Right Ascension Dial

Hi

I've recently moved house.

It seems that since my move, this dial may have come loose as when I
went to move it to do some observing, I noticed that the dial with the
numbers on was spinning freely.

Is it easy to re-calibrate a mount or get it repaired?

Thanks

McSlemon

PS I have a Tasco Galaxsee Reflector.

The RA dial should of course be free to move. The Dec dial is fixed
once adjusted for your observing location.

I don't know what the setup is for your scope but it should be similar
for all scopes. If you find objects from RA and Dec coordinates, you
first get your object in the centre of a low-power eyepiece and track
it. Next, you spin the RA dial to match the RA coordinate and from
there on, you can find any other object in the sky as your scope is
synchronised to the sky.

I hope that helps.

Pierre MK-UK

Ok,

Please forgive my ignorance as I'm fairly new to astronomy still.

Are you saying that even without moving the telescope from its
position, its ok to spin this dial?

See picture

http://www.inception2.co.uk/images/dial.jpg

If so, can someone explain how right ascention works. I'm assuming that
when you aline the scope to the North Star, the declenation is set at
whatever the North Star should be set at... what happens with the RA
dial? Do you move it to whatever it should be accordiing to the
software I have.

At this current moment, from my postion here, Polaris is RA 44.22 DEC
-11.74. So, if I were to be able to see it now, then I should set my
dial to that?

"McSlemon" wrote:
[RA setting circle]
Are you saying that even without moving the telescope from its
position, its ok to spin this dial?

Absolutely, that's why they provide a thumbscrew to lock/unlock it.

If so, can someone explain how right ascention works. I'm assuming that
when you aline the scope to the North Star, the declenation is set at
whatever the North Star should be set at... what happens with the RA
dial? Do you move it to whatever it should be accordiing to the
software I have.

Polaris is the worst choice for setting your RA, as its position
barely changes in the sky. Choose something close to the celestial
equator (Declination=0).

At this current moment, from my postion here, Polaris is RA 44.22 DEC
-11.74. So, if I were to be able to see it now, then I should set my
dial to that?

Yes (but with another star, as above). Having said that, relatively
small setting circles like you have aren't much use - you can't
reliably put a target in the FOV of the main scope with them. I can
get targets in the finder just by pointing the tube the right way. As
you have to use the finder anyway with smaller setting circles I don't
bother with them at all. If you want to use setting circles to locate
objects you really need big ones with a vernier or digital ones.

I can't remember the last time I tried to find something from its
coordinates, at least without printing them out on a star chart first.


Tim
--
You are being watched. This gives you power.

Polaris is a convenient bright close to the Pole, ideal for polar
aligning.
Choose bright stars elsewhere, preferably not at high celestial
latitudes (= declination) to use as clock stars. By clock stars, I
mean stars of known position to set the axis on your scope (like the
hands on a clock. Once you've done this and providing the scope is
driven, the optical axis of the scope are registered on the sky.
Still confused, try your local astronomical society and you will be
given first hand demonstration.
As somebody else has pointed out, the dial must be sufficiently large
to be of any use. The RA dial on my scope goes down to 4 arc minutes
increments and puts objects in a low power eyepiece.

Pierre MK-UK

"McSlemon" wrote in
oups.com:

At this current moment, from my postion here, Polaris is RA 44.22 DEC
-11.74. So, if I were to be able to see it now, then I should set my
dial to that?


Presumably you mean Altitude and Azimuth. If you think about it, whatever
object you point the scope at, the dials should read it's RA and Dec.
Typically you only need to set Dec once, or check it occasionally for
accuracy. However, the RA dial needs to be reset periodically unless it is
being driven by the mount. Certainly it will need to be set each time the
drive is switched on.

--
Colin J Denman
N 51º 54' 38" W 00º 29' 45" Elev: 125m
email: -- use my first name
home: http://www.cjdenman.freeserve.co.uk

Colin J Denman wrote in
. 10:

At this current moment, from my postion here, Polaris is RA 44.22 DEC
-11.74. So, if I were to be able to see it now, then I should set my
dial to that?


Presumably you mean Altitude and Azimuth

Actually, I on't know what you mean now that I think about it. What is
44.22, -11.74?

--
Colin J Denman
N 51º 54' 38" W 00º 29' 45" Elev: 125m
email: -- use my first name
home: http://www.cjdenman.freeserve.co.uk

"Dan Birchall" wrote in message
...
(Colin J Denman) wrote:
Colin J Denman wrote in
. 10:

At this current moment, from my postion here, Polaris is RA 44.22
DEC
-11.74. So, if I were to be able to see it now, then I should set my
dial to that?


Presumably you mean Altitude and Azimuth

Actually, I on't know what you mean now that I think about it. What is
44.22, -11.74?

I'm baffled too. Polaris should always have DEC 90, shouldn't it? And
neither altitude nor azimuth is likely to be negative...
One 'thought', would be that he is looking at the mount's latitude
calibration, and not the RA dial, and then reading the Dec dial for the
other figure, with this incorrectly zeroed (and hence getting a -ve
reading on this).

Best Wishes