Observations

A summary of the sky coverage, cadence, and image quality of the observations.

Sky coverage

Figure 1: A map of the DP2 coverage. Blue represents a density map of the number of visits; the quadrilaterals are 19-sided HEALPix, similar in size to the LSSTCam 9.6 square degree field of view. Open black squares mark the locations of tracts in the skymap, within which deep coadd images were made if there were a sufficient number of input visits.

Figure 2: A map of the i-band PSF limiting magnitude for DP2 deep coadd images. Deep coadd images are only made within the pre-defined tracts for which sufficient input visits exist. The total area covered by deep coadd images is approximatley 3000 square degrees.

Wide-fast-deep region

The region of sky covered somewhat similarly to the LSST’s future “wide-fast-deep” (WFD) stretches from Right Ascension ~240 to ~30 deg (passing through RA=0), and over a ~20 deg span of Declination. It is somewhat similar to the LSST in that it includes low-dust and dusty regions within the plane of the Milky Way, where the depth is shallower, as seen in Figure 2. The cadence and filter distribution are not representative of the future LSST strategy, and there are three small fields within this WFD region, as labeled in Figure 1, making it particularly non-uniform in depth (however, the future LSST sky coverage won’t be perfectly uniform in depth either, especially years with rolling cadence). Learn more about the WFD and the LSST strategy in the Survey strategy documentation.

Small fields

Selected to provide LSSTCam commissioning-era images for science validation across variety of environments (crowded, dusty, galactic, extragalactic, clustering, nebulosity, and so on). The small fields include M49 and Trifid-Lagoon, which produced the Rubin First Look images in June 2025. These coordinates are the mean RA and mean Dec for all visits associated with these fields.

Table 1: Small field survey area central coordinates.

Field Name	RA, Dec	RA, Dec [deg]
Abell 2764	00h22m00s -49d00m00s	5.5 -49
DESI SV3 R1	12h02m00s -00d18m00s	180.5 -0.3
M49	12h25m12s +06d54m00s	186.3 6.9
Prawn	16h54m00s -41d00m00s	253.5 -41
Trifid-Lagoon	18h06m48s -23d54m00s	271.7 -23.9
New Horizons	19h17m36s -20d12m00s	289.4 -20.2
Rubin SV 212 -7	14h06m48s -07d00m00s	211.7 -7
Rubin SV 216 -17	14h24m24s -16d42m00s	216.1 -16.7
Rubin SV 225 -40	15h00m00s -39d30m00s	225 -39.5
Rubin SV 280 -48	18h40m24s -48d00m00s	280.1 -48
Rubin SV 300 -41	20h01m12s -41d00m00s	300.3 -41
Rubin SV 320 -15	21h20m48s -15d06m00s	320.2 -15.1

Deep drilling fields

The LSST Deep Drilling Field (DDF) program includes 5 single-pointing fields, chosen to maximize multi-wavelength coverage with pre-existing surveys. The Euclid Deep Field South (EDFS) is larger and is split between an “a” and a “b” pointing which share the DDF visits. While these fields were covered during commissioning, observations did not follow the baseline DDF strategy (primarily, the seasons were short).

Table 2: Deep drilling field central coordinates.

Field Name	RA, Dec	RA, Dec [deg]
DDF ELAIS S1	00h38m00s -44d00m00s	9.5 -44
DDF XMM LSS	02h22m24s -04d48m00s	35.6 -4.8
DDF ECDFS	03h32m00s -28d06m00s	53 -28.1
DDF EDFS a	03h56m48s -49d12m00s	59.2 -49.2
DDF EDFS b	04h12m48s -47d48m00s	63.2 -47.8
DDF COSMOS	10h00m24s +02d06m00s	150.1 2.1

Visit images metadata

Filters

While observations in all six filters ugrizy are included in DP2, each field had a different distribution of visits per filter.

Table 3: Visit filter distribution by field.

