UseCase: PhotometrySearch

PrimaryActor:

Astronomer

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EndResult:

Synthesised colour data for a set of objects

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OtherActors:

type here

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PreConditions:

type here

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FlowOfEvents:

1. User has a large list of candidates with names in standard formats
2. User wants to select a sub-sample based on colour at optical wavelengths e.g. "V-I > 3"
3. Most of the objects in the parent sample have good photometry (some of the rest have poor photometry, some have spectrophotometry and some have nothing)
4. Relatively few have directly-comparable V and I measurements.
5. User makes the query as "V-I > 3",
6. The system searches all photometric and spectrophotometric data for in the range 400nm..1200nm
7. The system converts between filter and magnitude systems as appropriate.
8. The returned sub-sample is maximally complete - i.e. includes all borderline cases, but has flags for members made dubious by either statistical or systematic errors in photometry.

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PostCondition:

type here

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BasicAssumptions:

Three standardisations are required to process this sample selection:

• description of filter bands in wavelength/frequency terms so that all useful records can be easily found
• standard descriptions of photometric uncertainties
• easy translation between filter and magnitude systems

Filter photemetry is handled as coarse spectro-photometry

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AlternativeFlows:

type here

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KeyReferences:

Based on GTR use case: synthesise colour data for a set of objects

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GoodStyle: Please add comments below. This area should be used for refinement of the above document. If you want to ask questions or start a dialogue with the author, please use (or create) a topic in the Use Cases Forum.
Author: Once the refinements here and comments in the forum die down, perhaps you could rewrite the problem, incorporating the comments and refinements.

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-- NicholasWalton - 27 Jan 2002