Status Report

NASA Hubble Space Telescope Daily Report #4776

By SpaceRef Editor
January 24, 2009
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Continuing to collect World Class Science

PERIOD COVERED: 5am January 22 – 5am January 23, 2009 (DOY 022/1000z-023/1000z)


FGS 11963

FGS1r AMA Re-Optimization

This proposal re-optimizes FGS1r interferometric performance (S-curves) by adjustment of the instrument’s AMA. This will improve the FGS1r angular resolution in Transfer Mode while improving the reliability of Position Mode observations. Observations of close binaries (separations ranging from 12 to 20 mas) and all stars fainter than V=15 will benefit from this re-optimization. Moreover, this re-optimization will return FGS1r to the commissioning state that was deemed optimal for operating it as a guider in 1997.

FGS 11964

Post FGS1r AMA-Adjustment: OFAD Check and Alignment Calibration, 2008

The FGS1 AMA optimization proposal (11963) leaves the AMA mirror in a new position, which shifts the FGS1r FOV relative to FGS2r and FGS3 and has the potential to change the FGS1r OFAD solution. This proposal will use the astrometric open cluster NGC 5617 to check for 1 mas size changes in the OFAD and to establish the new alignment of FGS1r relative to FGS2r and FGS3 to a precision of approximately 25 mas. The OFAD check requires 4 HST orbits before, and 4 HST orbits after, the AMA adjustment. Each orbit observes the same stars in NGC 5617 with FGS1r in POS mode. The alignment aspect of this proposal uses data from these same orbits. The ICRS positions of the relevant stars are taken from the UCAC catalog, but the proper motions taken from the “special guide star plate ZZZT” provided by Yale University. We chose guide stars in FGS2r and FGS3, and astrometry targets that are common to GSC2, UCAC, and ZZZT. Each visit uses a unique guide star pair, so that all the visits taken together have guide stars spanning the guider FGSs FOV.

WFPC2 11944

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint to observe using ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass – radius relation.

WFPC2 11956

Hubble Heritage: Side B

We propose a program of 39 orbits to observe 6 targets with WFPC2 following a successful return to science using side B electronics. These observations will be used for Hubble Heritage releases in the months leading up to servicing mission 4. Because of launch delays, our reserve of releasable images is growing dangerously slim. We are proposing here to replenish one of our important lines of communication with the public.

We have carefully chosen targets that can efficiently use single pointings of WFPC2 to obtain images of visually striking and astrophysically interesting targets. Observations will reach high S/N and will be dithered and subsampled to improve the resolution and pixel scale to near ACS/WFC3 quality at a modest cost in exposure time. Most of the observations will schedule in the interim between a return to science and the availability of new science proposals that may be selected in response to an interim call for proposals.

WFPC2 11969

Satellite Search for Dawn Mission Targets, Vesta and Ceres

We propose to carry out a dedicated satellite search program for asteroids Vesta and Ceres. Despite being the two largest asteroids, and having clear evidence of a violent collisional history for Vesta, Vesta and Ceres do not have any satellites found so far, neither have there been any dedicated satellite search program for them reported. We propose to take short and long exposure mosaics to cover the whole Hill sphere while using specific observing strategies and image processing techniques to search in close to the center body. In addition to its significant scientific merit, this proposed project will be important for the planning of NASA’s Dawn mission. Currently Ceres is moving close to the Earth, making it more difficult to cover the whole stability region of satellites with minimal HST orbit requirement. Similar geometry will not repeat until the second half of 2009. Therefore we request DD time.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)




FGS GSacq 09 09 FGS REacq 01 01 OBAD with Maneuver 24 24


Flash Report:

The FGS1R AMA move and associated change of the Coarse Mode Angle check threshold was completed at 2009.022/13:17 UTC.

SpaceRef staff editor.