A novel quadruple beam imaging polarimeter and its application to Comet Tanaka-Machholz 1992 X

Geyer, E. H.; Jockers, K.; Kiselev, N. N.; Chernova, G. P.

doi:10.1007/bf00645780

Cited by 32 publications

(18 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The focal reducer of the MaxPlanck Institute für Aeronomy (Germany) was used with a four-beam Wollaston assembly as a polarimetric analyser as described by Geyer et al (1996). The focal reducer was equipped with a CCD camera.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

CCD imaging polarimetry of Comet 2P/Encke

Kiselev¹,

Jockers

Bonev

2004

Icarus

View full text Add to dashboard Cite

Section: Observations and Data Reductionmentioning

confidence: 99%

CCD imaging polarimetry of Comet 2P/Encke

Kiselev¹,

Jockers

Bonev

2004

Icarus

View full text Add to dashboard Cite

“…Geyer et al 1996;Jockers et al 2000). In this way four polarization images are generated simultaneously on the CCD detector.…”

Section: Overviewmentioning

confidence: 99%

“…The errors of polarization degree σ P and angle σ θ were determined from the photon statistics of the counts (total intensity) of comet and background contained in the sum of useful images. The following equations were used (Shakhovskoy & Efimov 1972;Geyer et al 1996):…”

Section: Data Reduction Of Imaging Polarimetrymentioning

confidence: 99%

CCD imaging and aperture polarimetry of comet 2P/Encke: are there two polarimetric classes of comets?

Jockers¹,

Kiselev²,

Bonev³

et al. 2005

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. We present results of imaging and aperture polarimetry of the dust of comet 2P/Encke at phase angles [91][92][93][94][95][96][97][98][99][100][101][102][103][104][105] • , obtained during the 2003 apparition. We investigate how strongly molecular emissions transmitted by the filters used in the observations can affect the resulting polarization of cometary dust. This problem is of particular importance for so-called gasrich comets like comet 2P/Encke which has particularly strong molecular emission as compared to its dust continuum. Aperture polarimetry in the wide-band UBVR filters was performed at the 2.6-m Shain telescope and 1.25-m telescope of the Crimean Astrophysical Observatory on November 17-24. From these measurements a dust polarization of ≈8% is derived, which puts the comet in the class of comets with low polarization. The imaging observations of comet 2P/Encke were carried out at the 2-m telescope of the Bulgarian National Astronomical Observatory on November 20-22, 2003. Narrow-band filters centered on the 0-7-0 transition of the Ã 2 A 1 -X 2 B 1 electronic band system of NH 2 (662 nm) and on an adjacent red continuum at 642 nm were employed. The polarization of NH 2 averaged over the 0-7-0 vibronic transition amounts to ≈7% at phase angles close 90• , similar to the polarization of the two-atomic molecules CN and C 2 . The dust polarization however, when corrected for the effect of molecular emissions, is larger than 30%. We conclude that the division of comets into two polarimetric classes with one class having in the visual wavelength range a maximum polarization less than 20% is caused by ignoring the contribution of molecular emission and therefore is an artifact. Whether the comet displays a strong silicate feature (i.e. its dust grains are small) or not, the dust polarization is high.

show abstract

“…In the case of a object having a slow flux-distribution spatially, the polarization error is estimated to be < .P =200/%. Any cross-talk ghosts between o-and e-images, described by Geyer et al (1996), are not visible.…”

Section: Ghost Imagementioning

confidence: 99%

“…However, OOPS is not suitable for extended objects because e-images obtained using the Rochon prism show severe distortions and lateral chromatic aberrations; this means that e-images are not available for improving the S=N ratio (see Furusho et al 1999 for more details). Geyer et al (1996) developed a unique polarimeter, called the quadruple-beam polarimeter; it uses a pair of Wollaston prisms to produce four fully polarized beams having polarization angles of 0 ı , 90 ı , 45 ı , and 135 ı . Owing to simultaneous measurements of four position angles, both Q=I and U=I images can be obtained in a single exposure.…”

Section: Introductionmentioning

confidence: 99%

Polarimetric Imager for Comets, PICO

Ikeda¹,

Kawakita²,

Furusho³

et al. 2007

Publications of the Astronomical Society of Japan

View full text Add to dashboard Cite

We constructed an imaging polarimeter, PICO, that was optimized for comets and/or cometary objects. PICO has a field-of-view of 5 0 10 0 and employs a fixed Wollaston prism as an analyzer. In the case of polarimeters using a double-beam prism, such as a Wollaston prism, lateral chromatic aberrations originating from the prism often degrade the image quality and measurement accuracy. However, PICO suffers little lateral chromatic aberration due to compensation provided by newly designed lens systems that generate opposite lateral colors. Owing to this design, PICO can obtain highly resolved and very accurate polarization images throughout the FOV (field-of-view). The total accuracy is estimated to be ∆P ' OE.P =85/ 2 + 0:3 2 1=2 % in polarization degree and Â Ä 3 ı in position angle; these values are satisfactory for cometary studies.

show abstract

A novel quadruple beam imaging polarimeter and its application to Comet Tanaka-Machholz 1992 X

Cited by 32 publications

References 10 publications

CCD imaging polarimetry of Comet 2P/Encke

CCD imaging polarimetry of Comet 2P/Encke

CCD imaging and aperture polarimetry of comet 2P/Encke: are there two polarimetric classes of comets?

Polarimetric Imager for Comets, PICO

Contact Info

Product

Resources

About