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Author name code: mcmath
ADS astronomy entries on 2022-09-14
author:"McMath, Robert R." 

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Title: Solar Instruments.
Authors: McMath, R. R.; Mohler, O. C.
1962HDP....54....1M    Altcode:
  Instruments for the measurement of the total solar radiation
  Radio telescopes The image-forming instruments of solar astronomy
  Construction and housing of solar telescopes Auxiliary instruments
  for solar telescopes Instruments for the observation of solar eclipses
  Some instrumental problems of solar observation Bibliography

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Title: Telescope Driving Mechanisms
Authors: McMath, R. R.; Mohler, O. C.
1961tele.book...62M    Altcode: 1961S&SS....1...62M
  No abstract at ADS

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Title: The Large Solar Telescope at Kitt Peak II
Authors: McMath, Robert R.; Pierce, A. Keith
1960S&T....20..132M    Altcode:
  No abstract at ADS

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Title: The Large Solar Telescope at Kitt Peak, II
Authors: Pierce, A. K.; McMath, R. R.
1960S&T....20..132P    Altcode:
  No abstract at ADS

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Title: The Large Solar Telescope at Kitt Peak I
Authors: McMath, Robert R.; Pierce, A. Keith
1960S&T....20...64M    Altcode:
  No abstract at ADS

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Title: The Large Solar Telescope at Kitt Peak, I
Authors: Pierce, A. K.; McMath, R. R.
1960S&T....20...64P    Altcode:
  No abstract at ADS

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Title: Solar Features Associated with Ellerman's "Solar Hydrogen
    Bombs"
Authors: McMath, Robert R.; Mohler, Orren C.; Dodson, Helen W.
1960PNAS...46..165M    Altcode:
  No abstract at ADS

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Title: Preliminary Results with a Vacuum Solar Spectrograph.
Authors: McMath, Robert R.; Mohler, Orren C.; Pierce, A. Keith;
   Goldberg, Leo
1956ApJ...124....1M    Altcode:
  New observations of the solar spectrum with a high-resolution vacuum
  spectrograph reveal a wealth of detail in the cores of all Fraunhofer
  lines observed both in the normal disk and in areas exhibiting
  various kinds of solar activity. The lines show fluctuations in width,
  intensity, and position over intervals as small as 2 seconds of arc. A
  representative collection of photographs is presented, together
  with tentative conclusions derived from inspection and preliminary
  measurement. Measurements of Doppler shifts have been carried out in
  considerable detail for the two lines Cr X 4626 and Ba+ X 5853. The
  random turbulent velocity at the center of the disk is 0 70 km/sec
  for the chromium line and O. km/sec for the ionized barium line. For
  both lines the random turbulent velocity appears to increase toward
  the limb. The velocity shifts observed for the Ha and sodium D lines
  are of the same order of magnitude as those of the weaker metallic
  lines. The disk observations of the Fraunhofer lines of hydrogen and
  ionized calcium seem to he consistent with a qualitative model of the
  low chromosphere, consisting of relatively hot clouds of gas and with
  cooler regions both above and between the hot regions. Both the K2
  emission in ionized calcium and the wide absorption features in Ha
  seem to originate in the hot regions; from the appearance of these
  line features near the limb it seems that the hot regions contribute
  a substantial fraction of the hydrogen and ionized calcium emission
  in the very low chromosphere. The profiles of Ha at the extreme limb
  and of the K line and other strong metallic lines on the disk favor
  the conclusion of Adams and Burwell that central self-reversal is a
  general characteristic of most strong chromospheric profiles. The
  similarity between the intensity and velocity fluctuations in the
  core of the strong magnesium line X 5167 and in those of neighboring
  weaker lines implies either a chromospheric origin for the centers of
  these weaker lines or the extension of the photospheric granules into
  the low chromosphere. The preliminary nature of the foregoing results
  is emphasized.

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Title: Photometry of Solar Flares.
Authors: Dodson, Helen W.; Hedeman, E. Ruth; McMath, Robert R.
1956ApJS....2..241D    Altcode:
  On the basis of photometric light-curves for 194 flares and subflares,
  the following data have been derived. 1.Ha intensity often varies
  differently in different parts of the same flare. 2.The change of Ha
  intensity with time in a flare can be well represented by the series
  of curves given by the equation iog =(iog Ii ax) t a(t-trnax), where
  t is measured in minutes and a is positive for the ascending branch,
  negative for the descending branch, and takes values between 0.40 and
  0.00313. For the descending branch of the light-curve, a is always
  smaller than for the ascending branch. The most usual value of a for
  the ascending branch is 0.10; for the descending branch a is -<0.025
  for 87 per cent of the cases. 3.Ha flare intensities have been measured
  in units of both the local and the centra] continuum at x 6590. In the
  former, average Ha intensity at flare maximum ranged from 0.66 for
  subflares and 0.88 for flares of importance 1 to intensity 1.17 and
  1.28 for flares of importance 2 and 3, respectively. In units of the
  central continuum the average values are about 0.1 lower. The brightest
  measured maximum was 1.9 times the local continuum for a flare at CMD 72
  . 4.No convincing relationship has been found between rate of increase
  of intensity and maximum intensity attained by the flare. However,
  the slowest rate of increase apparently diminishes the chances of
  attaining a maximum as bright as the contmuous spectrum. 5.There is
  evidence for center-to4imb variation in numerous characteristics of
  the Ha flares in this study. The slowest rates of rise and decline
  were observed only for flares ithin 55 of the central meridian, and
  the fastest rates of decline only for flares within 40 of the solar
  limb. Average intensity in units of the local continuum increased
  with increasing central meridian distance of the flares. In units of
  the central continuum, the average intensity diminished from center
  to limb. "Limb-darkening" equations for the flares and subflares are
  as follows: Flares: lc=O.63+O.34COS 0, Subilares: lc=O.36+O.26CC)S
  0. For flares of the same importance, average duration diminished with
  increasing distance from the center of the disk. Near the center of
  the disk, the Ha flare usua]ly lasted as long as, or longer than,
  the associated ionospheric disturbance, but for flares near the
  limb the reverse was true. 6.For the flares in this study, area and
  intensity increase together, but the correlation coefficient of these
  two measures is only 0.58 + 0.03 p.e. 7.Flare duration was associated
  more closely with flare area than with maximum intensity. The duration
  of flares as measured by photometric light-curves is much longer than
  the average duration of flares reported in the Quarterly Bulletin of
  Solar Activity. 8.The reported starting times of SID's usually fall
  during the period of increasing intensity in the flare. Except in
  unusual cases, SID's were not reported unless the flare intensity was
  at least 0.8 of the local continuum and the area was of the order of
  200 millionths of the solar disk. Near the limb the SID often lasts
  longer than the Ha flare. 9.There is apparently less diminution from
  center to limb in the ionizing radiation from flares than in Ha. 10. The
  ionospheric disturbances were unusually small for certain large and
  relatively bright flares associated with the onsets of 200-Mc/s noise
  storms. 11. Examination of ionospheric records for the times of the
  flares and subflares in this study has provided evidence for a new
  type of flare-associated ionospheric effect, a gradual ionospheric
  disturbance, in contradistinction to the sudden SID or Dellinger
  effect. The 45 reported SID's have been augmented by 19 additional,
  well-confirmed ionospheric disturbances and by 23 less certain
  events. 12. There is no evidence to indicate that subflares are not
  just smaller, fainter examples of the flare phenomenon. Flares and
  subflares in this study have similar disk distributions and rates of
  increase and decrease of intensity. Ionospheric disturbances accompanied
  at least four of the brightenings here classified as subflares.

