NGC 6210 -- Planetary Nebula in Hercules
When the images of NGC 6210 from the Hubble Space Telescope were made available to
the public, the consensus was that it looked like “turtle swallowing a seashell”. NGC 6210
has been referred to as the Turtle Nebula ever since.
I could not recognize any turtle eating dinner in my small 110mm refractor. At low power the
Planetary Nebula is star-like. At a magnification of 96x it is no longer star-like but a tiny
bluish glow with an extended (not star-like) bright center. By pushing the power up to 257x
and waiting for the atmosphere to settle down, I could see the bright center dissolve into
knots. These pseudo-knots were very fleeting, and I was never sure of their exact location.
The impression I got were that they were absent from the true center of the nebula. Try as I
might, I could not make out the 13th magnitude central star.
The Oxygen III nebula filter is not needed (this is a bright nebula) and did little to enhance the
view. The filter was however initially helpful separating the star-like planetary from the
surrounding stars while at low power.