PUMA publications for /user/asteroidguy/sofiaMon Dec 15 18:18:21 CET 2025The Planetary Science Journal04Stellar Occultations in the Era of Data Mining and Modern Regression Models: Using Gaussian Processes to Analyze Light Curves and Improve Predictions2024SOFIA imported myown 01Mon Dec 15 18:18:21 CET 2025AGU Fall Meeting Abstracts12Results from a stellar occultation by KBO Varda2019ATUS SOFIA astronomy imported myown We present results obtained from a stellar occultation by the classical Kuiper belt object (174567) Varda on 10 September 2018. Varda is a known binary system and among the largest TNOs known today, but has not been studied during an occultation before. Among our collaborators, 24 stations were able to acquire data at the time of the event, of which 15 obtained a clear detection, making this the best-sampled occultation of a TNO to date. As potential stellar duplicity could cause a significant shift of the ground path, we studied the target star in advance through speckle imaging with 'Alopeke at Gemini North. The reconstructed shape is an ellipsoid, which supports Varda's status as a dwarf planet candidate. Albeit slightly smaller, the calculated size is in agreement with the radiometric diameter based on Herschel/PACS FIR measurements. Post-event analysis of the dataset obtained at DCT revealed a faint, unresolved companion or background star very close to the target, which was well under the detection limit of our speckle imager data, but had practically no effect on the predicted path. No atmosphere has been detected. The occultation helped to constrain size and albedo, which in turn helps to better constrain Varda's density....Tue Oct 30 19:39:47 CET 2018AAS/Division for Planetary Sciences Meeting Abstractsoct416.10{Airborne and Ground Observations of the Stellar Occultation by Triton on 5 October 2017}502018SOFIA astronomy myown Wed Jul 18 04:01:38 CEST 2018Proc. SPIE107022V{Adding a second spectral channel to the SOFIA FPI+ science instrument}107022018SOFIA myown The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a heavily modified Boeing 747SP aircraft, accommodating a 2.7 meter infrared telescope. This airborne observation platform operates at flight altitudes of up to 13.7 km (45,000 ft) and therefore allows a nearly unobstructed view of the visible and infrared universe at wavelengths between 0.3 µm and 1600 µm. The Focal Plane Imager (FPI+) is SOFIA’s main tracking camera. It uses a commercial, off-the-shelf camera with a thermoelectrically cooled EM-CCD. The back-illuminated sensor has a peak quantum efficiency greater than 95% at 550 nm and the dark current is as low as 0.01 e-/pix/sec. Since 2015, the FPI+ has been available to the community as a Facility Science Instrument, and can be used to observe stellar occultations by solar system objects such as dwarf planets, moons, asteroids, and comets, and transits of extra-solar planets. To date, SOFIA has conducted multi-channel observations of occultations, e.g. the occultation by Pluto in June of 2015 or the occultation by Triton in October 2017, using three instruments, HIPO and FLITECAM at the main instrument flange of the telescope, and the FPI+. This multi-wavelength sampling is important for enabling discrimination of particle sizes and constituents of hazes in the atmosphere of bodies such as Pluto and Triton, and the coma material of comets. Multi-wavelength observations also serve to allow us to place constraints on the chemical compositions of these formations. After the retirement of the two other instruments, the FPI+ is now SOFIA’s only remaining observing tool for occultations. In order to preserve some of the multi-color observing capability of the platform, we here discuss the addition of a second spectral channel to the FPI+. In a first upgrade step, a beamsplitter will split the incoming light and send it to two EMCCD cameras, one working in the ”blue”, e.g. SLOAN g’ band, and the other working in the ”red”, e.g. SLOAN i’ or z’ band. In a second upgrade step, the ”red” channel could be equipped with a NIR camera in order to provide a wider wavelength separation of the two bands. This will however require a modified dichroic coating on the tertiary (Nasmyth) mirror of the SOFIA telescope. This paper presents a preliminary design study of the opto-mechanical configuration of the dual channel FPI+.Fri Oct 28 22:29:33 CEST 2016Proc. SPIE99730J-99730J-14Deutsches SOFIA Institut (DSI) at the SOFIA Science Center: engineering and scientific contributions to the airborne observatory 99732016ATUS SOFIA myown The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5-meter infrared telescope built into a Boeing 747SP. In 2014 SOFIA reached its “Full Operational Capability” milestone and nowadays takes off about three times a week to observe the infrared sky from altitudes above most of the atmosphere's water vapor content. Despite reaching this major milestone, efforts to improve the observatory's performance are continuing in many areas. The team of the Deutsches SOFIA Institut, DSI (German SOFIA Institute) at the SOFIA Science Center in Moffett Field, CA works in several engineering areas to improve the observatory's performance and its efficiency. DSI supports the allocation process of SOFIA's observation time for guest observers, provides and supports two facility science instruments and conducts an observing program of stellar occultations by small objects of the solar system. This paper summarizes results and ongoing work on a spare secondary mirror made of aluminum, the new and improved Focal Plane Imager (FPI+) that has become a facility science instrument, the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS), new cameras and optics for the Fine Field and Wide Field Imagers (FFI+ and WFI+), real-time astrometric solution of star field images, ground support equipment and astronomical observations. Fri Oct 28 03:31:19 CEST 2016Proc. SPIE991307-991307-14Computer-aided star pattern recognition with astrometry.net: in-flight support of telescope operations on SOFIA 99132016ATUS SOFIA myown SOFIA is an airborne observatory, operating a gyroscopically stabilized telescope with an effective aperture of 2.5 m on-board a modified Boeing 747SP. Its primary objective is to conduct observations at mid- to far-infrared wavelengths. When SOFIA opens its door to the night sky, the initial telescope pointing is estimated from the aircraft's position and heading as well as the telescope's attitude relative to the aircraft. This initial pointing estimate needs to be corrected using stars that are manually identified in tracking camera images; telescope pointing also needs to be verified and refined at the beginning of each flight leg. We report about the implementation of the astrometry.net package on the telescope operator workstations on-board SOFIA. This package provides a very robust, reliable and fast algorithm for blind astrometric image calibration. Using images from SOFIA's Wide Field Imager, we are able to display an almost instant, continuous feedback of calculated right ascension, declination and field rotation in the GUI for the telescope operator. The computer-aided recognition of star patterns will support telescope pointing calibrations in the future, further increasing the efficiency of the observatory. We also discuss other current and future use cases of the astrometry.net package in the SOFIA project and at the German SOFIA Institute (DSI).