Speckle interferometry circumvents atmospheric seeing limitations, facilitating astrometric observations of visual binaries with small separations. Some of these closely-spaced binaries have short periods, allowing complete orbits to be obtained in just a few years. Speckle observations of close visual binaries have been made by an eclectic group of student, amateur, and professional astronomers with an EMCCD camera on two smaller telescopes and then on both 2.1and 0.8-meter telescopes at Kitt Peak National Observatory. Advanced technologies to increase the reach of speckle interferometry are also being pursued by this group, which includes a number of engineering faculty and students. These technological advances include full automation to increase the quantity of observations in an economical manner, and masks adapted from exoplanet imaging to disperse the bright primary starlight away from “discovery zones” so that faint secondary stars can be detected. Consideration is being given to the development of a large, four-meter-class, dedicated automatic sparse-aperture telescope for high spatial-resolution speckle interferometry. This sparse-aperture telescope may only cost about one-hundredth the cost of an equivalent filled-aperture telescope. Close Visual Binaries and Speckle Interferometry Astrometric orbits can be used to establish the “dynamical mass” (the sum of the two individual stellar masses) of a binary if the distance to the binary is also known. Knowing this distance allows an angular separation—the semi-major axis of the elliptical orbit—to be translated into an actual physical separation. Kepler’s Third Law can then be applied to determine the dynamical mass sum. However, what is needed to develop and refine stellar evolutionary models is the individual component masses, not the combined dynamical mass. Astrometric orbits, when combined with radial velocity curves, allow the summed dynamical mass to be parsed into individual stellar masses. Most of the visual binaries’ orbits established prior to 1980 had periods of many decades or even centuries. Thus there was little overlap between these astrometric binaries, with their long periods and slow movements, and the radial velocity curves of spectroscopic binaries, with their short periods and high velocities. What was needed were more astrometric orbits of shorter-period, faster-moving binaries so that spectroscopic radial velocity curves would be available for the same binaries to provide complete, individual-mass solutions. Unfortunately, most such short-period binaries have angular separations that are less than the seeing disk. With normal imaging, atmospheric jitter causes these binaries to jump about at high speed, hopelessly smearing images of binaries with separations below the typical seeing limit of about one arc second or more. This causes them to appear as a single star. In 1970, Anton Labeyrie, a French astronomer, beat the seeing limit by taking hundreds of very shortexposure images of close double stars with a high-speed film camera (Labeyrie 1970). Each exposure contained many distinct binary star images randomly superimposed on each other. Although atmospheric jitter caused the images to radically change from one exposure to the next, Labeyrie found that as long as both stars were within the “isoplanatic patch” (which typically has a diameter of about five arc seconds), their jitter was correlated. By taking the Fourier transform of each image and processing many images in Fourier space, the most frequent position angles and separations in the images became apparent. Vol. 11 No. 1S Journal of Double Star Observations | September 2015 Genet 184 These were, of course, the position angles and separations of the double star being observed, although there was an inherent 180° ambiguity in the position angle. By the end of the 1970s, Harold McAlister and his associates were making high speed film camera observations of very close binaries on the 2.1and 4.0-meter telescopes at Kitt Peak National Observatory (McAlister 1985). They obtained, for the first time, astrometric orbits on many spectroscopic binaries with existing radial veracity curves, thus yielding individual stellar masses for those all too few binaries that also had known distances. High-speed Tri-X film was not an easy medium to use, however. With the advent of early microcomputers and intensified CCD (ICCD) cameras, observations were made from the warm room at the 4-meter telescope instead of the Cassegrain cage as shown in Figure 1. Figure 1. A young William Hartkopf (left) captures high-speed frames with an early Osborn portable computer from an intensified CCD (ICCD) camera located at the Cassegrain focus of the 4-meter telescope at Kitt Peak National Observatory (right). Similar observations were also made on the 2.1-meter telescope at Kitt Peak. The European Space Agency launched the Hipparcos astrometric satellite in 1989 (Figure 2). At the time of its launch, the most capable computers on the planet did not have sufficient computational power to analyze the expected data. Trusting Moore’s Law, they had the requisite capability when it came time, a few years later, to reduce and analyze their data (Perryman 2010). Hipparcos provided accurate distances of about 100,000 stars, most for the first time. Binaries with astrometric (angular separation) orbits based on observations patiently built up over the decades and centuries, but previously at unknown distances, immediately became more valuable since the known distances finally allowed dynamical masses to be calculated. Hipparcos discovered large numbers of new binaries, suspected binaries, and close double stars, a rich source we are still actively mining decades later (Perryman 2012). When, in the near future, the results from the European Space Agency’s latest astrometric telescope, Gaia (Figure 3), become available, we will know the distances to many additional binaries. Furthermore, the already known distances to binaries will be refined by about a factor of ten (Eyer et al. 2013). Since distance uncertainty is often the major error source, recomputation of dynamical masses will significantly improve their accuracy. Not only will Gaia provide accurate distances, but, similar to Hipparcos, Gaia should discover a large number of binaries, suspected binaries, and close double stars. We may find this rich source of close binaries difficult to effectively follow up on unless we significantly improve our ability to obtain astrometric orbits of a large number of close visual binaries. Vol. 11 No. 1S Journal of Double Star Observations | September 2015 Genet 185 Figure 2. The European Space Agency’s Hipparcos astrometric satellite. Figure 3. The European Space Agency’s Gaia astrometric satellite. Amateurs and Students Carry On with Wide Visual Binaries With professional astronomers concentrating on speckle interferometry observations of close visual binary stars, continuing the observations of wide visual binaries (and other double stars) fell on the shoulders of amateur and student astronomers (Argyle 2012). Many amateurs and students have used an astrometric eyepiece with a ruler and protractor etched into a reticle to observe wide, bright double stars (Genet et al. 2010), while others have used CCD cameras to reach fainter magnitudes and somewhat closer separations. An astrometric eyepiece is a self-contained, easy-to-use astronomical instrument that costs less than $200 USD (Figure 4). These eyepieces have been used by well over 100 students in an Astronomy Research Seminar offered by Cuesta College every fall for the past eight years and a summer-camp version of the seminar at the University of Oregon’s Pine Mountain Observatory. The student teams’ observations ended up as published papers, including over two dozen papers published in the Journal of Double Star Observations. Recently, Cuesta College’s Astronomy Research Seminar was expanded as a hybrid online/in-person course that included 38 students from 10 different schools. The overall seminar instructor, Genet, was aided by 14 assistant instructors (primarily local high school science teachers) and a number of advanced amateur astronomers and other professional astronomers. Most of the students were high school students, taking the seminar as their first college course. One team observed double stars with an astrometric eyepiece, while most of the others used CCD cameras—some in person and others remotely at robotic observatories (Figure 5). Although most of the teams observed wider double stars, two teams were involved with speckle interferometry observations of close double stars. Vol. 11 No. 1S Journal of Double Star Observations | September 2015 Genet 186 Figure 4. Astrometric eyepieces with a laser-etched reticle were used by Arroyo Grande High School students taking Cuesta College’s Astronomy Research Seminar. Figure 5. Cadet teams at the Army and Navy Academy in Carlsbad, California, made remote observations using iTelescope’s network of robotic telescopes (left). A student team in Pearl City, Hawaii, used a CCD camera on the 0.5-meter telescope at Leeward Community College for their observations (right). Speckle Interferometry Moves to Smaller Telescopes Florent Losse, an amateur astronomer in France, was a key pioneer of small-telescope speckle interferometry (Figure 6, left). Because he did not have access to an intensified CCD (ICCD) camera or an electron multiplying CCD (EMCCD) camera, the read noise on regular CCD cameras would have been very high at fast readout speeds. Thus Florent patiently took the time for slow readouts, one frame at a time for hundreds of frames on each double star. Losse’s speckle observations of close visual binaries began appearing in the 6 Orbit Catalog, and were right in line with speckle observations made by professional astronomers with larger telescopes. Florent also extended his user-friendly, well-documented double 

