Pub Date : 2018-12-01DOI: 10.1142/S2251171718400056
T. Herter, J. Adams, G. Gull, J. Schoenwald, L. Keller, B. Pirger, C. Henderson, G. Stacey, T. Nikola, J. D. De Buizer, W. Vacca, K. Ennico
We describe the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST) which is presently operating as a facility instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA). FORCAST provides imaging and moderate resolution spectroscopy capability over the 5–40[Formula: see text][Formula: see text]m wavelength range. In imaging mode, FORCAST has a 3.4[Formula: see text] field-of-view with 0.768[Formula: see text] pixels. Using grisms, FORCAST provides long-slit low-resolution ([Formula: see text]–300) and short-slit, cross-dispersed medium-resolution spectroscopic modes ([Formula: see text]–1200) over select wavelengths. Preceded by both Spitzer and Herschel, the discovery phase space for FORCAST lies in providing unique photometric bands and/or spectroscopic coverage, higher spatial resolution and exploration of the brightest sources which typically saturate space observatories.
{"title":"FORCAST: A Mid-Infrared Camera for SOFIA","authors":"T. Herter, J. Adams, G. Gull, J. Schoenwald, L. Keller, B. Pirger, C. Henderson, G. Stacey, T. Nikola, J. D. De Buizer, W. Vacca, K. Ennico","doi":"10.1142/S2251171718400056","DOIUrl":"https://doi.org/10.1142/S2251171718400056","url":null,"abstract":"We describe the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST) which is presently operating as a facility instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA). FORCAST provides imaging and moderate resolution spectroscopy capability over the 5–40[Formula: see text][Formula: see text]m wavelength range. In imaging mode, FORCAST has a 3.4[Formula: see text] field-of-view with 0.768[Formula: see text] pixels. Using grisms, FORCAST provides long-slit low-resolution ([Formula: see text]–300) and short-slit, cross-dispersed medium-resolution spectroscopic modes ([Formula: see text]–1200) over select wavelengths. Preceded by both Spitzer and Herschel, the discovery phase space for FORCAST lies in providing unique photometric bands and/or spectroscopic coverage, higher spatial resolution and exploration of the brightest sources which typically saturate space observatories.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42298217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400068
E. Pfüller, J. Wolf, M. Wiedemann
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a heavily modified Boeing 747SP aircraft, accommodating a 2.7[Formula: see text]m infrared telescope. This airborne observation platform operates at flight altitudes of up to 13.7[Formula: see text]km (45,000[Formula: see text]ft) and therefore allows a nearly unobstructed view of the visible and infrared universe at wavelengths between 0.4[Formula: see text]μm and 1600[Formula: see text]μm. The Focal Plane Imager (FPI+) is SOFIA’s main tracking camera. It uses a commercial, off-the-shelf camera with a thermoelectrically cooled EMCCD. The back-illuminated sensor has a peak quantum efficiency greater than 95% at 550[Formula: see text]nm and the dark current is as low as 0.001 e-/pix/sec. Since 2015, the FPI[Formula: see text] has been available to the community as a Facility Science Instrument (FSI), and can be used as a high speed photometer for events in the visual wavelength range. This paper presents a detailed overview of the design and optical configuration of the FPI+. Different settings and specifications of the camera are explained and the focal plane sensor is described. The camera’s performance in regards to sensitivity and frame rate is shown. The operation of the instrument is described as well as the support for guest observers throughout the process from proposing to data analysis. To date, SOFIA has conducted multiple FPI+ observations of stellar occultations, e.g. occultations by Pluto in 2011 and 2015, the occultation by 2014MU69 in July 2017 and the occultation by Triton in October 2017. Additionally, multiple observations of exo-planet transits have been observed with the FPI+. Throughout these observations, the FPI+ has proven to be an excellent photometer for astronomical events that have challenging requirements for sensitivity and temporal resolution.
