Re: Limited Sky View


brian skinner
 

Hi chaps, with my limited sky view I am finding that my OTA ends up consistently slewing to around 15 degrees to the right of my selected alignment stars. The end of slew position means my target stars are outside the field of view of my finderscope. This results in a fair amount of final adjustment in order to centre the stars.
My mount when parked is pointing true north, level and so on and tracks fine. I am wondering whether it would help to start alignment with Polaris centred in my finder scope and not be quite so worried whether the mount is pointing North? In other words does the park position assume the OTA/mount is pointing north or at Polaris???
Your expert thoughts as always would be very much appreciated.
Kind regards, Brian 

On Tue, 9 Apr 2019 08:33 brian skinner via Groups.Io <brianjimskinner=gmail.com@groups.io wrote:
Hi chaps, true north is almost at magnetic North here so sorry to miss lead....
Kind regards, Brian 

On Mon, 8 Apr 2019 14:19 Wes Mcdonald <wesmcd6@... wrote:
Richard:

I would only amend Brian's remark as follows.  One should try to point at TRUE north.  This will be deviated from magnetic north by some number of degrees.  Around here it is 10 degrees.  Ordinarily your phone compass will have a setting for True or Magnetic.  Just set it to True.  The app knows your location and the deviation and will correct things for you.

There are two apps I would suggest you get for your phone.  One is PSAlign.  This thing is a swiss army knife.  But the best thing is it has an alignment aid.  It provides a cross-hair which you center a spot indicative of the north celestial pole.  The phone needs to be placed flat on the top of the telescope tube and when you have the az-alt just right the spot will be centered on the cross-hair (place tube in home position).  You will be danged near polar aligned...and no need to see Polaris.  You can do this in the daytime.  

The other app is SkySafari.  It is a fantastic planetarium program that has a virtual reality feature.  It shows you the sky as you hold it in front of you and turn around.  This is the high tech version of a planisphere.  It will show you basically every star and nebula and deep sky object you can and can't see.  Get it.  It will help you plan your  viewing and especially the alignment stars you are going to be able to use.

Wes.
 

--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

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