Polar Alignment HELP

Hi

After stupidly losing the alignment on my polar alignment scope (Orion
Europa 200) I decided to use the method described he

http://www.celestron.com/polar.htm

Everything seemed to go well. I had polaris dead centre on the crosshairs
in my finderscope through a full 180 degree rotation of the scope around the
Dec axis. Surely this means my finderscope optical axis is aligned with the
north axis of my mount. (well close enough to the N.C.P for visual work)

The problem is when I then find a target in my finderscope it is not visible
through my telescope eyepiece. After finding the target in my eyepiece I
then checked back to the finderscope and found it to be roughly 2 degrees
out.

What could still be wrong? If I have understood correctly and things are
all nicely lined up surely my finderscope and eyepiece should be in union.

Thanks in advance for any help.

Dave.

On Tue, 21 Oct 2003 12:15:39 +0100, "Davey B"
wrote:

After stupidly losing the alignment on my polar alignment scope (Orion
Europa 200) I decided to use the method described he

http://www.celestron.com/polar.htm

Everything seemed to go well. I had polaris dead centre on the crosshairs
in my finderscope through a full 180 degree rotation of the scope around the
Dec axis. Surely this means my finderscope optical axis is aligned with the
north axis of my mount. (well close enough to the N.C.P for visual work)

The problem is when I then find a target in my finderscope it is not visible
through my telescope eyepiece. After finding the target in my eyepiece I
then checked back to the finderscope and found it to be roughly 2 degrees
out.

What could still be wrong? If I have understood correctly and things are
all nicely lined up surely my finderscope and eyepiece should be in union.

Thanks in advance for any help.

Polar alignment and finder scope alignment are not connected in any
way shape or form.

If you polar align your scope properly, then your equatorial mount
will allow you to track a centred celestial object by moving it in RA
only (i.e. no need to adjust the up/down (Dec.) component).

Polar alignment is therefore used to align your mount.

The finderscope on your scope is used to help you find ojbects in the
night sky. It's a sighting device and needs to be aligned with
respect to the main telescope.

It can (and will!) get knocked and nudged out of alignment (probably
quite often). It's best to get in to the habit of aligning it when
you have everything outside and ready for observing - just before you
start.

Alignment is pretty easy. Pick a low power eyepiece for your main
scope. Point the scope at a brightish star. If the finder is really
out of alignment, you may have to sight along the tube to do this.
With a low power eyepiece the field of view should be wide enough so
that with a bit of jiggling, you can eventually see the bright star in
through the main scope.

Centre the star in the main scope (as near as damn it). Now switch to
the finder. If the star isn't on the crosshairs, use the adjustment
screws around the finder holder to adjust the position of the finder.
There are normally three (sometimes more) screws that can be adjusted.
Do it slowly while looking through the finder. Get used to the
movement and adjust until the crosshairs are on the star.

Now go back to the main scope. Notice how the star has moved off
centre g. It may not have done - but often does. If it has, then
re-centre in the main tube and repeat the process with the finder
adjustment.

If you want more accuracy, once you are happy that the finder is
pretty much spot on, replace the main scope's eyepiece with a shorter
focal length one. Repeat the process again.

The higher the eyepiece power, the faster a star will appear to move
out of the centre of the field of view (unless the scope is driven).
Locating a star near to the pole reduces this effect somewhat.
Polaris is more or less ideal (because it hardly moves) but is a real
pig to see with an equatorial mount.

--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy

"Pete Lawrence" wrote in message
...
On Tue, 21 Oct 2003 12:15:39 +0100, "Davey B"
wrote:

After stupidly losing the alignment on my polar alignment scope (Orion
Europa 200) I decided to use the method described he

http://www.celestron.com/polar.htm

Everything seemed to go well. I had polaris dead centre on the
crosshairs
in my finderscope through a full 180 degree rotation of the scope around
the
Dec axis. Surely this means my finderscope optical axis is aligned with
the
north axis of my mount. (well close enough to the N.C.P for visual work)

The problem is when I then find a target in my finderscope it is not
visible
through my telescope eyepiece. After finding the target in my eyepiece I
then checked back to the finderscope and found it to be roughly 2 degrees
out.

What could still be wrong? If I have understood correctly and things are
all nicely lined up surely my finderscope and eyepiece should be in
union.

Thanks in advance for any help.