{"title":"The SOFIA Focal Plane Imager: A Highly Sensitive and Fast Photometer for the Wavelength Range 0.4 to 1 Micron","authors":"E. Pfüller, J. Wolf, M. Wiedemann","doi":"10.1142/S2251171718400068","DOIUrl":"https://doi.org/10.1142/S2251171718400068","url":null,"abstract":"The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a heavily modified Boeing 747SP aircraft, accommodating a 2.7[Formula: see text]m infrared telescope. This airborne observation platform operates at flight altitudes of up to 13.7[Formula: see text]km (45,000[Formula: see text]ft) and therefore allows a nearly unobstructed view of the visible and infrared universe at wavelengths between 0.4[Formula: see text]μm and 1600[Formula: see text]μm. The Focal Plane Imager (FPI+) is SOFIA’s main tracking camera. It uses a commercial, off-the-shelf camera with a thermoelectrically cooled EMCCD. The back-illuminated sensor has a peak quantum efficiency greater than 95% at 550[Formula: see text]nm and the dark current is as low as 0.001 e-/pix/sec. Since 2015, the FPI[Formula: see text] has been available to the community as a Facility Science Instrument (FSI), and can be used as a high speed photometer for events in the visual wavelength range. This paper presents a detailed overview of the design and optical configuration of the FPI+. Different settings and specifications of the camera are explained and the focal plane sensor is described. The camera’s performance in regards to sensitivity and frame rate is shown. The operation of the instrument is described as well as the support for guest observers throughout the process from proposing to data analysis. To date, SOFIA has conducted multiple FPI+ observations of stellar occultations, e.g. occultations by Pluto in 2011 and 2015, the occultation by 2014MU69 in July 2017 and the occultation by Triton in October 2017. Additionally, multiple observations of exo-planet transits have been observed with the FPI+. Throughout these observations, the FPI+ has proven to be an excellent photometer for astronomical events that have challenging requirements for sensitivity and temporal resolution.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49050282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400020
Z. Ali, P. Alvarez, A. Cheng, K. Hanna, M. Kandlagunta, J. Lott, G. Perryman, L. Tanaka, C. Kaminski, M. Woodworth, J. Wong, N. McKown
The NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5[Formula: see text]m telescope in a modified Boeing 747SP aircraft that is flown at high altitude to do unique astronomy in the infrared. SOFIA is a singular integration of aircraft operations, telescope design, and science instrumentation that delivers observational opportunities outside the capability of any other facility. The science ground operations are the transition and integration point of the science, aircraft, and telescope. We present the ground operations themselves and the tools used to prepare for mission success. Specifically, we will discuss operations from science instrument delivery to aircraft operation and mission readiness. We will also provide a discussion of instrument life cycle including maintenance and repair, both before and after acceptance by the observatory as well as retirement. Included in that will be a description of the facilities and their development, an overview of the SOFIA telescope assembly simulator, our deployment capabilities, as well as an outlook to the future of novel science instrument support for SOFIA.
