Guide for operating SAND-3 (HEFEI reference)

Data description

The data is contained in the following directory structure:

public_html/data/<YYYY>/<MM>

where <YYYY> is the year (4 digits) and <MM> the month (2 digits).

This directory contain:

1. one subdirectory for each day. Each of them contain the sky spectrums in .fits format.
2. one subdirectory for the sky webcam images acquired every 15 min. Those images are especially usefull to get an evaluation of the cloud cover before and after a given night. The webcam images are also used by the system to estimate the mean ambient light level.

Data download

The download of the data acquired during a given month should be done after the end of that month. To initiate the transfer, we need to know the IP address (<IP>) of the SAND-3 router. We use the secure ssh2 protocol with the non standard port 2022. To download the data you then need a ssh client of a ftp client capable of using the ssh2 protocol.

From the command line, you just have to type the following command to create a local directory:

Then dowloading:

Then the data may be concatenated and compressed

To kill an acquisition sequence

Then wait at least 15 min to let the ccd get back to ambient temperature. At any time you can read the ccd temperature by typing:

When the temperature is in equilibrium, restart an observing sequence: