An Extreme Precision Doppler Spectrometer for the WIYN Observatory


The Department of Physics and Astronomy at Texas A&M University, in partnership with scientists at the University of Texas at Austin, Johns Hopkins University, Indiana University, NOAO, and the Johns Hopkins University Applied Physics Laboratory, present a proposal to design, fabricate, integrate, test, deliver, and commission the Extreme Precision Doppler Spectrometer (EPDS) to NASA for the WIYN telescope. Our design consists of an echelle spectrograph coupled to the upper bent Cassegrain port of WIYN that delivers a high resolution spectrum of R=λ/δ(λ)=70,000 simultaneously over the 365<λ<680 nm optical waveband. The instrument will be fiber-fed and located in a vacuum enclosure to maximize instrument stability. EPDS observations will include simultaneous fiber-fed calibration spectra provided by multiple sources including a laser frequency comb. The calibration system will enable observations with a single measurement precision of 10 cm/s.

On this website we provide additional information about the instrument, including an exposure time calculator.



Figure1

Figure1
Optical layout of the EPDS design and an echellogram produced by the preliminary optical design.


Figure1
Three views of the concept for the EPDS optical bench and enclosure. Vibration-isolating legs provide stability. The vacuum enclosure provides thermal stability and surrounds the bench; it is connected via vacuum bellows around the legs.


Figure1

Figure1
Two views of the location of EPDS instrument in the ground floor ‚Äúspectrometer laboratory‚ÄĚ of the WIYN telescope. The laser frequency comb is located in the existing thermally controlled darkroom towards the back of this area. The EPDS optical bench assembly is located in the new room created by the addition of the wall as indicated. The existing wall between these two areas may not need to be removed. The red path on the floor indicates the required 28 inch wide emergency exit path from the room located behind the EPDS instrument room.
 
Astronomy Group
4242 TAMU
College Station, TX 77843-4242
Ph: (979) 845 7717
Texas A&M University - College of Science