K. P. Jaehnig

University of Wisconsin, Madison, Madison, MS, United States

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Publications (26)21.05 Total impact

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    ABSTRACT: The ST5000 is a star tracker developed at the University of Wisconsin and used in NASA's sounding rocket payloads. In order to demonstrate the ST5000's suitability for pointed balloon-borne telescopes, we flew an ST5000 on a stratospheric balloon on May 6, 2011. This flight addressed our four basic questions: will the ST5000 work from 120,000 ft (it does), what was the rms performance (about 0.6"), what angular rates of motion would cause the ST5000 to fail (greater than 0.5 degrees/sec) and could the ST5000 serve as a daytime star tracker (not without modifications). We will briefly present the results from the flight and describe the ST5000's quantitative performance. We will also describe the problems with background light as a function of wavelength, altitude and angle from the Sun. We will discuss approaches to improve the daytime performance using infrared detectors and longer focal lengths/reduced platescales. Solutions that have finer platescales have the potential to improve the star tracker's error signal to the 0.1" level, which is better than the diffraction limit of a one meter telescope at 5000 Å.
    IEEE Aerospace Conference Proceedings 01/2012;
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    ABSTRACT: After a year of observations from its new location on Cerro Tololo, the Wisconsin Halpha Mapper (WHAM) has nearly completed survey observations below delta < -30°. This new data combined with the Northern Sky Survey provides the first kinematic, all-sky survey of diffuse Halpha from the Milky Way. Aside from many large-scale, locally-ionized regions, much of this emission arises from the Warm Ionized Medium (WIM), a diffuse but thick component of the ISM that extends several kiloparsecs into the Galactic halo. WHAM was designed primarily to study the WIM, delivering a spatially integrated spectrum from a one-degree beam on the sky covering 200 km s-1 with 12 km s-1 spectral resolution. The short exposures of the survey reach sensitivity levels of about 0.1 R (EM 0.2 pc cm-6) and reveal emission toward nearly every direction in the sky. Here, we present our early efforts at reducing this new southern dataset and offer a first look at the global distribution and kinematics of diffuse ionized gas throughout the Galaxy. WHAM and the research presented here are funded by NSF award AST-0607512. We also thank the excellent and responsive staff at CTIO in Chile for helping to keep our remote installation fully operational.
    01/2011;
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    ABSTRACT: After a successful eleven-year campaign at Kitt Peak, we moved the Wisconsin H-Alpha Mapper (WHAM) to Cerro Tololo in early 2009. Here we present some of the early data after a few months under southern skies. These maps begin to complete the first all-sky, kinematic survey of the diffuse H-alpha emission from the Milky Way. Much of this emission arises from the Warm Ionized Medium (WIM), a significant component of the ISM that extends a few kiloparsecs above the Galactic disk. While this first look at the data focuses on the H-alpha survey, WHAM is also capable of observing many other optical emission lines, revealing fascinating trends in the temperature and ionization state of the WIM. Our ongoing studies of the physical conditions of diffuse ionized gas will continue from the southern hemisphere following the H-alpha survey. In addition, future observations will cover the full velocity range of the Magellanic Stream, Bridge, and Clouds to trace the ionized gas associated with these neighboring systems. Comment: 4 pages, 2 figures. To appear in "The Dynamic ISM: A celebration of the Canadian Galactic Plane Survey," ASP Conference Series
    08/2010;
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    ABSTRACT: The results of a project to develop a spatial heterodyne spectrometer (SHS) for a sounding rocket mission to study the Cygnus Loop, a prototypical middle-aged supernova remnant, are discussed. The goal was to obtain a radial velocity-resolved spectrum of the C IV λλ 1550 emission line from bright features of the Cygnus Loop, as a test for mapping the diffuse hot interstellar medium (ISM). A full Fourier-transform analysis of Cygnus Loop emission data is presented, showing lack of velocity-resolved C IV emission detection. Optics contamination is shown to be the most likely problem, and ways to eliminate this contamination for future SHS sounding rocket and satellite missions are discussed.
