juliensimon/hst-observations

Hubble Space Telescope Observation Catalog

Credit: NASA

Part of a dataset collection on Hugging Face.

Dataset description

The Hubble Space Telescope Observation Catalog is a complete index of every observation obtained by NASA/ESA's Hubble Space Telescope since its launch on April 24, 1990, drawn from the Mikulski Archive for Space Telescopes (MAST). Hubble's 2.4-meter primary mirror and suite of instruments have produced one of the most scientifically productive archives in astronomy, with over 35 years of continuous operation in low Earth orbit.

Each row in this catalog is one HST observation — a unit of telescope time executing an exposure with a specific instrument, detector, filter, and target pointing. Rows include the proposal under which the observation was taken (proposal ID, PI, title, category: GO, SNAP, GTO, DDT, CAL), the target (name, coordinates, moving/fixed flag), the instrument and detector (ACS WFC/HRC/SBC, WFC3 UVIS/IR, WFPC2 WF/PC, STIS, COS, NICMOS, plus legacy FOC/FOS/HRS/FGS), and the observation intent.

This dataset is the canonical reference for answering questions like: what has Hubble observed near a given RA/Dec? Which proposals used STIS for UV spectroscopy? Which targets have the deepest imaging coverage? It is designed for cross-matching with target catalogs (galaxies, quasars, stars, solar system bodies), for program-level summaries, for planning parallel JWST follow-up, and as training data for observation-recommendation systems.

This v1 provides observation-level metadata only. Per-observation timing and exposure data — which require joining with MAST's dbo.caomplane table (4.6M rows) — will arrive in a v2 as we build an async batched pipeline. For now, detailed timing/filter information can be retrieved per observation via the MAST Portal or the astroquery.mast Python package.

The catalog is derived from MAST's CAOM (Common Archive Observation Model) table dbo.caomobservation and is refreshed weekly as HST observations enter the archive. Calibration and engineering observations are included but are distinguishable via the intent column.

This dataset is suitable for tabular classification tasks.

Schema

Column	Type	Description	Sample	Null %
obs_id	string	MAST observation identifier (e.g., 'hst_05773_54_wfpc2_wf_pc_f547m'); encodes proposal, visit, instrument, aperture, and filter. Primary key.	f05i0201m	0.0%
obstype	string	CAOM observation type code: 'S' (simple), 'C' (composite)	S	0.0%
intent	string	Observation intent: 'science' or 'calibration'	science	0.0%
proposal_id	string	HST proposal identifier (string, e.g., '5773'); groups related observations by Principal Investigator's program	1538	3.3%
proposal_pi	string	Last name, first initial of the proposal Principal Investigator	BRADY	3.3%
proposal_title	string	Full title of the HST observing proposal	PRE-ALIGNMENT OTA CALIBRATION	34.1%
proposal_project	string	Proposal project code (e.g., 'GO', 'GTO', 'SNAP', 'DDT', 'CAL'); GO = General Observer, SNAP = snapshot survey, DDT = Director's Discretionary, CAL = calibration	OV/OTA	3.5%
target_name	string	Target name as provided by the proposer (may include survey designations, coordinates, or informal names)	1538_2	0.0%
target_ra	float64	Target right ascension in decimal degrees (ICRS). May be 0 for moving or calibration targets.	165.9390011752	0.3%
target_dec	float64	Target declination in decimal degrees (ICRS). May be 0 for moving or calibration targets.	-58.28425312885	0.3%
target_moving	bool	True if the target is a moving solar system body (asteroid, comet, planet, moon); False for fixed celestial targets	False	0.0%
instrument	string	Instrument name: ACS, WFC3, WFPC2, STIS, COS, NICMOS, FOC, FOS, HRS, FGS (from 'INSTRUMENT/DETECTOR' split)	FGS	0.0%
detector	string	Detector or observing mode within the instrument (e.g., 'WFC', 'UVIS', 'IR', 'HRC', 'SBC', 'PC', 'WF'); from 'INSTRUMENT/DETECTOR' split	WFC	4.8%

Quick stats

• 2,629,868 HST observations (1990–present)
• 2,166,999 science, 462,869 calibration
• 12,293 distinct proposals
• Top instruments: WFC3 (897,359), ACS (543,445), WFPC2 (377,101), NICMOS (345,395), STIS (244,436)

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/hst-observations", split="train")
df = ds.to_pandas()

from datasets import load_dataset

ds = load_dataset("juliensimon/hst-observations", split="train")
df = ds.to_pandas()

# Science observations with WFC3 UVIS detector
import pandas as pd
wfc3_uvis = df[(df["intent"] == "science") & (df["instrument"] == "WFC3") & (df["detector"] == "UVIS")]
print(f"WFC3 UVIS science observations: {len(wfc3_uvis):,}")

# Proposals per decade
df["decade"] = df["proposal_id"].astype(str).str[:1].replace({
    "5": "1990s", "6": "1990s-2000s", "7": "1990s-2000s",
    "8": "2000s", "9": "2000s", "1": "2000s-2020s",
})
df.groupby("instrument")["proposal_id"].nunique().sort_values(ascending=False).head(15).plot.bar()
import matplotlib.pyplot as plt
plt.ylabel("Distinct proposals")
plt.title("HST proposal count by instrument")
plt.show()

# Cone search around a target (Hubble Deep Field)
import numpy as np
ra, dec = 189.139, 62.217
sep = np.hypot(df["target_ra"] - ra, df["target_dec"] - dec)
nearby = df[sep < 0.1]
print(f"HST observations within 0.1 deg of HDF: {len(nearby):,}")

# Instrument usage pie
df["instrument"].value_counts().head(10).plot.pie(autopct="%1.1f%%")
plt.title("HST instrument usage (observation count)")
plt.show()

Data source

https://archive.stsci.edu/

Update schedule

Weekly (Monday at 13:30 UTC) via GitHub Actions.

Related datasets

• juliensimon/jwst-observations

• juliensimon/chandra-x-ray-sources

• juliensimon/erosita-erass1-xray

• juliensimon/4xmm-dr14-xray-sources

• juliensimon/nasa-exoplanets

If you find this dataset useful, please consider giving it a like on Hugging Face. It helps others discover it.

About the author

Created by Julien Simon — AI Operating Partner at Fortino Capital. Part of the Space Datasets collection.

Citation

@dataset{hst_observations,
  title = {Hubble Space Telescope Observation Catalog},
  author = {juliensimon},
  year = {2026},
  url = {https://huggingface.co/datasets/juliensimon/hst-observations},
  publisher = {Hugging Face}
}

License

CC-BY-4.0