Re: Help with orthogonality


observe_m13
 

If your telescope is orthogonal to the mount and the mount is even
moderately well polar aligned, when you point the telescope right at
the pole, Polaris will NOT be centered. It will be noticeably offset
even in a low power eyepiece field. Polaris can be used as a quick
alignment star for visual use of a moderately wide field telescope
with goto in most cases.

To rough polar align I use the PASILL with great success. In fact,
with a bit of care, I manage to achieve very good to excellent polar
alignment. One can drift after that to fine tune it further if
shooting close to the poles where field rotation really makes a mess
of things if you are not well polar aligned.

Rick.

--- In ap-gto@yahoogroups.com, "spcrichey" <drichey@...> wrote:

So, one person says "Uh, no you should not be able to center
Polaris, Polaris is not at the
pole, it is beside it." , and another says "the mount can certainly
go to Polaris." I am very
confused. Is not being able to center Polaris an orthogonal error,
or not? I have a "normal"
refractor and "normally well" machined rings, so either I am not
well enough polar aligned,
or my equipment isn't "normal." --- In ap-gto@yahoogroups.com,
chris1011@ wrote:

In a message dated 4/24/2007 4:35:40 PM Central Daylight Time,
drichey@ writes:


I beleive it is .8ยบ for CNP. So how does one do the alignment
routine in the AP manual using Polaris and another star?
The mount can certainly go to Polaris. No problem. When properly
polar
aligned, any mount can go to Polaris. If you have orthogonal error
larger than 0.8
degrees in your telescope, then no equatorial mount will be able
to access
Polaris. The mount will point to Polaris for sure, but the scope
will point
elsewhere. I assume that every amateur knows that the direction
that a telescope
points to is not necessarily the direction that the mount points
to. It is up to
you, the user, to align the two. Every basic book on astronomical
instruments
will point this out.

Rolando


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