We present the sixth catalog of Kepler candidate planets based on nearly four years of high precision photometry. This catalog builds on the legacy of previous catalogs released by the Kepler project and includes 1493 new Kepler Objects of Interest (KOIs) of which 554 are planet candidates, and 131 of these candidates have best-fit radii <1.5 Å R . This brings the total number of KOIs and planet candidates to 7348 and 4175 respectively. We suspect that many of these new candidates at the low signal-to-noise ratio limit may be false alarms created by instrumental noise, and discuss our efforts to identify such objects. We re-evaluate all previously published KOIs with orbital periods of >50 days to provide a consistently vetted sample that can be used to improve planet occurrence rate calculations. We discuss the performance of our planet detection algorithms, and the consistency of our vetting products. The full catalog is publicly available at the NASA Exoplanet Archive.

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MK spectral types are presented for 100 stars previously classified F0. This comprises a portion of a larger project to assign accurate spectral types to the stars in the Bright Star Catalogue.

The NICMOS coronagraphic capability is a unique resource. It has been used to search for and/ or confirm the presence of planetary or brown dwarf companions around nearby stars, to probe the structure of circumstellar disks, and to study the host environment of quasars with damped Lya systems. These and other programs are expected to continue with NICMOS, using the recently installed NICMOS cooling system. In this paper we present an operational overview of NICMOS coronagraphy from its inception on 1998 February 6 through 1998 December 18. During this time interval, which corresponds to H ubble Space Telescope (HST) cycles 7 and 7N, coronagraphic observations of 329 targets for 22 programs were obtained. The flight software was enhanced to locate the position of the hole as well as the target during onboard acquisitions. Coronagraphic images are affected by changes in the point-spread function (PSF) due to thermally induced HST focus changes, NICMOS cold-mask movement, and light scatter around the coronagraphic hole. Proper PSF subtraction requires a well-planned observing strategy that is appropriate for the target, and a matched PSF target. For example, for point sources, observations with the same filter taken back-to-back in the same orbit with a roll of the spacecraft between observations yields good results. For circumstellar disks, contemporaneous observations of a matched PSF target are required.

We describe a 1-meter space telescope plus free-flying occulter craft mission that would provide direct imaging and spectroscopic observations of Jovian and Uranus-sized planets about nearby stars not detectable by Doppler techniques. The Doppler technique is most sensitive for the detection of massive, close-in extrasolar planets while the use of a free-flying occulter would make it possible to image and study stellar systems with planets comparable to our own Solar System. Such a mission with a larger telescope has the potential to detect earth-like planets.Previous studies of free-flying occulters reported advantages in having the occulting spot outside the telescope compared to a classical coronagraph onboard a space telescope. Using an external occulter means light scatter within the telescope is reduced due to fewer internal obstructions and less light entering the telescope and the polishing tolerances of the primary mirror and the supporting optics can be less stringent, thereby providing higher contrast and fainter detection limits. In this concept, the occulting spot is positioned over the star by translating the occulter craft, at distances of 1,000 to 15,000 km from the telescope. Any source within the telescope field-of-view can be occulted without moving the telescope.In this paper, we present our current concept for a 1-m space telescope matched to a free-flying occulter, the Umbral Missions Blocking Radiating Astronomical Sources (UMBRAS) space mission. An UMBRAS space mission consists of a Solar Powered Ion Driven Eclipsing Rover (SPIDER) occulter craft and a matched (apodized) telescope. The occulter spacecraft would be semi-autonomous, with its own propulsion systems, internal power (solar cells), communications, and navigation capability. Spacecraft rendezvous and formation flying would be achieved with the aid of telescope imaging, RF or laser ranging, celestial navigation inputs, and formation control algorithms.Al Schultz is an Instrument Scientist at the Space Telescope Science Institute (STScI). He has worked at STScI for ∼12 years. Since launch, Dr. Schultz has supported HST operations in PODPS, which is now part of OPUS, the GHRS, STIS, NICMOS, and WFPC2 instruments. (Send correspondence to schultz@stsci.edu; Telephone: 410-338-5044)High-Contrast Imaging for Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/17/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 4860 57 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/17/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx