BLAST: Balloon-borne Large Aperture Telescope

Link to BLAST Web site

I. General project/facility description

1. Overview of the facility/project
   BLAST, the "Balloon-borne Large-Aperture Sub-millimeter Telescope," will fly from a Long Duration Balloon (LDB) platform and incorporate a 2-meter primary mirror with large-format bolometer arrays operating at 250, 350 and 500 µ. By providing the first sensitive large-area (~0.5-40 square degrees) submillimeter surveys at these wavelengths, BLAST will address some of the most important cosmological and Galactic questions regarding the formation and evolution of stars, galaxies and clusters.
   Managing institution and organization
   
2. Funding source(s)
   
3. Construction history and cost
   
4. Operational history and cost
   

II. Technical details

1. Specifics of telescope/instrument
   The BLAST gondola incorporates a 2 m primary mirror, a 50 cm diameter correcting secondary mirror, and a rigid support structure for the secondary. The secondary mirror has been designed to give diffraction limited performance over a 14' x 7' FOV at the Cassegrain focus at λ = 250 µ. The estimated antenna efficiency is >=80%, and is determined by a combination of the 5 µ rms surface accuracy of the primary and the quality of the re-imaging optics.
   Radiation from the telescope will enter the cryostat through a 7.7 cm diameter vacuum window near the Cassegrain focus. The f/5 Cassegrain focus of the telescope is about 18 cm behind the back surface of the primary mirror. The cryostat window will be made from 0.002 inch thick polypropylene, which has <0.1% loss. Blocking filters at the intermediate cold stages of 77 K and 20 K will reduce the radiation loading on the LHe to <10 mW.

2. New capabilities anticipated/planned in next 5-10 years
   Future facility: NA

III. User profile

1. % of "open skies" time
   
2. Institutional affiliations of users
   BLAST participants come from the Universities of Pennsylvania, Brown, Miami, Toronto, British Columbia, and Cardiff as well as JPL and INAOE, Mexico.

3. Student access, involvement, usage
   

IV. Science Overview

1. Current forefront scientific programs
   Future facility: NA

2. Major discoveries (through 1999)
   Future facility: NA

3. Science highlights of last 5 years
   Future facility: NA

4. Main future science questions to be addressed
   BLAST's primary goals are to:
   • Measure photometric redshifts, rest-frame FIR luminosities and star formation rates of high-redshift starburst galaxies, thereby constraining the evolutionary history of those galaxies that produce the FIR/submillimeter background

   • Measure cold pre-stellar sources associated with the earliest stages of star and planet formation
   • Make high-resolution maps of diffuse galactic emission over a wide range of galactic latitudes
   • Observe solar system objects including planets, large asteroids, and trans-Neptunian objects.
5. Synergies with other major forefront facilities
   
6. Unique contributions
   

V. Education/Outreach activities

1. Visitor facility
   
2. Student programs
   
3. Other (as apply)
   

VI. Documentation/website URLs

1. URL of facility website
   http://chile1.physics.upenn.edu/blastpublic

2. URL of EPO website
   
3. URL(s) of any brief overviews of project/facility
   
4. URL(s) of miscellaneous documentation