    Applied Optics 01/2010; 49(17). · 1.69 Impact Factor
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    ABSTRACT: The University of Wisconsin's Space Astronomy Laboratory has designed and built a Star Tracker suitable for use on sounding rockets and class D satellites. This device brings together autonomous attitude determination ("Lost in Space" mode), multi-star tracking, and a novel form of Progressive Image Transmission (US patent #5,991,816), which allows the device to be used as an ultra-low bandwidth imager. The Star Tracker 5000 (ST5000) reached operational status in a suborbital sounding rocket flight in August 2007. The ST5000 determined the rocket's inertial (FK5) attitude with arcsecond precision using its autonomous attitude determination capability, and then provided continuous sub-arc-second tracking for the full 360-second on-target portion of the flight. The ST5000 RMS tracking error was 0.54 arc-seconds in yaw and pitch, and 17 arc-seconds in roll. The vehicle RMS jitter was 0.5 arc-seconds in yaw and pitch, and 10 arc-seconds in roll. The ST5000 was funded by NASA grants NAG5-7026 and NAG5-8588.
    Proc SPIE 08/2008;
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    ABSTRACT: The University of Wisconsin's Space Astronomy Laboratory has designed and built a Star Tracker suitable for use on sounding rockets and class D satellites. This device brings together autonomous attitude determination ("Lost in Space" mode), multi-star tracking, and a novel form of Progressive Image Transmission, which allows the device to be used as an ultra-low bandwidth imager. The Star Tracker 5000 reached operational status in a suborbital sounding rocket flight in August 2007. The ST5000 determined the rocket's inertial (FK5) attitude using its autonomous attitude determination capability, and then provided continuous sub-arcsecond tracking for the full 360-second on-target portion of the flight. The ST5000 RMS tracking error was 0.54 arc-seconds in Yaw and Pitch, and 17 arc-seconds in Roll. The vehicle RMS jitter was 0.5 arc-seconds in Yaw and Pitch, and 10 arc-seconds in Roll. The ST5000 was funded by NASA grant NAG5-8588.
    12/2007;
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    ABSTRACT: Using a newly developed spatial heterodyne spectrometer, we have obtained the first radial velocity resolved observations of interstellar 3727 A emission and confirmed the superb performance of the technique for observing spatially extended faint sources.
    02/2007;
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    ABSTRACT: This paper describes the use of a newly developed Spatial Heterodyne Spectrometer (SHS) designed to observe radial velocity resolved profiles of diffuse [OII] 3726 Å and 3729 Å emission lines from the warm (104 K), low-density (10-1 cm-3), ionized component of our Galaxy's interstellar medium (WIM). The [OII] SHS combines interferometric and field-widening gains to achieve sensitivities much larger than conventional grating instruments of similar size and resolving power, and comparable to the Wisconsin Halpha Mapper (WHAM) Fabry-Perot, but in the near UV where WHAM cannot observe. The high spectral resolution and sensitivity of the SHS allowed us to spectrally isolate for the first time Galactic from terrestrial [OII] emission. We were able to identify the terrestrial [OII] foreground emission and other nearby airglow lines in directions toward very low intensity Galactic [OII] emission regions. The terrestrial [OII] lambda 3729/lambda 3726 line intensity ratio was measured to be 0.47 ± .05:1, compared to an emission ratio of 1.5:1 predicted (and observed) for the interstellar [OII] emission lines in the low density limit. Atmospheric foreground characterization, spectral calibration and absolute intensity calibration are discussed. This research was supported by the NSF through an Astronomy and Astrophysics REU site grant (AST-0453442) at UW-Madison.
    12/2005;
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    ABSTRACT: Using a newly developed Spatial Heterodyne Spectrometer (SHS), we have achieved the first detection of diffuse [OII] 372.6 nm and 372.9 nm emission lines from the warm (10,000 K), low density (0.1 cm-3) ionized component of our Galaxy's interstellar medium (WIM). These [OII] lines are a principal coolant for this wide spread, photoionized gas and are a potential tracer of variations in the gas temperature resulting from unidentified interstellar heating processes that appear to be acting within the Galaxy's disk and halo. We have also detected numerous, weak airglow lines, including terrestrial [OII] emission. In our SHS system, Fizeau fringes of wavenumber-dependent spatial frequency are produced by a Michelson interferometer modified by replacing the return mirrors with diffraction gratings. These fringes are recorded on a position sensitive detector and Fourier transformed to recover a spectrum over a limited range centered at the grating Littrow wavenumber. SHS combines interferometric and field-widening gains to achieve sensitivities much larger than conventional grating instruments of similar size and resolving power, and comparable to the Wisconsin Halpha Mapper (WHAM) Fabry-Perot, but in the near UV where WHAM cannot observe. Our early results confirm the superb performance of the SHS technique for measurements of spatially extended faint emissions, including the first detection of [OII] emission lines extending out to 20 degrees from the Galactic equator in the longitude range of 110 to 150 degrees. [OII] intensities range from tens of Rayleighs near the Galactic plane to less than one Rayleigh at high Galactic latitudes. The [OII] line profiles clearly show structure indicating emission along the lines of sight from both local interstellar gas and more distant gas in the Perseus spiral arm. Preliminary line ratio comparisons with WHAM [NII] (658.4 nm) and Halpha (656.3 nm) observations confirm the utility of the [OII] observations as a temperature diagnostic for the WIM. This work is supported by the National Science Foundation through grants AST-0138228 and AST-0138197. The Wisconsin Halpha Mapper is funded by the National Science Foundation through grant AST- 0204973.
