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 |
Flat Fielding FITS |
5700-7100 |
||
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