Planetary Nebula

Lyra
RA 18 53 35
DEC +33 01 45
Magnitude 8.8 (v)


There’s a lot of information available about M57, the Ring Nebula, and given its iconic status as one of the northern hemisphere’s most interesting and brightest planetary nebulae, there’s not much I’ll add here. However, given that this beautiful nebula was the first deep sky object I ever observed through a telescope in 1968, there are a few things I’m still curious about even though I’ve observed it approximately a million times since then.

M57_panstarrs.JPG

Color
I’ve found that M57 is a favorite for kids to look at through my 28-inch scope. After they’ve had a look, I’ve made it point to ask them what colors they saw, and they almost always instantly answer “red, green and blue”. The most I’ve detected is a very slight warm hue along the outside perimeter of the Ring.

Young eyes seemingly have no problems seeing these colors, so I’m curious if any of you have been able to see any definite colors in M57, and if so under what circumstances.

Central stars
The actual white dwarf central star has a well-deserved reputation for being difficult to see, and even though it’s rather easy in scopes 16-inches and larger, the seeing still needs to be rather steady to see it well. Also, a second and only slightly fainter star can be seen “within” the Ring just slightly northwest of the actual central star.

Even so, I’ve seen it definitely only and handful of times with my 28-inch scope and only suspected it once or twice with my old 20-inch. What’s the smallest scope anyone here has used to see this second “central star”?

Also, there’s a third star superimposed on the southwest border of the Ring, and even though it’s considerably brighter than either of the central stars it’s also fighting the much brighter nebulosity of the Ring's annulus. I’ve never seen it in my own scopes but had a remarkable view of it through the 90-inch Bok telescope on Kitt Peak a few years ago.

Uwe started a wonderful thread on these and other M57 stars a few years ago here:

http://www.deepskyforum.com/showthre...7-stars-inside

He saw many of the fainter stars in the PanSTARRS image above with Jimi’s 48-inch scope while using a “central star filter” that suppressed the nebula but allows stars to come through nearly undimmed. Has anyone else had a similar experience using a filter like this?

Halo
The outer halo can be seen fairly easily on a great night with a big scope, but those opportunities are few and far between. What’s the smallest size scope someone has used to see it? I’ve seen it with and without a nebula filter at low power and the view seemed much the same either way, but I prefer the view without the filter. Is your observing experience similar? To me the size of outer halo appears about the same as in the PanSTARRS image - how big does it appear to you?

Interior nebulous structure
You can see two parallel, nebulous streamers running through the interior of M57’s round central cavity along the nebulae’s outer major axis in the HST/ESA image below. I saw these streamers quite clearly from my light polluted backyard with my old 12.5-inch f/7.8 scope at 260x with a UHC filter in 1988 – and never since! And not because I haven’t tried. No matter what scope/filter/magnification combination I’ve used, these streamers have never appeared again.

Ring_HubbleDonatiello_960.jpg

Did I get an observation of a lifetime back then with that 12.5-inch scope or is this a fairly common feature that others see in M57 all the time?

Give them a go and let us know!