    12/2004;
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    ABSTRACT: This paper describes the characteristics and performance of a novel spatial heterodyne spectrometer designed to measure the extremely faint [OII] 372.6 nm (lambda3726 Å) and 372.9 nm (lambda3729 Å) emission lines from the warm (10,000 K) ionized component of our Galaxy's interstellar medium. These [OII] lines are a principal coolant for this wide spread, photoionized gas and are a potential tracer of variations in the gas temperature resulting from unidentified interstellar heating processes that appear to be acting within the Galaxy. In the basic SHS system, Fizeau fringes of wavenumber-dependent spatial frequency are produced by a Michelson interferometer modified by replacing the return mirrors with diffraction gratings; these fringes are recorded on a position sensitive detector and Fourier transformed to recover the spectrum over a limited spectral range centered at the Littrow wavenumber of the gratings. The system combines interferometric and field-widening gains in tandem to achieve 10,000-fold sensitivity gains compared to conventional grating instruments of similar size and resolving power. SHS systems also have relaxed flatness tolerances (20-50 times compared to Fabry-Perots) and do not require precision imaging to achieve diffraction-limited spectroscopic performance. Defects can largely be removed in data processing. Early results from our [OII] SHS system confirm the superb performance of the SHS technique for measurements of spatially extended faint emissions, including the first detection of [OII] emission lines extending out to 20 degrees from the Galactic equator ([OII] intensities ranged from tens of rayleighs near the Galactic plane to less than one rayleigh at high latitudes; the [OII] line profiles show structure indicating emission along the lines of sight from both the local interstellar gas and more distant gas in the Perseus spiral arm).
    Proc SPIE 09/2004;
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    ABSTRACT: The Wisconsin H-Alpha Mapper (WHAM) has surveyed the distribution and kinematics of ionized gas in the Galaxy above declination -30 degrees. The WHAM Northern Sky Survey (WHAM-NSS) has an angular resolution of one degree and provides the first absolutely-calibrated, kinematically-resolved map of the H-Alpha emission from the Warm Ionized Medium (WIM) within ~ +/-100 km/s of the Local Standard of Rest. Leveraging WHAM's 12 km/s spectral resolution, we have modeled and removed atmospheric emission and zodiacal absorption features from each of the 37,565 spectra. The resulting H-Alpha profiles reveal ionized gas detected in nearly every direction on the sky with a sensitivity of 0.15 R (3 sigma). Complex distributions of ionized gas are revealed in the nearby spiral arms up to 1-2 kpc away from the Galactic plane. Toward the inner Galaxy, the WHAM-NSS provides information about the WIM out to the tangent point down to a few degrees from the plane. Ionized gas is also detected toward many intermediate velocity clouds at high latitudes. Several new H II regions are revealed around early B-stars and evolved stellar cores (sdB/O). This work presents the details of the instrument, the survey, and the data reduction techniques. The WHAM-NSS is also presented and analyzed for its gross properties. Finally, some general conclusions are presented about the nature of the WIM as revealed by the WHAM-NSS. Comment: 42 pages, 14 figures (Fig 6-9 & 14 are full color); accepted for publication in 2003, ApJ, 149; Original quality figures (as well as data for the survey) are available at http://www.astro.wisc.edu/wham/
    The Astrophysical Journal Supplement Series 09/2003; · 16.24 Impact Factor
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    ABSTRACT: The Wisconsin Halpha Mapper has been designed to produce a survey of Halpha emission from the interstellar medium (ISM) over the entire northern sky. The instrument combines a 0.6 meter telescope and a dual-etalon 15cm Fabry-Perot spectrometer. In the primary spectral mode, an exposure captures a 200km/s spectral region with 8-12km/s velocity resolution from a one-degree beam on the sky. With a large-aperture design and modern CCD technology, WHAM can detect Galactic emission as faint as 0.05 Rayleighs in a 30 second exposure. For gas at 10000K, this observed intensity corresponds to an emission measure of about 0.1cm-6pc, more than 10 million times fainter than the Orion Nebula. (1 data file).
    VizieR Online Data Catalog. 08/2003;
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    ABSTRACT: Spatial Heterodyne Spectroscopy stands poised to play a significant role in astrophysics and atmospheric remote sensing from space and ground-based platforms. This paper will briefly describe the technique and applications in process.
    02/2003;
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    ABSTRACT: Linear spectropolarimetry of spectral lines is a neglected field in astronomy, largely because of the lack of instrumentation. Techniques that have been applied, but rarely, include investigation of the dynamics of scattering envelopes through the polarization of electron- or dust-scattered nebular light. Untried techniques include promising new magnetic diagnostics like the Hanle Effect in the far-ultraviolet and magnetic realignment in the visible. The University of Wisconsin Space Astronomy Lab is developing instrumentation for such investigations. In the visible, the Prime Focus Imaging Spectrograph (PFIS) is a first light instrument for the Southern African Large Telescope (SALT), which at an aperture of 11m will be the largest single telescope in the Southern Hemisphere. Scheduled for commissioning in late 2004, PFIS is a versatile high-throughput imaging spectrograph using volume-phase holographic gratings for spectroscopic programs from 320nm to 900nm at resolutions of R=500 to R=6000. A dual-etalon Fabry-Perot subsystem enables imaging spectroscopy at R=500 and R=3000 or 12,500. The polarization subsystem, consisting of a very large calcite polarizing beam-splitter used in conjunction with half- and quarter-wave Pancharatnam superachromatic plates, allow linear or circular polarimetric measurements in any of the spectroscopic modes. In the FUV, the Far-Ultraviolet SpectroPolarimeter (FUSP) is a sounding rocket payload, scheduled for its first flight in 2003, that w ill obtain the first high-precision spectropolarimetry from 105 - 150 nm, and the first astronomical polarimetry of any kind below 130 nm. The 50 cm primary mirror of the telescope is F/2.5. At the prime focus are the polarimetric optics, a stressed lithium fluoride rotating waveplate, followed by a synthetic diamond Brewster-angle mirror. The spectrometer uses an aberration-corrected spherical holographic grating and a UV-sensitized CCD detector, for a spectral resolution of R=1800.
    Proc SPIE 02/2003;
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    01/2003; 291:395.
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    ABSTRACT: The Cosmic Ultraviolet Polarimetric Imaging Device (CUPID) is a suborbital sounding rocket payload designed to perform wide-field, polarimetric imaging of the extragalactic ultraviolet background. In doing so, it will also measure the contribution to the UV background from the diffuse Galactic light (DGL), starlight from the Milky Way scattered off of dust. Current uncertanties in the contribution of the DGL to the UV background are due almost entirely to a poor knowledge of the optical properties of the dust in the diffuse ISM at ultraviolet wavelengths. The polarization of the scattered light is sensitive to scattering angle and thus CUPID imaging may help to constrain the spatial distribution and scattering properties of Galactic dust.
    01/2003;
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    ABSTRACT: This paper will report on the implementation of the field-widened Spatial Heterodyne Spectrometer (Harlander, J., Reynolds, R.J., & Roesler, F.L., 1992. ApJ, 396, 730) in its first field test, a sounding rocket flight to detect CIV emissions lines (near 155.0 nm) from the Cygnus Loop at high spectral resolution (20 km/s). The ultimate motivation for the development of this SHS is an all-sky, radial velocity-resolved map of the hot component of the diffuse interstellar medium (ISM). The large-scale dynamics and filling fraction of the hot ISM are not well understood, in part because there are no kinematic sky surveys of hot gas emission lines analogous to those of the cooler components of the ISM via CO, 21 cm, and H-alpha emissions. Such a survey of the hot component requires a spectrometer with sufficient etendue and spectral resolution to accomplish the mapping in a reasonable time. That spectrometer also needs to be compact and sturdy, to make it useful for space-based applications. The suitability of SHS in these areas will be described. The Cygnus Loop was chosen as an initial subject, principally, to test the efficacy of SHS in the field. Because the detected rate of CIV emissions from the Cygnus Loop was lower than expected, the SHS was not successful in providing a spectrum for those lines. However, thorough post-flight efficiency tests of the payload optics convincingly located the loss factor, indicating the problem was avoidable contamination, and not a fundamental failing of the SHS. The paper will conclude with the ways SHS was shown to be viable by this mission, and how it can be improved for continued studies of the Cygnus Loop and the hot diffuse ISM. We gratefully acknowledge the support of NASA for this project.