Field Name	u	g	r	i	z	y	Total
DDF ELAIS S1	57	153	128	232	141	59	770
DDF XMM LSS	42	15	8	47	10	10	132
DDF ECDFS	10	61	50	96	61	11	289
DDF EDFS a	7	31	33	59	33	7	170
DDF EDFS b	5	37	33	57	33	7	172
DDF COSMOS	105	87	173	162	110	77	714
Abell 2764	0	6	0	2	0	0	8
DESI SV3 R1	0	0	0	3	0	0	3
M49	234	280	378	213	0	0	1105
Prawn	193	159	139	91	30	0	612
Trifid-Lagoon	231	201	129	119	9	6	695
New Horizons	37	53	77	116	80	33	396
Rubin SV 212 -7	0	139	187	123	0	0	449
Rubin SV 216 -17	0	27	28	59	0	0	114
Rubin SV 225 -40	307	524	391	381	239	104	1946
Rubin SV 280 -48	30	29	26	30	29	0	144
Rubin SV 300 -41	0	8	0	0	30	0	38
Rubin SV 320 -15	12	47	104	259	211	77	710
All	1964	4166	4856	7959	5809	3944	28698

Epochs

The number of visits, and the number of unique nights (epochs), varies by field.

Table 4: Number of visits and unique nights, by field.

Field Name	visits	nights	mean(visits/night)
DDF ELAIS S1	770	62	12
DDF XMM LSS	132	23	6
DDF ECDFS	289	37	8
DDF EDFS a	170	51	3
DDF EDFS b	172	50	3
DDF COSMOS	714	21	34
Abell 2764	8	2	4
DESI SV3 R1	3	1	3
M49	1105	7	158
Prawn	612	7	87
Trifid-Lagoon	695	23	30
New Horizons	396	24	16
Rubin SV 212 -7	449	5	90
Rubin SV 216 -17	114	2	57
Rubin SV 225 -40	1946	28	70
Rubin SV 280 -48	144	1	144
Rubin SV 300 -41	38	2	19
Rubin SV 320 -15	710	34	21
All	28698	131	219

Seeing

The DP2 images were acquired during commissioning, during which the Active Optics System (AOS) to stabilize image quality was also being commissioned for operations. These values are not representative of the future expected image quality distributions.

Table 5: The mean seeing (PSF FWHM in arcsec) across all detectors and visits.

Field Name	u	g	r	i	z	y
DDF ELAIS S1	1.63	1.51	1.51	1.32	1.46	1.33
DDF XMM LSS	1.52	1.24	1.08	1.01	0.99	0.94
DDF ECDFS	1.68	1.59	1.35	1.15	1.34	1.32
DDF EDFS a	1.56	1.39	1.39	1.12	1.29	0.94
DDF EDFS b	1.34	1.41	1.39	1.16	1.3	0.91
DDF COSMOS	1.36	1.16	1.25	1.14	1.17	1.22
Abell 2764	nan	1.01	nan	0.85	nan	nan
DESI SV3 R1	nan	nan	nan	1.47	nan	nan
M49	1.49	1.37	1.27	1.22	nan	nan
Prawn	1.49	1.38	1.28	1.24	1.42	nan
Trifid-Lagoon	1.22	1.15	1.15	1.03	1.1	1.55
New Horizons	1.26	1.36	1.12	1.04	1.01	1.12
Rubin SV 212 -7	nan	1.42	1.3	1.12	nan	nan
Rubin SV 216 -17	nan	1.35	1.25	1.32	nan	nan
Rubin SV 225 -40	1.5	1.42	1.27	1.24	1.31	1.25
Rubin SV 280 -48	1.69	1.54	1.51	1.34	1.53	nan
Rubin SV 300 -41	nan	1.86	nan	nan	1.65	nan
Rubin SV 320 -15	1.26	1.68	1.47	1.36	1.37	1.15
All	1.36	1.3	1.27	1.18	1.21	1.19

Magnitude limits

For the same reason as described above, these values are also not representative of the future expected mean depths per image (see LSST Key Numbers).

Table 6: The mean \(5\sigma\) PSF magnitude limit across all detectors and visits.

