May 21^st, 2001 APT Visit Planner Meeting

Attendees: Tricia Royle, Karla Peterson, Rusty Whitman, Chris Odea, Leslie Zimmerman, Jesse Doggett

We basically free-form discussed the thoughts in the agenda. (Actions are highlighted with double square [[brackets]].)

• Constraints are anything that affects how Spike schedules a Visit.

• An ExposureSpecification is probably the lowest level at which constraints can be applied to affect scheduling.

• Spike only has absolute, relative and physical constraints. In general, Spike absolute constraints map into "Base" constraints. Spike relative constraints map into either "Relational" or "Grouped" constraints. Spike physical constraints map into "External" constraints.

• For HST the coordinate constraints are no allowed to significantly change after Phase 1 without careful consider in due process.

• We need to decide if we should adopt the suggested constraint groups or stick with Spike's. The new groupings were derived from trying to consider the user's perspective. The Spike terminology is more familiar.

• [[Karla is going to make a list of current HST constraints so next time we can see how the two sets of groupings look with HST's constraints.]]

• [[Rusty is going to check out the current SEA's visit planner (this is a different thing from VOLT)]

• [[Jesse is going to contact Jeremy about giving a demo about VOLT with emphasis on observations for a single observatory observatory]]

• The APT data model terminology is NOT the terminology that will be for users. There currently is no language decided upon for users, so we're going to switch to using HST words. So, instead of ExposureCollection and ExposureSpecification, we're going to use Visit and Exposure.

• We're going to ask Tony Krueger to sit in as an expert on Spike.

• We will meet next week, probably switching to Thursday because of Memorial day.

The first thing we should do is determine the requirements for the Visit Planner. And, by requirements, I don't mean how the tool will function, how will it look, or how will it work. We should first determine the need we are trying to fill. This will become the charter for the Visit Planner from which all downstream decisions should support.

I had a discussion with Karla sometime ago and here are thoughts she helped me to thrash out (and subsequent expansion by me) about a visit planner.

An observer needs to know

• what the opportunities are to observe an ExposureCollection.*
• how to modify the constraints of an ExposureCollection to change the opportunities to observe.

The constraints which can affect the opportunities for observation can be divided into four categories which I call base, relational, grouped and external.

Base

Constraints used to describe an ExposureSpecification such coordinates, position angle or absolute time.

Relational

Constraints for an ExposureSpecification or ExposureCollection with respect to another ExposureSpecification or ExposureCollection such as same position angle or afterwards.

Group

Constraints for which no absolute value is required, but for which a group of ExposureCollections or ExposureSpecifications must be the same within a tolerance such as within so many days or use the same guide stars.

External

Constraints over which the observer as no control such as minimum sun distance.

The Visit Planner tool should be able to show an observer the opportunities to observe an ExposureCollection and have the capability to modify an ExposureCollection to change the opportunities for observation.