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David Callejas

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January 20, 2019

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Andrea Iorio
Marino, Rome, italy

03/12/2024
08:00 pm

Photographer's Website

Equipment Details:

RIG1:
ZWO ASI533MC Pro (gain 101, offset 40, -10°C)
ZWO OAG & ASI 120MM for guiding
Skywatcher 130PDS f5 with 1X coma corrector
Optolong L-eNhance filter
RIG2:
Tecnosky 60ED APO
ZWO ASI 715MC (gain 50, offset 40)
Optolong L-eNhance filter

Skywatcher EQM-35 Pro

Post-processing Details:

Pixinsight and Photoshop

Image Details:

Although Abell 21, or Sh2-274, has a large apparent diameter of 10 arcminutes, its surface brightness is so low, with features ranging from magnitude 16-25, that it was not discovered until 1955. It is a planetary nebula lying at a distance of 1,500 light-years in the constellation Gemini, which gives it an estimated diameter of 4 light-years. The parent star, now a white dwarf, is thought to be the deep blue star near the center of the nebula.

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January 20, 2019

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David Callejas

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About the Author:

David Callejas, Marketing Director, helps bring EarthSky's content to the world via online ads and other products. He creates strategies that help people around the world find us and appreciate the work we do. He helps manage the EarthSky Store and bring to you the new products that you love. He's the chief liaison between EarthSky.org and the world of commerce. All that, plus he helps post content and populate our pages on Facebook, Google+ and Twitter. Go David!