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Title: Solar Spectroscopy with a Vacuum Spectrograph.
Authors: McMath, Robert R.
1956ApJ...123....1M    Altcode:
  No abstract at ADS

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Title: Doppler Shifts in Solar Granules.
Authors: McMath, Robert R.; Mohler, Orren C.; Pierce, A. Keith
1955ApJ...122..565M    Altcode:
  No abstract at ADS

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Title: The 50-foot focal length vacuum spectrograph for solar
    research.
Authors: McMath, R. R.; Mohler, O. C.; Pierce, A. K.
1954AJ.....59R.328M    Altcode:
  It is plain that an adequate study of the profiles of a large number
  of Fraunhofer lines demands a spectrograph of high resolving power
  and great linear dispersion. Through the kindness of Drs. I. S. Bowen
  and H. W. Babcock we have been able to use one of their fine gratings,
  6X8 inches, in our Pfund system.' With this arrangement we immediately
  found an asymmetry and variable features in the center of Ha.2 However,
  further work on faint solar lines and on the absorption spectrum of
  iodine indicated a resolving power lower than anticipated with this
  particular grating. Photoelectric traces made by placing the steep
  portion of an absorption line or the very steep intensity change at
  the zero order on the exit slit of the spectrometer indicated from the
  strong random fluctuations of the signal that spectrographic seeing
  was the undoubted cause of lowered resolution. For photographic work
  the criteria for the design of large stellar spectrographs, as given
  by I. S. Bowen,3 require that the resolving power of the photographic
  plate be matched to the linear resolving power of the grating at the
  focal plane. A photograph taken with a spectrograph approximating this
  condition will show considerable graininess if a narrow slit of width
  equal to the resolving power is used in the photometer. Where there is
  ample light the use of a longer focal length and a larger scale permits
  the use of wider microphotometer slits with a gain in smoothness of the
  recording with no loss in resolving power. In addition, with the larger
  scale spectrograph the slits are mechanically easier to construct and
  the effects of dust, defects and non- parallelism of the slit jaws are
  percentagewise less. The latter points are of considerable importance in
  problems which involve photometry of details of the solar surface that
  the slit intersects along its length. However, a longer focal length
  aggravates the seeing problem. Following the high resolution work on
  Ha and an experimental investigation of our spectrographic seeing,
  both at Lake Angelus and at the Snow telescope at Mount Wilson,
  Dr. McMath started in January 1954 the design and construction of
  a large vacuum spectrograph which would completely eliminate the
  spectrograph seeing problem, and which would give adequate scale and
  vacuum wave lengths. The design utilizes the 50-foot focal length
  off-axis mirror system of the existing McGregor Tower to form an image
  of the sun at the first slit of a predisperser before the grating
  spectrograph. The optical arrangement of the spectrograph follows
  the design described by M. Czerny and A. F. Turner,4 but the mirrors
  and grating are now placed in a vacuum tube 52 feet long and 4 feet
  internal diameter. Other tube specifications are: Rolled and welded
  plate, thickness ~` inch, reinforced with rings every four feet. The
  end plates are 14' inches thick and are heavily reinforced with 6-inch
  deep ribs of i-inch plate welded to the inside faces. Light from the
  entrance slit located behind a quartz field lens which also acts as a
  window to the vacuum tank is collimated by a i~-inch spherical mirror
  and returned to the grating located several feet inside the head of
  the tube. The dispersed beam is focused on the second slit by a second
  i~-inch spherical mirror and after passing through a quartz window is
  received by a photomultiplier. A third concave i~-inch mirror at the
  far end of the tube is arranged so that a short region of the spectrum
  can be returned to a photographic plate. All mirrors, and the grating
  table, are provided with complete motions in all degrees of freedom
  through the use of electrical motors. The final adjustments can be
  made by push buttons after the tank has been pumped down and assumed
  its slightly altered shape under the atmosphere pressure load of 700
  tons. The head of the spectrograph is to be provided with air locks
  at every point. The adjustment and repair of the slits,: or of the
  photocell, are thus facilitated without destroying the vacuum of the
  main tank. A special cassette and air lock will permit a quick plate
  change to be made. The tank, constructed by Whitehead and Kales of
  Detroit, proved to be vacuum-tight on erection. The first pump-down with
  a Kinney vacuum pump, Model VSD-88i I, of 45 cubic feet displacement per
  minute, required one hour to reach I cm pressure I mm after two hours. A
  pressure of 70 microns has been obtained and it is expected that still
  lower values will be achieved after the inside surfaces, painted with
  red lead, have occluded their more volatile constituents. Tests have
  shown that the rate of pressure rise on the tank is so small, 0.1 mm
  rise per 24 hours, that it will be possible to pump out the tank at
  night and then to shut off the pump during the operating day. This is
  a necessary requirement as the pump, though on an isolated pier with
  flexible connection to the tank, carries a perceptible vibration to the
  optics. This spectrograph will allow the use of one of Babcock's superb
  gratings in the fifth order, and should allow the grating to develop
  its full resolving power of about 600,000. The linear dispersion in
  the fifth order will be 6.92 mm per angstrom at 5000 A. This dispersion
  should make3]possible faint line profile work containing a relatively
  small instrumental contribution. The scattered light is to be evaluated
  by interferometric and other methods. Precision measurements of profiles
  of the stronger lines by photoelectric methods requires an exceptional
  sky. Our experience has been that sky transparency over long intervals
  of time is so rarely obtained that means of monitoring the background
  intensity is very desirable. For this purpose we are planning to use a
  modification of the system employed by Hiltner and Code.5 One photocell
  will monitor a 200 A interval as passed by the predisperser through
  the first slit, and the other will record the spectrum through the
  second slit. Reflecting slits of stellite will allow one to guide
  accurately on details seen through a Lyot filter which will present
  a field bisected by the slit. 5.R. R. McMath and 0. C. Mohler,
  J. Opt. Soc. Amer. 39, 903, `949. 2.Ap. J. in press. 3.Ap. J. is6,
  5, 5952. 4.Zs. Phys. 6i, 792, 5930. 5.J. Opt. Soc. Amer. 40, `49,
  5950. McMath-Hulbert Observatory, University of Michigan, Pontiac, Mich.