    04/2001; 33:789.
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    ABSTRACT: The Wisconsin H-alpha Mapper (WHAM) is a recently completed facility for the detection and study of faint optical emission lines from diffuse ionized gas in the disk and halo of the Galaxy. WHAM consists of a 15 cm diameter Fabry-Perot spectrometer coupled to a 0.6 m `telescope', which provides a one degree diameter beam on the sky and produces a 12 km s^-1^ resolution spectrum within a 200 km s^-1^ spectral window. This facility is now located at Kitt Peak in Arizona and operated remotely from Madison, Wisconsin, 2400 km distant. Early results include a velocity resolved H-alpha map of a 70x100 sq. deg. region of the sky near the Galactic anticenter, the first detections of H-alpha emission from the M I and A high velocity clouds, and the first detections of [O I] lambda-6300 and other faint `diagnostic' lines from the warm ionized medium. Through the summer of 1998, WHAM will be devoted almost exclusively to a survey of the northern sky, which will provide maps of the distribution and kinematics of the diffuse HII through the optical H-alpha line in a manner that is analogous to earlier sky surveys of the HI made through the 21 cm line.
    Publications of the Astronomical Society of Australia 01/1998; 15:14-18. · 3.12 Impact Factor
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    ABSTRACT: The Wisconsin Hα Mapper (WHAM) has been surveying the northern sky in Hα from Kitt Peak, Arizona since January 1997. Using a high-throughput, 15-cm diameter double-etalon Fabry-Perot spectrometer and a sensitive CCD detector, the WHAM survey provides the first calibrated, velocity-resolved map of Hα emission in our Galaxy. The WHAM survey data have one-degree angular resolution, 12 km s(-1) velocity resolution, a 200 km s(-1) velocity range (typically centered near the Local Standard of Rest), and are sensitive down to 0.1 R (EM ~ 0.2 cm(-6) pc). Remote operation and semi-automated procedures allow extremely efficient observations, averaging over 100 spectra per hour. The WHAM survey finally allows detailed comparisons of the Warm Ionized Medium to the other major components of the interstellar medium that have been previously surveyed. With over 85% of the sky above delta = -20arcdeg completed after the first year, we present selected regions of this new view of ionized gas in the Galaxy. A fresh look at well-studied regions examines the Orion-Eridanus complex and the X-ray bright Monogem Ring supernova remnant. Complex networks of faint, ionized filaments dominate this region of the sky and include an impressive, faint (1--2 R), ~ 50arcdeg -long, 2arcdeg wide vertical filament extending upwards perpendicular to the Galactic plane near l = 225arcdeg . This work is supported by the National Science Foundation.
    11/1997; 29:1294.
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    ABSTRACT: The Wisconsin Halpha Mapper (WHAM) has been surveying the northern sky in Halpha from Kitt Peak, Arizona since January 1997. Using a high-throughput, 15-cm diameter double-etalon Fabry-Perot spectrometer and a sensitive CCD detector, the WHAM survey provides the first calibrated, velocity-resolved map of Halpha emission in our Galaxy. The WHAM survey data have one-degree angular resolution, 12 km s(-1) velocity resolution, a 200 km s(-1) velocity range (typically centered near the Local Standard of Rest), and are sensitive down to 0.1 R (EM ~ 0.2 cm(-6) pc). Remote operation and semi-automated procedures allow extremely efficient observations, averaging over 100 spectra per hour. The WHAM survey finally allows detailed comparisons of the Warm Ionized Medium to the other major components of the interstellar medium that have been previously surveyed. With over 85% of the sky above delta = -20arcdeg completed after the first year, we present selected regions of this new view of ionized gas in the Galaxy. A fresh look at well-studied regions examines the Orion-Eridanus complex and the X-ray bright Monogem Ring supernova remnant. Complex networks of faint, ionized filaments dominate this region of the sky and include an impressive, faint (1--2 R), ~ 50arcdeg -long, 2arcdeg wide vertical filament extending upwards perpendicular to the Galactic plane near l = 225arcdeg . This work is supported by the National Science Foundation.
    01/1997;