Table · dataset · 2021
A comparison of centering in ISS astrometry
Listed in IVOA Registry (Virtual Observatory)
In the caviar software package, a standard tool for astrometry of images from the Cassini imaging science subsystem (ISS), Gaussian fitting is used to measure the centre of point-like objects, achieving a typical precision of about 0.2 pixels.
Description
In this work, we consider how alternative methods may improve on this. We compare three traditional centroiding methods: two-dimensional Gaussian fitting, median, and modified moment.
Results using 56 selected images show that the centroiding precision of the modified moment method is significantly better than the other two methods, with standard deviations for all residuals in sample and line of 0.065 and 0.063 pixels, respectively, representing a factor of over 2 improvement compared to Gaussian fitting. Secondly, a comparison of observations using Cassini ISS images of Anthe is performed. Anthe results show a similar improvement.
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The modified moment method is then used to reduce all ISS images of Anthe during the period 2008-2017. The observed-minus-calculated residuals relative to the JPL SAT393 ephemeris are calculated. In terms of {alpha}xcos({delta}) and {delta} in the Cassini-centred international celestial reference frame, mean values of all residuals are close to 0km, and their standard deviations are less than 1km for narrow angle camera images, and about 4km for wide angle camera images.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/505/5253 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2021MNRAS.505.5253Z ui.adsabs.harvard.edu/abs/2021MNRAS.505.5253Z ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/mnras/505/5253 ↗
catalogue entry · from IVOA Registry
Topics
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Astronomical sciences 71% · Image 65% · Imaging 75%
Provenance · 1 source records, 10 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/mnras/505/5253 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:group:5101 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (71%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].local:modality:image | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (65%) |
| concepts[modality].local:modality:imaging | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (75%) |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |