ALFALFA Sky Coverage
ALFALFA will cover 7074 square degrees of the high galactic latitude sky accessible to the Arecibo telescope, i.e. the regions between 0° and +36° in Declination (subdivided into 9 bands of tiles, each 4° wide), 07h30m to 16h30m and 22h to 03h in Right Ascension. The full region of the survey will be mapped in drift mode, following a 2--pass strategy (i.e. each Declination band will be scanned at two different epochs, separated by a few months) with the ALFA system, requiring a total of 4130 hours of telescope time. The completion of the full survey is projected to require 5 years.
Proposed sky coverage of the ALFALFA survey, in the Virgo (upper) and
anti-Virgo (lower) directions. In each panel, the solid red
lines outline the proposed survey area. The Arecibo telescope
is located at a latitude of 18°21' N and can survey
zenith angles less than 20°, but the sensitivity drops
sharply at Z.A. > 18°. The dotted red lines
make the designated ALFALFA "tile" boundaries.
The cyan lines mark
the lines of b = +20° (upper) and -20° (lower)
while the green lines trace SGL = -10°,
0° and +10°.
Blue filled circles mark galaxies with observed heliocentric
recessional velocities cz < 700 km/s while
open magenta circles denote objects believed to lie with 10 Mpc
(Karachentsev et al. 2004), based largely on primary distances.