Astronomy

[trolls' bane]

Atronomy is so cool, and I am dying to hear about all of the things that the news and Astronomy.com say. I am also eager to meet amateur astronomers like myself. Please post any cosmic events (meteor showers, etc.) so people have a broader income of such news; as well as anything else to do with astronomy.

Now, could someone please explain to me in terms someone 13 years of age can understand, what "log" means in advanced math. If it's not that easy, try your best. The reason I ask is because I want to figure out the meaning of the equation used for finding out the absolute magnitude of a star by using its apparent magnitude:
M=(m+5) -5 log D
Might as well be in French.

Oh, and all HVEL members interested, the Hidden Valley Telegram has an astonomy section, so if I get enough people to give some more info, it will be more up to date.

[trolls' bane]

Hurray for Solar Sail Tech!
[Music: "I've got a Golden Ticket!"]
I never thought I'd see the day,
When solar sails would sail away.
I've got a solar sail, I've got a solar sail,
I'll colonize Rigel when I'm eighty,
I've got a solar sail, I've got a solar sail!

(I haven't heard it in a while, obviously.)

Anyway, solar sail tech is one of the most ingenious ideas that I have ever heard. I have become so enthusiastic of the idea that ships can sail at nearly light speed (Which is relatively little, but better than we are doing now) by using the solar wind. I don't care that the simplest configuration, a disk-shaped sail, would have to be a square mile for minimal effect. If I were a billionare, I would bet my money on solar sail tech (unless discovering nuclear fusion power was on the ballot). Are there any other solar sail enthusiasts?


Edit: This Wednesday, there will be an occultation when the moon passes in front of Jupiter. Jupiter, btw, is the brightest object (aside from the Moon) in the sky right now, so it is quite visible even in the worst light polluted cities (I live a few blocks away from the car dealerships on Van Nuys, and they never turn off their lights).

[Nurvingiel]

About your first post and the equation M=(m+5) -5 log D:

Log is a function, just like square root, or powers, multiplying, or other functions. To calculate this, your really need a scientific calculator with the log function. (A good scientific calculator should have it. The calculator that comes with Windows has this function, when viewed in scientific mode.)

Many functions in math have opposites, like multiplying and dividing. You already know how this works - if you divide a number, x by 5, then multiply x/5 by 5, then you get x again. Multiplying and dividing undo each other.

You can think of log, short for logarithm, the same way. The logarithm of x , log(x) is the opposite of 10 to the power of x, 10^x.

This is why log(1)=0, and 10^0=1. This is the same as writing:
square root(9)=3 and 3^2=9.

^ means "to the power of"

So log is nothing to worry about (though using it is something you won't see until you're in grade 10 or 11). The difficult part in the formula is what is M, m, and D? That part might be harder to calculate, unless the textbook or example gives them to you.

m might be mass, but how to you calculate the mass of a star? I think you're getting into pretty advanced physics there, so good on you for challenging yourself. And good luck!

[trolls' bane]

Thank you, Nurv! (And LTNS! )

I think:
M=Absolute Magnitude
m=Apparent Magnitude
and
d=distance
This would make sense, because the apparent magnitude is partially determined by distance, and since M is the dependant variable and you are trying to find out the absolute magnitude, them absolute magnitude must be M. These would make sense, because Absolute Magnitude is measuring the brightness of stars if they were all the same distance (this includes the sun), at a distance of only 10 Parsecs.

The book where I got it from is an extremely poor translation of an Italian book. The index isn't even in alphabetical order. You end up with this:

A

-Apple page 12
-Angry page 167
-Abacus page 4
-Astronomy page 1

[Nurvingiel]

Wow... the mind boggles. Physics was never my strong suit, though I did take it in grade 12. You need to get yourself a decent Astronomy book though! That will help you a lot I imagine. Good luck.

[trolls' bane]

The hard part is finding a good astronomy book. Other than the Italian one (which would be worthwhile if you had the Italian version and could read it), all I can find are books meant for kids my age with things I learned years ago.
I do, however, have a planetarium program, which does not give explanations for things like htat equation, but does have an astronomy dictionary.

[mithrand1r]

Logarithms was a type of shortcut for doing mathematics back when people did not have calculators available. (One type of tool that used logarithms is the slide rule)

Originally Posted by trolls' bane

Thank you, Nurv! (And LTNS! )

I think:
M=Absolute Magnitude
m=Apparent Magnitude
and
d=distance
This would make sense, because the apparent magnitude is partially determined by distance, and since M is the dependant variable and you are trying to find out the absolute magnitude, them absolute magnitude must be M. These would make sense, because Absolute Magnitude is measuring the brightness of stars if they were all the same distance (this includes the sun), at a distance of only 10 Parsecs.

The book where I got it from is an extremely poor translation of an Italian book. The index isn't even in alphabetical order. You end up with this:

A

-Apple page 12
-Angry page 167
-Abacus page 4
-Astronomy page 1

[trolls' bane]

Wow, that is a cool pic! I have a similar one that is panoramic. IT's an HST image. Can't beat the Hubble Ultra-Deep field, which shows galaxys from 13 billion years ago.

[trolls' bane]

Well, aside from me *ahem*, this raises some interesting questions.
The real question besides "Is there life on other worlds (i.e. Mars)?" is now a much different question than 100 years ago. We must ask ourselves, "What kind of life?" Our ultimate goal, as humans, is to find other intelligent beings like yet unlike ourselves. This is the question about Mars. If we found life, what form would it take? Microbial life is the most likely and the first choice. Intelligent life, we now know, is not currently living on the planet Mars. We know this because of radio telescopes. Remember, visible light and radio waves are related. They are both part of the electromagnetic spectrum. Currently, our knowlege of the universe is mainly based on the electromagnetic spectrum.
The electromagnetic spectrum is simple to recognize. From right to left (this will have a few errors), we have: microwaves, radio waves, infrared, visible light (all of the colors we can see, with red on the right and violet on the left end), ultraviolet, x-rays, and gamma rays. Light, as we know, travels extremely fast, and vast distances in space are measured in light years, the distance it take light to travel in a year. Therefore, sicne they are all related, we know that all wavelengths of the spectrum (from microwaves, or long wavelengths, to gamma rays, with microscopic wavelengths) travel at the speed of light. Therefore, if there were, perchance, a planet orbiting Proxima Centauri, the closest star, which is four light years away, they are as of this moment receiving radio waves from 2001. It will take four years for what we are broadcasting right now to reach the planet.
Now, if there were intelligent beings on that planet who used radio to communicate, they would have been getting radio waves from us. Earth is a "noisy" planet, because advanced intelligent beings tend to make noise, not in the sense of sound, but in the sense of radio broadcasts, doctors using x-rays, etc.

Now for us, this would work the other way around. If there were intelligent being on mars, we would be hearign radio broadcasts made by them in only about ten minutes. We do not, however, hear anything of the sort. Therefore, if there are intelligent beings on Mars, they must be far less advanced than us, they must be extremely durable (with 200 mile/hour dust storms, tornados, dry ice snowing, little water, no vegitation, 1% Earth's air pressure, little atmosphere made out of Carbon Dioxide, and other problems. Bacteria, however, is very likely to be living on Mars.

[trolls' bane]

Just got a real powerful telescope! Doubleplusgood!

[Khamûl]

That's cool. What kind is it and how much aperture does it have?

[trolls' bane]

Here's the Telescope info:
Meade ETX-70AT
It's a refractor telescope.
Apeture: 70mm
Focal Lenght: 350mm
I also got with it one 9mm and one 25mm eyepiece, and I bought a barlow extender, doubling its magnification. It's real hard to use, but worth the trouble.

[Khamûl]

Originally Posted by trolls' bane

Here's the Telescope info:
Meade ETX-70AT
It's a refractor telescope.
Apeture: 70mm
Focal Lenght: 350mm
I also got with it one 9mm and one 25mm eyepiece, and I bought a barlow extender, doubling its magnification. It's real hard to use, but worth the trouble.

Does it have a GOTO (or Autostar) function? That should make it easier to use. I want to think I remember reading that the ETX-70 doesn't have a finderscope. If you find it hard to point, you might want to look into a Telrad or Rigel Quickfinder. I've never used one, but have heard that they work quite well. Sounds like you've got a good starter telescope.

[trolls' bane]

Yes, it does have the autostar feature, but that's what I'm having trouble with. I do the easy two star alignment, and it points the wrong way by usually no less than 10 degrees. When looking for the proper guide star, I can't seem to find it. I will do a search for what you mentioned, but I'm also going to get a viewfinder.
TG for google .

[Gwaimir Windgem]

clickety-click

[Acalewia]

You have got to be joking!

[cee2lee2]

And the new way to remember what they are:

My Volkwagon Emits Mick Jagger Songs Until Noon
M(ercury) V(enus) E(earth) M(ars) J(upiter) S(aturn) U(ranus) N(eptune)


I didn't come up with the memory trick; heard it yesterday on NPR on the Says You program.

[Gwaimir Windgem]

Volkswagon.

[cee2lee2]

Originally Posted by Gwaimir Windgem

Volkswagon.

Ooops!

[Insidious Rex]

Boy they are opening up a can of worms when we start trying to categorize planets outside our solar system with this decision. If its a gas giant that should be sufficient to call it a planet. No matter whatever else applies to it.