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Title: Table of Infrared Solar Lines, 1.4-2.5 μ.
Authors: Mohler, Orren C.; Pierce, A. Keith; McMath, Robert R.;
   Goldberg, Leo
1953ApJ...117...41M    Altcode:
  Accurate wave lengths and measurements of equivalent width are given
  for 888 solar lines in the spectral region 1. 2.5 . The number of
  solar lines has been more than doubled, as compared with previous
  preliminary studies in this spectral region. The wave lengths of
  the solar lines are referred to those of the Fraunhofer lines in the
  visible and very near infrared spectrum by the method of overlapping
  orders. The root-mean-square errors of the infrared standard wave
  lengths, as derived from repeated measurements of individual lines,
  are +0.13 A for the l.6 region and +0.17 A for the 2.3 region. The
  equivalent widths are preliminary. The estimated errors are between
  10 and 100 per cent, depending upon the degree of blending. About 470
  infrared solar lines have been tentatively identified with atoms of H,
  K, C, At, Na, Si, Mg, Ca, Ni, and Fe and with first overtone lines
  of CO. Comparisons between solar wave lengths and those measured in
  the laboratory or predicted from term values reveal somewhat closer
  agreement, on the average, between the solar and the predicted values
  than between the solar and the laboratory values.

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Title: Tower Telescopes and Accessories
Authors: McMath, R. R.
1953sun..book..605M    Altcode:
  No abstract at ADS

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Title: Solar Research at the McMath-Hulbert Observatory
Authors: McMath, Robert R.
1952PASP...64..151M    Altcode:
  No abstract at ADS

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Title: The Abundance of CO in the Sun and in the Earth's Atmosphere
Authors: Goldberg, Leo; McMath, Robert R.; Mohler, Orren C.; Pierce,
   A. Keith
1952PhRv...85..481G    Altcode:
  No abstract at ADS

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Title: Identification of CO in the Solar Atmosphere
Authors: Pierce, A. K.; Goldberg, L.; McMath, R. R.; Mohler, O. C.
1952PhRv...85..140P    Altcode:
  No abstract at ADS

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Title: The Limb Flare of may 8, 1951.
Authors: Dodson, Helen W.; McMath, Robert R.
1952ApJ...115...78D    Altcode:
  Published data indicate that flares have been observed at the limb
  of the sun with elevations above the chromosphere of 8000-80,000
  km. Continuous records of the solar limb and disk secured on Ha
  spectroheliograms at the McMath-Hulbert Observatory show the outbreak
  and development of a number of these flarelike prominences. They
  range in form from relatively small cap-type prominences to the
  great flare prominence of May 8, 1951. This latter object rose to a
  height of 50,000 km in less than 90 seconds. During this interval the
  Ha lines of the spectrum were 8-10 A wide and showed large Doppler
  displacements. Throughout the remainder of the flare the change in
  height was negligible, and the Ha spectrum lines were 5-6 A wide and
  symmetrical. This flare prominence was four times as bright as the
  undisturbed Ha disk, was accompanied by an increase in 200-Mc/sec
  radiation from the sun, and was associated with a sudden disturbance
  of the earth's ionosphere.

