[APBeta] Galaxy position angle

[David Hill]

Paul R. -
 
I use an excellent computerized sky chart with fine spherical projections for practically any FoV.  All these galaxies (GX) from the NGC and IC - large and small, close and distant - are displayed horizontally as an ellipse (regardless of actual morphology).  With AP, I have always considered the tabulated GX position angle and size a real plus.
 
David H. -
 
> From: paul at ilanga.com
> Date: Sat, 21 Nov 2009 22:23:45 -0800
> To: apbeta at lists.astroplanner.net
> Subject: Re: [APBeta] Galaxy position angle
> 
> 
> On Nov 21, 2009, at 9:31 PM, Gary A. Ferguson wrote:
> 
> > Perhaps for an undefined position angle, you should just draw a circle.
> > 
> 
> Well, if it has an AxB size specified, a circle would "lose" that info.
> 
> What I thought was (optionally) displaying the position angle as a small tick with the value attached. For no position angle, display the galaxy horizontally (currently it is vertically oriented, which is aesthetically unpleasing) but with no tick mark or "?" next to a tick mark.
> 
> Or I could draw in the major axis for known pos angles, and leave it out for the rest.
> 
> Paul R.
> 
> > 
> > -----Original Message-----
> > From: apbeta-bounces at lists.astroplanner.net
> > [mailto:apbeta-bounces at lists.astroplanner.net] On Behalf Of Paul Rodman
> > Sent: Saturday, November 21, 2009 6:35 PM
> > To: AstroPlanner Beta Testers
> > Subject: [APBeta] Galaxy position angle
> > 
> > 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?
> > 
> > Paul R.
> 
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