2. Expected performance
The expected performance of KOOLS-IFU mounted on Seimei telescope is described below.
Note: KOOLS-IFU has neither the imaging nor the slit-spectrocopy mode.
# Spatial Performance
(after 2020/Oct.)
| Number of fibers |
117 (= 110 for objects and 7 for sky) |
| FoV of a fiber |
regular hexagon of 0.42 arcsec inradius |
| Fiber pitch |
0.84 ± 0.07 arcsec |
| Total FoV |
8.4 x 8.0 arcsec for object and 2.5 x 2.4 arcsec for sky |
| Fiber core filling factor |
~100% |
(before 2020/Sep.)
| Number of fibers |
127 |
| FoV of a fiber |
0.93 ± 0.04 arcsec diameter (design: 0.91 arcsec) |
| Fiber pitch |
1.16 ± 0.05 arcsec (design: 1.14 arcsec) |
| Total FoV |
15.1 ± 0.7 arcsec diameter (design: 14.8 arcsec) |
| Fiber core filling factor |
58% |
# Spectral Performance
(after 2020/Oct.)
| Grism |
VPH-blue |
VPH-red‡ |
VPH 495 |
VPH 683‡ |
| Wavelength coverage |
4100-8900 Å |
5800-10200 Å |
4300-5900 Å |
5800-8000 Å |
| Spectral resolution |
~500 |
~800 |
~1500 |
~2000 |
| Total peak throughput* |
~7% |
~6% |
~5.5% |
~4% |
(before 2020/Sep.)
| Grism |
VPH-blue |
VPH-red‡ |
VPH 495 |
VPH 683‡ |
| Wavelength coverage |
4100-8900 Å |
5800-10200 Å |
4300-5900 Å |
5800-8000 Å |
| Spectral resolution |
~500 |
~800 |
~1500 |
~2000 |
| Total peak throughput† |
5.6% |
4.7% |
4.3% |
3.0% |
*: not measured yet
†: including the fiber core filling factor at the 2D array (58%)
‡: in normal observations, use an order-sorting filter O56, which blocks < 5600 Å light
# CCD
| Overhead time per exposure |
16 seconds |
| Recommended exposure time |
1-1800 seconds (integer only) |
| Linearity |
~1% or better |
| Saturation count |
65535 ADU (plan) |
# Other information
| Typical time of grism change |
10-20 seconds |