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Title: The Abundance of CO in the Sun and in the Earth's Atmosphere
Authors: Pierce, A. K.; Goldberg, L.; McMath, R. R.; Mohler, O. C.
1952PhRv...85..418P    Altcode:
  No abstract at ADS

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Title: Photometric studies of solar flares.
Authors: Dodson, Helen W.; McMath, Robert R.; Hedeman, E. Ruth
1951AJ.....56...37D    Altcode:
  The development, at the McMath-Hulbert Observatory during 1950, of
  a new and improved densitometer for the measurement of intensities
  of features photographed on 35 mm motion picture film has permitted
  an extension of the study of the "light curves" of solar flares. The
  intensity of the flare is expressed in terms of the intensity of the
  adjacent undisturbed disk as recorded on Ha spectroheliograms taken
  with slits 0.4A wide. The study to date has included twenty-one flares
  photographed in 1949, eight of importance I, nine of importance 2,
  and four of importance 3. The intensities at maximum range from 1.6 to
  5 times the intensity of the undisturbed Hot background. All flares
  in this study for which the intensity of the flare was greater than
  3 times that of the background were accompanied by sudden ionospheric
  disturbances regardless of the location of the flare on the solar disk
  or the area of the disturbance. Sudden ionospheric disturbances were
  not restricted to association with only the largest and most intense
  flares. On August 22, 1949 a flare of importance I, ~~O from the center
  of the sun, was accompanied by a sudden ionospheric disturbance even
  though it covered only 51 millionths of the solar hemisphere and reached
  an intensity of only 2.4 at maximum. This flare occurred directly over
  two spots. Two flares that took place on November I, 1949 in the same
  plage area, about 400 from the center of the sun, present an interesting
  anomaly. The first flare began at 1637 U.T., reached intensity 2.4 at
  maximum and extended over 130 millionths of the solar hemisphere. It
  was accompanied by a sudden ionospheric disturbance. The second flare
  broke out in the same plage area at 1954 U.T. This flare was more
  intense (2.75), larger (376 millionths) and lasted for a longer time
  (66 minutes) but there is no report of a sudden ionospheric disturbance
  for the period of its occurrence. Although both flares took place in
  the same plage area and between the same two large spots, the detailed
  regions involved in the two flares did not coincide or overlap in any
  way. The light curves of the flares make possible not only a study
  of the role of the maximum intensity in flare effects, but they also
  permit an investigation of the time relationships between the first
  indications of flare activity on the sun, the attainment of maximum
  intensity, the onset of the sudden ionospheric disturbance, and the
  relative durations of the solar and ionospheric phenomena. Although the
  work to date includes only a portion of the flares recorded in 1949, it
  is hoped that the photometric measures can be extended to include much
  of the large body of observational material secured during the recent
  solar maximum. MeMath-Hulbert Observatory, Lake A ngelus. Pontiac. Mich

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Title: Solar spectroscopy with echelles.
Authors: Pierce, A. Keith; McMath, Robert R.; Mohler, Orren
1951AJ.....56R.137P    Altcode:
  The echelle grating has the advantage of compressing a large spectral
  range into a small angle about the blaze direction. A 150 X 75
  mm echelle has been installed at the McMath-Hulbert Observatory
  in an optical system using 14-foot focal length concave mirrors
  for collimator and camera. The observed resolving power at N5000 is
  about 250,000 with plate dispersion 2.9 mm/A. The instrumental profile
  shows a narrow central peak with a strong satellite line at about .o5A
  from the central peak. Photographs of the solar spectrum, prominence
  spectra, and of a Zeeman triplet in a sunspot magnetic field have been
  made. McMath-Hulbert Observatory, University of Michigan, Pontiac, Mich.

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Title: Reports: McMath-Hulbert Observatory. Lake Angelus, Pontiac,
    Michigan
Authors: McMath, Robert R.
1950AJ.....55..195M    Altcode:
  No abstract at ADS

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Title: Observations of Solar Limb Darkening Between 0.5 and
    10.2&mu
Authors: Pierce, A. K.; McMath, R. R.; Goldberg, Leo; Mohler, O. C.
1950ApJ...112..289P    Altcode:
  Measurements of solar limb darkening are tabulated for thirteen
  wave lengths between 0.5 and 10.2 . Observations in the wave-length
  region 0.5-2.2 were carried out with the McGregor Tower telescope and
  spectrometer for the interval cos 0 = 1.0 to cos 0 = 0.16. Measurements
  at three longer wave lengths were made with a Perkin-Elmer spectrometer
  attached to the 24inch reflector and covered the interval cos 0 = 1.0
  to cos 0 = 0.2. At certain wave lengths the near infrared measurements
  agree with those of Abbot's to within 0.1 per cent; at other wave
  lengths the systematic differences are as large as 1 per cent. It is
  found that the degree of limb darkening decreases in the infrared
  from 3.5 to 10.2 . This result is qualitatively consistent with a
  systematic increase of the solar continuous opacity toward longer wave
  lengths in the infrared, as predicted by theoretical calculations of
  the absorption coefficient of the negative hydrogen ion.

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Title: New Solar Lines in the Spectral Region 1.97-2.49 μ.
Authors: Goldberg, Leo; Mohler, Orren C.; Pierce, A. Keith; McMath,
   Robert R.
1950ApJ...111..565G    Altcode:
  Measurements of wave length and of percentage central absorption are
  given for 109 solar lines in the region 1.97-2.49 of the infrared
  solar spectrum. The lines were found on tracings obtained with
  the high-dispersion spectrometers and Cashman PbS cells of the
  McMath-Hulbert Observatory at Lake Angelus and at the Mount Wilson
  Observatory. Forty-seven lines have been identified as arising from
  neutral atoms of H, Na, Si, Mg, Al, Ca, and Fe. The relative scarcity
  of solar lines in the 2.2 IL region is discussed, and a qualitative
  explanation is given in terms of the variation with wave length of
  the continuous absorption coefficient of H- combined with the solar
  temperature gradient.