Field Name	u	g	r	i	z	y
DDF ELAIS S1	23.23	23.64	23.27	23.2	22.47	21.48
DDF XMM LSS	23.21	23.7	23.93	23.62	23.03	21.92
DDF ECDFS	23.01	23.52	23.17	23.42	22.57	21.68
DDF EDFS a	23.1	23.62	23.23	23.47	22.51	21.94
DDF EDFS b	23.26	23.68	23.25	23.42	22.48	21.96
DDF COSMOS	23.39	24.39	23.54	22.98	22.58	21.57
Abell 2764	nan	24.87	nan	23.41	nan	nan
DESI SV3 R1	nan	nan	nan	23.5	nan	nan
M49	23.29	24.3	23.85	23.44	nan	nan
Prawn	23.1	24.07	23.74	23.38	22.71	nan
Trifid-Lagoon	23.42	24.28	23.86	23.65	22.63	21.05
New Horizons	23.17	24.41	24.11	23.63	22.94	21.88
Rubin SV 212 -7	nan	24.23	23.83	23.71	nan	nan
Rubin SV 216 -17	nan	24.34	24.03	23.62	nan	nan
Rubin SV 225 -40	23.3	23.97	23.52	23.33	22.76	21.63
Rubin SV 280 -48	22.59	23.45	23.28	23.18	22.27	nan
Rubin SV 300 -41	nan	23.25	nan	nan	22.31	nan
Rubin SV 320 -15	23.55	24.08	23.29	23.05	22.39	21.67
All	23.37	24.12	23.58	23.32	22.65	21.68

Deep coadd images metadata

Depth

The \(5\sigma\) PSF magnitude depth of the deep coadd image at the center coordinates of each field

Table 7: Deep coadd PSF magnitude limits.

Field Name	u	g	r	i	z	y
DDF ELAIS S1	25.18	26.57	25.88	26.07	25.07	23.64
DDF XMM LSS	nan	nan	nan	nan	nan	nan
DDF ECDFS	24.35	25.84	25.47	25.87	24.76	22.23
DDF EDFS a	nan	25.63	25.53	25.65	24.53	23.08
DDF EDFS b	23.69	25.75	25.47	25.71	24.58	23.27
DDF COSMOS	25.77	26.73	26.35	25.94	25.0	23.69
Abell 2764	nan	25.88	nan	22.58	nan	nan
DESI SV3 R1	nan	nan	nan	nan	nan	nan
M49	25.62	27.03	26.72	26.05	nan	nan
Prawn	25.66	26.52	26.06	25.41	24.12	nan
Trifid-Lagoon	26.22	26.95	26.13	25.29	23.41	22.18
New Horizons	25.26	26.37	26.37	25.99	25.25	23.65
Rubin SV 212 -7	nan	26.81	26.56	26.09	nan	nan
Rubin SV 216 -17	nan	26.15	25.93	25.83	nan	nan
Rubin SV 225 -40	26.26	27.26	26.75	26.36	25.52	24.06
Rubin SV 280 -48	23.92	25.09	24.89	24.88	23.7	nan
Rubin SV 300 -41	nan	24.41	nan	nan	23.85	nan
Rubin SV 320 -15	24.09	24.82	24.42	24.99	24.21	22.42

PSF FWHM

The PSF FWHM of the deep coadd image at the center coordinates of each field.

Table 8: Deep coadd PSF FWHM, in arcseconds.

Field Name	u	g	r	i	z	y
DDF ELAIS S1	1.26	1.2	1.2	1.19	1.21	1.22
DDF XMM LSS	nan	nan	nan	nan	nan	nan
DDF ECDFS	1.19	1.18	1.03	1.06	1.01	1.36
DDF EDFS a	nan	1.16	1.09	1.01	1.11	0.96
DDF EDFS b	1.38	1.22	1.16	1.01	1.06	0.94
DDF COSMOS	1.3	1.09	1.17	1.02	1.11	1.12
Abell 2764	nan	1.0	nan	1.46	nan	nan
DESI SV3 R1	nan	nan	nan	nan	nan	nan
M49	1.38	1.26	1.19	1.16	nan	nan
Prawn	1.34	1.33	1.19	1.23	1.33	nan
Trifid-Lagoon	1.18	1.11	1.16	1.02	1.01	1.07
New Horizons	1.4	1.3	1.08	1.07	1.03	1.05
Rubin SV 212 -7	nan	1.26	1.23	1.11	nan	nan
Rubin SV 216 -17	nan	1.07	1.0	1.17	nan	nan
Rubin SV 225 -40	1.33	1.35	1.25	1.22	1.22	1.22
Rubin SV 280 -48	1.54	1.49	1.47	1.32	1.46	nan
Rubin SV 300 -41	nan	1.12	nan	nan	1.5	nan
Rubin SV 320 -15	1.08	1.41	1.19	1.26	1.24	1.15

Additional resources

See the Data quality page for interactive data quality plots, or the 301-series notebook Tutorials to recreate these tables and plots.