Polar alignment and finder scope alignment are not connected in any
way shape or form.

If you polar align your scope properly, then your equatorial mount
will allow you to track a centred celestial object by moving it in RA
only (i.e. no need to adjust the up/down (Dec.) component).

Polar alignment is therefore used to align your mount.

The finderscope on your scope is used to help you find ojbects in the
night sky. It's a sighting device and needs to be aligned with
respect to the main telescope.

It can (and will!) get knocked and nudged out of alignment (probably
quite often). It's best to get in to the habit of aligning it when
you have everything outside and ready for observing - just before you
start.

Alignment is pretty easy. Pick a low power eyepiece for your main
scope. Point the scope at a brightish star. If the finder is really
out of alignment, you may have to sight along the tube to do this.
With a low power eyepiece the field of view should be wide enough so
that with a bit of jiggling, you can eventually see the bright star in
through the main scope.

Centre the star in the main scope (as near as damn it). Now switch to
the finder. If the star isn't on the crosshairs, use the adjustment
screws around the finder holder to adjust the position of the finder.
There are normally three (sometimes more) screws that can be adjusted.
Do it slowly while looking through the finder. Get used to the
movement and adjust until the crosshairs are on the star.

Now go back to the main scope. Notice how the star has moved off
centre g. It may not have done - but often does. If it has, then
re-centre in the main tube and repeat the process with the finder
adjustment.

If you want more accuracy, once you are happy that the finder is
pretty much spot on, replace the main scope's eyepiece with a shorter
focal length one. Repeat the process again.

The higher the eyepiece power, the faster a star will appear to move
out of the centre of the field of view (unless the scope is driven).
Locating a star near to the pole reduces this effect somewhat.
Polaris is more or less ideal (because it hardly moves) but is a real
pig to see with an equatorial mount.

--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy

Thanks Pete,

I already understand how to align my finderscope with a target object my
problems lie with polar alignment. Let me explain a little more.

While trying to learn more about my telescope I got too "fiddling" with
certain bits. While fiddling I managed to move the alignment screws on the
polar finder thus losing my polar alignment facility. What I needed now was
a way to polar align my scope so I could re-align the polar finder. When I
read the section named "Accurate Polar Alignment" on the webpage I mentioned
in my initial post it seemed to be just the thing I was after. After
carrying the procedure out I assumed (maybe wrongly) that it would also
align my tube with my finderscope. The reason I believed this is that the
mount is aligned and locked to 90 degrees Declination and polaris is centred
in the finderscope crosshair for a full movement of 180 degrees around the
RA axis (not Dec axis as I said in my original post). As my mount and
finderscope are now pointing perfectly north I thought it was resonable to
assume that they would also be aligned with each other. They were not.

Hope this explains a little more what my problem is and hopefully someone
can help me see where I am going wrong.

One thing I did think could be causing it is - My mount IS pointing
accurately at the North Celestial Pole but my finderscope is pointing at
Polaris and that is where the error is (as Polaris is not located exactly at
the N.C.P). Please can someone tell me if I am correct in this assumption.

Dave

On Tue, 21 Oct 2003 16:04:22 +0100, "Davey B"
wrote:

Thanks Pete,

I already understand how to align my finderscope with a target object my
problems lie with polar alignment. Let me explain a little more.

While trying to learn more about my telescope I got too "fiddling" with
certain bits. While fiddling I managed to move the alignment screws on the
polar finder thus losing my polar alignment facility. What I needed now was
a way to polar align my scope so I could re-align the polar finder. When I
read the section named "Accurate Polar Alignment" on the webpage I mentioned
in my initial post it seemed to be just the thing I was after. After
carrying the procedure out I assumed (maybe wrongly) that it would also
align my tube with my finderscope. The reason I believed this is that the
mount is aligned and locked to 90 degrees Declination and polaris is centred
in the finderscope crosshair for a full movement of 180 degrees around the
RA axis (not Dec axis as I said in my original post). As my mount and
finderscope are now pointing perfectly north I thought it was resonable to
assume that they would also be aligned with each other. They were not.

Hope this explains a little more what my problem is and hopefully someone
can help me see where I am going wrong.

Davey, apologies - I should have read the article first! I was
talking from the standpoint of a mount with a dedicated polar
finderscope (inserted within the polar axis of the mount itself). The
thought of trying to twist either of my equatorially mounted scopes to
look at Polaris fills me with dread. I'll keep my mouth shut and let
someone else answer who knows your scope type.


