Re: OR: Lunatic in Palo Alto ...

>Harvey IMO is far harder to setup and transport what with the G11 to boot,
than a modern f/3.x to f/4 >22 inch truss tube Newtonian
 
    I agree. My 22" f3.6 Newtonian weighs 140Lbs complete. Wheels stay
permanently installed on the front of the rocker box. I insert two 6'
aluminum polls into the rear of the box then ramp it in and out of my truck.
I can be set up in under 15 minutes from the time I pull into the site. Even
faster if I'm completely gonzo. This is very convenient, I don't work up a
sweat, my back thanks me :-) As far as cooling, the 1 7/8" thick primary
mirror cools as fast as the ground I'm set up on does. I use an infrared
temp gun to back up this statement and have measured many a Taco's mirrors.
    Cassegrains are known to have long cool-down times because of their
enclosed mirrors but with good planning, one can easily get around that
problem. I used to set my C8 or C11 on a blanket on the floor of my truck
with an air conditioner vent pointed at it while driving to a site. That
worked really well for me.
    Like Jeff says, to each their own. After all, its just a hobby and most
people don't need a huge scope, it all depends on what your want to see at
the eyepiece. We can easily log thousands of objects with small aperture
scope but I like to tease out detail in objects, its what drives the hobby
for me. I'm surprised by how many objects give up the goods.
 
GML-celestial voyeur

  _____

From: tac-bounces@No-Spam [mailto:tac-bounces@No-Spam]
On Behalf Of Jeff Gortatowsky
Sent: Sunday, June 28, 2009 4:44 PM
To: TAC mailing list
Subject: Re: [TAC] OR: Lunatic in Palo Alto ...

I had not tried the TV-101 and the binoviewers. So I placed an AP BARCON in
the TV-101 and luck upon luck, the binoviewers came to focus. They would not
otherwise. My wife and I spend about 20 minutes outside, sipping and using
S&T's mirrored atlas of the moon. Lots of fun. The 'Serpentine Ridge' was
very prominent. Lunar binoviewing is fun! And easy on the eyes! :D

As an aside, without 'getting into it'...

I don't agree with Jay's statement about "upgrading significantly from a
C-14 involves a tremendous hit in cost, portability, and setup time" - well
*MAYBE* the cost. It would seem to me, if one can afford a Gran Turismo, one
can certainly probably afford a used 18 to 22 inch pushto dob. And maybe
even a tracking dob. Now I know he'll not agree, but Harvey IMO is far
harder to setup and transport what with the G11 to boot, than a modern f/3.x
to f/4 22 inch truss tube newtonian... and that would open up a brand new
range of vistas. But each to their own.

  _____

From: Michelle Stone <litebkt@No-Spam>
To: TAC mailing list <tac@No-Spam>
Sent: Sunday, June 28, 2009 10:30:44 AM
Subject: Re: [TAC] OR: Lunatic in Palo Alto ...

I like to use my 80mm Stellarvue refractor on a Desert Sky Alt/AZ mount and
Bogen heavy duty tripod for moon gazing. That extra 10mm gives me
significantly more detail than my 70mm Televue refractor. I find that I can
see more detail than illustrated in the Rukl atlas. I do reference the LAC
charts frequently. The Bogen tripod is especially helpful for me as well
since I can raise and lower the center shaft so that I can comfortably stand
(or sit) in a single position without bending my hed up or down or
contorting my body in some unnatural way.

There are times when I come inside to reference the LAC charts or if I have
more time, I'll drag my laptop out. I set up just outside my front door so
it's not a big bother either way.

The moon is up more often than it is not... so lunar lunacy is not a
terrible addition to the hobby.

I'm terrible with the moon names and rarely remember them. But I do remmber
the interesting craterlets and peaks that are visible as the sun rises. I
also love to see those peaks appear off the limb appearing to hang in space
as the sun rises. Crater rays are also very cool to watch if you can catch
them.

Michelle

On Fri, Jun 26, 2009 at 1:23 PM, Jay Reynolds Freeman
<jay_reynolds_freeman@No-Spam> wrote:

   I haven't been doing much deep-sky astronomy lately, mostly
because I have run out of things that I wanted to do, that I
could do with my biggest telescope, Harvey -- a Celestron 14 --
and because upgrading significantly from a C-14 involves a
tremendous hit in cost, portability and setup time. Recently I
decided to think carefully about things I could do with much
smaller and simpler equipment, that could be interesting, and
that perhaps could be done from the yard of my home in Palo
Alto, California.

   I should say in passing that if you had to pick a suburb in
a major metropolitan area in which to do astronomy, Palo Alto
might run high on your list: The city uses full-cutoff lighting
widely in its street lights, and has for a long time been
planting decorative trees, and encouraging homeowners to do
likewise. Thus, given the clarity of the air that blows in off
the Pacific, the sky above is much darker than in many similarly
populated areas. Furthermore, the city is close enough to the
Pacific coast that the seeing is often excellent -- during the
warmer parts of the year, I find that apertures of 10 or 15 cm
can run diffraction limited more often than not; that is, I can
set up such a telescope and usually count on seeing fairly
steady stellar Airy discs at high magnification.

