000004334 001__ 4334
000004334 005__ 20191216115934.0
000004334 0247_ $$2DOI$$a10.1117/12.2536008
000004334 037__ $$aSCART-2019-0209
000004334 100__ $$aGaly, C.
000004334 245__ $$aStraylight analysis on ASPIICS, PROBA-3 coronagraph
000004334 260__ $$c2019
000004334 520__ $$aPROBA-3 is a mission devoted to the in-orbit demonstration (IOD) of precise formation flying (F²) techniques and technologies for future ESA missions. The mission includes two spacecraft. One of them will act as an external occulter for scientific observations of the solar corona from the other spacecraft, which will hold the ASPIICS coronagraph instrument, under CSL responsibility. The ASPIICS instrument on PROBA-3 looks at the solar corona through a refractive telescope, able to select 3 different spectral bands: Fe XIV line @ 530.4nm, He I D3 line @587.7nm, and the white-light spectral band [540;570nm]. The external occulter being located at ~ 150 meters from the instrument entrance, will allow ASPIICS to observe the corona really close to the solar limb, probably closer than any internally or externally occulted coronagraph ever observed. This paper will present the straylight model and analyses carried out by CSL. A first specificity of the analysis is that the scene on the useful Field of View (FOV) is the solar corona which has a brightness dynamic range as high as 103 between the close corona, close to 1 solar radius (Rsun), and the “distant” corona around 3RSun. The specifications are very stringent for this type of instrument. A consensus was found and will be presented regarding the expected straylight within the FOV. It will also be shown that to achieve realistic estimations it is required to take into account the exact location of the created straylight as well as the entrance field. The second specificity that had to be analyzed is that the diffraction from the solar disk by the external occulter enters the instrument un-obstructed until the internal occulter, and with a brightness 100 times higher than the close corona (~1RSun) brightness. The simulation of this diffraction as well as its propagation inside the ASPIICS telescope creating additional straylight, had to be carefully established in order to give realistic results of its impact on the performances while being actually possible to compute.
000004334 594__ $$aNO
000004334 6531_ $$aASPIICS
000004334 6531_ $$astraylight
000004334 700__ $$aThizy, C.
000004334 700__ $$aStockman, Y.
000004334 700__ $$aGalano, D.
000004334 700__ $$aRougeot, R.
000004334 700__ $$aMelich, R.
000004334 700__ $$aShestov, S.
000004334 700__ $$aLandini, F.
000004334 700__ $$aZukhov, A.
000004334 700__ $$aKirschner, V. 
000004334 700__ $$aHorodyska, P.
000004334 700__ $$aFineschi, S.
000004334 773__ $$n111802H$$pProc. SPIE 11180, International Conference on Space Optics — ICSO 2018$$v11180$$y2019
000004334 8560_ $$fsergei.shestov@observatoire.be
000004334 85642 $$ahttps://www.spiedigitallibrary.org/conference-proceedings-of-spie/11180/2536008/Straylight-analysis-on-ASPIICS-PROBA-3-coronagraph/10.1117/12.2536008.full
000004334 905__ $$apublished in
000004334 980__ $$aREFERD