[APBeta] Galaxy position angle

[David Hill]

Paul, Erik -

 

It would seem that you have a real "sticky wicket."  The dashed circle idea has promise for display purposes only just to show "its in here somewhere"; however, for those who do Surface Brightness (SB) measurements, mag/'^2 or mag/"^2, or better yet, Surface Brightness, l/theta^2, ergs cm^-2 s^-1 deg^-2, these calculations would contain significant error.  There is a whole host of NGC and IC Objects (GXs) out there that do not have observed brightnesses (mag) tabulated , much less their angular diameters (size).  "It's been that kind of day."

 

David H. -
 
> Date: Sat, 21 Nov 2009 22:02:02 -0500
> From: emf1123 at gmail.com
> To: apbeta at lists.astroplanner.net
> Subject: Re: [APBeta] Galaxy position angle
> 
> Erik Fichtner wrote:
> > Paul Rodman wrote:
> >> If a catalogue has a defined position angle for a galaxy then it is drawn oriented at that position angle in the FoV. If it doesn't have a position angle defined, it is shown with position angle = 0. It would seem that (a) this causes confusion, and (b) a method of indicating that a galaxy does not have a position angle defined should be introduced. 
> >>
> >> Any ideas?
> > 
> > -1 ?
> 
> Heh.. I just realized you meant for display. (It's been that kind of day)
> 
> I suppose I'd expect something like a dashed circle of the size of the semimajor axis to indicate
> "it's in here somewhere", as is done for nebulae.
> 
> 
 		 	   		  
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