The Mauna Loa Solar Observatory (MLSO) is located on the of the NOAA Mauna Loa Observatory, on the island of Hawaii at an elevation of 3,440 meters. It is operated by the High Altitude Observatory, a division of the National Center for Atmospheric Research, which is located in Boulder, Colorado.
The MLSO telescopes are operated via several UNIX workstations in the on-site control center. Seated at the desk is Darryl Koon.
A suite of instruments designed to observe the solar atmosphere, including the Chromospheric Helium Imaging Photometer (CHIP, 1083.0nm), H-alpha prominence and solar disk monitor (PICS, 656.3nm), and the Mk4 K-coronameter, which observes the white light K-corona from 1.12-2.79 solar radii (700-950 nm).
The Mark-III instrument was the third generation white light K-coronameter instrument at MLSO, and it operated from 4 February 1980 through 30 September 1999.
The field of view of the Mark-III K-Coronameter (Mk3) was 1.122 to 2.44 solar radii (as measured from sun center). The sun's corona was scanned by a linear array detection system which is rotated in solar position angle about the center of the solar disk. It took about three minutes to acquire one coronal image.The Mark-III K-Coronameter data are scaled such that 104.4 pixels corresponds to one solar radius. Spatial sampling is 10 arcseconds radially by 0.5 degrees in azimuth. All data are rotated so that solar north is oriented straight up; solar north is known to within three degrees. Daily averaged images and mass ejection images from the K-Coronameter have instrumental `vignetting' left in the data to offset the coronal radial density gradient, allowing for better viewing of the corona. Calibrated images in units of polarization brightness (pB) are available and may be requested via the E-mail address listed above.
The Mark-IV K-coronameter, was constructed by HAO in collaboration with Rhodes College (Memphis, Tennessee). It has been in operation since October 1998 at MLSO.
The Mark-IV K-coronameter replaces its predecessor, the Mark-III and features a high speed liquid crystal polarization modulator, a low noise CCD line array detector, and an achromatic polarizing beam splitter. Polarization brightness maps of the lower corona, from about 1.14 to 2.86 solar radii are produced at a 3-minute cadence.The Mark-IV instrument is a significant improvement over its predecessor in the following ways: lower system noise due to an improved detector and associated electronics, better sky noise rejection due to improved polarization optics and faster polarization modulation rate, higher spatial resolution, and a wider field of view.
These improvements result in higher quality polarization-brightness images which may be taken over a greater range of sky conditions than was heretofore possible.
For additional information about the Mark-III K-Coronameter instrument,
see Fisher et al. (1981).
For information about the Mark-III K-Coronameter calibration technique,
see Elmore et al. (1996).
For information about the Mk4 K-Coronameter calibration technique,
see Elmore et al. (199?).
The first H-alpha [656.3 nm] telescope at MLSO was the Prominence Monitor (PMON), which went into operation on 4 February 1980. It acquired both disk and limb images on B/W 35mm film.
On 20 February 1994, the Acme 35mm film camera was upgraded to a Kodak Megaplus [Model 1.6] CCD detector (1534x1030 pixels) with a sample size of 3 arcseconds, and the telescope was renamed the Digital Prominence Monitor (DPM).
On 25 September 1997, the PICS instrument replaced the Digital Prominence Monitor at MLSO. It provides several improvements over the DPM instrument, including optics for polarization measurement (since removed), improved temperature control, a narrower bandpass filter for disk observations, and improved optics for limb observations.
The Chromospheric Helium-I Imaging Photometer (CHIP) was installed at the Observatory in April 1996. CHIP records images of the Sun in the 1083 nm line of neutral Helium and at a nearby continuum wavelength with a rapidly tuneable Lyot filter.
Seven line and continuum exposures are recorded within 2 seconds. The difference of line and one continuum exposures is computed every 3 minutes to produce one 1083 nm image.
The CCD pixel size is 2.3 arcseconds and the measured spatial resolution is ~8 arcseconds. For additional information on the tuneable filter see Kopp et al. (1996).
Observes the solar disk in three bandpasses: 605-610 nm (red), 408-412 nm (blue), and 393 nm (CaIIK).
The observatory begins daily operations (weather permitting) at approximately 17:00 U.T. and continues recording images for 3-10 hours depending on the weather. Fifty to one hundred white light coronal images are recorded on a typical observing day as well as approximately 100 full limb and 100 full disk H-alpha images and full disk Helium-I images.
Calibrated Mark-IV data are available approximately ten days after the raw data are recorded. Qualitative Mark-IV images are posted the day they are taken.
The difference of red and blue wing 1083 nm exposures are used to create qualitative velocity images.
Daily H-alpha disk and limb images, daily activity reports, and synoptic maps, are also available. Mass ejection images are provided as disk space allows.Access to this data is available via the Data & Movies tab at the top of this web page.
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