(IAAC) Re: [ATMoB-discuss] Seeing the Rosette... nebula visibility ratings?

[Lewis J. Gramer]

Jeff, I run a Website and email list for deep-sky observers,
called the "IAAC": the whole idea is that there ISN'T any one
number (Vmag, Bmag, surface brightness, isophote sizes - nor
your Limiting Magnitude, Telescopic LM, seeing rating, etc.)
which really tells you whether a particular object SHOULD be
visible, nor what it will look like ("how well" you see it),
nor how BEST to see it (with a UHC, OIII, H-beta, no filter,
what magnification, aperture, what conditions, etc.)!
  http://www.visualdeepsky.org

Instead, the best guide to what YOU might see (and the best
way to challenge yourself to see more, without just getting
overly frustrated) - the best way to judge that, is by what
OTHER observers have actually seen!


So for example, if you go onto the IAAC search page:
  http://www.visualdeepsky.org/search.html

and you search for the common name "Rosette", you will see
that it consists of a complex of individual NGC objects,
including open cluster NGC 2244, and several "pieces" of
nebulosity (NGC 2237, NGC 2238, NGC 2239, NGC 2246), plus
still more possibly "involved" objects within a 1o radius.

The result of this search is also a nice list of actual
observations - from people all over the Web who chose to
contribute their observations to the IAAC (among them,
Sue French, Martin Baur, Michael Geldorp, and me!)

Notice that several people made attempts to see the Rosette
with similar apertures to yours and NO filter - and some also
with smaller apertures than you and an H-beta or other filter.

It is indeed a tricky one to see - so you might guess that it
would be very dependent on conditions, including the altitude
of the object above your horizon, moonlight, light pollution,
etc. Note in particular, that someone DID see the nebulosity
(including structure!) from a "rural" site, with an 8" scope
using medium to high power, both with and without an OIII:
 http://www.visualdeepsky.org/logs/msg03130.html


I hope this helps answer your question, Jeff. And by the way,
if YOU would like to share your observing logs for this or any
other object - whether they're successful or not - we would
certainly welcome them on the IAAC! Just drop me an email, if
you would like to join the list or just contribute a few logs.

Clear skies!
Lew


Lew Gramer <owner at visualdeepsky.org>
Webmaster: http://www.visualdeepsky.org



> -----Original Message-----
> From: atmob-discuss On Behalf Of Jeff
> Sent: Friday, September 03, 2004 1:16 PM
> Subject: [ATMoB-discuss] Seeing the Rosette... nebula
> visibility ratings?
>
> So I've been hunting diffuse nebula with my 6" dob and a UHC filter.
>
> I've found lots of them in Saggatarius, and I've found the Veil (both
> parts) and even the North American.  This was from the cape
> in a sky that
> is slightly worse that the one at the clubhouse.
>
> I can't see the Rosette nebula.  I KNOW I'm looking at it as
> the central
> star pattern is very distinctive, but I still can't see it.
> I've looked
> for it with my 8" as well.  Has anyone seen this?
>
> I found the object database from
>
> http://www.saguaroastro.org/content/downloads.htm
>
> which listed surface brightness for many objects, but not
> diffuse nebula.
> Anyone know of such a list?  I'd love to prioritize my
> observing working
> from easiest to hardest.  I guess I could make my own by dividing
> magnitude by object area, but it wouldn't be as accurate.
>
> Thanks for any light anyone can shed on this!
>
> -Jeff