Speckle Interferometry of Close Visual Binaries

The 11 Hipparcos-discovered binaries studied in this paper were observed at Kitt Peak National Observatory during an eight-night run from October 16th-23rd, 2013 using an EMCCD camera attached to the 2.1-meter telescope. PlateSolve 3.44, a speckle reduction program, was utilized to reduce the observations and create autocorrelograms of the 11 binaries. Each autocorrelogram provided data on the position angle and separation between the stars. Accuracy of the results was measured by determining the mean, standard deviation, and standard error for the difference between the predicted and reduced results for both the position angle and separation. For , this calculation resulted in a mean of 1.65 ̊, standard deviation of 1.64 ̊, and a mean standard error of ±0.50 ̊. For ρ, it resulted in a mean of 0.0108’’, standard deviation of 0.0106’’, and a mean standard error of ±0.0032’’. Vol. 13 No. 1 January 1, 2017 Page 123 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries about 129,600mm and F/ratio of 61.7 when attached to the 2.1-Meter telescope (Genet et al. 2015b). Observations The observers were granted eight nights of observing time at Kitt Peak National Observatory. The observing conditions were completely clear each night, except for the last half of the eighth night (Genet 2015c). The eight-night run allowed for speckle observations of over 1,000 close double stars, many of which were binaries. Calibration As previously mentioned, the observations were calibrated with data collected from multiple observations of six binaries with previously published orbits. A comparison of these Kitt Peak observations with the published orbits allowed the camera angle, -11.0492 ̊ from true north, and plate scale, 0.0116′′/pixel, to be determined (Wallace 2015). Overall internal precision for the run was found to be 0.027 ̊ and 0.00226′′, and overall accuracy was determined to be 0.4138 ̊ and 0.0147′′. These values were obtained using statistical analysis of five calibration binaries made throughout the run (Wallace 2015). Reduction The PlateSolve 3.44 program, developed by David Rowe, was used to reduce observations of the 11 binaries. It also served to create autocorrelograms, such as the one seen in Figure 1, which depicts WDS 00428+1249. The autocorrelogram for each binary provided data on the position angle and separation between the stars. In order to include the maximum amount of useful data and exclude most unwanted noise, the Gaussian Lowpass was set to a 30-pixel radius and the Gaussian Highpass was set to a 3-pixel radius. Results Each observation was reduced six times using PlateSolve 3.44. The center of the target star was selected manually to find the angle, , and separation, . These six  and ρ values were used to derive the mean values for the binary, and were compared to the predicted values in Table 1. Figure 1. Autocorrelogram of WDS 00428+1249. Figure # Star Identifier Date (JD) Mean  ̊ Pred.  ̊ || Mean ρ" Pred. ρ" || 2 WDS 00085+3456 2456585.770 52.80 52.5 0.3 0.1337 0.134 0.0003 3 WDS 03035+2304 2456583.857 4.72 5.2 0.48 0.1645 0.167 0.0025 4 WDS 18084+4407 2456587.627 204.74 207.7 2.96 0.1348 0.134 0.0008 5 WDS 01166+1831 2456584.835 234.27 234.2 0.07 0.6037 0.616 0.0123 6 WDS 02249+3039 2456583.833 264.11 263.4 0.71 0.3443 0.335 0.0093 7 WDS 00251+4803 2456586.779 272.75 274.7 1.95 0.3250 0.34 0.015 8 WDS 01129+5136 2456585.807 107.18 106.4 0.78 0.0999 0.103 0.031 9 WDS 00495+4404 2456584.788 136.12 135.6 0.52 0.1913 0.196 0.0047 10 WDS 01108+6747 2456587.757 174.08 175.4 1.32 0.1333 0.13 0.0033 11 WDS 00428+1249 2456587.781 36.39 31.6 4.79 0.2905 0.262 0.0285 12 WDS 07092+1903 2456586.987 338.18 342.4 4.22 0.1464 0.135 0.0114 Table 1. Position Angle and Separation Vol. 13 No. 1 January 1, 2017 Page 124 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries In Figures 2 to 12, the predicted values for the ρ and  of the binaries were determined using a binary calibration Excel spreadsheet (Drummond 2011). These results, provided in Table 1, are labeled “Predicted ” and “Predicted ρ”. By finding the difference between the mean and predicted values for  and ρ, || and |"| were determined as shown in Table 1. Drummond’s spreadsheet solves Kepler’s equation for any given date of every binary with a published orbit. The date for each binary was recorded in the spreadsheet. For accuracy to be evaluated, the mean, standard deviation, and standard error were calculated for the difference between the predicted and actual values for both the position angle and separation, degrees and arcseconds. For the separation angle, this calculation resulted in a mean of 1.65, standard deviation of 1.64, and a standard error of ±0.50. For ρ, it resulted in a mean of 0.0108", standard deviation of 0.0106", and a standard error of ±0.0032". Discussion Figures 2 to 12 plot the results alongside orbital plots provided by Brian Mason from the U.S. Naval Observatory. Microsoft Paint served as a coordinategrid system for the orbital plots from the USNO. Since the scale varied for each plot, the arcsecond-to-pixel ratio was determined separately for each binary. The distance for both x and y coordinate positions was calculated from the angle and distance obtained with PlateSolve 3.44. After converting these values to pixel coordinates, they were used to plot the binary systems (marked as plus symbols in Figures 2 to 12). By definition, the calculated separation and position angle must fall on the path of the given orbit of the binary provided from the U.S. Naval Observatory (marked as a line intersecting the established orbit in Figures 2 to 12). The new data points, marked on the figures below, provide substantive information that may assist in confirming, refining, or modifying the published orbits. (Continued on page 130) Figure 2. Orbit of Binary Star System WDS 00085+3456. Observed on Sunday, October 20, 2013 Vol. 13 No. 1 January 1, 2017 Page 125 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Figure 3. Orbit of Binary Star System WDS 03035+2304. Observed on Friday, October 18, 2013 Figure 4. Orbit of Binary Star System WDS 18084+4407. Observed on Tuesday, October 22, 2013 Vol. 13 No. 1 January 1, 2017 Page 126 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Figure 5. Orbit of Binary Star System WDS 01166+1851. Observed on Saturday, October 19, 2013 Figure 6. Orbit of Binary Star System WDS 02249+3039. Observed on Friday, October 18, 2013 Vol. 13 No. 1 January 1, 2017 Page 127 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Figure 7. Orbit of Binary Star System WDS 00251+4803. Observed on Monday, October 21, 2013. Figure 8. Orbit of Binary Star System WDS 01129+5136. Observed on Monday, October 21, 2013. Vol. 13 No. 1 January 1, 2017 Page 128 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Figure 9. Orbit of Binary Star System WDS 00495+4404. Observed on Saturday, October 19, 2013. Figure 10. Orbit of Binary Star System WDS 01108+6747. Observed on Tuesday, October 22, 2013. Vol. 13 No. 1 January 1, 2017 Page 129 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Figure 11. Orbit of Binary Star System WDS 00428+1249. Observed on Tuesday, October 22, 2013. Figure 12. Orbit of Binary Star System WDS 07092+1903 . Observed on Monday, October 21, 2013. Vol. 13 No. 1 January 1, 2017 Page 130 Journal of Double Star Observations Speckle Interferometry of Eleven Hipparcos Binary Discoveries Conclusion By analyzing 11 of the binaries observed at the Kitt Peak National Observatory, the study accomplished the goal of contributing position angles and separations to their apparent orbits. Further analysis on the data may serve to refine orbital predictions. Acknowledgements We are grateful to Kitt Peak National Observatory for the use of the 2.1-meter telescope, and also to the team which conducted the observations in 2013. The speckle interferometry camera was obtained through funds from the American Astronomical Society’s Small Research Grants. We thank David Rowe for the use of the PlateSolve 3.44 Speckle Reduction Tool. This research made use of the Washington Double Star Catalog maintained at the U.S. Naval Observatory. We thank Jack Drummond for providing his binary calibration spreadsheet. Furthermore, we are grateful for the reviews of the paper given by Robert Buccheim, Richard Harshaw, and Vera Wallen. A special thanks to William and Linda Frost for providing funding to the Frost Undergraduate Summer Research Program at California Polytechnic State University, San Luis Obispo, California.

