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The White Mountain Polarimeter (WMPol) is a dedicated ground-based microwave telescope and receiver system for observing polarization of the Cosmic Microwave Background. WMPol is located at an altitude of 3880 meters on a plateau in the White Mountains of Eastern California, USA, at the Barcroft Facility of the University of California White Mountain Research Station. Presented here is a description of the instrument and the data collected during April through October 2004. We set an upper limit on $E$-mode polarization of 14 $\mu\mathrm{K}$ (95% confidence limit) in the multipole range $170, Comment: 35 pages. 12 figures. To appear in ApJS

The Background Emission Anisotropy Scanning Telescope (BEAST) is a 2.2m off-axis telescope with an 8 element mixed Q (38-45GHz) and Ka (26-36GHz) band focal plane, designed for balloon borne and ground based studies of the Cosmic Microwave Background. Here we present the Cosmic Microwave Background (CMB) angular power spectrum calculated from 682 hours of data observed with the BEAST instrument. We use a binned pseudo-Cl estimator (the MASTER method). We find results that are consistent with other determinations of the CMB anisotropy for angular wavenumber l between 100 and 600. We also perform cosmological parameter estimation. The BEAST data alone produces a good constraint on Omega_k = 1-Omega_tot=-0.074 +/- 0.070, consistent with a flat Universe. A joint parameter estimation analysis with a number of previous CMB experiments produces results consistent with previous determinations., 18 Pages, 7 figures

We present the first sky maps from the BEAST (Background Emission Anisotropy Scanning Telescope) experiment. BEAST consists of a 2.2 meter off axis Gregorian telescope fed by a cryogenic millimeter wavelength focal plane currently consisting of 6 Q band (40 GHz) and 2 Ka band (30 GHz) scalar feed horns feeding cryogenic HEMT amplifiers. Data were collected from two balloon-borne flights in 2000, followed by a lengthy ground observing campaign from the 3.8 Km altitude University of California White Mountain Research Station. This paper reports the initial results from the ground based observations. The instrument produced an annular map covering the sky from declinateion 33 to 42 degrees. The maps cover an area of 2470 square degrees with an effective resolution of 23 arcminutes FWHM at 40 GHz and 30 arcminutes at 30 GHz. The map RMS (smoothed to 30 arcminutes and excluding galactic foregrounds) is 54 +-5 microK at 40 GHz. Comparison with the instrument noise gives a cosmic signal RMS contribution of 28 +-3 microK. An estimate of the actual CMB sky signal requires taking into account the l-space filter function of our experiment and analysis techniques, carried out in a companion paper (O'Dwyer et al. 2003). In addition to the robust detection of CMB anisotropies, we find a strong correlation between small portions of our maps and features in recent H$\alpha$ maps (Finkbeiner, 2003). In this work we describe the data set and analysis techniques leading to the maps, including data selection, filtering, pointing reconstruction, mapmaking algorithms and systematic effects. A detailed description of the experiment appears in Childers et al. (2003)., Comment: 22 pages, 11 postscript figures, aastex, replaced verion corrects typos, adds refs,adds author