[APBeta] Double stars

[Paul Rodman]

On Nov 27, 2008, at 04:02 AM, David Crum wrote:

> Working with version 2.0b5 and Double stars, I am seeing "double".
>
> I start up a new session, select Search Catalogs, I choose the AL
> Double star one.  I then hit the "ok" button (selecting all
> constellations).  I then add all the objects found to the plan.  Once
> they are in the plan I sort it to the way I want it.
>
> I go to Beta Cygni (Alberio).  When I go to Field of View, things get
> a bit fuzzy.  There are now 4 stars in the field.  Alberio and ALDS85
> AND another copy of Alberio and ALDS85.
>
> This happens on every double star I tried it on in the AL Double  
> star catalog.
>
> I also tested this out on the Neglected Doubles I catalog, same  
> result.
>
> Do I have more then one catalog selected??

Is what is shown below what you are seeing?

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This occurs because the coordinates in the AL Double Star catalogue  
are not particularly accurate (RA and Dec only to the nearest arcmin  
or worse), whereas the stars in the Bright Star catalogue (which is  
selected here) are more accurate. The difference you're seeing is the  
difference between those two catalogues.

Paul R.