rave-dr6-recent-observations-plot

name	rave-dr6-recent-observations-plot
title	Plot the newest 100 RAVE DR6 observations (RA vs Dec)
author	Hermes Assistant
version	1
description	Retrieve the most recent 100 entries from the RAVE DR6 `dr6_obsdata` table and generate a simple RA‑Dec scatter plot. Handles missing Python dependencies, installs them if necessary, and falls back to astropy for galactic coordinates if needed.

Overview

When to Use

Retrieve the most recent 100 entries from the RAVE DR6 dr6_obsdata table and generate a simple RA‑Dec scatter plot. Handles missing Python dependencies, installs them if necessary, and falls back to astropy for galactic coordinates if needed.

Overview

This skill contains a reusable operational workflow. Follow the existing task-specific steps and examples in the sections below.

Canonical Routing

This is a specialized or legacy example skill. For new work, start with astro-data-access-umbrella and route through:

• rave-dr6-data-access
• astro-catalog-plotting-cache

Keep this skill for dataset-specific examples, but prefer the canonical skills for new implementations, live probes, REANA execution, and plotting/cache conventions.

Pitfalls

• Do not hardcode credentials, tokens, or personal secrets.
• Verify external service URLs, paths, and permissions before making changes.
• Keep generated outputs reproducible and record input assumptions.

Verification

• Confirm required inputs and credentials are available.
• Run the smallest safe command or example before scaling up.
• Check produced files, API responses, or plots before reporting success.

This skill demonstrates how to query the RAVE DR6 TAP service for the latest 100 observations, then produce a scatter plot of RA vs Dec (and optionally Galactic X/Y).

Prerequisites

# Install required Python packages (run once)
pip install --quiet pyvo pandas matplotlib seaborn astropy --break-system-packages

Steps

1. Create a Python script (rave_recent_plot.py) with the following content:

import warnings, numpy as np, pandas as pd, matplotlib
warnings.filterwarnings('ignore')
matplotlib.use('Agg')
import matplotlib.pyplot as plt, seaborn as sns, pyvo

# Connect to the RAVE TAP service
service = pyvo.dal.TAPService('https://www.rave-survey.org/tap/')

# Query the newest 100 observations (ordered by obsdate descending)
query = '''
SELECT TOP 100 ra_input, dec_input, obsdate
FROM ravedr6.dr6_obsdata
ORDER BY obsdate DESC
'''
result = service.run_sync(query)
# Convert to pandas DataFrame
df = result.to_table().to_pandas()

# Plot RA vs Dec
plt.figure(figsize=(8,6))
sns = sns.scatterplot(data=df, x='ra_input', y='dec_input', hue='obsdate', palette='viridis', edgecolor='white', s=80)
plt.title('Newest 100 RAVE DR6 Observations (RA vs Dec)')
plt.xlabel('RA (deg)')
plt.ylabel('Dec (deg)')
plt.legend(title='Obsdate', loc='best')
plt.grid(True, ls='--', alpha=0.5)
plt.tight_layout()
plt.savefig('rave_newest_ra_dec.png', dpi=180)
print('Saved plot to rave_newest_ra_dec.png')

2. Run the script:

python3 rave_recent_plot.py

The PNG file rave_newest_ra_dec.png will be created in the current directory.

3. (Optional) Plot Galactic X/Y if you need a galactic projection:
   • Add the following after step 1 (requires astropy):

from astropy.coordinates import SkyCoord
import astropy.units as u
# Convert RA/Dec to Galactic coordinates
coords = SkyCoord(ra=df['ra_input'].values*u.deg, dec=df['dec_input'].values*u.deg, frame='icrs')
gal = coords.galactic
l = gal.l.rad
b = gal.b.rad
# Compute planar projection
x = np.cos(b) * np.cos(l)
y = np.cos(b) * np.sin(l)
# Plot
plt.figure(figsize=(8,8))
sns = sns.scatterplot(x=x, y=y, hue=df['obsdate'], palette='plasma', edgecolor='white', s=80)
plt.scatter(0,0,c='gold',s=300,marker='o',edgecolor='orange',linewidth=2,zorder=10)
plt.title('Newest 100 RAVE DR6 Observations (Galactic X/Y)')
plt.xlabel('x = cos(b) cos(l)')
plt.ylabel('y = cos(b) sin(l)')
plt.axis('equal')
plt.legend(title='Obsdate', loc='best')
plt.grid(True, ls='--', alpha=0.5)
plt.tight_layout()
plt.savefig('rave_newest_xy_gal.png', dpi=180)
print('Saved galactic plot to rave_newest_xy_gal.png')

Pitfalls & Tips

• The dr6_obsdata table does not contain galactic longitude/latitude; you must compute them from RA/Dec (shown in the optional block).
• All 100 rows currently share the same obsdate = 20130404, so the hue will appear uniform. If you query a broader date range, colour coding becomes useful.
• If pyvo is missing, the install command above will add it; the --break-system-packages flag is required in the sandbox environment.
• Use service.run_sync() (synchronous) – avoid submit_job() which leads to errors on this TAP endpoint.
• Ensure the script runs in a directory where you have write permission for the PNG output.

Verification

After running, open rave_newest_ra_dec.png. It should display a scatter of points across the RA‑Dec ranges (~146°‑225° RA, –42° to –47° Dec) corresponding to the latest RAVE observations.