Cross-Dispersed Echelle Spectrograph

Tull Spectrograph 2 (TS2)

A high-resolution spectrometer available with TK3, a thin, grade 1, Tektronix 2048 x 2048 CCD. Two-pixel resolving powers in its two modes of operation are 60,000 (TS23) and up to 240,000 (TS21).

Two echelle gratings offer minimum inter-order separations of 10.5 and 15.5 arcsec. 

Co-addition is available. Remote field acquisition and guiding are available, and auto-guiding is available.

 

Instrument Characteristics

Detector(s):
TK3, a thin, grade 1, Tektronix 2048 x 2048 CCD (QE curve)

 

Wavelength coverage:
In TS23 mode: 3,400*–10,900 Å continuous, in as few as two exposures.
In TS21 mode: same available spectral range but 1/18 of the coverage of TS23

*Throughput falls off rapidly below 3600 Å.

 

Spectral resolving power:
TS23 has a resolving power of R~60,000 (depending on slit selection)
TS21 has a resolving power of up to R~240,000 (depending on slit selection) 

 

Throughput/sensitivity:

For TS23, signal/noise has been measured as:

V=6.03 K7V star with 575 sec exposure yields S/N = 470 @ 7480A, 220 @ 4800A

V=5.76 G1V star with 383 sec exposure yields S/N = 320 @7480A, 200 @ 4800A

V = 4.11 F8V star with 104 sec exposure yields S/N = 290 @7480A, 216 @ 4800A

S/N is per pixel

 

For TS21 and slit 3 (R~120,000), SNR=100 per resolution element is achieved for:
6 x 30-minute exposures at Ca II K (~4000 Å) with E1, 
2 x 30-minute exposures at K I (~7500 Å) with E1.
3 x 30-minute exposures at Na I D (~6000 Å) with E2.
 

Detailed Information About the Instrument and Its Uses

The following sub-manuals are referenced and linked in the User Manual and also are included here to be accessed individually. Click down arrow to show them.

TS2 Sub Manuals

Data reduction Pipeline (beta-version)

Exposure time Calculator (In Development)

ThAr Spectral Atlas


Scientist

PM

Phillip MacQueen

  • Chief Scientist
  • McDonald Observatory
  • Astronomy
Telephone Number:512 471 1470
Building: PMA
Room Number:17.334
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