Differences from Blanco
On SOAR, the regular optical guider can be used; it is preferred as it has a faster response and allows tip-tilt correction using the tertiary mirror. It is capable of doing precise offsets, but does not currently support non-sidereal guiding (as this requires continuously moving the guide probe during the observation). Note that the guider is behind a dichroic and therefore can be used on-axis (i.e., you can guide on your target if its brightness is suitable).
Short Wavelength Cut-Off
TSpec is fed by a reflection off a dichroic, which also transmits light to the guider. As a result, the response cuts off below 1.0 microns. Compare the response on Blanco (top) with the response on SOAR (bottom). The nominal point of 50% reflectivity of the dichroic is around 0.95 microns.
Figure 1 - Comparison of TSpec response on Blanco and SOAR telescopes. Note the reduced response on SOAR shortward of 1.0 micron. Above this wavelength, the SOAR response is comparable (possibly better).
Updated on June 9, 2021, 5:19 am