juliensimon/galex-observations

---
license: cc-by-4.0
pretty_name: "GALEX Observation Catalog"
language:
- en
description: "The GALEX Observation Catalog indexes every pointing observed by NASA's Galaxy Evolution Explorer (GALEX) mission between its launch on April 28, 2003 and the end of operations in June 2013. GALEX was"
task_categories:
- tabular-classification
tags:
- space
- galex
- nasa
- ultraviolet
- uv
- all-sky
- astronomy
- telescope
- open-data
- tabular-data
- parquet
size_categories:
- 100K<n<1M
configs:
- config_name: default
data_files:
- split: train
path: data/galex_observations.parquet
default: true
---

# GALEX Observation Catalog

<div align="center">
<img src="banner.jpg" alt="The GALEX space telescope in orbit with a UV view of the Andromeda Galaxy" width="400">
<p><em>Credit: NASA/JPL-Caltech</em></p>
</div>

*Part of a [dataset collection](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) on Hugging Face.*

## Dataset description

The GALEX Observation Catalog indexes every pointing observed by NASA's Galaxy Evolution Explorer (GALEX) mission between its launch on April 28, 2003 and the end of operations in June 2013. GALEX was a dedicated ultraviolet space telescope with a 50-cm primary mirror, imaging the sky simultaneously in two bands: Far-UV (FUV, 1350–1750 Å) and Near-UV (NUV, 1750–2750 Å). Its 1.2-degree circular field of view and low-noise microchannel-plate detectors enabled the first comprehensive UV all-sky survey, mapping over 60,000 square degrees and cataloguing hundreds of millions of UV sources.

Each row in this catalog is one GALEX observation, tagged with its survey origin. The surveys include AIS (All-sky Imaging Survey — shallow, wide), MIS (Medium Imaging Survey — overlapping SDSS), DIS (Deep Imaging Survey — deepest UV field survey to date), NGS (Nearby Galaxy Survey), and specialised Guest Investigator, calibration, and spectroscopic programs. Field centres are in ICRS RA/Dec degrees, and the `target_name` captures the proposer-assigned identifier for each tile.

This dataset is designed for cross-matching UV sources with catalogs at other wavelengths (optical Gaia/SDSS/Pan-STARRS, infrared WISE, X-ray Chandra/eROSITA), for stellar population studies (UV is a tracer of young star formation), for AGN selection (UV-bright galaxies and quasars), and for planning deep archival follow-up. It complements the Hubble, JWST, Chandra, and eROSITA observation catalogs in this collection, extending the multi-wavelength view into the UV.

The catalog is derived from MAST's CAOM table `dbo.caomobservation` (collection = 'GALEX'). The GALEX archive is static since 2013, so this dataset is refreshed quarterly for any late reprocessing.

This dataset is suitable for **tabular classification** tasks.

## Schema

| Column | Type | Description | Sample | Null % |
|--------|------|-------------|--------|--------|
| `obs_id` | string | MAST observation identifier for this GALEX observation (opaque numeric string). Primary key. | 2391589523080347648 | 0.0% |
| `obstype` | string | CAOM observation type code: 'S' (simple single exposure) or 'C' (composite, e.g. a co-added tile) | S | 0.0% |
| `intent` | string | Observation intent: 'science' (survey pointing) or 'calibration' | science | 0.0% |
| `survey_code` | string | GALEX survey code: AIS, MIS, DIS, NGS, GII, GIS, CAI, CAS, MSS, DSS, WSS, ETS. See `survey_name` for expansion. | NGS | 0.0% |
| `target_name` | string | Target field identifier, often encoding the pointing or an associated catalog source | NGA_NGC5398_580_F5_19_158 | 0.0% |
| `target_ra` | float64 | Field centre right ascension in decimal degrees (ICRS) | 210.54223247715905 | 0.0% |
| `target_dec` | float64 | Field centre declination in decimal degrees (ICRS) | -32.6804067553693 | 0.0% |
| `survey_name` | string | Human-readable survey name (e.g. 'All-sky Imaging Survey' for AIS) | Nearby Galaxy Survey | 0.0% |

## Quick stats

- **274,911** GALEX observations (2003–2013)
- **274,911** science, **0** calibration
- Top surveys: **AIS** (98,660), **GIS** (87,226), **MIS** (18,089), **ETS** (17,225), **CAS** (10,991)

