. We present Mookodi (meaning "rainbow" in Sesotho), a multipurpose instrument with a low-resolution spectrograph mode and a multi-filter imaging mode for quick-reaction astronomical observations. The instrument, mounted on the 1-m Lesedi telescope at the South African Astronomical Observatory in Sutherland (South Africa), is based on the low-resolution spectrograph for the rapid acquisition of transients (SPRAT) instrument in operation on the 2-m Liverpool Telescope in La Palma (Canary Islands, Spain). Similar to SPRAT, Mookodi has a resolution R approximate to 350 and an operating wavelength range in the visible (similar to 4000 to 8000 angstrom). The linear optical design, as in SPRAT, is made possible through the combination of a volume phase holographic transmission grating as the dispersive element and a prism pair (grism), which makes it possible to rapidly and seamlessly switch to an imaging mode by pneumatically removing the slit and grism from the beam and using the same detector as in spectrographic mode to image the sky. This imaging mode is used for auto-target acquisition, but the inclusion of filter slides in Mookodi's design also provides the capability to perform imaging with a field-of-view approximate to 10 ' x10 ' (similar to 0.6 '' /px) in the complete Sloan Digital Sky Survey filter set.

The 4m class New Robotic Telescope (NRT) is an optical facility designed to revolutionize the rapid follow-up and classification of variable and transient objects. The project is at the stage where key systems are progressing through their detailed design phases, which presents a major engineering challenge for all project partners to manage design progress of the high-level interfacing systems while still ensuring the delivery of top-level science requirements. The freezing of key system architecture features at the preliminary design review in 2021 has allowed significant progress to be made towards a target of Engineering First Light (EFL) in 2027. The project critical path is currently driven by the optics and the enclosure. Both of these components are novel in design: the NRT will have an 18-segment primary mirror and a large, fully-opening clamshell enclosure. Particular progress has been made regarding enclosure design, software & control, science & operations software and the focal station and associated science support instrumentation. The Critical Design Review for the M3 (fold mirror) was completed Q4 2022 which enabled manufacturing of the first NRT glassware to begin and prototyping of the complete opto-mechanical, hardware and software subsystem for its control to take place. The NRT will join the 2m Liverpool Telescope on La Palma, and as such this existing facility has been exploited to prototype the new science operations user interface and the NRT wavefront sensor.

The New Robotic Telescope (NRT) is an autonomous telescope that can operate multiple instruments at the Cassegrain focal station and the straight-through port. The optical beam is directed to the ports by a fold mirror subsystem in the focal station assembly. The fold mirror is elliptical in shape, manufactured by Instituto Nazionale di Astrofisica (INAF), and polished down to RMS surface deformation of lambda/20. An optomechanical analysis is performed to simulate the effect of gravity over the mirror surface deformation and the results have been compared to the interferometry plots to optimize the Ion Beam Figuring (IBF) process to polish the mirror aperture. The mirror assembly is supported by a bipod flexure design to reduce surface deformation under gravity and thermal loads. There are three sets of bipod elements and a central support in the quasi-kinematic support structure. Using wire EDM, the bipods were manufactured precisely as one piece. Following careful preparation and the development of multiple glue jigs to ensure an even glue thickness, the bipods, and central pads are glued to the mirror, and multiple experimental tests have been performed to ensure the glue layer's strength and durability. Other components of the mirror assembly, such as the mirror cell, mirror stand, and moving platform, are being machined out of INVAR, assembled, and mounted on the linear stage and a rotary stage before being installed over the mechanism platform in the A&G box. The design and manufacturing of the mirror assembly, including the gluing process, will be summarised as part of this article.

The 2-metre Liverpool Telescope will soon be assisted by the New Robotic Telescope (NRT), a 4-metre-class telescope, robotic and fully autonomous, at the Roque de los Muchachos Observatory (ORM) on La Palma, Canary Islands, Spain. The 4-metre primary mirror of the NRT will be comprised of 18 hexagonal segments of 1-meter diameter each. All the individual segments need to be sufficiently aligned to deliver images that can be successfully exploited by the telescope instrumentation. We therefore need an instrument to assist in the alignment of the different segments. To that end, we designed a wavefront sensor that would be not only reliable and robust (indispensable for a robotic telescope), but also economical, and therefore with as many on-the-shelf components as possible. We chose a Shack-Hartmann type of wavefront sensor, that rests on the use of a lenslet array. The assembly of segments can be mapped onto the array imaged at the image plane by the lenslet array. This will allow us not only to detect the misalignment of each segments with respect to the other segments, but also the misalignment of the primary mirror with respect to the secondary mirror. From these information, the position of the primary mirror segments and of the secondary mirror can be altered. A prototype Shack Hartmann wavefront sensor for the NRT has been tested in the laboratory and also on the 2-m Liverpool Telescope. We demonstrate that the basic functionality requirements are met. Detailed analysis of the images is currently underway.

