Recent content by Jenab6

The mass luminosity relation isn't a physical model; it's an empirical curvefit. The best fit isn't necessarily a pure power function. It can be L/L๏ = K (M/M๏)^a But K isn't required to be 1. It can also be more complicated, such as L/L๏ = K₁ (M/M๏)^a₁ + K₂ (M/M๏)^a₂ For example, the mass...

Sky, star, sky, comparison star, repeat. You have to subtract the sky. You also need to subtract the system dark current. m = −2.5 log F − 18.88 m = apparent magnitude F = flux in watts per square meter

Right. The reason I used the term hillbilly was to make that very point. I'm a hillbilly living in the West Virginia Allegheny Mountains. I'm a celestial mechanic. I have been employed as a defense contractor physicist. My last job, before I retired, was book editor for a small publishing...

If a spaceship first enters an orbit that takes it above or below the ecliptic, it can then do a course adjustment that makes the departure point (or trajectory adjustment point) the perihelion of a hyperbolic transfer orbit to Jupiter that avoids the ecliptic until arrival. It just can't begin...

Algebra, trigonometry, vectors, and occasionally a little bit of calculus. The ease of doing the calculations, or in finding out which calculations are right to do, is as much dependent on being able to visualize the goings-on as it is understanding the math.

Here's my solution to the ephemeris problem. Yahoo Answers staff didn't like it, but it's a correct general solution with a worked example for Jupiter's position on a given date. http://jenab6.livejournal.com/15453.html Here's a BASIC program I wrote (with double precision) to evolve a...

Here's a mass luminosity relationship that fits the empirical data closely. Lower main sequence (M < 0.6224) log L = 2.5186 log M - 0.4814 Middle main sequence (0.6224 < M < 1.6959) log L = -1.142866 (log M)^2 + 4.621390 log M Upper main sequence (M > 1.6959) log L = 3.8931 log M + 0.1069...

Certainly, there is a lot of vector arithmetic used in celestial mechanics work. We do vector subtractions and additions, we rotate from one coordinate system to another, we convert from spherical to rectangular and vice versa. We sometimes have to find a vector's direction and magnitude from...

My LiveJournal article on how to calculate a hyperbolic transfer orbit is now published! Improved procedure for Elliptical Transfer Orbits http://jenab6.livejournal.com/12053.html Improved procedure for Hyperbolic Transfer Orbits (NEW!) http://jenab6.livejournal.com/15054.html Jerry...

I wasn't recommending it be done. I was only pointing out the possibility of doing it. The energy involved in diverting Midas is 488 megatons TNT equivalent, about equal to five of the largest hydrogen bombs.

Here's an assessment of the feasibility of diverting asteroid 1981 Midas into a collision with Earth in the year 2018. I'm posting this to show the potential military-political advantage to controlling access to space. Note the relatively small size of the divert delta-vee. Only about 301.5...