Why does the cursor not match the screen position of a chosen object?
The Problem:
A month ago I bought a new LX200 ACF GPS scope and set it
up in permanent polar mode on a wedge in my observatory. This scope
has to be started up in one particular sequence or it
doesn't operate properly. When the scope is turned on the GPS receiver
gets a signal from three satellites to establish the exact time and the scope's
location. Next, because it's already polar aligned, I can choose a star
from the handbox's celestial
object database list in order to do a one-star alignment to enable the
scope's newly found GPS settings to sync to the sky. Then when I press GOTO
on the handbox the scope slews to the alignment star and on
reaching it I must centre the star, again using the handbox. The
alignment position for both the scope and the star is fixed when I press Enter
on the handbox.
At this point I can turn on Starry Night,
click Telescope, then Connect and Disconnect shows. Now the scope and
Starry Night are perfectly synchronised and this is shown when the Starry Night
cursor appears on the screen next to the same star I earlier chose in the
one-star alignment process showing where the scope is now pointing. So far,
so good.
Now, as you know, using Starry Night I can now choose any
object to image with my camera because both the scope and Starry Night
are synchronized and talking to each other. After choosing and
clicking on a new object on the Starry Night screen the
scope will start slewing directly to it. And as the
scope slews the cursor on the screen follows the
scope's trajectory as it moves to the new object I selected.
Eventually the scope will reach its
destination and stop. The object will be in the scope's eyepiece. Again, so far,
so good.
I should also mention that I prefer the screen to stand still
in its original state because I don't want the object to be centered on the
screen. I like the screen to match the sky so my cursor does all the
moving, tracking along with the scope.
Now here is where the problem arises . . . the +LX200 cursor, which started moving to the new object when the scope
did, should track across the Starry Night screen in step with the
scope's movements in order to end up snug to the new object, but
it doesn't. For some strange reason when the scope
and the cursor stop moving the scope is right on target but the cursor is way
off target. It doesn't make it all the way, it stops moving before it
reaches the object.
If the scope goes directly to the object
which is here------> (+)
the cursor on the screen stops------>(+) here, short of the mark and
to the right lower side, never the left side.
The cursor should be right next to the chosen object, like
this (+)(+) , but it isn't, it stops way off to the right.
All other scope and Starry Night functions work well except
for this peculiar habit, and I mentioned earlier that it can be lived with as
long as one can remember which object it was that was chosen, which really
shouldn't be a problem.
I should mention that I used Starry Night for many years
with my older Meade Classic and I was very satisfied with it. This odd behaviour
only started after I bought the new GPS scope a month ago and connected the
same computer and Starry Night program to it.
So there it is: nothing to do with centering, only the
cursor not ending up where it is supposed to be after slewing to an object.
I hope this sheds a little more light on it.
The Solution:
In the back of my mind I've had this niggling idea that Starry
Night wasn't the cause of the problem I've been having. So tonight I went
through the handbox Setup Menu until I reached Daylight Savings. It was set to
On. And that reminded me of something I'd seen on the Ascom web site when I
downloaded their Platform and Mount Drivers. It was a list of things to check
out for polar aligned Meade LX200 GPS scopes. So I revisited the site and
trolled through it and there it was: a recommendation to turn off Daylight
Savings.
I went back to the handbox and turned it
off, as suggested, and after running the start-up procedure and the one-star
alignment the Starry Night cursor was bang on in position, exactly where it was
supposed to be, and I breathed a grateful sigh of relief.
Apparently, leaving the Daylight Savings setting ON
resulted in the cursor being one-hour out of sequence. For instance, if I
clicked on an object that was at 20h the cursor would position itself on the
screen at 19h! What clued me in to suspecting a Setup problem was noticing
that the cursor positioned itself on the screen to match the curved shape of the
celestial horizon. This is hard to explain to someone! However, the scope wasn't
an hour out of sync, it precisely slewed to any object for the reason, I
suppose, that it had already obtained a GPS fix. But, on the other
hand, the cursor may have been overuled by the Daylight Savings
setting.
After all that, my imaging session tonight was a sweet reward
even though the moon was full. It ran perfectly with no problems.
