Re: New user help


"Purploid" <purploid@xxxxxxxxxxx> wrote in message
news:1151847112.423871.149900@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi,
I am wondering if any of you can help me out with a small problem I
seem to be encountering.
I have recently bought a Sky Watcher 4.5" (114mm) Catadioptric-
Newtonian telescope with a EQ1 mount.
I have set it up, balanced it and taken it out and located Ploaris with
not much trouble at all, but, I am running into all sorts of problems
when I try to locate my second star.
The star I have tried to locate is Mizar, not too far away from Polaris
and easy to tell if I've found it.
I am using Starry night to obtain my RA and Dec.
So, my telescope is set to Polaris RA 2h31 Dec 89deg, then I try and
locate Mizar RA 13h24 Dec 54.53deg.
My telescope will not turn on my RA axis that far without colliding
with the mount.
I have taken my scope apart and started again just to check all is set
up ok and still the same thing.
I am sure I am doing something wrong, but cannot work out what.

Please can some one point me in the right direction ( hoho)

Anji
First thing, is that Polaris, is possibly the worst start in the sky, to
try to set the RA on!. A _tiny_ error in the polar alignment, can lead to
huge errors in it's apparent RA. However I suspect your problem is the
'meridian flip'. According to your location, and the time you are
starting, Polaris, should probably be slightly to the east of the true
pole. Going to Mizar, will then involve a 'meridian flip'. When an
equatorial mounted scope wants to 'swap' to stars the other side of the
meridian, the tube has to reverse 180 degrees on the Dec axis, and the RA
also has to move round by 180 degrees. In general, the gear play involved
in this, is sufficient, that you should aim to use a star on the same side
of the meridian as you 'reference'. So, rotate the OTA, aim at Mizar, set
it's RA, and then use this as the refernce to find dimmer objects on this
side of the meridian.

Best Wishes


.

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