It is a not very often imaged object because of several reasons that make it an extremely difficult object for imaging:
- the remnant spans a region of 3×3 degrees in the sky (which is about 8 full moons), making it too large for a telescope
- the nebula has an estimated surface brightness of magnitude +24, which is very, very low
- the nebula is only visible in H-alpha and OIII (which is even much fainter), making good filters a necessity
- the nebula was only discovered in 1952 using a 25″ telescope in Russia
Recently we had a clear night here and I wanted to see if I could catch it using my 100mm Canon F2.0 lens. I downed it to F2.8 and used 600s exposures using my Astrodon 5nm Ha-filter on a QSI583ws. For guiding a separate guidescope (500mm/f7) was used on an NEQ6.
I was very surprised to see how well the nebula already showed up.
18x600s H-alpha 5nm
Canon 100mm F/2.8