DM42 vs hp49gp (performance-wise)

[roberto_abraham]

Hi Gour -

I've got a DM42 and I have used Urania a fair bit on a HP50g. Urania is really something pretty special... essentially the whole of Meeus' Astronomical Algorithms book in a nicely packaged library.

I think individual programs based on algorithms in Meeus' book (which is pretty much the gold standard for moderate accuracy positional astronomy on small machines) are pretty easy to find for the HP41, so there are lots of great HP41 astronomy programs for things like planet positions. Individual HP41 programs are generally super easy to port to the DM42. And the DM42 definitely has the horsepower needed to calculate things like planet positions without annoying long waits.

One caveat though is that the astronomy programs I've seen for the HP41 are mostly self-contained things that calculate interesting quantities but they take input and provide output in ways that don't make it easy to chain programs together. (I'm obviously generalizing here). Anyway, the nice thing about Urania is the way everything is so logically laid out and well documented and the routines are explicitly designed to call each other and be interoperable. As a result, I haven't found anything that can replace Urania on my DM42, though I think if you're keen enough to try to produce such a thing the calculator is powerful enough to allow you to do that.

Bob

P.S. I'm an astrophysicist and this is the first time in my life I've ever tried to help somebody cast a horoscope! :-)