CADC The Canadian Astronomy Data Centre
If you have used CADC facilities for your research, please include the following acknowledgment:
This research used the facilities of the Canadian Astronomy Data Centre operated
by the National Research Council of Canada with the support of the Canadian Space Agency.
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The CADC website is undergoing major changes to improve appearance, web content accessibility and functionality in both official languages. The goal is to provide simpler and more effective ways to access CADC services. Many older CADC web pages will no longer be accessible after April 2014. If you require assistance with this transition please email us here cadc@nrc.gc.ca .

Le site du CCDA subit une transformation majeure pour améliorer l'apparence, l'accessibilité aux contenus Web et la fonctionnalité dans les deux langues officielles. L'objectif est de fournir des moyens simples et plus efficaces pour accéder aux services du CCDA. De nombreuses pages Web anciennes du CCDA ne seront plus accessibles après avril 2014. Si vous avez besoin d'aide avec cette transition, s'il vous plaît, communiquez avec nous ici ccda@cnrc.gc.ca.

MegaPrime Elixir Nightly Photometric Solution Query Help


General Description

This form can be used by registered CFHTLS users to browse the catalog of Elixir nightly photometric solutions. These solutions are computed using all standard star observations taken during the nights for which they apply. The basic relevant photometric equations are:
where m is the instrumental magnitude in the internal photometric system, DN are counts in digital units, EXPTIME is the exposure time in seconds, M is the calibrated magnitude in the target photometric system, Zp_obs is the observed zeropoint, C_airmass is the airmass term, C_color is the color term, FILTER1 is the magnitude measured in the filter specified by FILTER1, and FILTER2 is the magnitude measured in the filter specified by FILTER2.

Queries are executed based upon time constraints. The time span of a nightly photometric solution must be between Start and Stop (below) time in order to be returned by the query.

Time Constraints

Field Name Description
Start Time Start time of search period.
Stop Time Stop time of search period.


Photometric Constraints

Field Name Description
Zp_obs Observed zeropoint for nightly photometric solution.
Zp_ref Reference zeropoint for nightly photometric solution.
Zp_err Zeropoint error for nightly photometric solution.
C_airmass Airmass term for nightly photometric solution.
C_color Color term for nightly photometric solution.
Filter1 Name of first filter used for color term in nightly photometric solution.
Filter2 Name of second filter used for color term in nightly photometric solution.
Int_Phot_Sys Name of internal (i.e., instrumental) photometric system.
Ref_Phot_Sys Name of target photometric system.
NStars Number of stars used in computing nightly photometric solution.
NTimes Number of observations used in computing nightly photometric solution.