{"title":"A Review of Science Ground Operations for the Stratospheric Observatory for Infrared Astronomy (SOFIA)","authors":"Z. Ali, P. Alvarez, A. Cheng, K. Hanna, M. Kandlagunta, J. Lott, G. Perryman, L. Tanaka, C. Kaminski, M. Woodworth, J. Wong, N. McKown","doi":"10.1142/S2251171718400020","DOIUrl":"https://doi.org/10.1142/S2251171718400020","url":null,"abstract":"The NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5[Formula: see text]m telescope in a modified Boeing 747SP aircraft that is flown at high altitude to do unique astronomy in the infrared. SOFIA is a singular integration of aircraft operations, telescope design, and science instrumentation that delivers observational opportunities outside the capability of any other facility. The science ground operations are the transition and integration point of the science, aircraft, and telescope. We present the ground operations themselves and the tools used to prepare for mission success. Specifically, we will discuss operations from science instrument delivery to aircraft operation and mission readiness. We will also provide a discussion of instrument life cycle including maintenance and repair, both before and after acceptance by the observatory as well as retirement. Included in that will be a description of the facilities and their development, an overview of the SOFIA telescope assembly simulator, our deployment capabilities, as well as an outlook to the future of novel science instrument support for SOFIA.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48163508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400147
C. Risacher, R. Güsten, J. Stutzki, H. Hübers, R. Aladro, A. Bell, C. Buchbender, D. Büchel, T. Csengeri, C. Durán, U. Graf, R. Higgins, C. Honingh, K. Jacobs, M. Justen, B. Klein, M. Mertens, Y. Okada, A. Parikka, P. Pütz, Nicolás Reyes, Nicolás Reyes, H. Richter, Oliver Ricken, D. Riquelme, N. Rothbart, N. Schneider, R. Simon, M. Wienold, H. Wiesemeyer, M. Ziebart, Paul Fusco, S. Rosner, S. Rosner, B. Wohler, B. Wohler
We present the performance of the upGREAT heterodyne array receivers on the SOFIA telescope after several years of operations. This instrument is a multi-pixel high resolution ([Formula: see text]) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receivers use 7-pixel subarrays configured in a hexagonal layout around a central pixel. The low frequency array receiver (LFA) has [Formula: see text] pixels (dual polarization), and presently covers the 1.83–2.07[Formula: see text]THz frequency range, which allows to observe the [CII] and [OI] lines at 158[Formula: see text][Formula: see text]m and 145[Formula: see text][Formula: see text]m wavelengths. The high frequency array (HFA) covers the [OI] line at 63[Formula: see text][Formula: see text]m and is equipped with one polarization at the moment (7 pixels, which can be upgraded in the near future with a second polarization array). The 4.7[Formula: see text]THz array has successfully flown using two separate quantum-cascade laser local oscillators from two different groups. NASA completed the development, integration and testing of a dual-channel closed-cycle cryocooler system, with two independently operable He compressors, aboard SOFIA in early 2017 and since then, both arrays can be operated in parallel using a frequency separating dichroic mirror. This configuration is now the prime GREAT configuration and has been added to SOFIA’s instrument suite since observing cycle 6.
本文介绍了经过几年的运行，upGREAT外差阵列接收机在SOFIA望远镜上的性能。该仪器是平流层远红外天文观测台(SOFIA)的多像素高分辨率光谱仪。接收器使用围绕中心像素以六边形布局配置的7像素子阵列。低频阵列接收器(LFA)具有[公式:见文]像素(双偏振)，目前覆盖1.83-2.07[公式:见文]太赫兹频率范围，允许在158[公式:见文][公式:见文]m和145[公式:见文][公式:见文]m波长处观察[CII]和[OI]线。高频阵列(high frequency array, HFA)覆盖63 m[公式:见文][公式:见文]m处的[OI]线，目前配备一个极化(7像素，可在不久的将来升级为第二个极化阵列)。4.7太赫兹阵列已经成功地使用来自两个不同组的两个单独的量子级联激光局部振荡器飞行。2017年初，NASA在SOFIA上完成了双通道闭式循环制冷机系统的开发、集成和测试，该系统具有两个独立可操作的He压缩机，从那时起，两个阵列可以使用频率分离二向色镜并行运行。这种配置现在是主要的GREAT配置，并且自观测周期6以来已添加到SOFIA的仪器套件中。
{"title":"The upGREAT Dual Frequency Heterodyne Arrays for SOFIA","authors":"C. Risacher, R. Güsten, J. Stutzki, H. Hübers, R. Aladro, A. Bell, C. Buchbender, D. Büchel, T. Csengeri, C. Durán, U. Graf, R. Higgins, C. Honingh, K. Jacobs, M. Justen, B. Klein, M. Mertens, Y. Okada, A. Parikka, P. Pütz, Nicolás Reyes, Nicolás Reyes, H. Richter, Oliver Ricken, D. Riquelme, N. Rothbart, N. Schneider, R. Simon, M. Wienold, H. Wiesemeyer, M. Ziebart, Paul Fusco, S. Rosner, S. Rosner, B. Wohler, B. Wohler","doi":"10.1142/S2251171718400147","DOIUrl":"https://doi.org/10.1142/S2251171718400147","url":null,"abstract":"We present the performance of the upGREAT heterodyne array receivers on the SOFIA telescope after several years of operations. This instrument is a multi-pixel high resolution ([Formula: see text]) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receivers use 7-pixel subarrays configured in a hexagonal layout around a central pixel. The low frequency array receiver (LFA) has [Formula: see text] pixels (dual polarization), and presently covers the 1.83–2.07[Formula: see text]THz frequency range, which allows to observe the [CII] and [OI] lines at 158[Formula: see text][Formula: see text]m and 145[Formula: see text][Formula: see text]m wavelengths. The high frequency array (HFA) covers the [OI] line at 63[Formula: see text][Formula: see text]m and is equipped with one polarization at the moment (7 pixels, which can be upgraded in the near future with a second polarization array). The 4.7[Formula: see text]THz array has successfully flown using two separate quantum-cascade laser local oscillators from two different groups. NASA completed the development, integration and testing of a dual-channel closed-cycle cryocooler system, with two independently operable He compressors, aboard SOFIA in early 2017 and since then, both arrays can be operated in parallel using a frequency separating dichroic mirror. This configuration is now the prime GREAT configuration and has been added to SOFIA’s instrument suite since observing cycle 6.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400147","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48242845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400135
M. Richter, C. DeWitt, M. McKelvey, E. Montiel, R. Mcmurray, M. Case
The Echelon-cross-echelle spectrograph (EXES) is a high spectral resolution, mid-infrared spectrograph designed for and operated on the Stratospheric Observatory for Infrared Astronomy (SOFIA). EXES has multiple operational modes, but is optimized for high spectral resolution. The heart of the instrument is a one meter long, diamond-machined echelon grating. EXES also uses a 10242 Si:As detector optimized for low-background flux. We will discuss the design, operation and performance of EXES.
{"title":"EXES: The Echelon-cross-echelle Spectrograph for SOFIA","authors":"M. Richter, C. DeWitt, M. McKelvey, E. Montiel, R. Mcmurray, M. Case","doi":"10.1142/S2251171718400135","DOIUrl":"https://doi.org/10.1142/S2251171718400135","url":null,"abstract":"The Echelon-cross-echelle spectrograph (EXES) is a high spectral resolution, mid-infrared spectrograph designed for and operated on the Stratospheric Observatory for Infrared Astronomy (SOFIA). EXES has multiple operational modes, but is optimized for high spectral resolution. The heart of the instrument is a one meter long, diamond-machined echelon grating. EXES also uses a 10242 Si:As detector optimized for low-background flux. We will discuss the design, operation and performance of EXES.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400135","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41600776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/s2251171718400044
S. Colditz, S. Beckmann, A. Bryant, C. Fischer, F. Fumi, N. Geis, M. Hamidouche, T. Henning, R. Hönle, C. Iserlohe, R. Klein, A. Krabbe, L. Looney, A. Poglitsch, W. Raab, F. Rebell, D. Rosenthal, M. Savage, M. Schweitzer, W. Vacca
The field-imaging far-infrared line spectrometer (FIFI-LS) is a science instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA). FIFI-LS allows simultaneous observations in two spectral channels. The “blue” channel is sensitive from 51[Formula: see text][Formula: see text]m to 125[Formula: see text][Formula: see text]m and the “red” channel from 115[Formula: see text][Formula: see text]m to 203[Formula: see text][Formula: see text]m. The instantaneous spectral coverage is 1000–3000[Formula: see text]km/s in the blue and 800–2500[Formula: see text]km/s in the red channel with a spectral resolution between 150[Formula: see text]km/s and 600[Formula: see text]km/s. Each spectral channel observes a field of five by five spatial pixels on the sky. The pixel size in the blue channel is 6.14 by 6.25 square arc seconds and it is 12.2 by 12.5 square arc seconds in the red channel. FIFI-LS has been operating on SOFIA since 2014. It is available to the astronomical community as a facility science instrument. We present the results of the spectral and spatial characterization of the instrument based on laboratory measurements. This includes the measured spectral resolution and examples of the line spread function in the spectral domain. In the spatial domain, a model of the instrument’s point spread function (PSF) and the description of a second pass ghost are presented. We also provide an overview of the procedures used to measure the instrument’s field of view geometry and spectral calibration. The spectral calibration yields an accuracy of 15–60[Formula: see text]km/s depending on wavelength.
