Object of the Week April 29th, 2018 – M94 The Cat’s Eye Galaxy

M94


Canes Venatici


NGC4736
UGC7996


RA 12 50.9 53.1
DEC 41 07 14


Size 14.3’ x 12.1’


Mag 8.2

Although there are other galaxies worthy of a peek - M106 for one - quite often when we think of Canes Venatici, we typically think of one object and one object alone, M51. And why not? It is the quintessential face-on spiral galaxy that looks more and more as its namesake as aperture increases – somewhat of a rarity in deepsky objects. But within Canes lies another beautiful face-on that deserves a spot as an OOTW.


Discovered in 1781 by French astronomer Pierre Méchain, M94 was confirmed and cataloged by Charles Messier several days later, hence the M designation. M94 is a unique object. It’s one of the closest galaxies to our own Milky Way lying a mere 16 million light-years. It is the***** “anchor” galaxy for what is known as the M94 group, or CVn I cloud. In 1975, DeVaucouleurs described this group as a loose and scattered grouping containing 16-24 galaxies lying approximately 14-20 million light years away. He also included M106 as part of the M94 group but that was refuted in 1992 when its redshift showed it was much further away.

Another unique feature of M94 is that it’s one of, if not the closest, ring galaxy to us. M94 has 2 rings surrounding its nucleus. The inner ring has an apparent diameter of 70 arcseconds and is in area of intense star formation. Wikipedia names such a ring a “starburst” ring. It’s outer ring appears to be different than the inner ring though. In IR and UV images, the outer ring is actually a complex spiral arm structure, giving the galaxy the appearance of 2 rings. Studies show that the outer ring is a superior star forming region to the inner.. Essentially, although the inner ring forms more stars, it does it at a greater expense of energy and matter.


Visually, M94 is a pleasing view in telescopes. Much like M51, the more aperture you employ, the better your view. Heck, that’s nearly every object, isn’t it? M94 typically exhibits a bright nucleus, stellar in smaller scopes and a quite apparent and extended disk in larger scopes. The inner core appears as a disk-like oval surrounding the brighter nucleus and spiral structure and mottling is often seen in scopes as small as the 12 to 15 inch range.


So the question now is….. Who has seen both rings? Did the inner ring ever present itself as a true “ring” or has it always appeared to you as a disk? And have you seen the outer ring as a “ring”? Or has it always presented itself as arms? I’m very curious to what some of our observations will be!

And as always,

“Give it a go and let us know!”

I'm not really sure what happened to my pictures but here are 3 attachments....

Attachment 3023

Attachment 3024

Attachment 3025

I think of it as having three concentric pseudorings. The innermost one (#1) is the one with the diameter of 70 arcsec that you are giving. The middle one (#2) is the main bright part, and the outermost one (#3) is very large and faint.

Six years ago in 16" from a blue-zone site (75-225x), I saw a small bar in the middle of ring 1, which was actually two opposed segments. #2 and #3 were concentric groups of three arc segments each.

Last month with my new 20" (F/4) I recorded: "M94 in the 24 mm Panoptic with Paracorr [x1.15] appears to be a sort of one-arm pseudoring spiral with a bright, small inner ring brightest on the S side, sizable inner halo enhanced on the SE edge, and the outer split ring surrounding it. The ring is broad N of the core, most distinct SE of the core, and broadens again where it stops curving [CCW] and points outwards to the W between 2 stars SSW [sic, actually SSE] of core. The beginning of the arm/ring is thin and slightly overlaps the thick end where it [the beginning] passes through the N of the 2 stars."

The last image in above post shows the outer structure beautifully but is mirror-reversed with N down and W right.

Hello all,

As far as I am concerned, M 94 is a galaxy rather hard to ''extract'' somme details,
With my 10'' LX200, the galaxy is bright, with a very bright core. The extern halo is 3,5' x 2,5', and ce central concentration 1,5' x 1,0', with, in the middle, a non stellar nucleus.
Some hints of dark lane, suspected but no sure.

Attachment 3029

Through the 25'', the outer halo is bright, L2 to 3, in a scale from 1 to 10, with 5 parts of dark lanes, seen with great difficulties. The close stars allow to scale it precisely*: 6' x 4'.
The central area is very bright, L5 to 6, with a quasi stellar nucleus, L10. This central zone seems as the galaxy was a barred spiral, with two dark areas each side of the bar.

Attachment 3030

All in one, M 94 is a bright galaxy with a very concentrated central zone, which is itself rathed difficult to analyze

Attachment 3031

Clear skies
Bertrand
http://www.deepsky-drawings.com/dsdlang/en/

I liked very much with my small scope 4" very bright nucleus and great descending halo, galaxy quite large and bright. I want to look at the 16" if it stops raining once in my country, 5 months without always observing rain on new moon...

Regards.
Roberto.
Attachment 3032

Perhaps one of the most overlooked (or better forgotten) Messier Galaxy, very good reminder Dragan.

Like Ivan mentioned I also tend to speak about three rings.

And to my experience the visibility of all three rings are extremely dependently of the used aperture. I think not only about the pure visibility but the merging of details because of the smaller aperture.

For my former 14.5-inch the inner ring was clearly and easily visible as a closed ring which was bright and obvious. The second ring of the outer spiral arms was only visible as a segmented faint glow and was not closed to a ring. The third ring of the outer halo was not visible.

14.5", 202x-283x, NELM 6m5+, seeing II
Attachment 3033

The picture changed with more aperture. With my 27-inch the inner ring was also visible as a closed ring but decomposes more like a segmented spiral arm detail without connections to the inner core. The second ring is visible as a closed ring with brighter sections. 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.