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We present new cosmic microwave background (CMB) anisotropy results from the combined analysis of the three flights of the first Medium Scale Anisotropy Measurement (MSAM1). This balloon-borne bolometric instrument measured about 10 square degrees of sky at half-degree resolution in 4 frequency bands from 5.2 icm to 20 icm with a high signal-to-noise ratio. Here we present an overview of our analysis methods, compare the results from the three flights, derive new constraints on the CMB power spectrum from the combined data and reduce the data to total-power Wiener-filtered maps of the CMB. A key feature of this new analysis is a determination of the amplitude of CMB fluctuations at $\ell \sim 400$. The analysis technique is described in a companion paper by Knox.

The third flight of the Medium-Scale Anisotropy Measurement (MSAM1), in 1995 June, observed a new strip of sky, doubling the sky coverage of the original MSAM1 data set. MSAM1 observes with a 05 beam size in four bands from 5 to 20 cm-1. From these four bands we derive measurements of cosmic microwave background radiation (CMBR) anisotropy and interstellar dust emission. Our measurement of dust emission correlates well with the 100 μm IRAS Sky Survey Atlas; from this comparison we determine an effective emissivity spectral index between 100 μm and 444 μm of 1.46±0.28. Analysis of our measurement of CMBR anisotropy shows that for Gaussian-shaped correlation functions with θc = 03, we place a limit on total rms anisotropy of 2.2×10−5

Whole disk brightness ratios for Jupiter, Saturn, and Mars are reported at 5.7, 9.5, 16.4, and 22.5 cm$^{-1}$. Using models for the brightness temperature of Mars, the whole disk brightness temperatures for Jupiter and Saturn are also given for the four frequencies., 13 pages, LaTeX+aasms4 package, 2 included PostScript figures. Submitted to Ap.J Letters

The goal of the second flight of the medium-scale anisotropy measurement (MSAM1-94) was to confirm the measurement of cosmic microwave background radiation (CMBR) anisotropy made in the first flight (MSAM1-92). The CMBR anisotropy and interstellar dust emission signals from the two flights are compared by forming the sum and difference of those portions of the data with the same pointings on the sky. The difference data are consistent with a null detection, while the summed data show significant signal. We conclude that MSAM1-92 and MSAM1-94 measured the same celestial signal.

We report the characterization of bright, compact features in the cosmic microwave background radiation (CMBR) detected during the June 1992 and June 1994 balloon flights of the Medium Scale Anisotropy Measurement (MSAM1-92 and MSAM1-94, respectively). Spectral flux densities are determined for each feature at 5.7, 9.3, and 16.5 cm$^{-1}$. No viable counterparts for these features were found in source catalogs at 5 GHz or at 100 $\mu$m. The measured spectrum of each feature is consistent with a temperature fluctuation in the CMBR. The existence of these features is consistent with adiabatic fluctuation models of anisotropy in the CMBR., Comment: 17 pages, LaTeX+aasms4 package, 2 included PostScript figures. Submitted to Ap.J Letters

Observations from the first flight of the Medium Scale Anisotropy Measurement (MSAM1-92) are analyzed to search for the Sunyaev-Zel'dovich (SZ) effect towards the Coma cluster. This balloon-borne instrument uses a $28\arcmin$ FWHM beam and a three position chopping pattern with a throw of $\pm40\arcmin$. With spectral channels at 5.7, 9.3, 16.5, and 22.6~\icm, the observations simultaneously sample the frequency range where the SZ spectral distortion in the intensity transitions from a decrement to an increment and where the fractional intensity change is substantially larger than in the Rayleigh-Jeans region. We set limits on the Comptonization parameter integrated over our antenna pattern, $\Delta y \leq 8.0 \times 10^{-5}$($2 \sigma$). For a spherically symmetric isothermal model, this implies a central Comptonization parameter, $y_o \leq 2.0 \times 10^{-4}$, or a central electron density, $n_o \leq 5.8 \times10^{-3}$cm$^{-3}h_{50}$, a result consistent with central densities implied by X-ray brightness measurements and central Comptonization estimates from lower frequency observations of the SZ effect., Comment: 11 pages, LaTeX+aasms4 package, 1 PostScript figure. Submitted to Ap.J Letters

The second flight of the Medium Scale Anisotropy Measurement (MSAM1-94) observed the same field as the first flight (MSAM1-92) to confirm our earlier measurement of cosmic microwave background radiation (CMBR) anisotropy. This instrument chops a 30\arcmin\ beam in a 3 position pattern with a throw of $\pm40\arcmin$, and simultaneously measures single and double differenced sky signals. We observe in four spectral channels centered at 5.6, 9.0, 16.5, and 22.5~\icm, providing sensitivity to the peak of the CMBR and to thermal emission from interstellar dust. The dust component correlates well with the \IRAS\ 100~\micron\ map. The CMBR observations in our double difference channel correlate well with the earlier observations, but the single difference channel shows some discrepancies. We obtain a detection of fluctuations in the MSAM1-94 dataset that match CMBR in our spectral bands of $\Delta T/T = 1.9^{+1.3}_{-0.7}\times 10^{-5}$ (90\% confidence interval, including calibration uncertainty) for total rms Gaussian fluctuations with correlation angle 0\fdg3, using the double difference demodulation., Comment: 11 pages, 4 postscript figures, uses aastex 4.0. Transmitted in uuencoded gzipped tar file

Observations from the first flight of the Medium Scale Anisotropy Measurement (MSAM) are analyzed to place limits on Gaussian fluctuations in the Cosmic Microwave Background Radiation (CMBR). This instrument chops a 30\arcmin\ beam in a 3 position pattern with a throw of $\pm40\arcmin$; the resulting data is analyzed in statistically independent single and double difference datasets. We observe in four spectral channels at 5.6, 9.0, 16.5, and 22.5~\icm, allowing the separation of interstellar dust emission from CMBR fluctuations. The dust component is correlated with the \IRAS\ 100~\micron\ map. The CMBR component has two regions where the signature of an unresolved source is seen. Rejecting these two source regions, we obtain a detection of fluctuations which match CMBR in our spectral bands of $0.6 \times 10^{-5} < ��T/T < 2.2 \times 10^{-5}$ (90\% CL interval) for total rms Gaussian fluctuations with correlation angle 0\fdg5, using the single difference demodulation. For the double difference demodulation, the result is $1.1 \times 10^{-5} < ��T/T < 3.1 \times 10^{-5}$ (90\% CL interval) at a correlation angle of 0\fdg3., 13 pages + 3 figures (included), LaTeX + AASTeX v3.0