LIRIC


LIRIC under development in lab (covers removed). ©2023 A.Piascik

Introduction

The Liverpool Infra-Red Imaging Camera is an instrument development project co-funded by STFC and LJMU. It was designed and built by the ARI and will be available from 2024 Q1, replacing the now-decommissioned IO:I camera. It offers rapid X and Y axis fixed-distance offsetting (nodding) for sky background subtraction.

Status

2024 Q1:
Installed on-mount and available for raw observation. Pipeline in development

Specifications & Performance

Data is for detector temperature = -20°C

Detector 640 x 512 pixel InGaAs sCMOS by SCD.USA
Image area 607 x 510 pixel Excluding bias strip and edge rows
Pixel scale 0.29 arcsec/pixel (no binning available)
Field of view 3.0 x 2.5 arcmin (no windowing available)
Gain 0.52 electrons/ADU
Dark current 821 electrons/second
Read Noise 32 electrons
Linearity < 1 %
Bit depth 8520 electrons
Exposure 0.1 or 1.0 seconds co-added for longer exposure time
Approximate Zeropoint 22.8 (H-band)

Filter Set

LIRIC has an uncooled 5-position filter wheel. Currently, R-band, J-band and a FELH1500 low pass filter installed. The FELH1500 filter and sCMOS detector response combine for a pseudo H-band.

Filter Name

FWHM Wavelength Range
(Angstrom)

Flat Fielding FITS

5700-7100

Barr J

11200-13800

15200-16700

Dithering

Dithering is achieved by two cams to mechanical offset the camera X and Y positions within the image plane. The camera position cycles through each offset in sequence for each exposure up to the number of positions requested. Movement between positions takes between 2-4 seconds.
The base exposure time at each offset position is set in the configuration to 100ms or 1000ms. The actual exposure time at a position is the sum of co-added base exposures times. Read-out time is negligible.


Phase II Options

Instrument Config - Create New Instrument Config

Detector Config - Binning
1x1 only available

Filter Specification - Filter Wheel 1
FELH1500 - pseudo K-band filter
Barr-J
Bessell-R

Nudgematic - Offset Size
Sets the linear offsets from the centre position
None - No offset, camera will not move
Small - 20 arcsec linear offsets
Large - 60 arcsec linear offsets

Co-add - Exposure Length
Base exposure time used for co-adding images to produce a FITS file for a position
100ms
1000ms

Exposure Dialog Box

Exposure
Mult-run button must be selected

repeats
The number of offset positions the camera will move to
Offset positions are visited in the order, 1-9
Positions are omitted if repeats < 9, or revisited if repeats > 9

Exposure Time
The total exposure in seconds for a single visit to an position
It must be a multiple of Co-add - Exposure Length