ULTRACAM Observing Checklist

The purpose of this is to provide a one-stop shop of reminders for what to do when ULTRACAM observing. The emphasis is on being brief. This is tilted towards NTT observing.

Last updated: 13 January 2026 (by VSD)

Afternoon

• Has last night's data copied correctly? Be absolutely sure it has.
• Is there enough space available for the upcoming night?
• Do you need a filter change?
• If you're on La Silla, go up to do the hardware checks (no water leaks, etc)
• Make sure no lights are on anywhere.
• Start with full frame biases. Check noise and bias levels with Vik's quality control script. Repeat if not in spec.
• Take biases for last nights' data formats. (See pipeline script 'unique'.) It is vital that every different windowing, binning and readout noise setup used for science has bias frames taken for it.
• Make sure you know when sunset is for sky flats.

Start of night

• Take sky flats. Try to start while peppered. Ensure guide probes are parked and that the TO has started the telescope spiralling script to avoid stars appearing in the flat.
• Ask the TO to perform the active optics (AO) calibrate procedure (this takes about 10 minutes).
• Move to flux standard. If observing over many nights, try to observe standards spanning a good range of colours.
• Remember to make sure guide probes don't vignette the field.
• Get going on flux standard (use a readout mode with a clear); start a reduce script in order to measure focus.
• Note the focus value and the telescope temperature.
• Move to science targets.

During night

• Make sure you have the right filters in and the right ones listed in udriver.
• For new targets, get Stu Littlefair's ufinder finding chart tool going as you may have to adjust position.
• Move to target, set rotator angle while doing so.
• Check positions of target and comparisons; take account of bad pixels in all CCDs.
• Is the exposure OK? Are the counts in all three CCDs OK?
• If using drift mode, put the focal plane mask in; if you previously used drift mode, take the mask out!
• Get running, but don't relax just yet ...
• Set up a reduce script asap; you need it to keep an eye on the focus.
• Save the final setup on udriver - it makes the job of taking bias frames in each setup much easier the following afternoon.
• Keep an eye on the FWHM in all CCDs. The NTT is esepcially bad in this regard and can never be left alone for long. Record focus/temperature values after you make any adjustments.
• Now you can relax.
• Remember to write the blog for the night: problems, weather etc.
• If you hit problems and need to power off/on, always take a swift bias as the first exposure to check all is OK.

End of night

• If this is the last night of the run (so there is no ULTRACAM observer tomorrow night), take biases for all of the different window/bin/readout-speed setups you used during the night.
• Another chance for sky flats, especially if you had to change filters at all.
• Home the focal-plane slide (in case ESO need to move the M4 mirror).
• Tell the TO that is it.
• Finish night blog.
• Get Paul Kerry's data copying stuff going.
• Go to bed.