Good Target Names
In order to improve searchability and general utility of the Chandra archive,
we are asking that observers double-check that their target names carry
sufficient information to unequivocally identify the astronomical source
or area of the sky observed and follow
With the exception of TOO observations where the target is not yet
known, observers should therefore:
Check that the target name is recognized as a unique source by at least one
of the following:
If the target name is not recognized by either of the services above,
the next step is to check if there is an existing "resolvable" name,
i.e., one that corresponds unambiguously to a unique set of sky coordinates
and that can be "resolved" into these coordinates, following these guidelines:
- Please do not use underscores "_" in your target name. Instead,
use blanks " " or no space.
- If your target is spatially associated with, contained in, superimposed on,
or part of an extended/diffuse astronomical source with a resolvable
designation (for example, a stellar source in a globular cluster or
galaxy with a resolvable target name), please prepend the resolvable
name of the "parent" object to your target name,
e.g., "M31 BHXN", where BHXN stands for Black Hole X-ray Nova.
- When available, use a catalog identifier (or a reference for the
paper containing the catalog), or more generally any useful "subcomponent"
of the designation as defined at
in the target name.
- Check that the field coordinates part is correct and carries
enough spatial resolution
Sometimes, no practical resolvable name will be available, but a
suitably informative name can be assigned. Such cases may include:
- Composite target names, which do not resolve as a whole but
contain resolvable substrings, e.g., "Abell1882 - Filament #1"
- Surveys, deep fields, etc. that have no single "center" or "location"
attached to them
- Transients, variable sources, or EM counterparts of multi-messenger
events. Their designations do not usually follow IAU specifications
and are not immediately resolvable (e.g.,, "GW170817" was not
resolvable for more than 1 year after detection) but they are
distinguishable and clear.
Observers can also check if the target was observed in the past but
with a different name in the Chandra Archive by using
and may consider using that name.
For additional help, please contact email@example.com.
for more information on the Chandra Archive Operations team's
work on this subject.