Engineering topics
Publications and source records attributed to Phelps, R..
In an attempt to use Cepheid variables to determine the distance to the Centaurus cluster, we have obtained images of NGC 4603 with the Hubble Space Telescope for 9 epochs (totalling 24 orbits) over 14 months in the F555W filter and 2 epochs (totalling 6 orbits) in the F814W filter.
This is one of the galaxies being observed as part of the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale which aims to determine the Hubble Constant to 10% accuracy.
The distance to NGC 4725 has been derived from Cepheid variables, as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale.
Using the Hubble Space Telescope (HST) thirty-seven long-period Cepheid variables have been discoverd in the Fornax Cluster spiral galaxy NGC 1365.
We report the Discovery of Cepheid variable stars in the galaxy NGC 4414, as part of the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale. Observations were obtained with the HST Wide Field and Planetary Camera 2 (WFPC2) for 13 epochs at V (F555W) and 4 at I (F814W).
The determination of an accurate value of the Hubble constant requires the measurement of accurate galaxy distances and velocities. Both the Virgo and Fornax clusters of galaxies are close enough to be studied in considerable detail.
We report the detection of Cepheids and a new distance to the spiral galaxy NGC 2541, based on data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope (HST).
We report the discovery of Cepheid variable stars in the galaxy NGC 4414, as part of the Hubble Space Telescope (HST) key project on the Extragalactic Distance Scale.
The distance to NGC 7331 has been derived from Cepheid variables observed with HST/WFPC2, as part of the Extragalactic Distance Scale Key Project. Multi-epoch exposures in F555W(~V) and F814W (~1), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, which were used to detect a total of 14 reliable Cepheids, with periods between 11 and 42 days.