Re: (SNES) Why can't I see it?

["??d ???" <graywwoolf@msn.com>]

Doug, I hate to burst your bubble of hydrogen gas...

I observed the Horsehead from Westford, MA in 1987. In January of that year,
with my 13" scope, in 20 mph winds, 0 degrees outside, nestled behind a
building. Not much of a sight, especially when you can only see the dark rift
of B33 splitting between the nebulous IC434 only very slightly.

The Helix is a breeze and the veil is easy. The hard part of of the veil is
tracing the entire circle of the veil. The eastern part of the veil is easy
because you can use 40 Cygni as a starting point. Finding the middle triangle
of of the veil is tough.

The hard part of the Helix is finding the amorphous glow with no real field
stars and that the PNe is located very far south. In most cases, I have light
polluted skies to find it in of Westford, MA.

The "tricky" part of finding PNe is not that they are faint, or large and
faint, its the location of field stars or asterisms as guide posts. Plus, a
large amorphous glow say over 100" in diameter, is the surface brightness like
in my post to you earlier today explaining about Jack Marling's formula.
Anything smaller than 60" is easy, because it is compact and its light is
concentrated into almost a pinpoint. To this date since lastyear, I have seen
about 100+ "new" PNe. I have the recorded reports for proof. My favorites are
the proto planetaries CRL 2688 "The Egg" and M2-9 "The Butterfly". These 2
cannot be seen with with any filter aid, since they havent "turned" on theri
OIII emissions yet. Good luck finding those 2, without any kind of GOTO or
electronics.

One thought goes through my mind everytime I want to find a new object: I have
pushed my eyes, my scope and my knowledge to the limits before I give up on
finding a particular object. I rarely miss a target, but I dont count it as a
loss, its still a success because I have said the above statement.

Finding many objects are based on your eyesight, your visual acuity. I use
both eyes to detect detail, size and shape. Your optics are directly
proportional to your ability to "see". The scope is rated, no matter what
skies. My scope is said to be able to reach mag 16. I have seen mag 15.5
objects, not just stars. You have to want it to be able to see it. Like any
pursuit, you push yourself to the limits.

Also your quality of EP's also affects what you will see. Clean optics and
clean EP's and clean filters. Dew removers and fans. As long as you have the
ability to stay the dew and reduce your mirror down to ambient temperature
fast and prevent the optics from fogging up, you will have made it part way.
Next is your ability to see. I eat sugary confections before I observe. I eat
carrots...LOL...for snacks. I breathe deeply and care for my night vision. I
rest between objects and take notes.

Dave Aucoin
----- Original Message -----
From: Albireo54@aol.com
Sent: Monday, July 23, 2001 4:18 PM
To: snegazers@brainiac.com
Subject: (SNES) Why can't I see it?

Hi Ernie and everyone,

WOW, that big long thesis I wrote about image and surface brightness
certainly landed with a resounding THUD! Not a murmer from anyone. Oh well, I
guess that means it was so very excellent that no one felt they could improve
upon it - or it was so abominably bad that no one wanted to cause me further
embarrassment by pointing out how far off base I was!  LOL

Of course, the issue keeps coming up, and will continue to do so - it's one
of those areas of astronomy open to considerable "interpretation". Ernie
Evans emailed the FDO mailing list today to question why so many nebulous
objects, which supposedly are visible in much smaller scopes, have been quite
INVISIBLE in FDO's 16" and Hanks 20" light buckets.

(I also enjoyed reading Dave Aucoin's observation reoprt from FDO last
Saturday about planetaries - also often very tricky to pick out.)

In the case of diffuse reflection and / or emission nebulae, it's been my
experience that many manufacturers grossly overblow what the average observer
is likely to be able to see in a given scope. Yes, if you took FDO's 16"
LX200, relocated it to a desert environment, at an altitude of 7,000 or 8,000
feet, and that site was 40 or 50 miles from the nearest town - then the
wonders you would be able to see would be mind boggling.

However, we're talking real world here. Sea level environment (or nearly so),
terribly changeable weather, high humidity, air pollution, fogs, urban
sprawl, etc., etc. No optical device used under these conditions can possibly
perform to its full potential. But these are the conditions that 95% of
America has to deal with. FDO is just fortunate in that some of the
conditions are mitigated by its rather remote location. Yes, its skies are
darker, all the time. But it faces all of the other regional hazards.

A good example of this situation in practice is the Horsehead Nebula in
Orion. In some parts of the country (described in the ideal, above), this
faint, low contrast object has been seen in 10" and possibly even 8" scopes.
Here in RI, even under FDO's dark skies, we had to combine all of the 16's
power with our own years of observing experience to spot this elusive object.
And our experience has been similar with other famous DSOs: the Veil Nebula,
the Helix planetary, and many others.

So I always look at ads in astronomy magazines with a rather jaded eye.
Theory is one thing, actual observing under real world conditions is quite
another!

Doug Stewart
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