[prev in list] [next in list] [prev in thread] [next in thread] 

List:       kde-bugs-dist
Subject:    [Bug 83855] focus box RA display does not update
From:       <kstars () 30doradus ! org>
Date:       2004-06-27 16:41:47
Message-ID: 20040627164147.6570.qmail () ktown ! kde ! org
[Download RAW message or body]

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.
      
http://bugs.kde.org/show_bug.cgi?id=83855      




------- Additional Comments From kstars 30doradus org  2004-06-27 18:41 -------
Hi,

Sorry about the confusion.  You might want to have a look at the section 
on sky coordinates in the KStars Handbook (in the AstroInfo chapter) if 
you are unclear what RA, Dec, Azimuth and Altitude are.  

Try to think of KStars as a telescope simulator.  

If the telescope is parked in one position on its mount, then looking 
through the eyepiece, you will see the sky drift by (due to the 
spinning of the Earth).  This is the "not tracking" mode.  In this 
mode, the Azimuth and Altitude remain fixed with time, and the RA  
changes.

If you turn on the telescope's sidereal drive motor, it will rotate the 
telescope to keep up with the rotating sky.  Looking through the 
eyepiece, the stars will not drift by, they will remain in the field of 
view over time.  This is the "tracking" mode.  In this mode, RA and Dec 
remain fixed, and Az and Alt change over time.  (Of course if you want 
to track on a solar system body, the telescope must not only rotate to 
keep up with the Earth spinning; it must also keep up with the body's 
motion across the sky.)

On Sunday 27 June 2004 09:03 am, rhardy visi com wrote:
> Using horizontal coordinates, I see three behaviors:
>
> Focused on star:    Everything updates.  RA doesn't change.
Dec should not change either.

> Focused on moon:    Everything updates.
This is the correct behavior, because we have to keep up with the moon's 
changing position across the sky.

> Focused on Az/Alt:  RA doesn't update.  Az doesn't change.
>
What do you mean by "focused on Az/Alt"?  If you used the Manual Focus 
tool to set the Az/Alt coordinates, then tracking is not engaged 
(because if you think about it, "not tracking" in RA/Dec is the same as 
"tracking" in Az/Alt).  If you instead explicitly engaded tracking on 
empty sky, then this should be the same as tracking on a star (i.e., 
Az/Alt change; RA/Dec remain fixed).

> Is there a "not focused" case distinct from " focused on nothing"? 
>
Yes, unfortunately there is some ambiguity here.  When you see "Focused 
on: nothing" it can mean either that you are not tracking, or that you 
are tracking on an empty patch of sky.  The first situation is much 
more common.  Unless you explicitly double-click on empty sky, choose 
"Center & Track" from the popup menu for an empty sky point, or click 
on the "lock" toolbar/menu item, "Focused on: nothing" will mean you 
are not currently tracking.

If you want an unambiguous notification, look at the "lock" icon in the 
toolbar.  The lock will be open if you are not tracking.  I am 
considering putting an LED indicator in the statusbar that will light 
up when tracking is engaged.  Do you think that would help?

> I haven't looked at at the equatorial case yet; I'll do that after I
> look at "focused on nothing" a little more.  And then I may just drop
> it.  :-)

I'm actually seeing a different behavior in the CVS version than you are 
reporting here.  Unfortunately, it seems that none of the Focus 
coordinates get updated at all as time passes, whether tracking or not!
I'll look into this apparent regression today.

thanks for the reports,
Jason
[prev in list] [next in list] [prev in thread] [next in thread]