Abstract

Analyses of historical data suggest that the solar diameter may vary with time with an amplitude of a few tenths of a second of arc. The High Altitude Observatory has constructed a special purpose telescope, the Solar Diameter Monitor, designed to detect any such changes. The telescope is an f/50 transit instrument with an aperture of 10 cm and is almost completely automated to avoid observer bias. Each day at solar noon, it measures the sun’s horizontal diameter by timing the solar disk transit time and the vertical diameter by comparing the image size to that of a stable length standard. Preliminary estimates suggest that these observations will allow a test of the solar diameter’s constancy at the 1-sec of arc/century level in an observing time of 3–5 years.

© 1982 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Changes in the radiometric sensitivity of SeaWiFS determined from lunar and solar-based measurements

Robert A. Barnes, Robert E. Eplee, Frederick S. Patt, and Charles R. McClain
Appl. Opt. 38(21) 4649-4664 (1999)

Long-term analysis of GOME in-flight calibration parameters and instrument degradation

Melanie Coldewey-Egbers, Sander Slijkhuis, Bernd Aberle, and Diego Loyola
Appl. Opt. 47(26) 4749-4761 (2008)

Solar magnetic and velocity-field measurements: new instrument concepts

Jan O. Stenflo
Appl. Opt. 23(8) 1267-1278 (1984)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (7)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription