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Add Source Catalogs to Turtle

Modification Request #1 (C05 2005)

1. Introduction

This MR describes the changes to the GBT's Observation Management System (Code Named "Turtle") in this cycle for specifying positional information beyond spherical coordinate systems. This includes:

• The facilities available to specify positions in different ways. For example, specify a planet simply by its name, an extragalactic radio source by a single J2000 Ra and Dec, a comet by an Ephemeris or a satellite using the Nasa/Norad "two-line element" format.
• How these different formats can be used to define single objects in an observing script.
• How information for a set of objects can be read in from a catalog (ascii text file on disk).

The complete specifications may be found here (r1.25).

2. Background

Currently turtle provides the ability to control the antenna by movements specified in the common spherical coordinate systems, but does not allow referencing of positions by names and/or catalogs, nor does it allow specifications by mechanisms other than spherical, i.e., Ephemeris, NNTLE, and Conic. This MR describes these new abilities.

3. Requirements

Those portions of the requirements (r1.25) not being implemented this cycle are:

• Conic System for specifying positions
• Selection of subsets of catalogs
• Tracking radial velocities for NNTLE and CONIC type catalogs
• Automatic adjustment of scan specifications to transform them into legal antenna movements

4. Design

Offset

• Derive Offset and Trajectory from a new base class IOffset
• Data members cosv and coordinateMode and any methods pertaining only to them, e.g., GetCoordinateMode() or IsExpressedAsDegrees(), are defined in IOffset
• Declare pure virtual methods __eq__(), __repr__(), GetFinalOffset(), and GetTrajectory(scanLength) in IOffset to be defined in derived classes
• Define GetOffsets in Trajectory for generating primary offset segments

Location

• Derive the current Location (representing spherical locations) and the new classes EphemerisLocation and NNTLELocation from the new base class ILocation
• Declare GetSegments(startTime, scanLength) in ILocation for generating primary or user segments by derived classes

Turtle

• Change arguments of SetPrimarySegment() and SetPrimaryOffset() in TelescopeConnection to accept Location and Trajectory objects
• Absorb SetPrimaryOffsetTrajectory computations from TelescopeConnection into Trajectory
• The Antenna class in the ygor module generates Trajectory objects from Offset objects
• Trajectory objects specified outside of scans are translated into final Offset positions

Catalogs

• Implement new class Catalog in the user module containing (at minimum): a dictionary of attribute dictionaries indexed by source name, a list containing the original order of sources, and a class attribute which is the composite of all the objects across all defined catalogs
• Names are translated into Locations and set as the source in Telescope in the user module
• A Catalog is capable of parsing catalog formats for appending to its sources
• Implement EphemerisCatalog and parser
• Implement an internal Catalog called PlanetCatalog which is initially added to the composite catalog which computes rather than stores its Ephemerides
• Implement NNTLECatalog and parser

5. Deployment Checklist

Code

This MR only requires changes in turtle which is a subset of the source and installation of sparrow, so the normal sparrow installation steps will make all of the new capabilities available.

System Catalogs

The sponsor is responsible for selecting and populating the directory of system catalogs. The system.conf file in the telescope's installation needs to define the keyword CATALOGS to specify the directory's location.

Documentation

• The descriptions in the Observing API documentation need to be modified to reflect the new capabilities.
• The sponsor will provide a description of the creation and use of user-defined catalogs as part of the Observing API documentation.

6. Test Plan

Unit Tests

From the design, it is apparent that the changes required for this enhancement affect only the internal classes to turtle. Those classes which interact with systems outside turtle, e.g. Grail, the database, FITS files, and the user will not need to be modified. The result is that almost all the code can be exercised by adding unit tests, and augmenting and running current unit tests.

Integration Tests

Run scan types Track (with and without offsets), Daisy, and Peak on named objects and locations specified by spherical, NNTLE, and Ephemeris objects from both user and system catalogs.

Signatures

APPROVED: I acknowledge that my request is fully contained in this MR, and if the SDD delivers exactly what I specified, I will be happy.

ACCEPTED: I acknowledge that I have validated the completed code according to the acceptance tests, and I am happy with the results.

Status

Written	- MarkClark - 26 Jul 2005
Checked	- AmyShelton - 12 Jul 2005
Approved/Signed by Sponsor	- FrankGhigo - 12 Jul 2005
Approved/Signed by CCC	- RichardPrestage - 26 Jul 2005
Accepted/Delivered (spherical only)	- FrankGhigo - 13 Aug 2005
Accepted/Delivered	- FrankGhigo - 21 Sept 2005

Symbols:

• Use %X% if MR is not complete (will display )
• Use %Y% if MR iscomplete (will display )

CCC Discussion Area

We (Richard, John, Ron) discussed this MR at the 25th July 2005. Generally, it seemed fine. However, we prefer the names of sources not to have their case changed. "3C279" is spelt with capitcal "C" (stands for "Cambridge"). We would prefer that the system be case-insensitive (e.g. "Moon" = "moon" = "MOON", and "3C279" = "3c279" for someone who supplies it in lower case). But, we would prefer user-supplied source names not have their case changed. So, case changing should be done one-the-fly for comparison only. We discussed an issue (initially raised by Frank?) that this would potentially mean user's might have to take care of case in their own user-written scripts. We decided that was acceptable.

If Mark, Amy and Frank are happy with this, they should edit the "Catalogs" section above appropriately, and then I'll sign on behalf of the CCC. If not, we should talk further. -- RichardPrestage - 25 Jul 2005