{"title":"Spectral and Spatial Characterization and Calibration of FIFI-LS — The Field Imaging Spectrometer on SOFIA","authors":"S. Colditz, S. Beckmann, A. Bryant, C. Fischer, F. Fumi, N. Geis, M. Hamidouche, T. Henning, R. Hönle, C. Iserlohe, R. Klein, A. Krabbe, L. Looney, A. Poglitsch, W. Raab, F. Rebell, D. Rosenthal, M. Savage, M. Schweitzer, W. Vacca","doi":"10.1142/s2251171718400044","DOIUrl":"https://doi.org/10.1142/s2251171718400044","url":null,"abstract":"The field-imaging far-infrared line spectrometer (FIFI-LS) is a science instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA). FIFI-LS allows simultaneous observations in two spectral channels. The “blue” channel is sensitive from 51[Formula: see text][Formula: see text]m to 125[Formula: see text][Formula: see text]m and the “red” channel from 115[Formula: see text][Formula: see text]m to 203[Formula: see text][Formula: see text]m. The instantaneous spectral coverage is 1000–3000[Formula: see text]km/s in the blue and 800–2500[Formula: see text]km/s in the red channel with a spectral resolution between 150[Formula: see text]km/s and 600[Formula: see text]km/s. Each spectral channel observes a field of five by five spatial pixels on the sky. The pixel size in the blue channel is 6.14 by 6.25 square arc seconds and it is 12.2 by 12.5 square arc seconds in the red channel. FIFI-LS has been operating on SOFIA since 2014. It is available to the astronomical community as a facility science instrument. We present the results of the spectral and spatial characterization of the instrument based on laboratory measurements. This includes the measured spectral resolution and examples of the line spread function in the spectral domain. In the spatial domain, a model of the instrument’s point spread function (PSF) and the description of a second pass ghost are presented. We also provide an overview of the procedures used to measure the instrument’s field of view geometry and spectral calibration. The spectral calibration yields an accuracy of 15–60[Formula: see text]km/s depending on wavelength.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251171718400044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47716003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400032
C. Fischer, S. Beckmann, A. Bryant, S. Colditz, F. Fumi, N. Geis, M. Hamidouche, T. Henning, R. Hönle, C. Iserlohe, R. Klein, A. Krabbe, L. Looney, A. Poglitsch, W. Raab, F. Rebell, D. Rosenthal, M. Savage, M. Schweitzer, C. Trinh, W. Vacca
We describe the design of the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS), operated as a Facility-Class instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA). FIFI-LS is an imaging spectrometer for medium resolution spectroscopy. Since being commissioned in 2014, it has performed over 50 SOFIA commissioning and science flights. After operating as a principal investigator instrument in 2014 and early 2015, it was accepted as a Facility Science Instrument in 2015. In addition to the description of the design, we report on the in-flight performance and the concept of operation. We also provide an overview of the science opportunities with FIFI-LS and describe how FIFI-LS observations complement and complete observations with the PACS instrument on the Herschel observatory.
