Types of Mountings

"Altazimuth mountings tend to be cheaper, lighter, less clumsy, and more
quickly set up than equatorial ones, mountings tend to be cheaper,
lighter, less clumsy, and more quickly set up than equatorial ones,..."

OK, I am immersed in FAQs (really, I'm doing my homework before posting,
really) and I am getting these two terms thrown on the wall but folks
are taking for granted the reader has some clue what they mean.

Can someone 'splain in one or two sentences what an:

'Altazimuth mounting' is as well as what an

Equatorial one is, as in what's the basic diff?

I had two 'regular' (Refractors, also known as dioptrics) telescopes
over the years (many moons ago) and it had two basic knobs to turn; one
for tilt 'up-n-down', the other for rotation around a vertical axis, or
'spin in a circle'.

I'm having fun with Google but some real basic, simple terms would be a
wonderful thing.


Thx in advance,
TBerk

"T" wrote in message
. com...

Can someone 'splain in one or two sentences what an:

'Altazimuth mounting' is as well as what an

Equatorial one is, as in what's the basic diff?

T,

An altazimuth mounting moves the telescope up and down (altitude), and also
turns about a vertical axis (azimuth - back and forth motion, parallel to
the horizon). To follow the stars you have to move it in two directions.

An equatorial mount has one exis tipped parallel to the Earth's axis, so
moving it around that axis in a direction opposite to the Earth's rotation
(west) allows you to follow the stars (and a motor turning it once a day
westward allows it to track without help). The two motions of an equatorial
mount are sky north and south, and sky east and west.

I hope that clears things up.

Clear skies, Alan

"T" wrote in message news:4mDgd.36693

Can someone 'splain in one or two sentences what an:

'Altazimuth mounting' is as well as what an

Equatorial one is, as in what's the basic diff?

Thx in advance,
TBerk

T,

Your old mount was an altazimuth. The up and down adjustment is altitude,
and the spin-in-a-circle adjustment is azimuth. Hence altazimuth.

Equatorial mounts are designed to move on two axis as well, but they are
tilted to make only one axis needed to follow objects as they follow their
course across your view. As shown in the animations he

http://www.astronomyboy.com/eq/

Ed T.

"Edward" wrote in message

Your old mount was an altazimuth. The up and down adjustment is altitude,
and the spin-in-a-circle adjustment is azimuth. Hence altazimuth.

Equatorial mounts are designed to move on two axis as well, but they are
tilted to make only one axis needed to follow objects as they follow their
course across your view. As shown in the animations he

http://www.astronomyboy.com/eq/

Ed T.

I should add that the page referenced shows the movement of an equitorial
mount to a target, *not* the tracking aspect.

Ed T.

'Altazimuth mounting' is as well as what an

The same type of motion you get with your typical photographic or
video tripod. It goes up and down and side to side. For comparison
to the Equatorial mounts, consider a string hanging from the center of
a tripod. Your choice of directions to move the telescope are up and
down (towards or away from the string) or side to side (around the
string).


Equatorial one is, as in what's the basic diff?


OK. At the risk of losing you completely, the basic motion choices
are EXACTLY the same. The difference is the orientation of the
string!

Imagine the following. Start with your Alt/Az Mount and your string
(make it a REALLY stiff string). Move your telescope so it is
pointing straight up (parallel with the string). Now, take your
string and align it so that it is parallel with the spin axis of the
earth with the string pointing south and the telescope pointing north.

You now have an equatorial motion setup. Your motion choices are
towards or away from the string (north/south (declination)) and around
the string (east/west (right ascension)).

The telescope motion is the same in both. The end of the telescope
rides on the same sphere for both. The only difference are the axes
of rotation.

Mark Smith wrote:
snip
Imagine the following. Start with your Alt/Az Mount and your string
(make it a REALLY stiff string).

OK, My string is Really STIFF now.* ;])

ahem

I want to thank you guys for making it clear, I see that once you align
the E mount to the Earth's rotational axis you lock it down.

From there it's pretty much the same as the more 'primitive' mount.

I thank you one an all.


TBerk
* (I enjoin the gentle read to search out the song lyrics for
Parliament/Funkadelic's "Mr Wiggles" Totally OT but you will enjoy
hearing it for yourself, I assure you.)

I am going to recomend a couple of books for your reading pleasure, "How
to Use An Astronomical Telescope" by James Murden. Also another along
this line is "Through The Telescope" by Patricia L. Barnes-Svarney, both
books should be at your local Barnes & Noble or Borders.

On Sat, 30 Oct 2004 02:52:48 +0000, T wrote:


"Altazimuth mountings tend to be cheaper, lighter, less clumsy, and more
quickly set up than equatorial ones, mountings tend to be cheaper,
lighter, less clumsy, and more quickly set up than equatorial ones,..."

OK, I am immersed in FAQs (really, I'm doing my homework before posting,
really) and I am getting these two terms thrown on the wall but folks
are taking for granted the reader has some clue what they mean.

Can someone 'splain in one or two sentences what an:

'Altazimuth mounting' is as well as what an

Equatorial one is, as in what's the basic diff?

I had two 'regular' (Refractors, also known as dioptrics) telescopes
over the years (many moons ago) and it had two basic knobs to turn; one
for tilt 'up-n-down', the other for rotation around a vertical axis, or
'spin in a circle'.

I'm having fun with Google but some real basic, simple terms would be a
wonderful thing.


Thx in advance,
TBerk

"Alan French" wrote:
[snip]
An equatorial mount has one exis tipped parallel to the Earth's axis, so
moving it around that axis in a direction opposite to the Earth's rotation
(west) allows you to follow the stars (and a motor turning it once a day
westward allows it to track without help).

Just to confuse even more, it needs to turn once every sidereal day,
which is about four minutes shorter than a normal day. Sidereal time
is 'star time' as apposed to 'sun time'. The difference is due to us
"gaining" a rotation relative to the stars, but not relative to the
sun, as we make one complete orbit (a year) of the sun.


Tim
--
Anyone who qualifies their comments with "just my
two cents" is usually over-valuing their contribution.

On Sat, 30 Oct 2004 02:52:48 GMT, T wrote:


"Altazimuth mountings tend to be cheaper, lighter, less clumsy, and more
quickly set up than equatorial ones, mountings tend to be cheaper,
lighter, less clumsy, and more quickly set up than equatorial ones,..."

OK, I am immersed in FAQs (really, I'm doing my homework before posting,
really) and I am getting these two terms thrown on the wall but folks
are taking for granted the reader has some clue what they mean.

Can someone 'splain in one or two sentences what an:

'Altazimuth mounting' is as well as what an

Equatorial one is, as in what's the basic diff?

I had two 'regular' (Refractors, also known as dioptrics) telescopes
over the years (many moons ago) and it had two basic knobs to turn; one
for tilt 'up-n-down', the other for rotation around a vertical axis, or
'spin in a circle'.

I'm having fun with Google but some real basic, simple terms would be a
wonderful thing.

You gotta google for the "real basic, simple terms pages." Adding
the word glossary to any term I don't know has always given me good
pages:
Altazimuth glossary (just click on I feel lucky)
Equatorial glossary Okay, the third link is the first relevant one,
but that page has a "Click here to learn more about types of
telescope mounts" link: http://www.starizona.com/basics/mounts.html
This page shows four types, but the extras appear to be just
variations on the two basic types.



Thx in advance,
TBerk

-----
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