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Title: The 3n3 Band of Telluric CO<SUB>2</SUB> in the Solar Spectrum
Authors: Pierce, A. K.; Goldberg, L.; Mohler, O. C.; McMath, R. R.
1950PhRv...78...74P    Altcode:
  No abstract at ADS

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Title: N<SUB>2</SUB>O Bands in the Solar Spectrum
Authors: Pierce, A. K.; McMath, R. R.; Mohler, O. C.; Goldberg, L.;
   Donovan, R. A.
1950PhRv...78...65P    Altcode:
  No abstract at ADS

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Title: Telluric Bands of CH_{4} in the Solar Spectrum.
Authors: McMath, Robert R.; Mohler, Orren C.; Goldberg, Leo
1949ApJ...109...17M    Altcode:
  An all-reflecting telescope and spectrometer have been employed in
  conjunction with a Cashman PbS cell to secure a direct-intensity map
  of the solar spectrum in the region of 0.8-2.5 ~i with a resolution
  of about 50,000. Four molecular-band systems at 1.66, 2.20, 2.32,
  and 2.37 ~ have been identified as the P1 + V4~ V3 + P4 and ~2 + P3
  transitions of CH4 in the earth's atmosphere. A preliminary analysis
  of the wave numbers of the 2P3 rotational components indicates
  second-order deviations from theory. The average half-spacing B0 is
  found to be 5.163, as compared with the value B0 = 5.252 obtained by
  Childs. A comparison of the 2P3 telluric line intensities with those
  produced by a measured quantity of methane at room temperature leads
  to a calculated methane abundance in the earth's atmosphere of 1.2
  parts in a million by mass, and a temperature of -37° C

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Title: New Solar Lines in the Spectral Region 1.52-1.75 μ.
Authors: Goldberg, Leo; Mohler, Orren C.; McMath, Robert R.
1949ApJ...109...28G    Altcode:
  Accurate wave lengths and measurements of percentage central absorption
  are given for nearly three hundred new solar lines discovered in the
  region 1.52-1.75 ~ of the infrared solar spectrum. The lines were found
  on high-resolution, direct-intensity tracings of the spectrum obtained
  at the McMath- Hulbert Observatory with the McGregor spectrometer
  and a Cashman cell. Ninety-three of the lines have been identified as
  belonging to neutral atoms of C, Mg, Al, Si, Fe, Mn, and Ni, mainly
  on the basis of wave lengths computed from term values. In addition,
  the third, seventh, and eighth members of the Brackett series of
  hydrogen have been identified, together with the Na I 4s-4p doublet
  at XX 22,054 and 22,081. INTRODUCTIO

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Title: Note on Methane in the Infra-Red Solar Spectrum
Authors: Pierce, A. K.; McMath, R. R.; Mohler, O. C.; Goldberg, L.
1949PhRv...76.1533P    Altcode:
  No abstract at ADS

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Title: Carbon Dioxide in the Infra-Red Solar Spectrum
Authors: Pierce, A. K.; Goldberg, L.; Mohler, O. C.; McMath, R. R.
1949PhRv...76.1848P    Altcode:
  No abstract at ADS

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Title: Solar Filament of September 7, 1948
Authors: Dodson, Helen W.; McMath, Robert R.
1948PASP...60..366D    Altcode:
  No abstract at ADS

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Title: Simultaneous observations of solar flares, surges, and
    high-speed dark flocculi
Authors: McMath, R. R.; Mohler, O.
1948Obs....68..110M    Altcode:
  No abstract at ADS

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Title: A Solar Infrared Reflecting Spectrometer
Authors: McMath, Robert R.; Mohler, Orren C.
1948S&T.....7..143M    Altcode:
  No abstract at ADS

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Title: New Bands in the Telluric Spectrum
Authors: McMath, Robert R.; Mohler, Orren
1948PASP...60..119M    Altcode:
  No abstract at ADS

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Title: Recent developments in infra-red solar spectroscopy.
Authors: McMath, R. R.; Mohler, O. C.; Goldberg, L.
1948AJ.....54Q..44M    Altcode:
  Since the late fall of 1947, the ~cGregor tower of the McMath-Hulbert
  Observatory has been used for study of the infra-red solar spectrum
  beyond the photographic limit. A specially designed, all-mirror optical
  system and Pfund-type grating spectrometer, with monochromator,
  have been used in conjunction with a Cashman leadsulphide cell to
  obtain direct-intensity tracings of the solar spectrum over the
  entire region between 8ooo and 25000 A. The spectrum is re corded on
  a scale of about five millimeters per angstrom. In the 15000 X region,
  lines with separation of 0.3 angstroms are just resolved. Water vapor
  absorption almost completely obliterates the spectrum in the regions I
  .3-1.5 microns and 1.75-1.95 microns. The intervening portions of the
  spectrum, however, are relatively clear and contain a wealth of solar
  atomic lines, as well as telluric molecular lines and bands. Progress in
  identification has been slow, largely because of the complete absence
  of high-resolution laboratory studies in this region of the infra-red
  spectrum. Approximately 200 solar atomic lines have been identified
  in the infra-red spectrum on the basis of wave lengths computed from
  known atomic energy levels. The elements for which lines have been
  found include Fe, Si, Na, AIg, Al, C, Ca, as well as the third and
  seventh members of the Brackett series of hydrogen. The vast majority
  of these lines have excitation potentials higher than five volts. Band
  systems of molecules originating in the earth's atmosphere constitute
  some of the most interesting features of the infra-red spectrum. Among
  these are four CO1 bands in the 1.6 micron region, which have been
  resolved for the first time, and three strong bands of CO1 at 2.1
  microns. Among the identified molecular bands, those of ammonia and
  methane are particularly noteworthy. The evidence for ammonia as
  a constituent of the earth's atmosphere is very strong, while the
  evidence for methane is conclusive. Mc Math- Hulbert Observatory,
  Pontiac, Mich. and University of Michigan Observatory, Ann Arbor, Mich.

