Instrument Scientist:
Deputy Instrument Scientist:
Email Contact:
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 |