Parameter

FPI

FFI

WFI

notes

Optics description:

main 3.5m TA (Cassegrain) + 8x reduction

Schmidt-Cass + field expander

F/2 Petzval lens

FPI has ±60 cm focus range, reticle, reimaging optics

aperture diameter:

2500 mm

254 mm

68 mm

FOV:

9’ diam.

67’ x 67’

6.0° x 6.0°

image scale (arc—sec/pixel):

0.55 ”/pxl

4.1 ”/pxl

21 ”/pxl

FPI scale varies 10% over focus range

star image size:

(80% Enc Energy)

7 ”

13 ”

~1.2 ’

FPI seeing-limited;

FFI, WFI optics limited

R-band sensitivity:

(S/N = 10 in 1 s)

13

11

9

centroid precision:

(S/N = 10)

~0.05 ”

~1 ”

~8 ”

Filters available:

• 3 ND’s
• red (day)
• clear
• blankoff

• 3 ND’s
• red (day)
• clear
• blankoff

• 3 ND’s
• red (day)
• clear
• blankoff

ND T: 8% - 75%

“red” = Schott RG1000

( l > 900 nm)

Parameter

Value or range

Notes

Array dimensions:

1024 x 1024 image area

frame transfer readout

Pixel size:

14 microns

Binning options:

1x1, 2x2, 4x4

4x4 done off chip

Integration time:

10 – 10,000 ms

Data format:

14-bit or 8-bit

2 MHz or 5 MHz rate

Maximum frame rate:

8 frames / s

2x2 binning, 5 MHz

Peak Q. E.:

18% at l 550 nm

electronic shutter, fill factor

Read noise:

60 e - = 5 DN

Dark current (25 °C):

12500 e -/s

No FPI cooling, CCD ~at cabin temperature in flight

Dark current (-20 °C):

200 e -/s

Likely for WFI, FFI

Gain (14-bit mode)

12 e - / DN

~600 e -/ DN in 8-bit mode

saturation

170,000 – 200,000 e -