Details
| Original language | English |
|---|---|
| Title of host publication | The 2007 ESO Instrument Calibration Workshop |
| Subtitle of host publication | Proceedings of the ESO Workshop held in Garching |
| Pages | 409-412 |
| Number of pages | 4 |
| Publication status | Published - 14 May 2008 |
| Externally published | Yes |
Publication series
| Name | ESO Astrophysics Symposia |
|---|---|
| Volume | 2008 |
| ISSN (Print) | 1431-2433 |
| ISSN (electronic) | 1611-6143 |
Abstract
Typical astronomical spectrographs have a resolution λ/Δ λ ranging between a few hundred to 200,000. Deconvolution and correlation techniques are being employed with a significance down to 1/ 1000th of a pixel. HeAr and ThAr lamps are usually used for calibration in low and high resolution spectroscopy, respectively. Unfortunately, the emitted lines typically cover only a small fraction of the spectrometer's spectral range. Furthermore, their exact position depends strongly on environmental conditions. A problem is the strong intensity variation between different lines 1 (intensity ratios >300). In addition, the brightness of the lamps is insufficient to illuminate a spectrograph via an integrating sphere, which in turn is important to calibrate a long-slit spectrograph, as this is the only way to assure a uniform illumination of the spectrograph pupil. Laboratory precision laser spectroscopy has experienced a major advance with the development of optical frequency combs generated by pulsed femto-second lasers. These lasers emit a broad spectrum (several hundred nanometers in the visible and near infra-red) of equally-spaced "comb" lines with almost uniform intensity (intensity ratios typically <10). Self-referencing of the laser establishes a precise ruler in frequency space that can be stabilized to the 10 -18 uncertainty level, reaching absolute frequency inaccuracies at the 10 -12 level per day when using the Global Positioning System's (GPS) time signal as the reference. The exploration of the merits of this new technology holds the promise for broad-band, highly accurate and reproducible calibration required for reliable operation of current and next generation astronomic spectrometers. Similar techniques are also proposed in [5, 6].
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Astronomy and Astrophysics
- Physics and Astronomy(all)
- Physics and Astronomy (miscellaneous)
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The 2007 ESO Instrument Calibration Workshop: Proceedings of the ESO Workshop held in Garching. 2008. p. 409-412 (ESO Astrophysics Symposia; Vol. 2008).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - A new generation of spectrometer calibration techniques based on optical frequency combs
AU - Schmidt, Piet Oliver
AU - Kimeswenger, S.
AU - Käufl, H. U.
PY - 2008/5/14
Y1 - 2008/5/14
N2 - Typical astronomical spectrographs have a resolution λ/Δ λ ranging between a few hundred to 200,000. Deconvolution and correlation techniques are being employed with a significance down to 1/ 1000th of a pixel. HeAr and ThAr lamps are usually used for calibration in low and high resolution spectroscopy, respectively. Unfortunately, the emitted lines typically cover only a small fraction of the spectrometer's spectral range. Furthermore, their exact position depends strongly on environmental conditions. A problem is the strong intensity variation between different lines 1 (intensity ratios >300). In addition, the brightness of the lamps is insufficient to illuminate a spectrograph via an integrating sphere, which in turn is important to calibrate a long-slit spectrograph, as this is the only way to assure a uniform illumination of the spectrograph pupil. Laboratory precision laser spectroscopy has experienced a major advance with the development of optical frequency combs generated by pulsed femto-second lasers. These lasers emit a broad spectrum (several hundred nanometers in the visible and near infra-red) of equally-spaced "comb" lines with almost uniform intensity (intensity ratios typically <10). Self-referencing of the laser establishes a precise ruler in frequency space that can be stabilized to the 10 -18 uncertainty level, reaching absolute frequency inaccuracies at the 10 -12 level per day when using the Global Positioning System's (GPS) time signal as the reference. The exploration of the merits of this new technology holds the promise for broad-band, highly accurate and reproducible calibration required for reliable operation of current and next generation astronomic spectrometers. Similar techniques are also proposed in [5, 6].
AB - Typical astronomical spectrographs have a resolution λ/Δ λ ranging between a few hundred to 200,000. Deconvolution and correlation techniques are being employed with a significance down to 1/ 1000th of a pixel. HeAr and ThAr lamps are usually used for calibration in low and high resolution spectroscopy, respectively. Unfortunately, the emitted lines typically cover only a small fraction of the spectrometer's spectral range. Furthermore, their exact position depends strongly on environmental conditions. A problem is the strong intensity variation between different lines 1 (intensity ratios >300). In addition, the brightness of the lamps is insufficient to illuminate a spectrograph via an integrating sphere, which in turn is important to calibrate a long-slit spectrograph, as this is the only way to assure a uniform illumination of the spectrograph pupil. Laboratory precision laser spectroscopy has experienced a major advance with the development of optical frequency combs generated by pulsed femto-second lasers. These lasers emit a broad spectrum (several hundred nanometers in the visible and near infra-red) of equally-spaced "comb" lines with almost uniform intensity (intensity ratios typically <10). Self-referencing of the laser establishes a precise ruler in frequency space that can be stabilized to the 10 -18 uncertainty level, reaching absolute frequency inaccuracies at the 10 -12 level per day when using the Global Positioning System's (GPS) time signal as the reference. The exploration of the merits of this new technology holds the promise for broad-band, highly accurate and reproducible calibration required for reliable operation of current and next generation astronomic spectrometers. Similar techniques are also proposed in [5, 6].
UR - http://www.scopus.com/inward/record.url?scp=43149119466&partnerID=8YFLogxK
U2 - 10.1007/978-3-540-76963-7_55
DO - 10.1007/978-3-540-76963-7_55
M3 - Conference contribution
AN - SCOPUS:43149119466
SN - 9783540769620
T3 - ESO Astrophysics Symposia
SP - 409
EP - 412
BT - The 2007 ESO Instrument Calibration Workshop
ER -