Brief description

TopHAT is a fully-automated photometry follow-up tool for the HAT Network. The main optics is a Takahashi BRC-250 optical assembly with 25cm diameter and 1.25m focal length. The typical field of view with one of our 2Kx2K Apogee E10 or E42 cameras is 1.29 deg. TopHAT uses a robust Fornax fork-mount that was developed by our team for this specific purpose. Great advantage of the mount is that it has identical electronics and software control to that of the HATs. The wormgear---cogwheel drive system is slip-free, as opposed to friction drives.

Most electronic cards have been doubled, and we have the ability to remotely switch between cards in case of failure. This "spaceship" technique improved the reliability of TopHAT. The system is protected against inclement weather by a large clamshell dome. TopHAT has been installed to the Fred Lawrence Whipple Observatory (FLWO) of the Smithsonian Astrophysical Observatory (SAO) in 2005. Except for smaller interruptions, it has been operational most of the time.
TopHAT, close-up TopHAT with dome and electronics

Scientific goals

The prime purpose of TopHAT is to follow-up shallow transit candidates of HATNet that need confirmation (whether the transit is real), or characterization of the transit shape. TopHAT proved to perform well, and achieve photometry at the 3mmag r.m.s level (at 0.5min cadence). Thus, TopHAT has been also used to follow up known planetary transits, such as those of HD149026 or HD189733. Finally, TopHAT is also used for monitoring couple of selected, low galactic latitude (dense) stellar fields.
Last updated 2006-12-31
by Gaspar Bakos.