Planetary in M15
Craig Carver
planetary nebula in M15? If so, what did you use (scope, filter,
eyepiece)?
Hubble recently imaged it. You can see it at:
http://oposite.stsci.edu/pubinfo/PR/2000/25/pr-photos.html
Craig C.
John J. Kasianowicz
pinkish hue to it, whereas M2 did not. However, I did not record seeing a
distinct object that was the source of the color. Of course, the fact that K
648 appears pink in the Hubble image may be a coincidence; my eyes may have
played a trick on me a few years ago.
I did not use an O-III filter on M15. I will though.
Michael Richmann
its 1 arcsecond size along with the fact that it's significantly offset
from the center of the globular. All the sources I've seen on this
indicate the only practical way to observe Kuestner 648 (Pease 1, PK
65-27.1, etc.) is by using a filter holder that allows you to "blink" by
swapping a nebular filter in and out...
John J. Kasianowicz
Hi Michael,
By the core, I meant the inner region (not necessarily the dead center),
rather than the extreme edge, of the globular.
As I mentioned in my first post in this thread, I don't know why I sensed a
faint pastel color in M15 (I've noted it on more than one occasion), but
that color is absent in other globs I've observed.
As I noted below, I will try an O-III filter on M15 the next time I schlep
my Dob to a dark site.
Best,
John
Michael Richmann
>
> Hi Michael,
>
> By the core, I meant the inner region (not necessarily the dead center),
> rather than the extreme edge, of the globular.
Exactly my point. PK 65-27.1 is offset well to the edge of the
globular.
>
> As I mentioned in my first post in this thread, I don't know why I sensed a
> faint pastel color in M15 (I've noted it on more than one occasion), but
> that color is absent in other globs I've observed.
Good question. The eye has very poor sensitivity to anything other than
the central green portion of the spectrum. Even an intensely bright
nebula such as M42 typically generates user reports of a green glow.
Attilla Danko
Pease 1, as far as I know.
We used Mike's 25 inch obsession under mag 6.0 to 6.4 skies. It was
difficult. We spent a couple of hours spread across 3 or 4 observing
sessions before we got it.
I drew and memorized micro-constellations on a photograph
of M15 so we could star hop at high power. Even then, we needed
to blink an OIII filter to confirm the location of the
planetary nebula which looked star-like. Picking out just
one star, close to the core, in a globular is not easy.
It actually took us several attempts at filter blinking. We found
that simply waving the filter between eye and eyepiece dosent
work very well. (We were too likely to loose the exact point
inside M15 where we needed to look.) We finnally nailed the
Pease 1 with a lumincon sliding filter assembly and a barlow
(to get enough back focus).
It was a tough but interesting observation.
Anybody try for the planetary in M22?
-ad
Randy Muller
Craig Carver <cmca...@facstaff.wisc.edu> wrote:
> Has anyone among us amateur astronomers observed Kuestner 648, a
> planetary nebula in M15?
Yes. I was with Steve Gottlieb when he observed it in his scope. I
took a look at it and helped verify it.
> If so, what did you use (scope, filter,
> eyepiece)?
17.5" f/4.4 dob, UHC filter, don't know eyepiece, but it was giving
500x. It might have been an 8mm + 2x barlow.
From http://www.observers.org/reports/99.11.06.html here is Steve's
report on this object:
Pease 1 is one of only four known PNe within globulars and the only one
which is a reasonable target in 12-inch and up scopes (V = 15, size =
1"). A good finder chart is a necessity, though, as the planetary is
located is just 25" from the center of M15! At 380x (with an equatorial
platform) and a detailed finder chart it was not difficult to identify
a quartet consisting of two easy pairs of mag 14 stars located 1.5' NW
of the center. Getting a feel for the scale in the eyepiece compared to
the finder chart, I next identified a 30" string of three or four mag
14.5 stars ~50" NE of the center. Pease 1 is situated midway between
this string and the center of the nucleus. At 500x, the precise
location was pinned down within a small unresolved clump of stars at
the edge of the nucleus 25" NE of center. Blinking with a UHC filter
(which dramatically dimmed the cluster), revealed a definite
brightening at the NE edge of this clump. With extended viewing this
brightening sharpened to a stellar point several times, particularly
with the filter attached!
Sent via Deja.com http://www.deja.com/
Before you buy.
John J. Kasianowicz
hues including pink, orange and yellow. These colors, and their locations,
were confirmed by an observing friend. I did not tell him where I thought
the colored sections were located or what the colors were. The wings of the
Great Nebula appear to be a shade of dusky gray-purple.
On several nights, M20 appeared to have pastel colors and jet black dust
lanes. Observations like these made me pine (more like lust) for a 25" or
30" Dob.
I still don't know what is the source of my observation of the pastel color
on M15. I'll be pleasantly surprised (more like shocked) if it is the PN.
JJK wrote
> > As I mentioned in my first post in this thread, I don't know why I
sensed a
> > faint pastel color in M15 (I've noted it on more than one occasion), but
> > that color is absent in other globs I've observed.
In reply, Michael Richmann wrote:
[snip]
Peter
> I still don't know what is the source of my observation of the pastel
color
> on M15. I'll be pleasantly surprised (more like shocked) if it is the PN.
>
Be shocked, cos it is!!
http://www.blackskies.com/pn_gc_challenges.htm
Peter W
The views expressed here are my own.