{"title":"FIFI-LS: The Field-Imaging Far-Infrared Line Spectrometer on SOFIA","authors":"C. Fischer, S. Beckmann, A. Bryant, S. Colditz, F. Fumi, N. Geis, M. Hamidouche, T. Henning, R. Hönle, C. Iserlohe, R. Klein, A. Krabbe, L. Looney, A. Poglitsch, W. Raab, F. Rebell, D. Rosenthal, M. Savage, M. Schweitzer, C. Trinh, W. Vacca","doi":"10.1142/S2251171718400032","DOIUrl":"https://doi.org/10.1142/S2251171718400032","url":null,"abstract":"We describe the design of the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS), operated as a Facility-Class instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA). FIFI-LS is an imaging spectrometer for medium resolution spectroscopy. Since being commissioned in 2014, it has performed over 50 SOFIA commissioning and science flights. After operating as a principal investigator instrument in 2014 and early 2015, it was accepted as a Facility Science Instrument in 2015. In addition to the description of the design, we report on the in-flight performance and the concept of operation. We also provide an overview of the science opportunities with FIFI-LS and describe how FIFI-LS observations complement and complete observations with the PACS instrument on the Herschel observatory.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46322716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400081
D. Harper, M. Runyan, C. Dowell, C. Wirth, M. Amato, T. Ames, M. Amiri, S. Banks, A. Bartels, D. Benford, M. Berthoud, E. Buchanan, S. Casey, N. Chapman, D. Chuss, B. Cook, R. Derro, J. Dotson, R. Evans, D. Fixsen, I. Gatley, J. A. Guerra, M. Halpern, R. Hamilton, L. Hamlin, C. Hansen, S. Heimsath, Alfonso Hermida, G. Hilton, R. Hirsch, M. Hollister, Carl F. Hostetter, K. Irwin, C. Jhabvala, M. Jhabvala, J. Kastner, A. Kovács, Sean Lin, R. Loewenstein, L. Looney, E. Lopez-Rodriguez, S. Maher, J. Michail, T. Miller, S. Moseley, G. Novak, R. Pernic, T. Rennick, H. Rhody, E. Sandberg, Dale Sandford, F. Santos, R. Shafer, E. Sharp, P. Shirron, J. Siah, R. Silverberg, L. Sparr, Robert Spotz, J. Staguhn, Armen S. Toorian, Shannon Towey, J. Tuttle, J. Vaillancourt, G. Voellmer, C. Volpert, Shu I. Wang, Edward J. Wollack
High-resolution Airborne Wide-band Camera (HAWC[Formula: see text]) is the facility far-infrared imager and polarimeter for SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy. It is designed to cover the portion of the infrared spectrum that is completely inaccessible to ground-based observatories and which is essential for studies of astronomical sources with temperatures between tens and hundreds of degrees Kelvin. Its ability to make polarimetric measurements of aligned dust grains provides a unique new capability for studying interstellar magnetic fields. HAWC[Formula: see text] began commissioning flights in April 2016 and was accepted as a facility instrument in early 2018. In this paper, we describe the instrument, its operational procedures, and its performance on the observatory.
{"title":"HAWC+, the Far-Infrared Camera and Polarimeter for SOFIA","authors":"D. Harper, M. Runyan, C. Dowell, C. Wirth, M. Amato, T. Ames, M. Amiri, S. Banks, A. Bartels, D. Benford, M. Berthoud, E. Buchanan, S. Casey, N. Chapman, D. Chuss, B. Cook, R. Derro, J. Dotson, R. Evans, D. Fixsen, I. Gatley, J. A. Guerra, M. Halpern, R. Hamilton, L. Hamlin, C. Hansen, S. Heimsath, Alfonso Hermida, G. Hilton, R. Hirsch, M. Hollister, Carl F. Hostetter, K. Irwin, C. Jhabvala, M. Jhabvala, J. Kastner, A. Kovács, Sean Lin, R. Loewenstein, L. Looney, E. Lopez-Rodriguez, S. Maher, J. Michail, T. Miller, S. Moseley, G. Novak, R. Pernic, T. Rennick, H. Rhody, E. Sandberg, Dale Sandford, F. Santos, R. Shafer, E. Sharp, P. Shirron, J. Siah, R. Silverberg, L. Sparr, Robert Spotz, J. Staguhn, Armen S. Toorian, Shannon Towey, J. Tuttle, J. Vaillancourt, G. Voellmer, C. Volpert, Shu I. Wang, Edward J. Wollack","doi":"10.1142/S2251171718400081","DOIUrl":"https://doi.org/10.1142/S2251171718400081","url":null,"abstract":"High-resolution Airborne Wide-band Camera (HAWC[Formula: see text]) is the facility far-infrared imager and polarimeter for SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy. It is designed to cover the portion of the infrared spectrum that is completely inaccessible to ground-based observatories and which is essential for studies of astronomical sources with temperatures between tens and hundreds of degrees Kelvin. Its ability to make polarimetric measurements of aligned dust grains provides a unique new capability for studying interstellar magnetic fields. HAWC[Formula: see text] began commissioning flights in April 2016 and was accepted as a facility instrument in early 2018. In this paper, we describe the instrument, its operational procedures, and its performance on the observatory.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" 6","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41251851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1142/S2251171718400019