---------------------------------------------------------
Title: The use of a high dispersion spectrograph in the wave-length
    region 1.0 to 2.0 microns.
Authors: McMath, Robert R.; Mohler, Orren
1948AJ.....53R.114M    Altcode:
  The recent development of photoconductive cells, sensitive in the near
  infra-red, has made possible the observation of the solar spectrum with
  a dispersion not previously possible. The McGregor tower telescope of
  the McMathHulbert Observatory and the McGregor Littrowtype spectrograph
  have been provided with a lead-sulfide, photoconductive cell, and means
  for recording the cell output. With this equipment we have produced a
  complete map of the infra-red solar spectrum on a scale of 1.6 mm/A,
  ending at 2o,6ooA. The wave-length limit of the map is set by the
  strong absorption of the telescope objective and the spectrograph
  collimator-camera lens. The measured resolving power on tracings
  obtained with this equipment is 32,000 at i6,oooA. Observations at
  large and small zenith distances from the sun have been made to aid
  in separating solar lines from the general background of terrestrial
  lines in this region of the solar spectrum. Many atomic lines have been
  identified on the first tracings obtained. Mc Math-Hulbert Observatory,
  University of Michigan, Lake Angelus, Pontiac, Mich.

---------------------------------------------------------
Title: A reflecting spectrometer for the solar infra-red.
Authors: McMath, Robert R.; Mohler, Orren C.
1948AJ.....53R.200M    Altcode:
  In order fully to utilize the possibilities of the new photoconductive
  infra-red detectors, such as the lead-sulfide cells now constructed
  by R. J. Cash man at the Northwestern Technological Institute, a
  reflecting optical system must be employed. Experiments during the
  past year (1947) at the McMath-Hulbert Observatory have revealed so
  many new and important features of the solar infra-red spectrum under
  high dispersion, that we have designed and constructed a reflecting
  spectrometer for use wi th the McGregor tower telescope. One of the
  original telescopes of the McMath-Hulbert Observatory, a ~o-21-inch
  Cassegrainian telescope of equivalent focal length 45 feet, and a
  calcium fluoride prism monochromator constitute the image-forming and
  predispersing system that precede the main spectrograph. Since our
  interest is primarily in highly dispersed solar spectra, we have used
  an aluminized speculum metal diffraction grating as the dispersing
  element. The grating we are now using has been very kindly loaned to
  us by the Mount Wilson Observatory. It is ruled with 600 lines per
  millimeter and is very bright in the first order infra-red at about
  20,OOOA wave length. The chief problem encountered in the design of
  any spectrometer is the provision of an absolutely smooth rotation
  of the grating about an axis parallel to its rulings. This problem
  is comparable to that of producing an errorless drive for a large
  telescope, and the long experience of Dr. McMath in the construction
  of telescope drives led to the following solution. The grating table
  is mounted on a specially selected precision grinder spindle, which
  acts as the axis of rotation for the grating. The grating table is
  rotated by steel belts attached under tension to a lapped nut that is
  driven by a precision ground lead screw. Both the lead screw and the
  spindle were obtained through the courtesy of the Ex-Cell-O Corporation
  of Detroit, Michigan. They have proved to be entirely satisfactory
  under all tests that we have applied. Especial care was necessary to
  eliminate vibration set up by the grating drive motor, and to prevent
  transmission of minute stresses to the grating table as it rotated. The
  drive motor is mounted on a lead pad on the concrete floor of the
  McGregor spectrograph, while the grating table is carried on the
  isolated pier that supports the grating and collimating lens of the
  McGregor Littrow spectrograph. As further precautions, the drive motor
  is connected to the first reduction gears by a soft rubber belt, and
  the drive shafts connecting the several reducing units are constrained
  to transmit only rotation, while remaining free to move over short
  distances in a longitudinal direction. No errors are detectable in
  the drive when the spectrum is examined visually with a twenty power
  microscope. As already mentioned, the grating drive is carried on the
  collimator pier of the McGregor Littrow spectrograph. Also on this
  pier are the 6-inch aperture, ~77-inch focal length, collimating and
  image-forming mirrors. The mirrors and grating drive are attached to
  the pier in such a way that only a few minutes are required to place
  either the reflecting spectrometer or the refracting McGregor Littrow
  system into use. The same entrance slit serves for both instruments. We
  have adopted the Pfund optical system because it keeps aberrations at a
  minimum, and visual examination of the higher order spectra shows that
  the definition of the spectrum lines is very good indeed. The spectrum
  is finally focused on a second, exit, slit which selects the narrow
  region of the spectrum that falls on the lead- sulfide cell to produce
  the photoelectric signal. As the grating is rotated by the drive motor,
  the spectrum sweeps slowly across the second slit, and in this way,
  scanning of any wave length region can be effected. Variations in
  intensity occurring in the spectrum are recorded, after appropriate
  amplification of the photoconductive signal, on a Leeds and Northrup
  Speedomax Recorder. Two scanning speeds are provided, 0.10 and 0.05
  mm/sec. At IO,500A, these linear speeds correspond to o.2~A/sec
  and 0.1 2A/sec, since the linear dispersion at this wave length is
  2.~~A/mm; but in the region of 22,OOOA the dispersion has increased to
  I .87A/n~m with correspondingly slower rate of scan in wave length. The
  recording paper is driven at 0.644 mm/sec, or 6.44 times the fastest
  (o. 10 mm/sec) scanning speed, hence the resulting dispersions on the
  recording paper are 2.65 mm/A at 10,500A and ~3.43 mm/A at 22,OOOA. The
  measured resolving power on the recording paper is 22,000 at IO,500A and
  44,000 at 22 ,000A. This resolving power is determined entirely by the
  slit width, which is 0.20 mm for both entrance and exit slits. There
  are almost no laboratory standards for aiding the identification of
  atomic lines with wave length longer than 20,OOOA but we have observed
  the third member of the Brackett series of hydrogen at 21 ,655.7A,
  and the two sodium lines 4S 15 - 4p 2P~~, 22,052.7A (predicted); and
  45 25 - 4p 2P~, 22,079.4A (predicted). This pair of lines has been
  observed in emission in the laboratory. Measurements of wave lengths
  and identifications of solar atomic lines are being made, and we hope
  to complete a list of solar lines extending to 25,OOOA. McMath-Hulbert
  Observatory, Lake Angelus, Pontiac, Mich.

