**Tuesday, 15th May, 2,012.**

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**ZZ37**

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**My New Astronomy Course, Lesson Two.**

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**Please understand. Astronomers lack a good DISTANCE finder. Which is very important to Astronomy – of course. Hubble’s Law is good.**

**I hope to show you how to get the best and exact distances. From those masses,etc.can be worked out.**

**There are TWO main ways to get distances. Apparent Magnitudes,v, Absolute Magnitude(Intrinsic Luminosity)mv adjusted. AND Radial velocities.(rv)**

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**To understand the problem better, let me use an analogy to illustrate:-**

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**We are out in the country-side at night. It is pitch dark. Looking back along the road a car’s headlights are seen approaching. How far away is the car?**

**What we see is The Apparent Magnitude. We need to know how powerful the headlight’s lamps are(Absolute Magntitude). It is a foggy night. How thick is the fog? How much does the road bend?(To determine its distance by road.)**

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**What is the car’s speed?(Radial velocity.Rv.) The pitch of the engine may tell me.(The analogy fails here. But with stars,etc.the rv radial velocity helps me to determine the distance of the object.)**

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**(Note that in Astronomy(a point of interest), trigonometric parallax is used to get the distances of the near-by stars. That is easy with straight space, but space is curved! And warped!!(Per the masses in it.))**

**Astronomers use The Cepheid Variables(And R-Lyrae stars) to get the distance of some stars.**

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**What I do is take the ORTHODOX distances, and then ADJUST them per things I have found out from my maps,etc. For this I use a formula.**

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**My BASIC line is that the distance obtained by apparent magnitudes EQUALS the distance found by radial velocities.**

**So I take The Geometric Mean of the two. Rooting because rates. So I go Square Root of v, apparent magnitude(adjusted for absolute magnitude) TIMES The Radial Velocity(rv). – Divided by 2.(To get The Mass, take The Arithmetic Mean, do the sum of the two, and divide by two.) Equals The Distance. Making The Equatiion.**

**Subtract The Obscuring Matter(Extinction Effect.). I find that The Reddening, R, gives a good indication of how much the light has been dimmed.**

**I used the principle that ON THE AVERAGE, one factor would be up as much as the other was down. (From Magnitudes and Velocities.) And that their mean should give the best distance away.**

**Square Root of (x + 3 times y – 3) is x), where x = y.(Geometric mean.)**

**Units will be in light-years.**

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**PLEASE read my old article A1058, which I give again next, for further details on my distance finder.**

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**Vic.**

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