The EXOplanet high resolution SPECtrograph (EXOhSPEC) is a design of high resolution spectrograph based on exploiting inovations in optics and control
Radial velocities for TauBoo using EXOhSPEC - plot generated using https://dace.unige.ch
Spectra of Sun compared to Sunspots, taken in Hatfield so strong atmsopheric lines, notice broadening of lines increasing for lines with higher Lande geff, ie. magnetically sensitive
The Spectrograph
Top view
At Thai National Telescope
Design
Zeemax optical design
Solid Works mechanical design
NARIT designed, manufactured and tested achromatic triplet
Modelling Tapered fibres
COMSOL tapering calculation, e.g, for different input beam (between 0 and 17 degrees) and larger and smaller tapers
Setups for measuring fibre performance used to investigate fibres with different geometries, tapered fibres and different modal noise properties
AO feedback system to ensure spectrograph stable
Centroiding and piezo adjustment running and correcting positions of arc lines, e.g., see x and y tracking error graph, metrology system achieving 0.017 pixel
The Telescope at AstroPark
Spectrograph housed ground floor, Telescope control middle floor
NARIT spectrograph lab at Astropark
Prototype instrument for the Thai National Telescope
First Light - a spectrum of the Moon, through thick cloud
Acquisition and Guiding Unit
Designed to couple a star image at the focal plane of the Thai National Telescope to an optical fibre. This allows simultaneous direct imaging of the target star and the focused image of the star at the fibre face. The internal camera is used for closed loop guiding of the telescope.
This ‘donut’ is the image of the output fibre. The darker area is the core of the fibre which is the location to place the image of the star. The fibre image can be placed anywhere in the camera field of view by using the two adjustments on the mirror.
Point telescope to the target star. See one bright spot (maybe two). Centre the brightest spot on the object centre you recorded previously. Focus this image using the telescope focus. See two bright spots. Fine position and fine focus using the telescope focus and pointing to give the smallest image on the fibre location. Keep it there. Check for maximum light at the spectrograph. Take data.
