Hectospec
Observing Preparation

Get positions to better than 0.25 arcseconds

From Catalogs

• You should use only a large catalog with good sky coverage and good astrometry, such as the GSC II, 2MASS PSC, USNO-B1.0, and the smaller Tycho-2.

• The UCAC2 has more accurate positions but is incomplete, so sources may appear where you don't expect them.

• You may have problems using the GSC II as the STScI server is often down on weekends and at other awkward times.

• The catalog from which you select positions should contain all program objects plus guide stars.

• WCSTools scat should be able to convert anything reasonable into an acceptable input for the next step.

• Astrometric cluster catalogs are probably not OK because there usually will not be available guide stars on the same system.

From Images

• Use the procedure outlined on the "Getting Good Coordinates" web page to make catalogs for each image using WCSTools software using one of the above catalogs as the reference catalog. The large catalog can then provide guide star candidates.
• Software is still needed to merge catalogs into single project catalog.

Find fiber assignments and select guide stars

Do not go to the telescope without prepared and checked coordinate lists.