Re: Moon Study Attn: Chris p

I have sent you two direct e-mails with data to help, but it seems you are
using a phony e-mail address. So much for help in the future...

--
Jan Owen

To reach me directly, remove the Z, if one appears in my e-mail address...
Latitude: 33.6
Longitude: -112.3
"Doink" <skyman102a@xxxxxxx> wrote in message
news:8uudnWX93cpDyNzZRVn-jg@xxxxxxxxxxxxxxx
Who sells an f/8 8" Newt? I never see them except to rare home-made
model.

Doink
"Chris L Peterson" <clp@xxxxxxxxxxxxxxxxxx> wrote in message
news:vej242ddpkp1m2ckt4gvir5v62gcpk9jne@xxxxxxxxxx
On Sat, 15 Apr 2006 11:42:00 -0700, "Doink" <skyman102a@xxxxxxx> wrote:

Really? I thought a reflector might mush up the view.

I think that's putting it a little strongly. Given an obstructed and
unobstructed scope of the same aperture, some observers my find the
obstructed scope to produce slightly less contrast. IMO this is more of
an issue with planetary viewing than lunar, however. And with just a
little more aperture, the obstructed scope will outperform the
unobstructed one.

The reason I recommended a Newt (and I'd go further, and say a Newt of
moderate focal ratio, like f/8 or higher), is that the obstruction is
small- too small for most observers to detect the effect. But it allows
you to get a good deal of aperture at very reasonable cost. If you are
observing critically, you are going to want to take advantage of
arcsecond seeing conditions or better, and that means you want an
aperture of at least 8", with 10" or 12" even better. You just aren't
going to be able to do that at reasonable cost with a refractor (and
even a good apo will show some chromatic aberration looking at the
Moon.)


What's the story on
Orion's off axis reflectors? The initial reviews were great---especially
for lunar viewing and then poof---nothing said.

Personally, I don't think they give better performance than a simple
Newt (and could easily be worse, given the increased collimation
demands).

It is hard to beat a basic large aperture Newt as a high resolution
visual instrument, and impossible to beat in terms of bang for the buck.


I see the Meade RC 10" OTA can be had for $1700 Can't find any details on
that----do you use rings to mount it? I like the idea of a mirror lock.

The standard way of mounting it to a GEM involves a rail, although I
suppose rings would be a possibility. The larger obstruction of the SCT
(which is closer to what it is than an RC) will impact your visual
performance somewhat more than the same aperture Newt. If you were
imaging, I'd go with the SCT on its standard fork, but for visual, I
think you'll be happier with the Newt.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com




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Relevant Pages

  • Re: Moon Study Attn: Chris p
    ... your Dobsonian mounted scope into an equatorial mounted scope for a ... unobstructed scope of the same aperture, ... The reason I recommended a Newt (and I'd go further, ... The larger obstruction of the SCT ...
    (sci.astro.amateur)
  • Re: Moon Study Attn: Chris p
    ... Maybe a good refractor or 10" RC is the better coice if mounted? ... unobstructed scope of the same aperture, ... The reason I recommended a Newt (and I'd go further, ... The larger obstruction of the SCT ...
    (sci.astro.amateur)
  • Re: Moon Study Attn: Chris p
    ... Latitude: 33.6 ... unobstructed scope of the same aperture, ... The reason I recommended a Newt (and I'd go further, ... The larger obstruction of the SCT ...
    (sci.astro.amateur)
  • Re: Moon Study Attn: Chris p
    ... using a phony e-mail address. ... unobstructed scope of the same aperture, ... The reason I recommended a Newt (and I'd go further, ... The larger obstruction of the SCT ...
    (sci.astro.amateur)
  • Re: Moon Study Attn: Chris p
    ... unobstructed scope of the same aperture, ... The reason I recommended a Newt (and I'd go further, ... you to get a good deal of aperture at very reasonable cost. ... The larger obstruction of the SCT ...
    (sci.astro.amateur)