equivalent to geographic latitude and longitude) slow motions are fitted. The declination and RA circles are large and the declination circle is provided with a reading telescope for one vernier. The eyepiece fitting of the telescope, with magnification up to 500X, is rotatable with a Position Angle circle and vernier allowing, with a micrometer eyepiece, accurate positional measurements.