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


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.

Cloud server for EXOhSPEC


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