The ornamental design for a spectrometer, as shown and described.
1.-2. Spectrometers
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Top
1.5 : Bottom
1.6 : Left
1.7 : Right
1.8 : Partial enlarged vertical sectional view
1.9 : Enlarged top view
1.10 : Partial enlarged perspective view
2.1 : Perspective
2.2 : Front
2.3 : Back
2.4 : Top
2.5 : Bottom
2.6 : Left
2.7 : Right
2.8 : Partial enlarged vertical sectional view
2.9 : Enlarged top view
2.10 : Partial enlarged perspective view
The broken line showing is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design. The dash-dot-dash lines represent the boundary of the claimed design.