Getting a bigger telescope (was: Lunatic in Palo Alto ...)

On Jun 28, 2009, at 7:55 PM, Jeff Gortatowsky wrote:

> [Comments about incremental increases in aperture]

As I said earlier in this thread, I never met an aperture
increase I didn't like, and even small increases over
Harvey's aperture have shown me things that were beyond
the C-14. My reluctance to get a larger telescope is
not so much based on any perceived inability of more
aperture to show more detail -- for it certainly does!
-- as on whether more aperture would allow me to do
kinds of observing that I cannot do with a C-14.

My pre-Harvey deep-sky telescope was a 6-inch f/4.7
"hand-braced" Newtonian -- a simple OTA that I would
use by setting its lower end on something solid and
supporting the upper end with my hands as I sought and
observed objects. If you thought early-Dobson tracking
and finding technology was crude, you should by all
means try a hand-braced Newtonian as a reality check.

With this instrument, I most commonly used 36x -- with
any more magnification, I couldn't find anything at all,
much less track it.

Getting a C-14 did not just mean that I could see more
of the same stuff that I was seeing in a six-inch at
36x; rather, it was a watershed, in the sense that Harvey
showed kinds of things, and kinds of detail, that I
could not see at all in the smaller instrument. These
included structural details in nearby external galaxies
(things like globular clusters and HII regions), rich
detail and resolution in deep-sky objects in the Milky
Way, and a lot of extremely low-surface-brightness
stuff that I could not see with the 6-inch simply
because I could not hold it still for long enough to
make a careful observation. (There have been times
I have sat on my seat at Harvey's eyepiece for fifteen
minutes or more with my eyes shut, hoping to see a
faint fuzzy in the first few seconds after opening
them, and also hoping that the local mountain lions
would not sneak up and start nibbling on my toes while
I wasn't looking.)

Looked at another way, the big wins for Harvey over
the six-inch at 36x were (1) raw aperture -- to see
fainter objects, (2) the ability to use high
magnification when conditions and the object warranted
it (I have usefully used 500x or so on Harvey fairly
often, and usefully used 978x -- a 4 mm eyepiece --
on rare occasions), and (3) the ability to scrutinize
a field for a long time while a well-driven mount
kept the object in question centered and stationary
in the view.

And I say again, what these wins produced was not
more of the same, but a chance to see entire kinds of
detail that were beyond the previous instrument.

For many of us, amateur astronomy is a collector's
passion -- a good part of what we do is run up
impressive life lists of objects viewed. I have
certainly been that way; last time I totaled up my
logbook I found I had observed more than 10000
deep-sky objects. But for me, that's enough! If
I want to seek faint fuzzy nothings at the limit
of visibility, I will chase after Messier galaxies
with the naked eye.

So my reluctance to get a larger instrument than
a C-14 has been based on a sense that there isn't
another watershed out there within a factor
of two or so beyond Harvey's aperture. Certainly
there is more of the same kind of stuff, but are
there new *kinds* of stuff, that you can see at 28
inches that you miss at 14?

Convince me there is, and I may buy a new telescope.

:-)

-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynolds_Freeman@No-Spam
http://web.mac.com/jay_reynolds_freeman (personal web site)

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