Robin
April 5th, 2021, 08:39 PM
Hi everyone,
Last night I took my new 20" Dobsonian to a new dark site, which I have "discovered" recently. As it turned out, at this site my telescopic limiting magnitude was increased by a few tenths of a magnitude.
One of the objects I observed was Messier 94. What a beautiful galaxy with a lot of structures this is, especially at large aperture! I was able to observe a closed inner ring and a second ring that was intersected by a dark area (or it was a dark area next to a spiral arm), all of this was embedded in a diffuse "halo".
But to my surprise my eyes detected another ring outside the rest of the galaxy. Its surface brightness and contrast with respect to background were very low, but it was definitely slightly brighter than the area between this ring and the diffuse "halo" mentioned above.
Please find attached a sketch of what I saw.
Now I wonder whether this really was the outer ring that can be seen on photographs or my eyes / brain fooled me. On the northwestern side of the galaxy there is a group of four 11-14 mag stars that looks like an arrow. And this faint ring went through this group of stars, which could mean that it was an illusion.
It may be entirely possible that I saw some contrast illusion, but since there is actually a ring at that location, I wonder if this is what I have seen.
Consider this image, for example:
https://www.astrobin.com/full/252061/C/
Has anyone observed this outer halo visually?
Searching on deepskyforum, I found this 3 years old thread:
https://www.deepskyforum.com/showthread.php?1157-Object-of-the-Week-April-29th-2018-%96-M94-The-Cat%92s-Eye-Galaxy
@Uwe, if you read this, in the last post of this old thread you wrote: "The third ring I remember as a very faint glow around the galaxy itself. It was difficult to separate it as a lonely ring. It seems more like a halo glow of a PN."
Did you observe the same thing or something different?
Clear skies,
Robin
Last night I took my new 20" Dobsonian to a new dark site, which I have "discovered" recently. As it turned out, at this site my telescopic limiting magnitude was increased by a few tenths of a magnitude.
One of the objects I observed was Messier 94. What a beautiful galaxy with a lot of structures this is, especially at large aperture! I was able to observe a closed inner ring and a second ring that was intersected by a dark area (or it was a dark area next to a spiral arm), all of this was embedded in a diffuse "halo".
But to my surprise my eyes detected another ring outside the rest of the galaxy. Its surface brightness and contrast with respect to background were very low, but it was definitely slightly brighter than the area between this ring and the diffuse "halo" mentioned above.
Please find attached a sketch of what I saw.
Now I wonder whether this really was the outer ring that can be seen on photographs or my eyes / brain fooled me. On the northwestern side of the galaxy there is a group of four 11-14 mag stars that looks like an arrow. And this faint ring went through this group of stars, which could mean that it was an illusion.
It may be entirely possible that I saw some contrast illusion, but since there is actually a ring at that location, I wonder if this is what I have seen.
Consider this image, for example:
https://www.astrobin.com/full/252061/C/
Has anyone observed this outer halo visually?
Searching on deepskyforum, I found this 3 years old thread:
https://www.deepskyforum.com/showthread.php?1157-Object-of-the-Week-April-29th-2018-%96-M94-The-Cat%92s-Eye-Galaxy
@Uwe, if you read this, in the last post of this old thread you wrote: "The third ring I remember as a very faint glow around the galaxy itself. It was difficult to separate it as a lonely ring. It seems more like a halo glow of a PN."
Did you observe the same thing or something different?
Clear skies,
Robin