The aim:

First of all, an explanation of how and why facilities are in the database (and hopefully an explanation of why some are not). This compendium is designed to collect information regarding facilities that might be used for extra-galactic survey astronomy. This was originally done as part of the Australian decadal review process (I was involved with the extra-galactic survey astronomy chapter) and the soon to be published 'SKA book' where our chapter investigated multi-wavelength extra-galaactic SKA synergies.

This discounts many stellar focussed survey facilities. It also discounts many significant facilities that do not offer substantial time to do survey work, and those that do not have a significant reputation for such work. The selection criteria are nebulous at best, but I have endeavoured to err on the side of inclusion. Some facilities have been genuinely missed, but others I had reason to discount. If you would like to see a facility added, or a number adjusted, please get in touch with me. I would appreciate a weblink and a paper reference on such occassions. My email is:

I hope you have fun playing with this, and constructive feedback is always welcome. Suffice to say, I do not need to be informed of whether or not 'the point' is apparent to you ;-)

Description of website contents:

The Plot tab displays the selected data from the database as a Gantt diagram of sorts, where the darkness of the colour bard reflects how 'fast' a particular facility is, given the figure of merit (FoM) constructed using the tick boxes mid-way down the side panel. The user is free to construct any FoM they believe best suits their experimental purposes.

Given inevitable variations in survey design there is not be a single FoM that covers all scientific purposes. For instance, for spectroscopic surveys an experiment designed to cover a huge area of sky at low redshift will need a large field of view but not necessarily huge multiplexing or collecting area given the distribution of sources on the sky. Equally, a high redshift study might need good multiplexing and a large collecting area but not a huge field of view. This said, typical FoMs seen in the literature include:

Imaging: Area.FoV/FWHM²

Spectra: Area.FoV.N_fib.R_spec/FWHM²

IFU: Area.FoV.N_fib.R_spec/FWHM²

Radio: (Area/T_sys)².FoV

The Table tab includes the raw information and the reference location (papers and weblinks) contained in the database. It also displays the dynamically calculated FoM given the selected options. The larger numbers reflect 'faster' facilities.

The user is also free to specify a new type of telescope using the options towards the bottom of the side panel. To display the new telescope they must select the 'Add new telescope to database/plot?'. They should also be careful to specify the 'Survey Type' and 'Wavelength Selection' in a meaningful manner. for instance it would be odd to create a new optical telescope for the Radio survey facilities.

Bugs: For reasons unknown to me you have to be on the Plot tab to update the page contents, i.e. the Table tab will only update if the Plot has already been regenerated. If you spot any other very odd behaviour please get in touch.