A Region Target is an array of RA/Dec coordinate pairs to fill a region of the sky. Each coordinate pair specifies where one Segment of the Pass Plan will be executed. Planning for the Region Target must take segment dimensions into account, in addition to segment overlap and orientation. Coordinates may be calculated using APT's Region Planner, or may be planned externally to APT.

Region Planner

The Region Planner allows the user to create the pointings for a Region Target by specifying the perimeter of the region. The Region Planner calculates pointings required to cover the region using the selected Mosaic Pattern.

To open the Region Planner, click the Region Planner tab.

Region Boundary

Enter the RA and Dec of the vertices that define the region to be covered. The order of the vertices can produce polygons of different shapes, so the Region Viewer is provided to support visual verification and iteration.

Mosaic

Select a Mosaic Pattern from this program. If NONE is selected, a single WFI tile is used with Segment Width/Height of 25.3 x 49.4.

Segment Width/Height

Segment Width

Segment Height

Displays the Tiling Height and Tiling Width of the selected Mosaic Pattern . Not editable. Segment Width and Height take into account any shifts or overlaps defined for the Mosaic Pattern.

Segment Overlap

Segment Overlap

Enter the amount of Segment Overlap in arcminutes. Segment Overlap is applied in addition to any overlaps defined for the Mosaic Pattern.

Aperture PA

Aperture PA

See also: Planned V3PA

Enter Aperture PA (Position Angle) in degrees, or use the slider. Aperture PA is the orientation of each segment covering the region while planning the Region Target. Note that  Aperture PA has no effect on the execution of the Observation of this Region Target. To request a specific orientation of the observations, use the  V3 PA Range special requirement.

 For more information about Roman orientation, see Coordinate Systems.

Tile Count

Tile Count

Displays the total number of region tiles planned for the region target. Unless otherwise stated, the word "tile" in this article means the extent of the segments - which is the size of the selected mosaic. The number is calculated by the APT software and cannot be manually edited. 

Apply Plan to Target

Click Apply Plan to Target to apply all the calculated pointing coordinates to the Region Target. All coordinates currently in the Region Target will be overwritten. 

Region Viewer

The Region Viewer shows an approximation of the segments required to cover the region specified. Segments are shown with the specified Segment Overlap and Tiling Orient. 

Region Information

A Region Target  is defined on the Region Information tab using a number of parameters described below. 

Number

Number Each target in your Program will be assigned its own unique number by APT but may be changed by the user (as long as it remains unique within the program). Number is required and may be from  1 TO 999 .

Name

Name  is a name you provide for the target within the Program. It provides a unique designation for a target for use throughout the Program. A name is required and must be 2 to 31 characters in length.

• Name may use upper and lower case letters, numbers, and “.”, “+”, “-”, and "_". No other characters are allowed including blanks.
• Same name with different case is not allowed (example: "M33" and "m33" is not allowed in the same program).

Resolvable Name

Resolvable Name is a name you provide for use by the Archive. Using a common name for the target (e.g. CRABNEBULA instead of NGC1952) can make a program more readable. Annotating the name (e.g. CRAB1, CRAB2) may be useful when sampling parts of an extended object. However, these names are not as helpful for people searching the Archive. So the Resolvable Name is an optional second target name. Proposers and archival researchers use these names to determine whether Roman has observed a particular object. This facility will be most useful if the names supplied are resolvable with standard name resolvers such as NED or SIMBAD.  

Resolvable Name is not required, but if used must be 2 to 31 characters in length.

Reference Position

The orientation of all segments in a Region Target is represented with respect to its Reference Position , specified as a single RA/Dec point. Reference Position is required and may be entered manually or automatically.

To add the Reference Position  automatically, click the Set Reference Position button below the list of coordinates. APT calculates the Reference Position as the center of all the Region Coordinates.

Right ascension ( RA ) and declination ( Dec ) must be entered as ICRS coordinates (International Celestial Reference System).

• RA may be entered in HMS format (hh mm ss.ssss) or as decimal degrees (ddd.dddd). Decimal numbers will be converted to HMS. 
• Dec may be entered in DMS format (dd mm ss.ssss) or as decimal degrees (ddd.dddd). Decimal degrees will be converted to DMS.

Planned V3PA

Planned V3PA is the spacecraft orientation (Position Angle) assumed when planning the region target. Planned V3PA is required. Allowed range is 0.0 TO 360.0 degrees.

Region Coordinates

The right ascension ( RA ) and declination ( Dec ) for the pointings necessary to cover the region are required and must be entered as ICRS coordinates. Note that a Region Target is not required to be geometrically continuous.

• RA may be entered in HMS format (hh mm ss.ssss) or as decimal degrees (ddd.dddd). Decimal numbers will be converted to HMS. 
• Dec may be entered in DMS format (dd mm ss.ssss) or as decimal degrees (ddd.dddd). Decimal degrees will be converted to DMS.

There are options to Add, Import, Export, Set Reference Position, Duplicate, and Remove.

For additional questions not answered in this article, please contact the Roman Help Desk.