## Usage

```python
from datasets import load_dataset

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

```python
from datasets import load_dataset

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

# Deep survey fields only
deep = df[df["survey_code"] == "DIS"]
print(f"Deep Imaging Survey pointings: {len(deep):,}")

# UV sky coverage map (All-sky Imaging Survey)
import matplotlib.pyplot as plt
ais = df[df["survey_code"] == "AIS"]
plt.figure(figsize=(12, 6))
plt.scatter(ais["target_ra"], ais["target_dec"], s=0.3, alpha=0.3)
plt.xlabel("RA (deg)"); plt.ylabel("Dec (deg)")
plt.gca().invert_xaxis()
plt.title("GALEX All-sky Imaging Survey (AIS) pointings")
plt.show()

# Observations per survey
df["survey_code"].value_counts().plot.bar()
plt.ylabel("Observation count")
plt.title("GALEX observations by survey program")
plt.show()
```

## Data source

https://archive.stsci.edu/missions-and-data/galex

## Update schedule

Quarterly (1st of Jan/Apr/Jul/Oct at 14:30 UTC) via [GitHub Actions](https://github.com/juliensimon/space-datasets).

## Related datasets

- [juliensimon/gswlc-galaxy-properties](https://huggingface.co/datasets/juliensimon/gswlc-galaxy-properties)

- [juliensimon/hst-observations](https://huggingface.co/datasets/juliensimon/hst-observations)

- [juliensimon/jwst-observations](https://huggingface.co/datasets/juliensimon/jwst-observations)

- [juliensimon/chandra-x-ray-sources](https://huggingface.co/datasets/juliensimon/chandra-x-ray-sources)

- [juliensimon/nasa-exoplanets](https://huggingface.co/datasets/juliensimon/nasa-exoplanets)

> If you find this dataset useful, please consider [giving it a like](https://huggingface.co/datasets/juliensimon/galex-observations) on Hugging Face. It helps others discover it.

## About the author

Created by [Julien Simon](https://julien.org) — AI Operating Partner at Fortino Capital. Part of the [Space Datasets](https://julien.org/datasets) collection.

## Citation

