astro-legacy-archive/iras-sky-flux-plates

IRAS Sky Flux Plates

[image]

IRAS high-resolution hours-confirmed survey intensity and statistical-weight plates in the four survey bands.

Data structure

Each represented .INTE or .STAT archive member is one source-named configuration. Raw FITS axes and any whole-pixel truncation are retained.

The holding has 4,827 source-named configurations from 212 served archives containing 4,832 members. Raw values, source order, FITS image axes and structured provenance are retained. For archived products, the source archive and member are both pinned. FITS BSCALE, BZERO, BUNIT, and BLANK cards are recorded in the structured decode record but are not applied to stored raw values.

Configuration grammar

PLnnnHnBm.TYPE identifies plate nnn, confirming survey pass H1–H3, band B1–B4 (12, 25, 60, or 100 µm), and an intensity (INTE) or statistical-weight (STAT) map. HCON-1 and HCON-2 interleave observations separated by about 1–2 weeks; HCON-3 was observed after the first six months. Archive membership varies because not every plate has all three passes.

Physical interpretation

The source describes nominal 16.5° gnomonic fields spaced about 15° apart, sampled at 2 arcmin with effective 4–6 arcmin resolution. The retained FITS WCS gives equatorial right ascension and declination at EME50, with coordinates referring to pixel centres. The projection is neither conformal nor equal-area: at a field edge its maximum angle and area distortions are 0.6° and 6%, and integrating fixed intensity contours overestimates flux.

How to use

Install in an isolated environment with python -m venv .venv && .venv/bin/pip install datasets huggingface_hub pyarrow.

import numpy as np
from datasets import load_dataset
data = load_dataset("astro-legacy-archive/iras-sky-flux-plates", "PL001H1B1.INTE", split="train[:1]")
raw = np.asarray(data[0]["PL001H1B1.INTE"])
physical = np.where(raw == -2000000000, np.nan, 0.0 + 0.05623824 * raw)
print(float(np.nanmin(physical)), float(np.nanmax(physical)))

14973988.608481921 19147958.89419984

import json, pyarrow.parquet as pq
from huggingface_hub import hf_hub_download
path = hf_hub_download("astro-legacy-archive/iras-sky-flux-plates", "PL001H1B1.INTE.parquet", repo_type="dataset")
meta = json.loads(pq.read_metadata(path).metadata[b"grid_map"])
print(meta["image"]["decode"].get("bunit", {}).get("value"), meta["image"]["decode"].get("blank", {}).get("value"))

JY/SR -2000000000

Interpretation notes

Five named members of 090.tar contain only zero bytes and therefore carry no measurement or FITS structure. They are excluded under the measurement-scope rule and pinned in facts.yaml so the 4,827 represented configurations reconcile with all 4,832 served archive members.

ISSA superseded these version 1.0 (1984 November) plates with improved destriping and zodiacal-model subtraction. Each matching PLnnnHnBm.STAT map is the source's dimensionless statistical weight for the same pixel grid as its INTE map; the published product page and FITS header give no mathematical definition or uncertainty/coaddition rule, so it must not be treated as an inverse variance without another source authority. Source-header extrema that disagree with served pixels are measured and listed below.

Excluded served members

• —090.tar#PL090H2B1.STAT — 501,120 bytes, member SHA-256 3c1119f7e16afeda6910f2fb9f92547e69f6a93901749aeee02f6c6bfc712270; every served byte is zero; containing archive 17,991,680 bytes, SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb; reason: contains no populated measurement value and no FITS header or axes; excluded under the archive measurement-scope rule.
• —090.tar#PL090H2B2.INTE — 996,480 bytes, member SHA-256 44b07f7f396d5545a29936520b24c72217e22217f1ff42ec4e112e1c9eae9fc5; every served byte is zero; containing archive 17,991,680 bytes, SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb; reason: contains no populated measurement value and no FITS header or axes; excluded under the archive measurement-scope rule.
• —090.tar#PL090H2B2.STAT — 501,120 bytes, member SHA-256 3c1119f7e16afeda6910f2fb9f92547e69f6a93901749aeee02f6c6bfc712270; every served byte is zero; containing archive 17,991,680 bytes, SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb; reason: contains no populated measurement value and no FITS header or axes; excluded under the archive measurement-scope rule.
• —090.tar#PL090H2B3.INTE — 996,480 bytes, member SHA-256 44b07f7f396d5545a29936520b24c72217e22217f1ff42ec4e112e1c9eae9fc5; every served byte is zero; containing archive 17,991,680 bytes, SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb; reason: contains no populated measurement value and no FITS header or axes; excluded under the archive measurement-scope rule.
• —090.tar#PL090H2B3.STAT — 501,120 bytes, member SHA-256 3c1119f7e16afeda6910f2fb9f92547e69f6a93901749aeee02f6c6bfc712270; every served byte is zero; containing archive 17,991,680 bytes, SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb; reason: contains no populated measurement value and no FITS header or axes; excluded under the archive measurement-scope rule.

