Chandra Archive and Target FAQs
- What is the Chandra Observation Catalog (OCAT)?
- How do I find out which targets have been observed, or will be observed, with Chandra?
- How do I download Chandra data?
- What is the status of my observation?
- Has my data been processed (or re-processed?)
- When does data on my favourite target become
public?
- Where do I find scheduling Information?
Q: What is the Chandra Observation Catalog (OCAT)?
The Chandra Observation Catalog (OCAT) includes information on ALL
Chandra observations, planned/completed, along with their status.
Q: How do I find out which targets have been observed, or will be
observed, with Chandra?
Search the OCAT. There are two ways to do this:
- The Chandra Target Search Form is a simple
HTML-based search routine with access to abstracts, observation planning and status
information for each target. It is possible to use SIMBAD to search
for a target, and DSS and ROSAT images are given for
most fields.
- ChaSeR is a Java application which
must be installed on a user's local machine or system. ChaSeR can be
used to search the Archive as well as to download data. A limited
version of this tool is also available via a web interface, WebChaSeR.
Plain ASCII lists of approved targets are also available here. These lists include targets
accepted from Chandra peer reviews, targets accepted from
the Hubble review as part of the joint Hubble/Chandra time
swap, and a list of observed targets. It also gives lists
of Director's Discretionary Time targets, and Targets of Opportunity.
Q: How do I download Chandra data?
There are several ways to download data:
- Using ChaSeR, observations may be
searched for using a variety of criteria and then specific products
may be selected and downloaded. Note that more than one ObsID may be
downloaded at a time. This is also the interface through which
proprietary data may be downloaded. Note that ChaSeR, a Java
application, must first be
installed on a user's machine or network.
An example showing how to install and use ChaSeR is given in the How To Download Chandra Data
From The Archive thread.
- WebChaSeR
is a web-based version of ChaSeR, so no installation is required.
However, it currently has limited capabilities; for example, data
products can only be batch downloaded in either Primary or Secondary bundles.
- Chandra Data can also be downloaded using the Provisional Search and Retrieve Interface. However, you need to know the ObsID in advance to be able to use the Provisional Search and Retrieve Interface. The ObsID for a given target can be found from the Target Search Form.
Q: What is the status of my observation?
Status information can be obtained via the Target Search Form, WebChaSeR
(note that not all "status" fields are selected by default), or ChaSeR. The status can be:
unobserved, scheduled, partially observed, observed, or archived.
Note that the status of a target changes from UNOBSERVED to OBSERVED
only when the data have been processed and inspected by a V&V
scientist; it may remain listed as SCHEDULED even after the actual observation as
taken place.
Q: Has my data been processed (or re-processed?)
The Processing Status Tool gives information on pipeline processing.
- If you know the ObsID of the observation in question, go to the Processing Status Tool.
- If you don't know the ObsID, use the Target Search Form to search for a target using the Simbad name resolver or search by PI name. Click on the status link to get the appropriate Processing Status Table.
Note: the Processing Status Table only has information on observations where data has been received by the CXC. If no data has been received there will be no link from the Target Search Form.
Q: When does data on my favorite target become public?
The Processing Status Tool gives the date an observation becomes public.
- If you know the ObsID of the observation in question, go to the Processing Status Tool.
- If you don't know the ObsID, use the Target Search Form to search for a target using the Simbad name resolver or search by PI name. Click on the status link to get the appropriate Processing Status Table.
Q: Where do I find scheduling Information?
- The Short Term Schedule provides a detailed list of each week of observing
once planned (1-2 weeks ahead of current time) and back to the beginning
of the mission.
- The Long Term Schedule lists the long-term plan forward from the current date
including primarily observations which are time constrained
Last modified:
08/11/05
