f/40 Questionnaire for Visiting Instruments

Optimal Value

Range

Instrument value

Instrument value

Instrument value

Instrument name:

MIRAC2

OSCIR

MIRLIN

P.I. of instrument

W. Hoffmann

C. Telesco

M. Ressler

Focal ratio

f/40

f/36 or f/45

f/35 or longer

Expected exit pupil position (in front of focal plane)

19.14 m

8.8 m

Position of focal plane with respect to mounting surface

162 mm

123-273 mm

~25 mm

280 mm

95 mm

Field of view

<= 174"

12"

9" x 9"

17"

Mass

<= 1000 kg

~35 kg

80 kg

45 kg

Bending moment

<= 470 kg m

~10 kg m

75 kg m

?

Rotational moment

<= 7900 kg m^2

?

150 kg m^2

?

Out-of-balance moment

<= 12 kg m^2/s^2

?

will counterweight to minimize

will counterweight to minimize

Maximum diameter

<= 1.75 m

~0.8 m

1.3 m

0.72 m

Maximum length

<= 1.0 m

~0.8 m

0.6 m

0.69 m

Required cabling through telescope cable wrap:
coax <= 4 4 4 <= 4
RS-422 <= 10 1 1 0
fiber optic <= 10 2 1 0
Cable length through wrap

100 m

OK

Dimensions of electronics rack on telescope

10x10x20 cm

25x25x110 cm

60x40x40 cm

Length of cable between instrument and nearby electronics rack

5 m

<= 1.8 m

1.2 m

Computer interface

ethernet (thinnet) or serial

ethernet and/or serial

Ethernet and serial

Ethernet

Cooling requirements: glycol

4.9 l/min

LN2

...

12 + 4 l/day

yes

30 l + 5 l/day

LHe

...

12 + 6 l/day

yes

20 l + 10 l/day

Electrical power requirements (commercial and clean)

<= 1 kW

standard (UPS)

<= 1 kW

Chopping requirements (for proposal)

2" @ 10 Hz

<= 32"

5" @ 5 Hz

20" @ 5 Hz

Mounting hole pattern #1:
dia. of bolt pattern = 18 in (457.2 mm),
1/2-13 bolts, 7 locations at ± (15°, 60°, 120°, 180°) from vertical

...

std IRTF

either

OK

Mounting hole pattern #2:
dia. of bolt pattern = 24 in (610 mm),
3/8-16 bolts, 12 locations at ±(15°, 45°, 75°, 105°, 135°, 165°) from vertical
preferred (allows more rotational freedom when mounting)

...