Source-header extrema discrepancies

• —PL145H1B1.INTE: measured scaled range 19455161.815617 to 200224200.0; source DATAMIN/DATAMAX 16133430.0 to 200224200.0; served image truncated at the leading source-stream extent: 108,720 of 248,992 pixels are present and 140,272 trailing pixels are absent; the retained WCS still addresses the declared grid; archive/member SHA-256 dd8761ff5922dbca576f44241596d22cd4d9543dfc03fdd5fc8e11defe44a8bb / f2744c10723d0152bf57d0b82e1aba2f70b2add506174ee88da3809a3bb55ca0.
• —PL090H2B1.INTE: measured scaled range 0.0 to 286365571.446894; source DATAMIN/DATAMAX 17683150.0 to 709111300.0; served image complete; archive/member SHA-256 7b1872365cf459f7c6c69bc21805cebf3ad2e58cc3968bca3f171d0bb55cdeeb / 4dcae69b2f4e90dcc5e58bab79b78cfd9e3e28cb595dff47f83943472bd0711f.
• —PL201H2B3.STAT: measured scaled range 0.09541279 to 686.49502405; source DATAMIN/DATAMAX 0.09541279 to 3053.211; served image truncated at the leading source-stream extent: 2,880 of 248,992 pixels are present and 246,112 trailing pixels are absent; the retained WCS still addresses the declared grid; archive/member SHA-256 b6c541fe642c790d1bca1ed508a53579cc0e19b98711ea30ac53ee5072d6512e / a3ee10ed7f17ab0fe582b1d0d25f277d86c83e7b1c0cbd91a30e68a7eaafafdb.

Preview provenance

The grid preview masks BLANK, applies BZERO + BSCALE * raw, and uses the 2nd–98th finite-value quantiles with the magma colour map. Its axes use the retained FITS WCS and its colour bar reports intensity (JY/SR; scaled for display). From the repository root at commit c463c89585003f678f88cd14fbc923bf28b91d1a, rebuild it with:

python tools/render_iras_preview.py grid data/iras-sky-flux-plates/PL001H1B1.INTE.parquet datasets/iras-sky-flux-plates/preview.png --title "IRAS Sky Flux Plates" --sky-coordinates --colourbar-label "intensity (JY/SR; scaled for display)"

Provenance, rights, and citation

The source inventory, exact file and archive-member hashes, listing order, and any served/index discrepancy are recorded in the repository census and embedded metadata. The source was checked on 2026-09-02.

the IRAS project produced the data. LAMBDA, part of HEASARC at NASA Goddard Space Flight Center, hosts this copy. The linked HEASARC page is a data-use policy, not a separately named formal licence. It states: “HEASARC materials are all available freely for your use.”

Requested acknowledgement (exact text):

We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA), part of the High Energy Astrophysics Science Archive Center (HEASARC). HEASARC/LAMBDA is a service of the Astrophysics Science Division at the NASA Goddard Space Flight Center.

Please cite Infrared Astronomical Satellite (IRAS) Catalogs and Atlases, vol. 1, Explanatory Supplement, 1988, ed. C. Beichman et al., NASA RP-1190.

Source-backed documentation for the statements above:

• —source product description and scientific caveats — SHA-256 7bf2043c6eed2bdb0c14f63dfe35496ddd69415a437a98d8b56e017c18037bf3 checked 2026-09-02.
• —gnomonic projection geometry and photometric caveats — SHA-256 3eb545f2f72cd657106f95c1bcb15616689a3d152fd00d309ef618bd5fa7650d checked 2026-09-02.
• —HCON confirming-survey timing — SHA-256 3bccf3b1a05fe9fba7b6a5dc29ba826c9d467e8fa5613f024335482b66c64de9 checked 2026-09-02.

Errata and requests

To report an erratum or ask a question, use the dataset Community tab. Confirmed corrections are made in the source conversion tools and published by rebuilding the dataset.