Re: Detecting the "ringness" of the Ring Nebula

From: Robert Cook (rbrtck_at_hotmail.com)
Date: 07/27/04 

Date: 27 Jul 2004 12:13:35 -0700

Ioannis <morpheus@olympus.mons> wrote in message news:<1090774498.957913@athnrd02.forthnet.gr>...
>
> Robert Cook wrote:
> [snip]
> > I'm not surprised, having looked through similar eyepieces in the
> > past. Light transmission and image definition in those things is
> > atrocious, making poor use of an already limited--though otherwise
> > sufficient--aperture (the objective lens, on the other hand, is
> > probably quite good). This is not a fair test of your abilities.
>
> I understand that :-)

I had to get that off my chest--I'm still haunted by bad memories from
my childhood. :-)

> Since then I've ordered a nice multicoated(?) zoom
> EP from Apogee, which although not very high quality, it will definitely
> improve on what the Tasco can do.

It should be good enough, from what I've heard of it. Its range of
magnification on the Tasco is pretty close to ideal.

> I am also thinking of realigning the 60mm objective, by removing this
> crappy plastic separator between the elements and placing 3 paper pieces
> at 120 angles to (maybe?) improve the objective's performance.

Also make sure that the optics aren't being pinched by the cell.

> Of course what makes all this exciting is the incredibly dark skies
> there. Milky way is routine, M31, M8 and M13 are all naked eye.

That must be like Heaven compared to Athens. :-)

[snip]
> > Well, M57 was definitely visible at 75x and 150x, but it was very
> > difficult to make out any structure, aside from its elliptical shape.
> > After several minutes of observing, I found that I could just barely
> > detect some darkening in the center, but only part of the time. I
> > kept observing for a good while to make sure that I wasn't using
> > "averted imagination," and now I'm confident that I really saw the
> > ring shape--at least a hint of it--at both 75x and 150x through a 40mm
> > aperture (with no filters).
>
> Well, if you saw it with 40mm's, this implies that with 60mm's it should
> be almost clearly visible.

As a reminder, this was a real struggle for me (especially at 150x),
because of the extreme dimness and/or lack of contrast. I forgot to
mention this, but I had to cover my head and eyepiece with dark cloth,
due to the less than ideal viewing conditions. With a 60mm aperture
and a truly dark sky, it should be much easier, but it's not
necessarily going to "jump out" at you right away--visually, it's not
a sharply defined ring with black space in the center in any telescope
I've viewed it through.

> For some reason I am fascinated by this
> object

So am I. For me, the reason is probably a combination of its shape
(simple yet unusual), the fact that it was one of the first
non-stellar celestial objects I had ever learned about (a bit of
nostalgia), and the fact that it represents the probable fate of the
Sun (a solemn reminder of our own impermanence). Imagination may be
undesirable with regard to determining what can and cannot be seen by
the eye, but it can play a vital part in how we perceive these objects
in a much grander sense.

- Robert Cook

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