Speckle Interferometry of Eleven Hipparcos Binary Discoveries

: Speckle interferometry (Labeyrie, 1970) is a well-tested and still used method for detecting and measuring binary stars that are closer together than the width of the atmospheric seeing disk. In this method, an average spatial power spectrum is computed from a series of short-exposure images. The power spectrum exhibits clearly defined cosine fringes, while the autocorrelation function (its Fourier Transform) contains a central peak with two side lobes. Over the years, several methods have been developed to analyze either the autocorrelation function or the power spectrum to determine the separation and orientation of the binary star system (Horch, 1996, Tokovinin, 2010). In this talk, a method for analyzing the fringes in the power spectrum will be described to robustly detect and measure the fringes. The method is based on the detection of the fringe minima and the inflection points between the minima and the maxima. An analysis of the effects of working with the uncalibrated (or poorly calibrated) power spectrum was done. It was found that this method provides a robust detection of the presence of fringes, but that the estimation of the separation of the binary star system has a systematic bias towards larger values. This bias can be overcome with a subsequent inspection of the fringes.

Measuring Close Binary Stars with Speckle Interferometry

Processing of Simulated and Experimental Images of Closely Spaced Binary Stars Using Speckle Interferometry Niels Christian Smidth Theory and methods of processing speckle interferometry data from close visual binary stars are presented and implemented. The effects of the optical systems used for observing close visual binary stars are explained and simulated from both the geometrical and physical optical viewpoints. The atmospheric phase distortion and shot noise responsible for the observed speckle patterns are simulated. The deconvolution technique originally presented by Labeyrie is implemented to extract astrometric data from close visual binary stars. This method is applied to both simulated and experimental data from Kitt Peak National Observatory as validation. Parts of the deconvolution process are optimized to allow for near real time calculations in an automated observatory.

https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=2776&context=theses

Processing of simulated and experimental images of closely spaced binary stars using speckle interferometry

Following mediocre results with pointing tests of the McMath-Pierce 0.8-meter East Auxiliary Telescope in April 2014, a team of astronomers/engineers met again in May 2014 to test other pointing models and assess the telescope’s ability to point with enough accuracy to permit the efficient use of speckle interferometry. Results show that accurate collimation is a pre-requisite for such accuracy. Once attained, the telescope performs extremely well. ! Definition of the Problem Speckle interferometry requires large aperture at very high focal ratios. The 0.8-meter East Auxiliary telescope at the McMath-Pierce Solar Observatory on Kitt Peak in Arizona certainly qualifies as a suitable aperture, given its objective and focal length (f50). The question is, does this telescope have the ability to acquire stars with enough accuracy to make placing the light of a double star on the small chip of an EMCCD camera? To test this question, a team of six astronomers convened at the McMath-Pierce 0.8-meter telescope in late May 2014 to run engineering tests and one speckle test of the instrument for possible uses as a speckle imaging system. The team is shown in Figure 1. Past Experiences With the 0.8-Meter One of the team members (Harshaw) was a member of a team that investigated this telescope in April 2014 (Wiley et al. 2014). During that engineering and observing run, the investigating team (Wiley, Harshaw, Boyce, Branston, Green, Genet, and Rowe) found consistent but minor pointing problems with the telescope, most acquisitions being slightly off center when the telescope was instructed to slew to a particular target. Since the placement of the target star tended to be consistently off by the same general quadrant and angular distance, the possibility existed that the April 2014 setup was slightly off-center of the telescope’s optical axis—that is, slightly off collimation. Therefore, collimation of the observation optical bench with the telescope’s optical axis was the first priority for this run of tests. Vol. 11 No. 1S Journal of Double Star Observations | September 2015 Harshaw et al. 297 Figure 1. Engineering Test Team (Ray, Prause, Douglass, Harshaw; not pictured: Branston, Genet). Figure 2. Douglass and Prause put the final touches on the collimation rig. ! Constructing the Pointing Accuracy System The team set about building a test rig for the pointing accuracy tests. This rig consisted of a sheet of foam core with quadrille graph paper (5 squares to the inch) affixed with Mastic. A small crosshair was drawn on the graph paper at the center of the collimated light path from the telescope and a small low-lux camera (a ZWO ASI120MC) was affixed to a magnetic mount on a steel pole near the telescope’s ceiling port. This would allow us to view a target star’s proximity to the crosshair from the nearby observing control room, letting us keep the observing room (Figure 2) totally dark. Figure 3. Douglass, Green, Prause, Ray at the Dining Hall. Vol. 11 No. 1S Journal of Double Star Observations | September 2015 Harshaw et al. 298 The Pointing Accuracy Tests Once the pointing test rig was completed, we waited for dark, having dinner in the Kitt Peak Lodge Dining Hall in the meantime (Figure 3). (Wayne Green, a spectroscopist from our April observing run, joined us as he was doing differential radial velocity measurements of double stars at the Coude Feed housed in the 2.1 meter telescope building.) We began our pointing tests by aiming the telescope at Arcturus. (The East Auxiliary telescope, while controlled directly by a DFM computer system, is aimed using Software Bisque’s TheSky (version 4) as the user interface. This makes issuing pointing commands as easy as finding the target in TheSky and issuing a slew command.) Once centered on Arcturus, we issued a “Sync” command through TheSky (this command tells the DFM computer that we were precisely on Arcturus, allowing the DFM computer to reset the encoder readings). From Arcturus we then issued commands to slew the telescope 2° north of Arcturus, then return, noting the aiming error by measuring the offset of the star from the crosshair on our rig. We then slewed 2° south and repeated the return to Arcturus. We then did slews 6° north and south, and finally 15° north and south. We then directed the telescope to Spica to repeat the tests, but as soon as we acquired Spica, we realized that we had a similar problem to what we encountered in April—the stars were always close to the crosshair, but never exactly on it. This suggested that our problem may have more to do with collimation than telescope control. The results of our aiming tests are summarized in Table 1, where the offsets from the crosshair are measured in grid squares north, south, east, and west of the crosshair. (At the image scale of the East Auxiliary telescope, 0.2 inches—the size of the quadrille squares—is approximately 36.6′′ of angular displacement.) Once the primary star (Arcturus or Spica) was acquired, a Sync command was issued to align the DFM computer with the sky, but no syncs were issued during the slews from the north or south. Table 1. Preliminary Pointing Test Results for the East Auxiliary Telescope.! As can be seen, without syncing between slews, the system errors seem to accumulate. However, it is of some comfort to see that the errors always lie on the same side of the crosshair, suggesting that a good pointing model can be built that would compensate for the errors. ! Collimation of the 0.8 Meter Telescope A group discussion the next morning led to the possibility that we were not precisely aligned with the East Auxiliary’s true optical axis—in other words, we were not precisely collimated. With the assistance of Detrick Branston, chief operator of the McMath-Pierce complex, we were able to set up as accurate a collimation as was possible the next afternoon. Figure 4 shows Prause, Ray, and Branston checking collimation using skylight in a darkened observing room. Star Direction of Slew Acquisition Error True Error Arcturus 2° from the north 9N, 4W 71” @ 336° 2° from the south 11N, 3 W 82” @ 345° 6° from the north 12N, 4 W 91” @ 342° 6° from the south 14N, 4W 105” @ 344° 15° from the north 15N, 5W 114” @ 342° 15° from the south 19N, 5 W 141” @ 345°

