Status & overview
What the array can observe at the moment, and what data already exist. Start here before planning an observation or a data request.
What is on sky tonight
16 of 20 telescopes are in routine operation. Units not listed as online are either awaiting installation or out of service for maintenance. Each operational unit carries a nine-slot filter wheel holding Sloan broad bands and a share of the medium-band set, so the number of distinct bands available on a given night depends on how many units are observing.
What a night produces
Over 754 observing nights since Oct 10, 2023, the array has recorded 2,199,304 science frames in 48,704 hours of open shutter. A typical night covers 36 tiles in 2,596 exposures and writes 375 GB of raw data, calibration frames included.
Medians rather than means: target-of-opportunity nights run to 24,570 exposures and would otherwise dominate the figure. Progress of each survey is on its own page — RIS, WTS and IMS.
Bands available
The filter set is what distinguishes 7DT from other survey arrays. Twenty medium bands of 25 nm width are spaced regularly at 25 nm from 400 to 875 nm. Fifteen further filters, installed in late 2025, fall between them with central wavelengths from 375 to 832 nm and bandwidths of 14 to 41 nm. Sloan g, r and i are carried by every unit; u is carried by one and z by three.
The original twenty are the calibrated set in operational use. Spectrophotometric calibration of the fifteen added filters is in preparation, and their central wavelengths are not aligned to a regular grid — check which bands a given tile actually carries on the data access page, which reports the medium bands observed on any tile.
| Original set (25 nm spacing) | 400, 425, 450, 475, 500, 525, 550, 575, 600, 625, 650, 675, 700, 725, 750, 775, 800, 825, 850, 875 |
|---|---|
| Added 2025 (irregular) | 375, 386, 412, 438, 462, 483, 512, 534, 561, 586, 615, 640, 661, 769, 832 |
| Broad bands | u, g, r, i, z |
Filter response curves
Curves are read from the reference data shipped with supy, which is also what its simulator module uses, so a response computed there matches this figure exactly.
What has been observed
60.9 percent of the reference tiling has been observed at least once: 15,513 of 25,472 tiles. A tile with data has calibrated images and a source catalog. Coverage per tile, including which bands were taken and how many frames exist, is on the sky coverage map.
Processing status
Data are reduced the same day they are taken. Raw frames are transferred from Chile overnight and a typical night clears the pipeline in about five hours of wall-clock time after transfer completes, so survey data are normally available the following day. Target-of-opportunity data skip compression and the wait for sunrise, which brings latency down to tens of minutes. What the pipeline produces, and the quality metrics attached to each product, are described under using the data.