01 Apr 2023 04:23 UT
logo
previous/precedent
next/suivant
Enter a date: Ex: 28/3/2001, 28.3.1, 28-3-01,YYYYMMDD or YYMMDD
language button
MySelection
NEWS
2023-01-30130 years of spectroheliograms at Paris-Meudon observatories (1892-2022) BASS2000
Broad-band observations of the solar photosphere began in Meudon in 1875 under the auspices of Jules Janssen.

For his part, Henri Deslandres initiated imaging spectroscopy in 1892 at Paris observatory. He invented, concurrently with George Hale in Kenwood (USA) but quite independently, the spectroheliograph designed for monochromatic imagery of the solar atmosphere. Deslandres developed two kinds of spectrographs: the "spectrohéliographe des formes", i.e. the narrow bandpass instrument to reveal chromospheric structures (such as filaments, prominences, plages and active regions); and the "spectrohéliographe des vitesses", i.e. the section spectroheliograph to record line profiles of cross sections of the Sun with a 20'-30' spatial step. This second apparatus was intended to measure the velocities (more exactly the Dopplershifts) of dynamic features. Deslandres moved to Meudon in 1898 with his instruments and tested various combinations, in order to improve the spectral and spatial resolutions, leading to the final large quadruple spectroheliograph in 1908. CaII K systematic observations started at this date and were followed in 1909 by Hα.

The service was organized by Lucien d’Azambuja and continues today. Optical and mechanical parts were revisited in 1989 and the digital technology was introduced in 2002. Full line profiles are registered for all pixels of the Sun since 2018, so that the instrument produces now data-cubes. The collection is one of the longest available (more than 100 000 observations). It contains sporadic images from 1893 to 1907 (during the development phase) and systematic observations along 10 solar cycles since 1908, in Hα and CaII K lines.

This paper summarizes 130 years of observations, instrumental research and technical advances.

Lire


 Other News
2021-06-11Video of the partial eclipse of 10 June 2021BASS2000Read ...
2020-04-17License for BASS2000 dataBASS2000Read ...
2019-12-06Data and instruments guides updatedBASS2000Read ...
2019-11-26Data access available!BASS2000Read ...
2019-11-21Data access suspended until 2019-11-27BASS2000Read ...
2019-05-291919 eclipse!Bass2000Read ...
2018-12-17F.A.Q. available!Bass2000Read ...
2018-03-21Latest data from Heliophysics Features CatalogueBass2000Read ...
2018-03-06How to contact BASS2000?Bass2000Read ...
2017-09-01Migration of BASS2000 serversBass2000Read ...
2017-06-28SPECTROCAM: new camera for the Spectroheliograph of MeudonBass2000Read ...
2017-03-09Synoptic data from year 1919BASS2000Read ...
2016-11-15New Webcam availableBass2000Read ...
2016-07-25Solar Spectrum tool updatedC ReniéRead ...
2015-03-11Link to HELIO Features CatalogC. ReniéRead ...
2015-02-23Status of Nancay RadioHeliographNRH teamRead ...
2014-02-25Update of the ephemerids and solar grid serviceC. RenieRead ...
2013-08-07Stopped or degraded NRH observationsA. KerdraonRead ...
2013-02-20New Educational resourcesC. ReniéRead ...
2012-12-06New observations at Meudon Solar TowerJ. AboudarhamRead ...
2008-08-08New version!Read ...
2008-08-01Movies from CLIMSORead ...
2008-06-19HeI observations from CLIMSORead ...
2008-01-22Green continuum images from Meudon HeliographRead ...
2007-11-09New data from Meudon HeliographRead ...
2007-10-18CaK observations from CLIMSORead ...
2007-06-15New data from CLIMSORead ...
2006-02-20Solar Spectrum in UVC. ReniéRead ...
2005-11-10Nancay Total Radio Flux AntennaA. KerdraonRead ...
2004-08-31Update of the Web SiteC. ReniéRead ...
2004-05-27Venus transit - June 8, 2004J-M MalherbeRead ...
2003-06-02May 31, 2003: pictures of the solar eclipse-Read ...
2003-04-25Mercury Transit - May 7, 2003J-M MalherbeRead ...
2003-02-28EGSO software for Meudon spectroheliograph FITS dataN.FullerRead ...
2003-01-28New Meudon's webcam: White lightJ-M MalherbeRead ...
2002-10-02Welcome to the new BASS2000 Solar Survey databaseJ. AboudarhamRead ...
Data availability - About - Copyright - Contact WDC-Solar Activity, Regular Member of
Last update: 17 Apr 2020 14:46