--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy

Davey, apologies - I should have read the article first! I was
talking from the standpoint of a mount with a dedicated polar
finderscope (inserted within the polar axis of the mount itself). The
thought of trying to twist either of my equatorially mounted scopes to
look at Polaris fills me with dread. I'll keep my mouth shut and let
someone else answer who knows your scope type.


--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy

Thanks for another speedy reply.

My mount has got a dedicated polar finderscope but that is what I "fiddled"
with and now it does not point north (well it does when I point it north but
it is no longer aligned with the axis of my mount). I needed a method to
polar align my telescope so then I can adjust the dedicated polar finder
back to north so I will never have to go through this again.

Lesson One: Dont fiddle with what you dont understand

Dave

On Tue, 21 Oct 2003 12:15:39 +0100, "Davey B"
wrote:

Hi

After stupidly losing the alignment on my polar alignment scope (Orion
Europa 200) I decided to use the method described he

http://www.celestron.com/polar.htm

Everything seemed to go well. I had polaris dead centre on the crosshairs
in my finderscope through a full 180 degree rotation of the scope around the
Dec axis. Surely this means my finderscope optical axis is aligned with the
north axis of my mount. (well close enough to the N.C.P for visual work)

The problem is when I then find a target in my finderscope it is not visible
through my telescope eyepiece. After finding the target in my eyepiece I
then checked back to the finderscope and found it to be roughly 2 degrees
out.

What could still be wrong? If I have understood correctly and things are
all nicely lined up surely my finderscope and eyepiece should be in union.

Thanks in advance for any help.

Dave.



Right, You want to get your polar scope aligned with the polar axis of
your telescope ?

Get this manual and it will show you, its dead fiddly....
http://robert.thegeakes.co.uk/astro/...polarscope.pdf

Rob

"anonymous" wrote in message
...
On Tue, 21 Oct 2003 16:04:22 +0100, "Davey B"
wrote:


I already understand how to align my finderscope with a target object my
problems lie with polar alignment. Let me explain a little more.

While trying to learn more about my telescope I got too "fiddling" with
certain bits. While fiddling I managed to move the alignment screws on
the
polar finder thus losing my polar alignment facility. What I needed now
was
a way to polar align my scope so I could re-align the polar finder.

Can this be of any help to you?
http://www.astroleague.org/al/astrnote/astnot15.html

Yes it will help... thank you very much

Sorry for the slow reply good old NTL news server has been down

Thanks again

Dave

"Robert Geake" wrote in message
...
On Tue, 21 Oct 2003 12:15:39 +0100, "Davey B"
wrote:

Hi

After stupidly losing the alignment on my polar alignment scope (Orion
Europa 200) I decided to use the method described he

http://www.celestron.com/polar.htm

Everything seemed to go well. I had polaris dead centre on the
crosshairs
in my finderscope through a full 180 degree rotation of the scope around
the
Dec axis. Surely this means my finderscope optical axis is aligned with
the
north axis of my mount. (well close enough to the N.C.P for visual work)

The problem is when I then find a target in my finderscope it is not
visible
through my telescope eyepiece. After finding the target in my eyepiece I
then checked back to the finderscope and found it to be roughly 2 degrees
out.

What could still be wrong? If I have understood correctly and things are
all nicely lined up surely my finderscope and eyepiece should be in
union.

Thanks in advance for any help.

Dave.



Right, You want to get your polar scope aligned with the polar axis of
your telescope ?

Get this manual and it will show you, its dead fiddly....
http://robert.thegeakes.co.uk/astro/...polarscope.pdf

Rob

Thanks very much Rob

I will give that a go on the next clear night we have.

Thanks again

Dave

"Jonathan Vogt" wrote in message
...
Dave this is how I aligned my Orion Europa polar scope. Dont mount the
scope on the Mount , Set up the mount as normal
Point the Polar scope at Polaris , centre polaris (dead centre in the
cross hairs if the polar scope has them) , now looking through the polar
scope rotate the axis by hand and see how polaris rotates in the scope ,
if it stays dead centre its aligned now if it wobbles you can align the
polar scope by trial and error... Jon

--
Jonathan Vogel



Thank you Jonathan

Will give it a try the next time we get a clear night and let you know how I
get on.

Thanks

Dave