Y. Lammen, Andreas Reinacher, Benjamin Greiner, Jörg F. Wagner, A. Krabbe
The Stratospheric Observatory for Infrared Astronomy (SOFIA) consists of a 2.7[Formula: see text]m infrared telescope integrated into a Boeing 747 SP. One of the most complex subsystems of the observatory is the secondary mirror assembly (SMA). This active steering mechanism is used for image stabilization and infrared chopping. Since its integration in 2002, the performance of the mechanism is limited by a structural resonance. Based on Finite Element (FE) simulations and experimental modal surveys, a ring shaped reaction mass was identified to be the causing element of this structural mode. Attenuating the resonance on the hardware level would result in a larger actuation bandwidth for faster chopping and image stabilization. Concentrating mass at the suspension points while keeping the inertia of the ring structure is expected to take strain energy out of the mode. An end-to-end simulation, including a FE model of the mechanism and a controller model was set up to predict the in-flight performance of this concept. A segmented ring made from tungsten and AlSiC (i.e. strong mass redistribution) mounted on the original suspension was selected for the design of a prototype. The prototype was manufactured and thoroughly tested on a full-scale mockup of the mechanism confirming the predicted performance. An actuation bandwidth improvement of 80% was achieved. The settling time for infrared chopping was reduced from 10 to 7[Formula: see text]ms providing about 3.3% higher efficiency for observations with 5[Formula: see text]Hz chopping.
{"title":"Increasing the SOFIA Secondary Mirror Mechanism’s Fast Steering Capability by Identification of a Structural Resonance and Its Subsequent Elimination Through Mass Re-Distribution","authors":"Y. Lammen, Andreas Reinacher, Benjamin Greiner, Jörg F. Wagner, A. Krabbe","doi":"10.1142/S2251171718400019","DOIUrl":"https://doi.org/10.1142/S2251171718400019","url":null,"abstract":"The Stratospheric Observatory for Infrared Astronomy (SOFIA) consists of a 2.7[Formula: see text]m infrared telescope integrated into a Boeing 747 SP. One of the most complex subsystems of the observatory is the secondary mirror assembly (SMA). This active steering mechanism is used for image stabilization and infrared chopping. Since its integration in 2002, the performance of the mechanism is limited by a structural resonance. Based on Finite Element (FE) simulations and experimental modal surveys, a ring shaped reaction mass was identified to be the causing element of this structural mode. Attenuating the resonance on the hardware level would result in a larger actuation bandwidth for faster chopping and image stabilization. Concentrating mass at the suspension points while keeping the inertia of the ring structure is expected to take strain energy out of the mode. An end-to-end simulation, including a FE model of the mechanism and a controller model was set up to predict the in-flight performance of this concept. A segmented ring made from tungsten and AlSiC (i.e. strong mass redistribution) mounted on the original suspension was selected for the design of a prototype. The prototype was manufactured and thoroughly tested on a full-scale mockup of the mechanism confirming the predicted performance. An actuation bandwidth improvement of 80% was achieved. The settling time for infrared chopping was reduced from 10 to 7[Formula: see text]ms providing about 3.3% higher efficiency for observations with 5[Formula: see text]Hz chopping.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47555614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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