```bibtex
@dataset{galex_observations,
title = {GALEX Observation Catalog},
author = {juliensimon},
year = {2026},
url = {https://huggingface.co/datasets/juliensimon/galex-observations},
publisher = {Hugging Face}
}
```

## License

[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)

许可证：CC-BY-4.0
美观名称："GALEX观测目录"
语言：
- 英语
任务类别：
- 表格分类
标签：
- 空间天文
- GALEX
- NASA
- 紫外
- UV
- 全天空
- 天文学
- 望远镜
- 开放数据
- 表格数据
- Parquet
数据规模：10万 < 记录数 < 100万
配置项：
- 配置名称：default
数据文件：
- 划分方式：train
路径：data/galex_observations.parquet
为默认配置

# GALEX观测目录

<div align="center">
<img src="banner.jpg" alt="在轨的GALEX空间望远镜与仙女座星系的紫外影像" width="400">
<p><em>图源：NASA/JPL-加州理工学院</em></p>
</div>

*本数据集属于Hugging Face平台上的[天文数据集合集](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743)。*

## 数据集描述

GALEX观测目录收录了美国国家航空航天局（NASA）星系演化探测器（Galaxy Evolution Explorer, GALEX）任务在2003年4月28日发射至2013年6月任务终止期间所有观测指向的索引信息。GALEX是一台专用紫外空间望远镜，配备50厘米主反射镜，可同时在两个紫外波段开展天空成像：远紫外（Far-UV, FUV，1350–1750 埃）与近紫外（Near-UV, NUV，1750–2750 埃）。其1.2度圆形视场与低噪声微通道板探测器助力完成了首次全面的紫外全天空巡天，测绘了超过60000平方度的天区，并编目了数亿个紫外源。

本目录的每一行对应一次GALEX观测，并标注了其所属巡天项目。这些巡天项目包括：AIS（全天空成像巡天——浅覆盖、大视场）、MIS（中等成像巡天——与斯隆数字巡天（SDSS）重叠）、DIS（深场成像巡天——迄今最深的紫外天区巡天）、NGS（近邻星系巡天），以及专项客座研究员项目、定标项目与光谱观测项目。天区中心采用国际天球参考系统（International Celestial Reference System, ICRS）下的赤经/赤纬（单位：度）表示，`target_name`字段记录了观测申请者为每个天区瓦片分配的标识符。

本数据集可用于紫外源与其他波段星表的交叉匹配（光学波段盖亚/SDSS/Pan-STARRS、红外波段WISE、X射线波段钱德拉/eROSITA）、恒星族群研究（紫外是年轻恒星形成活动的示踪剂）、活动星系核（Active Galactic Nucleus, AGN）筛选（紫外亮星系与类星体），以及深场档案后续观测规划。本数据集可补充本合集内的哈勃空间望远镜、詹姆斯·韦伯空间望远镜、钱德拉X射线天文台与eROSITA观测目录，将多波段观测视野拓展至紫外波段。

本目录源自米库尔斯基空间望远镜档案馆（Mikulski Archive for Space Telescopes, MAST）的CAOM表`dbo.caomobservation`（数据集集合标识为'GALEX'）。GALEX档案自2013年起处于静态状态，因此本数据集每季度更新一次，以纳入后续的重新处理数据。

本数据集适用于**表格分类**任务。

## 数据结构

| 列名 | 数据类型 | 描述 | 示例 | 空值占比 |
|--------|------|-------------|--------|--------|
| `obs_id` | 字符串 | 本次GALEX观测的MAST观测标识符（不透明数字字符串），为主关键字。 | 2391589523080347648 | 0.0% |
| `obstype` | 字符串 | CAOM观测类型代码：'S'（单次简单曝光）或'C'（复合曝光，例如叠加拼接的天区瓦片） | S | 0.0% |
| `intent` | 字符串 | 观测意图：'science'（科学观测指向）或'calibration'（定标观测） | science | 0.0% |
| `survey_code` | 字符串 | GALEX巡天代码：AIS、MIS、DIS、NGS、GII、GIS、CAI、CAS、MSS、DSS、WSS、ETS。详细名称参见`survey_name`字段。 | NGS | 0.0% |
| `target_name` | 字符串 | 目标天区标识符，通常编码了观测指向或关联的星表源 | NGA_NGC5398_580_F5_19_158 | 0.0% |
| `target_ra` | float64 | 天区中心赤经，采用十进制度数（ICRS坐标系） | 210.54223247715905 | 0.0% |
| `target_dec` | float64 | 天区中心赤纬，采用十进制度数（ICRS坐标系） | -32.6804067553693 | 0.0% |
| `survey_name` | 字符串 | 人类可读的巡天名称（例如AIS对应'All-sky Imaging Survey'） | Nearby Galaxy Survey | 0.0% |

## 快速统计
- **274,911** 条GALEX观测记录（2003–2013年）
- 其中科学观测**274,911**条，定标观测**0**条
- 占比最高的巡天项目依次为：**AIS**（98,660条）、**GIS**（87,226条）、**MIS**（18,089条）、**ETS**（17,225条）、**CAS**（10,991条）

## 使用方法
python
from datasets import load_dataset

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

python
from datasets import load_dataset

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

# 仅筛选深场巡天记录
deep = df[df["survey_code"] == "DIS"]
print(f"深场成像巡天指向数：{len(deep):,}")

# UV天区覆盖图（全天空成像巡天）
import matplotlib.pyplot as plt
ais = df[df["survey_code"] == "AIS"]
plt.figure(figsize=(12, 6))
plt.scatter(ais["target_ra"], ais["target_dec"], s=0.3, alpha=0.3)
plt.xlabel("赤经（度）"); plt.ylabel("赤纬（度）")
plt.gca().invert_xaxis()
plt.title("GALEX全天空成像巡天（AIS）观测指向")
plt.show()

# 各巡天项目的观测计数
df["survey_code"].value_counts().plot.bar()
plt.ylabel("观测计数")
plt.title("按巡天项目划分的GALEX观测数")
plt.show()

## 数据源
https://archive.stsci.edu/missions-and-data/galex

## 更新计划
每季度更新一次（每年1月、4月、7月、10月的14:30 UTC），通过[GitHub Actions](https://github.com/juliensimon/space-datasets)执行更新。

## 相关数据集
- [juliensimon/gswlc-galaxy-properties](https://huggingface.co/datasets/juliensimon/gswlc-galaxy-properties)
- [juliensimon/hst-observations](https://huggingface.co/datasets/juliensimon/hst-observations)
- [juliensimon/jwst-observations](https://huggingface.co/datasets/juliensimon/jwst-observations)
- [juliensimon/chandra-x-ray-sources](https://huggingface.co/datasets/juliensimon/chandra-x-ray-sources)
- [juliensimon/nasa-exoplanets](https://huggingface.co/datasets/juliensimon/nasa-exoplanets)

> 如果您认为本数据集对您有帮助，请前往Hugging Face平台为[该数据集](https://huggingface.co/datasets/juliensimon/galex-observations)点赞，这将有助于更多用户发现本数据集。

## 关于创建者
创建者：[Julien Simon](https://julien.org) — Fortino Capital人工智能运营合伙人。属于[Space Datasets](https://julien.org/datasets)合集。

## 引用格式
bibtex
@dataset{galex_observations,
title = {GALEX Observation Catalog},
author = {juliensimon},
year = {2026},
url = {https://huggingface.co/datasets/juliensimon/galex-observations},
publisher = {Hugging Face}
}

## 许可证
[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)