[Kstars-devel] Prakash's KSalmanach

[Khudyakov Alexey]

Hello

I've just checked out summer branch and looked through it. 

Begin/end time of twilight are calculated incorrectly. One cannot just use 
linear interpolation to obtain this times. Code below. 

> double KSAlmanac::getCivilTwilight( bool begin ) {
>    if(begin) return ( SunRise - 6 * riseRate ); 
>    return ( SunSet + 6 * riseRate );
> }

This way calculated twilights are longer than real. Moreover solution always 
exist even if sun never goes below 6/12/18 degrees. 

Right way to do this is to find when Sun goes above/below -6/12/18 deg. as done 
in SkyObject::riseSetTime. However it will require a lot of changes to that 
function. 


P.S. 

Quick hint to Prakash. 

You need not to explicitly cast KSsun* and KSMoon* to SkyObject*. Since they 
are subclasses they will be casted automatically.

> RiseSetTime( (SkyObject*)m_Sun, ....
> RiseSetTime( (SkyObject*)m_Moon, ....

--
  Best regards Khudyakov Alexey