SPRAT on LT works from 4000 - 8000 Angstroms. This "one-octave" range is the most one
can get before order overlap in a non cross dispersed spectrograph.
A possible design option is to combine SHOC and SPRAT into one instrument. The following
describes some testing of this concept on the Liverpool Telescope (LT) version of SPRAT.
=== Wavelength Range ===
On the afternoon of 2017 12 17 the 85mm f/1.8 Nikon camera lens
the camera slightly. A range of 3950 Angstroms is available, which basically
meets the design requirement to cover one full octave.
=== Optical Quality ===
Comparisons of the extracted arcs using either lens show essentially identical optical
quality:
[[File:sprat-comp-1.png]]
[[File:sprat-comp-2.png]]
The 50mm lens version looks slightly softer in images, but remember the pixel
sampling is half what it would be using the SHOK camera, so its not really
a fair comparison.
[[File:image-comp.png]]