VizieR Online Data Catalog: He-filter observations of WASP-69b & WASP-52b (Vissapragada+, 2020)

We observed WASP-69b through our helium filter and beam-shaping diffuser on 2019-August-16-(UT), and we observed WASP-52b with the same setup on 2019-September-17-(UT).

Our experiment is analogous to broadband transit photometry performed previously (Vissapragada+, 2020AJ....159..108V) with Wide-field Infrared Camera (WIRC) on the Hale 200" telescope at Palomar Observatory. The sole difference is that we use an ultranarrowband filter (manufactured by Alluxa) that is centered on the helium feature.

Specifically, our filter has a center wavelength of 1083.3nm in vacuum, at 77K, and at an angle of incidence (AOI) of 7°; an FWHM of 0.635nm; and a maximum transmission of 95.6% (averaged across five positions on the filter). To cover the full spectral range to which our 2.5μm cutoff Hawaii-II detector is sensitive, the filter also has OD4 absolute out-of-band blocking (i.e., a transmission less than 0.01% everywhere outside the passband) from 500-3000nm. We additionally utilize an engineered diffuser (located in a separate filter wheel from the helium filter) that molds the stellar point-spread functions (PSFs) into a top-hat shape with a FWHM of 3".

(3 data files).