Spectrograph

Astronomy

Accession Number: 2019.ast.192

Description:

This is a small prism spectrograph. It hands on tripod feed with screw holes that enable the instrument to be securely attached to a surface. Supported on a single cylindrical pillar there is a circular support in the middle of which there is a prism consisting of three right-angle prisms affixed together. This is encased in a cylindrical box with a round, removable lid. Emerging from this container are two tubes. At the end of one, the shorter, there is an attachment with a narrow aperture marked with a tiny scale. The other is a longer tube, which is open at the end, and contains a lens at the prism end.

A third attachment to the prism container is mounted below the container on a rotating arm attached to the pillar support of the instrument. This widens into a box shape which ends with a camera bellows and a recessed space for a rectangular photographic plate, mounted horizontally. Small latches are present to hold a plate in place. There is also a slot enabling a cover to be slid behind the plate to isolate it; there are latches to secure this as well. Below the camera mount, there are various screw adjustments, one with a vernier scale, permitting precise adjustment of the camera angle. Some of this appears to be disconnected, and pieces may be missing.

Emerging from the opposite side of the pillar to the camera mount, there is a metal rod with a cylindrical brass attachment lotted onto it, with a screw adjustment allowing the weight to be fixed in place. This is possibly intended to be a counterbalance.

Alternative Name: Spectroscope

Primary Materials:

Metal: Copper Alloy (Brass), Metal: Iron Alloy, Glass, Wood

Markings:

On the lid of the prism container: “Franz Schmidt & Haensch,
Berlin, S.”

Dimensions (cm): Length = 48, Width = 34, Height = 32.7

Function:

Likely for use with a small telescope focused on a celestial object such as the sun, or to demonstrate spectroscopy by being focused on some other light source. This instrument enables the photography of a spectrum of a source, together with the overlay of a scale.

Condition:

Good. The instrument is in relatively good condition. The metal surfaces are rusty where the paint has worn off (iron) or otherwise tarnished with fingermarks (brass surfaces). Parts of the instrument appear to have been mended; this includes the scale and perhaps the camera, which may have been sealed. It is possible parts of the instrument are missing. The cover for the photographic plate holder is missing.

Manufacturer: Franz Schmidt & Haesch, Berlin

Date of Manufacture: c. 1900-1915

Provenance:

This object was likely used at the Department of Astronomy either for demonstration or research. At some point, it was moved to the David Dunlap Observatory. Following the Observatory’s sale in 2009, it was moved to storage at the Department of Astronomy & Astrophysics at the St George Campus of the University of Toronto. In 2017, it was removed to a new space in the Department of Physics.