---------------------------------------------------------
Title: High-Dispersion Solar Spectrum in the 10,000 A to 20,000
    A Region
Authors: McMath, Robert R.; Mohler, Orren C.
1947PASP...59..267M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Evidence for coronal absorption on the solar disk.
Authors: McMath, Robert R.; Goldberg, Leo; Mohler, Orren C.
1947AJ.....52R.156M    Altcode:
  A broad, diffuse absorption line at 637A.45 I.A. + 0.01 has been found
  in the spectrum of the solar disk on plates obtained with the McGregor
  sbectrograph and the 70-ft. tower telescope of the McMath-Hulbert
  Observatory. Its width has been estimated at 0.3 to 0.4 A. The line
  is seen very faintly at the center of the disk, becoming strongly
  accentuated at the limb. It appears equally intense all around the
  limb and no significant variations in intensity or in wave length
  have been found. The appearance of the line and the closeness of its
  position to that of the red coronal line (given by Lyot as X6374.5I +
  0.03) suggest the possibility that the absorption line arises from
  atoms of Fe x. The evidence for or against the identification as Fe
  x is discussed, the results at present being inconclusive. If the
  line is due to Fe x, its intensity and distribution around the limb
  are such that a considerable abundance of Fe x must be present in the
  chromosphere. In this connection attention is called to the observation
  by H. D. and H. W. Babcock' of a similar diffuse absorption line
  at X6374.40 in the flash spectrum outside of eclipse. The Babcocks
  reported that the line was flanked by emission components on either
  side. A predicted line of Fe I (ziC2o - e702) occurs at X6374.43. No
  other members of this multiplet have been observed with certainty in
  the solar spectrum, however, and the width of the observed absorption
  line makes its identification as predicted Fe I unlikely, unless it
  is closely blended with another faint line. A search has been made
  for a similar absorption line at the position of the green coronal
  line 5302.86, identified by Edlen as arising from Fe xiv. No such
  absorption line has been found. It is pointed out that excitation
  conditions in the chromosphere favorable for the presence of Fe
  x would not necessarily produce Fe xiv. I.Pub. A. S. P. 46, 132,
  1934. McMath-Hulbert Observatory, Lake Angelus, Pontiac, Mich.

---------------------------------------------------------
Title: A description of the Francis C. McMath Memorial 24-inch
    reflecting telescope
Authors: McMath, Robert R.
1946PAAS...10..138M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A report on the solar prominence radial velocity program of
    the McMath-Hulbert Observatory
Authors: McMath, R. R.; Sawyer, H. E.; Brodie, John; Mohler, Orren
1946PAAS...10...59M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Heber Doust Curtis, 1872-1942.
Authors: McMath, Robert R.
1944ApJ....99..245M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Francis C. McMath memorial 24-inch reflecting telescope
    of the McMath-Hulbert Observatory
Authors: McMath, Robert Raynolds
1943POMic...8...95M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Julius F. Stone spectroheliograph for the determination
    of solar atmospheric radial velocities
Authors: McMath, Robert Raynolds
1943POMic...8..141M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The measurement of space motions of solar prominences
Authors: McMath, Robert Raynolds; Sawyer, Harold E.; Mohler, Orren C.
1943POMic...8..123M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A method of measuring radial velocities in solar prominences
Authors: McMath, Robert Raynolds; Sawyer, Harold E.; Mohler, Orren C.;
   Brodie, John
1943POMic...8...57M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Heber Doust Curtis, 1872-1942
Authors: McMath, Robert R.
1942PASP...54...69M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The McGregor Building and Tower Telescope of the McMath-Hulbert
    Observatory
Authors: McMath, Robert R.
1940Natur.146..287M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Doppler Effect in an Eruptive Prominence
Authors: McMath, Robert R.; Pettit, Edison
1939PASP...51..154M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Location of Velocity Changes in a Class IIIb Prominence
Authors: McMath, Robert R.; Sawyer, Harold E.
1939PASP...51..165M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Motion pictures of small chromospheric flocculi
Authors: McMath, R. R.
1939MNRAS..99..559M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The tower telescope of the McMath-Hulbert Observatory
Authors: McMath, Robert Raynolds
1939POMic...7....1M    Altcode: 1939POMic...7.....M
  No abstract at ADS

---------------------------------------------------------
Title: A review of Lake Angelus prominence observations
Authors: McMath, Robert Raynolds; Sawyer, Harold E.
1939POMic...7..191M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The development of eruptive prominences
Authors: McMath, Robert R.; Pettit, Edison
1939PAAS....9..159M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Prominence Studies.
Authors: McMath, Robert R.; Pettit, Edison
1938ApJ....88..244M    Altcode:
  Eruptive prominences.-Data for seven new eruptive prominences conftrm
  the laws of motion previously stated. The end velocity is now shown
  to revert occasionally to a whole multiple of the second preceding
  velocity, which explains some apparent excep- tions to the second
  law. One prominence reached the unparalleled height of 1,550,000 km
  and another the record velocity of 728 km/sec. The former was near the
  north pole of the sun. The dilemma of light-pressure-A calculation of
  the Milne effect shows that we can- not assume that light-pressure
  balances gravity at the sun's surface. Velocities of more than
  100 km/sec are developed in a few minutes from an initial 10 km/sec
  velocity. Calcium tends to separate widely from hydrogen. Prominences
  of class 111.-The motions in the fountain-like loops of class IIIb
  prominences are down both branches from the ends of the bright tops
  of the arches. Practically all obey the first law, and about 20 per
  cent the second law of prominence motion; 7 cases show no change in
  velocity. Ejections-Small faint lumps of chromospheric matter are
  sometimes ejected from a spot area, often at considerable angles
  to the vertical. These ejections seem to move in nearly straight
  trajectories and do not return. Centers of attraction-Examination of
  the dissolution of an active prominence pro- jected on the disk shows
  that centers of attraction are not visible as surface markings. With
  one exception, prominence streamers have always been seen to enter
  centers of attraction from one side only. Fifty per cent of all the
  streamers from class I promi- nences measured followed both laws of
  prominence motion. Coronal prominences -When a center of attraction
  becomes very active, long stream- ers not connected with the active
  prominence enter the center of attraction from great heights. These
  seem to come from space in the middle or outer corona. They obey both
  laws of motion of eruptive prominences

