NGC 6995 (The Bat Nebula) visible expansion over 68 years

NGC 6995 (The Bat Nebula) is a part of the Veil Nebula. Best viewed on a monitor at full screen. On mobile devices it might be (a lot) harder to see. The Veil Nebula is the remnant of a supernova that took place between 10,000 and 20,000 years ago. It is a expanding cloud of heated and ionized gas. This cloud is expanding at a velocity of about 1.5 million kilometers (932057 miles) per hour. This expansion was observed by the Hubble telescope which took images between 1997 and 2015, 18 years. This video has a longer observation time: 1953 and 2021, 68 years. I made it out of a capture made by the 18 inch Mount Palomar Schmidt telescope in 1953 and a capture by me with a Meade LX200 8 inch f/10 ACF telescope on a Ioptron CEM25EC mount in 2021. The 2 images are alternating between 1953 and 2021, giving it the “breathing“ effect. It very clearly shows the expansion of the clouds and proper motion of a few stars. The Palomar image has a lot more stars in it but that’s cause it has a bigger aperture and also because of almost no light pollution back then. It does look like most of the stars are moving but they are not: that’s an optical illusion caused by the nebula movement. Credits Palomar capture (POSS1 Blue) downloaded from Copyright: