Instrument Scientist:
Josh Walawender
Deputy Instrument Scientist:
Sherry Yeh
Email Contact:
KPF Support
This page attempts to compare KPF and HIRES for users who may be wondering which
instrument they should propose for.
| Comparison |
KPF |
HIRES |
| Optical Input |
1.14 arcsec octagonal fibers for science and sky (fixed format) |
Selectable deckers and slits for different sky projections
(e.g., B5 = 0.87 x 3.5 arcsec; C2 = 0.87 x 14 arcsec |
| Wavelength Coverage |
Fixed format:
445-870 nm (high-res) and
382-402 nm (med-res) |
~300-1000 nm in an adjustable format (moving a 3 CCD array over the
spectral format) |
| Resolving Power |
R=98k (445-870 nm) |
depends on slit
e.g., R=49k for 0.86 arcsec-wide slit
R=80k for 0.40 arcsec-wide slit |
Throughput
(sky to CCD) |
~8-10% peak-of-blaze (measured) |
5-6% peak-of-blaze for B5-B1 deckers (measured) |
| Doppler Precision |
0.5 m/s noise floor (req.) & 0.3 m/s (goal) |
~2 m/s systematic noise floor |
| Doppler Speed |
~8-10x faster than HIRES |
Limited by need for high SNR to model iodine spectrum |