---------------------------------------------------------
Title: A Quasi-Eruptive Prominence Observed in Hydrogen
Authors: McMath, R. R.; Pettit, Edison
1938PASP...50..240M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Motions in the Loops of Prominences of the Sunspot Type,
    Class III b
Authors: McMath, R. R.; Pettit, E.
1938PASP...50...56M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 597. Prominence studies.
Authors: McMath, Robert R.; Petitt, Edison.
1938CMWCI.597....1M    Altcode: 1938QB4.M93n597....
  No abstract at ADS

---------------------------------------------------------
Title: An Eruptive Prominence of Record Height and Velocity
Authors: McMath, R. R.; Pettit, E.; Sawyer, H. E.; Brodie, J. T.
1937PASP...49..305M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Some New Prominence Phenomena
Authors: McMath, R. R.; Pettit, E.
1937PASP...49..240M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Prominences of the Active and Sun-Spot Types Compared
Authors: McMath, Robert R.; Pettit, Edison
1937ApJ....85..279M    Altcode:
  Tue tower ielescope.-The 50-foot tower telescope at Lake Angelus,
  Pontiac, Michi- gan, records solar phenomena by means of the
  motion-picture camera. All instru- mental motions are electrically
  driven; the coelostat flat and camera are operated by the McMath-Hulbert
  controlled frequency drive and declination control. The scout camera
  and spectral-line control .-B oth H and K are used, K for the motion-
  picture camera; the H line, thrown to one side, enters a plate camera
  so that a promi- nence under observation can be photographed and
  developed for inspection at any time. To set the H and K lines on
  the slits of the spectroheliograph and to check their posi- tions
  an auxiliary fixed slit fed by a mercury arc is used. Observing and
  measuring-For the bulk of the work a focal length of 40 feet was used
  for the solar image. Exposure is determined by a photronic photometer
  and is usually of the order of 20-25 seconds on prominences with 2~
  seconds between expo- sures. The films are measured by projecting the
  frames upon a milk-glass screen; the position of a knot or streamer
  along its trajectory is determined with a flexible celluloid scale or,
  in some cases where the motion is small, by a cathetometer. Activity
  within a sun-spot group.-The ejection of bright flocculi has been
  observed. The velocity is about 100 km/sec, and the phenomenon
  occurs at intervals of about an hour. Prominences of the sun-spot
  type-Detailed measurements of the motions of knots and loop ends along
  their trajectories show that class III prominences obey the first law
  of motion of eruptive prominences and, when the projection factor is
  small, the sec- ond law as well. Many streamers have their origin high
  above the chromosphere, and the appearance cannot be accounted for
  by Doppler effect. The simplest explanation requires the presence of
  a chromospheric atmosphere in the corona. Surges-These rise from and
  sink back into the chromosphere in the vicinity of sun-spots, forming
  class hId. They are mostly small, but one was observed which reached
  a height of 8o,ooo km with a velocity of 240 km/sec. The ftrst law
  of motion seems to prevail in this type also. Quasi-eruptions-A case
  where an active prominence rose to a great height, nearly reaching the
  eruptive stage, before being drawn back to the center of attraction
  is cited. This forms a connecting link between active and eruptive
  prominences and sub- stantiates the idea that eruptions are extreme
  cases of the active or class Ilic stages. Active prominences.-Detailed
  measurements on these prominences show that the streamers and knots
  move along their trajectories, obeying both laws of motion of eruptive
  prominences

---------------------------------------------------------
Title: A short-lived solar disturbance
Authors: Petrie, Robert Methven; McMath, Robert Raynolds
1937POMic...6...43P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: No. 568. Prominences of the active and sun-spot types compared.
Authors: McMath, Robert R.; Petitt, Edison.
1937CMWCI.568....1M    Altcode: 1937QB4.M93n568....
  No abstract at ADS

---------------------------------------------------------
Title: A short-lived solar disturbance -- Motion picture film
Authors: Petrie, R. M.; McMath, R. R.
1936PAAS....8Q..49P    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The new solar tower of the McMath-Hulbert Observatory
Authors: McMath, R. R.
1936PAAS....8R.215M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: New method of driving equatorial telescopes
Authors: McMath, R. R.; Greig, W. A.
1936PAAS....8Q..16M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The spectroheliokinematograph
Authors: McMath, Robert Raynolds; Petrie, Robert Methven
1934POMic...5..103M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A new method of driving equatorial telescopes
Authors: McMath, Robert Raynolds; Greig, Walter A.
1934POMic...5..123M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Some new methods in astronomical photography, with application
    to moving pictures of celestial objects
Authors: McMath, Francis C.; McMath, Robert Raynolds; Hulbert,
   Henry Schoolcraft
1932POMic...4...53M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The McMath-Hulbert telechron driving-clock
Authors: McMath, Robert R.
1930PA.....38..460M    Altcode:
  No abstract at ADS