Monday, January 31, 2011

Comet 103P/Hartley 2 from New York City

From the public, his discovery brought cheers.

From his wife, it drew nothing but torrents of tears.

"For you see," said Ms. Halley,

"He used to come daily;

Now he comes once every 70 years!"

--Astronomy Jokes

In October 2010, the bright green comet 103P/Hartley 2 passed relatively close to Earth, offering a rare opportunity for urban astrophotography. This series was captured from Brooklyn, New York City — under heavy light pollution — using a piggyback DSLR setup mounted on a Celestron NexStar 4SE.

Despite the challenges of NYC skies, stacking multiple exposures revealed the comet’s distinct green coma, caused by glowing diatomic carbon (C₂) molecules in its atmosphere.

Image 1: Stacked result showing the comet within the surrounding star field.

Comet 103P Hartley 2 wide field image from Brooklyn NYC Canon 40D Celestron 4SE

Image 2: Closer crop revealing the bright coma.

Comet 103P Hartley 2 zoomed view green coma Brooklyn NYC astrophotography

Image 3: Maximum zoom view highlighting the comet nucleus region and surrounding glow.

Close-up of Comet 103P Hartley 2 green coma stacked DSLR image

Comet Hartley 2, Celestron 4SE Canon 40D Brooklyn

Capture Details

Object: Comet 103P/Hartley 2 (The Green Comet)
Date: October 12, 2010
Location: Brooklyn, NYC
Camera: Canon 40D
Mount: Piggybacked on Celestron NexStar 4SE
Lens: Canon EF 28–135mm f/3.5–5.6 IS USM
Focal Length: 28mm
Exposure: 27 × 60 seconds
ISO: 1250
White Balance: Daylight
Total Integration Time: 27 minutes

Processing Workflow

Urban light pollution required careful processing:

Stacking performed in DeepSkyStacker
Light pollution reduction using Photoshop (Median Noise Filter + Gaussian Blur)
Final contrast and color adjustments in Photoshop

The embedded video below demonstrates the light pollution removal process and stacking workflow.

For techniques on reducing light pollution, see Removing Light Pollution in Urban Astrophotography, where I demonstrate advanced processing from Golden Gate Bridge skies.

Piggyback Setup – Behind the Scenes

The following images show the DSLR piggyback configuration on the NexStar 4SE telescope. This method allows tracking with the telescope mount while capturing wide-field comet images.

Brooklyn Astrophotography, Celestron 4SE PiggyBack, NYC Astronomy

PiggyBack Camera Mount for Celestron NexStar 4SE (Item# BRKTPIG4), Comet Photo Setup, Brooklyn NYC Astrophotography

NYC Astrophotography, Celestron 4SE

Celestron 4SE and Canon 40D - NYC Astrophotography

Urban Comet Imaging – A Challenge Worth Taking

Capturing a comet from New York City is always a technical challenge. High skyglow, limited visibility, and atmospheric haze make faint objects difficult to detect. However, with careful stacking and processing, even a suburban or urban observer can document transient celestial visitors.

Comet 103P/Hartley 2 was especially memorable because it was visited by NASA’s EPOXI spacecraft during its 2010 flyby — making backyard imaging even more exciting.