The New Robotic Telescope (NRT) conceptual design has been developed to include an autonomous multi-instrument adaptor at the Cassegrain focal station. The focal station assembly is to consist of a field rotator to compensate the earth rotation, cable wrap, instrument adaptor, support structure, and a fold mirror mechanism to bring the telescope optical beam to the instruments. The design supports the use of multiple instruments around the Acquisition and Guidance box (A&G box) a single instrument port is located at the bottom of the box at the straight through port. The A&G box also includes an autoguider which will be mounted at the side of the box and fed a portion of the optical beam via a small pick off mirror. It will use a field outside that of usable the science field, and has been designed to comprise of off-the-shelf lenses, camera system and lens tubes to minimise cost. The field of view is large enough to conduct ‘blind autoguiding’ at an accuracy of 0.2” with the 4m class telescope. The entire assembly will then be mounted to the M1 cell, forming the bottom part of the telescope tube held between the telescope mount forks. The focal station assembly design will be summarised in this paper.

Mid-infrared observations are a vital tool for the study of a wide range of astrophysical phenomena. However, ground-based mid-infrared detectors must overcome the challenge of the overwhelming thermal background from sky and telescope emissions making them prohibitively costly for smaller ( < 3 m) facilities. We describe the design and testing of a simple prototype, low-cost 10 mu m imaging instrument built around an uncooled microbolometer camera. The instrument incorporates adjustable germanium re-imaging optics to rescale the image to an appropriate plate-scale for 1- 2 m class telescopes and uses a gold coated chopping mirror to remove overwhelming sky background contributions. The instrument was tested with a programme of observations of bright mid-infrared sources on the 2 m Liverpool Telescope and the 1.52 m Carlos Sanchez Telescope. With these observations we confirm the instrument can be used for diffraction-limited imaging and has a photometric stability of similar to 10 %. We report an in-practice sensitivity limit of similar to 600 Jy, and a theoretical sensitivity limit of similar to 450 Jy based on the noise equivalent differential temperature of the microbolometer system.

We present an update on the overall integration progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now scheduled for first light in early-2021, with almost all components now arrived at the observatory. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been implemented to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 mini integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000.

WEAVE is the new multi-object spectrograph for the William Herschel Telescope on La Palma. The culmination of prime focus, the large number of fibers and the wide resolution range has required a stringent optical design, which in turn demands a spectrograph with tight positional tolerances and large final focal plane. To capture this focal plane each of the two cryostats has two e2v 6k × 6k CCDs mounted as a mosaic. As well as being cooled to 150K via liquid nitrogen, the positional tolerances for the sensitive areas are flatness 60μm p-v over the entire image area, rotation around X and Y axis ±50 arcmin, translation in X, Y and Z ± 50 micron. We have used a Stil confocal measuring head mounted on two Thorlab translation stages to create a X,Y mount, controlled by a Raspberry Pi that is capable of recording measurements in Z to better than 1μm accuracy. This is used to measure the flatness and deformation of the image area under vacuum, and when cooled to 150K and the overall tip and tilt of the image plane to ensure they meet specification and are repeatable. In addition to this measuring system, we use a Thorlabs CMOS camera with a Navitar 50mm lens to ensure each CCDs image area is within specification with regards X and Y translation. In order to satisfy the above requirements, we designed the CCD mount to be adjustable (on initial setup), correctly constrained, isolated from liquid nitrogen boil-off vibration, and thermally insulating.

The Liverpool Telescope group have been designing astronomical instruments for the LT and other 2-4m class telescopes for a number of years. This paper covers a variety of issues which need to be addressed in order to benefit from the unique advantages of 3D printing. In particular we discuss our experience of designing, building and testing a simple prototype structure that is analagous to a simple reflecting grating spectrograph.

The Liverpool Telescope is a fully robotic 2-metre telescope located at the Observatorio del Roque de los Muchachos on the Canary Island of La Palma. The telescope began routine science operations in 2004, and currently seven simultaneously mounted instruments support a broad science programme, with a focus on transient follow-up and other time domain topics well suited to the characteristics of robotic observing. Work has begun on a successor facility with the working title 'Liverpool Telescope 2'. We are entering a new era of time domain astronomy with new discovery facilities across the electromagnetic spectrum, and the next generation of optical survey facilities such as LSST are set to revolutionise the field of transient science in particular. The fully robotic Liverpool Telescope 2 will have a 4-metre aperture and an improved response time, and will be designed to meet the challenges of this new era. Following a conceptual design phase, we are about to begin the detailed design which will lead towards the start of construction in 2018, for first light similar to 2022. In this paper we provide an overview of the facility and an update on progress.

We present an overview of and status report on the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT). WEAVE principally targets optical ground-based follow up of upcoming ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project is now in the final design and early procurement phase, with commissioning at the telescope expected in 2017.

WEAVE is the next-generation optical spectroscopy facility for the William Herschel Telescope and aims at spectroscopic follow-up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE places in the re-fitted prime focus either 1000 fibres, 20 fibre-coupled mini-IFUs or a single large 600 fibre IFU. A spectrograph on the Nasmyth platform analyses the light and supports, in a single exposure, either R~5,000 observations over the full 366- 975 nm wavelength range or simultaneous R~20,000 observations over two out of three pre-specified bands within this wavelength range. This paper describes the requirements, optical design and mechanical design of the WEAVE spectrograph.

We present the preliminary design of the WEAVE next generation spectroscopy facility for the William Herschel Telescope (WHT), principally targeting optical ground-based follow up of upcoming ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2 degree prime focus field of view at the WHT, with a buffered pick and place positioner system hosting 1000 multi-object (MOS) fibres or up to 30 integral field units for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R similar to 5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R similar to 20000.