Testing of the McMath-Pierce 0.8-Meter East Auxiliary Telescope's Acquisition and Slewing Accuracy

Speckle interferometry can be used to overcome normal seeing limitations by taking many very short exposures at high magnification and analyzing the resulting speckles to obtain the position angles and separations of close binary stars. A typical speckle observation of a close binary consists of 1000 images, each 20 milliseconds in duration. The images are stored as a multi-plane FITS cube. A portable speckle interferometry system that features an electron-multiplying CCD camera was used by the authors during two week-long observing runs on the 2.1-meter telescope at Kitt Peak National Observatory to obtain some 1000 data cubes of close binaries selected from a dozen different research programs. Many hundreds of single reference stars were also observed and used in deconvolution to remove undesirable atmospheric and telescope optical effects. The data base of well over one million images was reduced with the Speckle Interferometry Tool of PlateSolve 3. A few sample results are provided. During the second Kitt Peak run, the McMath-Pierce 1.6and 0.8-meter solar telescopes were evaluated for nighttime speckle interferometry, while the 0.8-meter Coude feed was used to obtain differential radial velocities of short arc binaries.

Kitt Peak Speckle Interferometry of Close Visual Binary Stars (Abstract)

Kitt Peak Speckle Interferometry of Close Visual Binary Stars

Observations were made in April 2014 to assess the utility of the 0.8-meter solar telescope at the McMath-Pierce Solar Observatory at Kitt Peak National Observatory for performing speckle interferometry observations of close binary stars. Several configurations using science cameras, acquisition cameras, eyepieces, and flip mirrors were evaluated. Speckle images were obtained and recommendations for further improvement of the acquisition system are presented.

Close Binary Star Speckle Interferometry on the McMath-Pierce 0.8-Meter Solar Telescope

We explored the aiming and tracking accuracy of the McMath-Pierce 1.6 m solar telescope at Kitt Peak National Observatory as part of an investigation of using this telescope for speckle interferometry of close visual double stars. Several slews of various lengths looked for hysteresis in the positioning system (we found none of significance) and concluded that the 1.6 m telescope would make a useful telescope for speckle interferometry.

Potential of the McMath-Pierce 1.6-Meter Solar Telescope for Speckle Interferometry

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Kitt Peak Speckle Interferometry of Close Visual Binary Stars (Abstract)

Kitt Peak Speckle Interferometry of Close Visual Binary Stars

Close Binary Star Speckle Interferometry on the McMath-Pierce 0.8-Meter Solar Telescope

Potential of the McMath-Pierce 1.6-Meter Solar Telescope for Speckle Interferometry