NavList:

Dear Bob,

I'm studying The Lore of Sliding The Rule. :)

The Lore teaches us to do the calculations with as few movements as possible. For this the rules usually feature the I-scale which allows for three-operands multiplication with as little as just two cursor's movements and one slider's movement inbetween.

Because in the background the formulas are like that:

• Hc = asin[ sin(LatEP)·sin(Dec) + cos(LatEP)·cos(Dec)·cos(LHA) ]
• Zc = atan[ cos(Dec)·sin(LHA) / { cos(LatEP)·sin(Dec) - sin(LatEP)·cos(Dec)·cos(LHA) } ]

I think it could be usefull to have one of trig scales in two versions: a regular and an inversed. Looks like it should be the cos(x) scale.

What do you think? What do The Lore gurus think?

Regards,

Tony