Planetary nebula PuWe 1

The planetary nebula PuWe 1, in the constellation Lynx, was discovered in 1980 by Alois Purgathofer and Ronald Weinberger on photographic plates from the Palomar Observatory Sky Survey. Its progenitor is the white dwarf WD 0615+556, located about 1300 light-years (390 pc) away. The apparent diameter of the nebula is about 0.36°, corresponding to a true diameter of roughly 8.1 light-years (2.5 pc).

Planetary nebula PuWe1
Click on the image to load it at full resolution in a JavaScript viewer.

In this false color composite H-alpha (including red continuum) is mapped to orange and [OIII] is mapped to bluish cyan. Stars are partially subtracted to improve the visibility of the nebulae. The progenitor WD 0615+556 lies almost exactly in the center of the nebula.

Image data

FOV (full view in the JavaScript viewer): 0.60° × 0.44°
Position (J2000): RA: 6h19m21s; DEC: 55°37′
Date: 2024-2025
Location: Pulsnitz, Germany
Instrument: 400mm Newton at f=1520mm
Camera Sensor: Panasonic MN34230 (Hα and [OIII]), Sony IMX455 (continuum)
Orientation: North is up
Scale: 0.8 arcsec/pixel (at full resolution)
Total exposure times:
Hα (3 nm): 17.4 h
[OIII] (3 nm): 24.1 h
Near infrared: 1.5 h
Blue: 1.4 h

Image processing

All image processing steps are deterministic and none of the algorithms use machine learning (often referred to as “AI”), which tends to generate plausible looking fake details. The software used can be downloaded here.

The image processing steps were:

  1. Bias correction, dark current subtraction, flatfield correction, noise estimation
  2. Alignment and brightness calibration using stars from reference image
  3. Stacking with outlier rejection, background estimation and optimal weighting based on noise estimation
  4. Star subtraction where star positions and intensities are extracted from continuum images
  5. Denoising and deconvolution of both components (stars and residual)
  6. Dynamic range compression using non-linear high-pass filter
  7. Color composition and tonal curve correction

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