   There are some downers. When there is enough wind from the
ocean, the fog layer that forms over the cold current off shore
moves inland and blocks the heavens. And my own property has no
single location from which I can see a good part of the sky.
There is a 35-meter redwood tree, plus many roses and a few
smaller trees, and plenty of street light glare in front. When
I do set up a telescope at home, I am forever having to pick it
up and move it around to get a good view.

   I have talked about an ecological niche for a "quick-look"
telescope in some of my web articles, that being an instrument
you keep ready to go inside your dwelling, that is easy to take
outside and set up in a hurry. So I decided to make a serious
effort to set up a particularly handy example of that kind of
equipment, and see what I could do with it. After a bit of
fussing with OTAs and mounts, what I ended up with was the
optical tube assembly for a 70 mm f/8 Vixen fluorite refractor,
mounted on an older (pre dovetail-slot convention) Vixen style
altazimuth mounting, in turn on a very light wooden tripod. As
I write these words, there are some images of that setup part
way down the "Telescopes" page of my main web site:

   http://web.mac.com/Jay_reynolds_freeman/My/Telescopes.html

   On this tripod, the Vixen 70 is light and compact enough
that it is a one-hand carry to get it outside. Since I leave it
set up inside, that means that i can go out for an observing run
in a single trip, with one hand carrying the telescope and the
other perhaps holding the back of a light chair and the strap of
a brief case holding a few charts and books and the like. An
instrument this small, and a refractor at that, comes to
temperature equilibrium almost instantly, so that when I decide
to go observing with this setup, I spend more time finding my
shoes and putting them on than I do fussing with telescope and
accessories.

   For an initial observing program, I decided to refamiliarize
myself with the Moon. During the lunation that started in late
May, 2009, I observed every night for nine days straight, from a
few days past new till almost full. The seeing was uniformly
excellent: On each night I was able to drop in a 4 mm eyepiece
for 140 diameters magnification, and have a rock-steady image.

   Why bother observe the Moon with so small a telescope? One
way to look at it is to note that the resolving power of a 70 mm
instrument is 1.6 arc seconds, whereas the lunar disc is about
1800 arc seconds -- over 1000 resolution elements -- across.
Thus in terms of area, a 70 mm aperture show about a million
different resolution elements -- pixels, if you will -- across
the Lunar disc. That is a lot of detail.

   I wasn't trying to make critical observations, really --
mostly just comparing things with the charts in my old copy of
Rukl's "Atlas of the Moon", and saying to myself, "Yes, I
remember that!" -- or, more honestly and more often, "I had
forgotten that!" But I did note a few highlights, that may give
you an idea of what a 70 mm can pull in, in good conditions.

   Early in the lunation, I could clearly see the Cauchy Wall,
but only suspected the Cauchy Rille. Two nights later I had a
good view of Rima Ariadaeus and Rima Hyginus. Later, I missed
the optimum sun angle for viewing the Triesnecker rille system
by half a day, but could still see a portion of the major
north/south rille. Several days later, the floor of Gassendi
showed many rilles, and as the Moon neared full I may have had a
glimpse of part of Rima Darwin.

   I spotted a couple of nice sunrise rays. How odd that those
pretty phenomena have clearly been around since the (*ahem*)
dawn of Lunar astronomy, but that no one seems to have noticed
them until the last few decades.

   One aspect of Lunar observing that is both vexing and
pleasant is that you can't expect to see all the major features
just by observing for short sessions on consecutive nights of a
lunation, as I did. Much of the surface detail is so subtle
that variations in solar elevation of as little as a few degrees
make vast differences in its appearance; since the sunrise line
on the Moon advances by about fifteen degrees per Earth day, it
follows that short sessions a day apart will skip lots of
things. I have already mentioned missing a good view of the
Triesnecker area, and I also did not get a good view of the
Straight Wall, Schroeter's Valley, or the magnificent apparition
of sunrise on Sinus Iridum.

   Lunar observers tend to focus so much on detail revealed by
the pattern of light and shadow near the terminator, that they
forget to look at those parts of the Moon where the sun is high.
What you are looking at then is a view optimized not for showing
topographic features but for distinguishing different kinds of
surface material on a planet-wide scale. We have all seen
geological maps of the Earth that use different shades of
unlikely colors to show Triassic lava flows here and Precambrian
granite there; to look at the Moon at high sun angle is to see
such a map made manifest by nature itself. The rough ejecta
streams from rayed craters and the contrast between the pale
anorthosite of the highlands and the darker and more basaltic
material of the maria are only the most obvious of these
features. What about the light chevron shape that lies
selenographic west of Mare Crisium? Or the very dark surface in
the Taurus/Littrow region? Apollo 17's landing site was
selected in part to investigate that last.

   By the way, here is a map of the surface geology of the near
side of the Moon, funny colors and all. The link is current as
of 26 June 2009:

http://www.lpi.usra.edu/resources/mapcatalog/usgs/I703/150dpi.jpg

   So I think I have proved my point, at least to myself, about
the prospect of doing interesting astronomy with a very small
telescope from a cramped suburban yard ... even if I do have to
look at the Moon to do it ...

-- 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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