I still don't understand why asfter only 10 min giuding (in the amlost same AR and DEC location) i see the mirror flop... The difect could be seen after half an hour of giuding i suppose, but not in this short time.
Unfortunatly last and tonight we have (Italy north part) cloudy weather...


> >
> >Ciao to all,

> >To understand my problem my situation must be explained.
> >I have the LX200 10” f6.3 with piggybacked a 2045. The 201 XT is coupled
> >with 2045 giuding >telescope using the flip mirror 644 model.
> >I did the calibration using the Cd and Cr rating as 20 and 15; in this way
> >I use all the chip for the >calibration (the star is positioned at
> >coordinates 1,1). I spoke with a friend of mine and told me to >use just 2
> >or 3.. I will try..
>
> Cd and Cr are measured in seconds. The manual mentions using 2, but that's
> when guiding through the main scope, which has a much longer focal length.
> In general, longer will be more accurate, but if you go too long, the star
> will end up off the chip.
> (Side note- starting with the star so close to the edge will make it easy
> for the star to end up off the chip after one of the calibration moves (due
> to backlash, it may not move exactly the same amount "dn" as "Up". Starting
> at (2,2) will reduce the chance of the calibration proceedure ending with
> that frustrating "Er" message.)
> The FOV of the guide chip on you guidescope is roughly 8' X 11'. At guide

> speed (sidereal rate, or 15"/sec), it will take about 16 seconds to go
> halfway across the short dimension of the chip (from (2,2) to (2,7) for the
> dec calibration move), so 15 seconds sounds just about right for Cd. The
> chip is longer in the other direction, so 20 sounds good for Cr.
>
>
> >Anyway, my problem is that just after 15 min of guiding (the display of 201
> >displays the correcting >values), the star has a little shifted from its
> >original position, but the 201 seems to see the star >position correctly.
>
> That's a common problem when using a guide scope with SCTs, due to mirror
> flop. Have you tried using a simple "bolt lock" for the mirror? In this
> case, your guide scope may also have mirror flop, if it uses a moving mirror
> for focus.
>
> >In fact when I try to put the star in its original position the 201 star to
> >applicate heavy corrections.
>
> Perfectly normal, since the view has shifted between the two scopes.
>
> -John
>
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