We use a GRISM to create slitless spectra of a field of stars. The GRISM is a transmission blazed diffraction grating from Rainbow Optics. The grating has 200 lines per mm with 67.6% of the total intensity at a wavelength of 632.5 nm blazed into the +1 order and 22.5% into the 0 order. All other orders have intensities of below 7%.


Grism filter and spectrum of Ring Nebula