The ULTRACAM Pipeline Software Version 9.10 Home Page

This is the main page for documentation on the ULTRACAM pipeline software. The purpose of this software is to enable reduction and analysis of ULTRACAM multi-CCD data. The software comes as a suite of stand-alone programs which carry out various obvious operations, such as adding two frames etc. The 'look & feel' is based upon STARLINK packages such as FIGARO and KAPPA, with a few differences. See the section on user input for more details; you should read this at least once, whether or not you are familiar with STARLINK software.

What is 'ULTRACAM'?

ULTRACAM is a high-speed CCD camera for astronomy; see Vik Dhillon's ULTRACAM pages for extensive details of it. The pipeline software is dedicated to turning the raw data that ULTRACAM produces in abundance into something understandable.

Overview of the Software

There are two main aspects to the pipeline software. First, data from the instrument is stored in two files, one an XML file containing a description of the data format, and named something like 'run034.xml', and the other a single large file containg all the raw data and times of a given run called in this case 'run034.dat'. Since a run could be many minutes or even hours on one target at high-speed, these data files can be very large. Owing to filesystems limitations they used to be no more than 2GB, and although they can now exceed this, they rarely do in practice. The pipeline software can interact with these files through several programs, collectively part of the Observing class. You can expect to need these programs quite a bit during an observing run. They access the raw data files through a server (the 'ATC server'). They make http requests and the server delivers the data over the network. You will need to have this server installed and running before using any of these programs in this way (unless you have the files on a local disk in which case the server is not required).

The second side of the pipeline software is all the other programs. These work on individual files, 1 per exposure, in the spirit of standard CCD observing, except that each file contains multiple (3 in the case of ULTRACAM) CCDs-worth of data. Thus a single 'run' could be split into hundreds of individual frames (see the program grab). These individual files come with the extension ".ucm". Most of the pipeline programs operate on these files. You can also convert them to FITS for display with other programs such as 'GAIA' (GAIA in particular makes a nice job of the multiple HDUs that are typically created).

Batch processing

If you expect to carry out batch processing with more than one ultracam program running simultaneously, you should review the nodefs option of the user input section or, better still, make use of the ability to redirect the location of the defaults files, again described in the user input section.

Reduce data file

The main reduction program reduce is primarily controlled through an ASCII input file. Although I try not to change the format of this file more than necessary, it does sometimes have to be updated. Download this file for an up-to-date example file which is compatible with version 9.10 of the pipeline.

Useful links to the pipeline and related material

Alphabetical Alphabetical list of all programs.
Classified Programs classified into groups of related purpose.
Getting Started A quick guide to getting going, useful during observing.
PDF guide A somewhat more detailed look at reduction.
User input How to specify command input, what options are available.
reduce file Example of the ASCII file for controlling the main reduction program, reduce.
Errors Descriptions of the meanings of error messages that you may encounter.
Timing A description of how the GPS timestamps are translated into the times listed by the pipeline. If you are interested in precise absolute times, be aware that the correctness of everything has yet to be demonstrated.
FAQ Frequently Asked Questions. If you are puzzled about something, perhaps the solution is here.
Calibration Page of information on aspects of ULTRACAM calibration.
Biases Database of bias frames. May save yourself some effort by downloading these.


Please refer to my main software page, for installation details.

Page generated Fri Jul 5 12:23:42 2013