Anyone keen to photograph some candles, for scientific experiment?

[tris_d]

......... There is apparent size, it's called Angular diameter. There is also radius, but none of them are part of the equation in regards to brightness, distance and inverse square law.
...........

Perhaps you would care to provide a list of how many stars (besides our own Sol) have had their angular diameter actually imaged? Last I heard, the total was 1.

There is a list in that article.

R Doradus 0.052″ – 0.062″
Betelgeuse 0.049″ – 0.060″
Eris 0.034" – 0.089″
Alphard 0.00909″
Alpha Centauri A 0.007″
Canopus 0.006″
Sirius 0.005936″
Altair 0.003″
Deneb 0.002″
Proxima Centauri 0.001″

 

[480sparky41 40]

......... There is apparent size, it's called Angular diameter. There is also radius, but none of them are part of the equation in regards to brightness, distance and inverse square law.
...........

Perhaps you would care to provide a list of how many stars (besides our own Sol) have had their angular diameter actually imaged? Last I heard, the total was 1.

There is a list in that article.

R Doradus 0.052″ – 0.062″
Betelgeuse 0.049″ – 0.060″
Eris 0.034" – 0.089″
Alphard 0.00909″
Alpha Centauri A 0.007″
Canopus 0.006″
Sirius 0.005936″
Altair 0.003″
Deneb 0.002″
Proxima Centauri 0.001″

Try again. Perhaps you would care to provide a list of how many stars (besides our own Sol) have had their angular diameter actually imaged?

 

[tris_d]

If the brightness does not vary with the square of the distance as Wikipedia says, then how in the world do you think they can measure any distance? ........

Red shift, for one. Parallax, for another. Quasars. Cepheid variables. SuperNovae. GRBs.

Red shift is related to relative velocity. Parallax is limited to nearby stars, and everything else is based on brightness.

 

[tris_d]

Try again. Perhaps you would care to provide a list of how many stars (besides our own Sol) have had their angular diameter actually imaged?

What in the world do you want from me, what is your agenda? You try again on some Astronomy forum. Sheesh!

 

[unpopular]

Red shift is related to relative velocity.

Astronomy fail.

 

[tris_d]

Red shift is related to relative velocity.

Astronomy fail.

Meaning?

 

[unpopular]

Meaning, all objects are moving apart from one another at a similar increasing rate, taking into account the speed of light you can determine their distance by the doppler effect.

Seriously. You're not about to upturn the universe through pictures of candles.

 

[Helen B]

If you want to use the brightness of the candle to measure distance (or relative distance) it isn't the image brightness that you should be comparing. You should be comparing the number of photons that pass through a given aperture. You could integrate the brighness value of each pixel that makes up the image of the candle flame.

 

[tris_d]

Meaning, all objects are moving apart from one another at a similar increasing rate, taking into account the speed of light you can determine their distance by the doppler effect.

It's used as a helper for some methods which then use brightness to determine the distance. I am not aware it can be used to directly measure the distance.

Seriously. You're not about to upturn the universe through pictures of candles.

Ah, yes. This thread is about photos of candles, so if you don't care to help me get those photos please just let me be.

 

[tris_d]

If you want to use the brightness of the candle to measure distance (or relative distance) it isn't the image brightness that you should be comparing. You should be comparing the number of photons that pass through a given aperture. You could integrate the brighness value of each pixel that makes up the image of the candle flame.

Number of photons (per surface area per unit time) is what light intensity is, and that's what determines image brightness. More photons - more brightness, right?

 

[480sparky41 40]

.......and everything else is based on brightness.

Fail.

 

[480sparky41 40]

Meaning, all objects are moving apart from one another at a similar increasing rate,.......

Called Hubble's Law.

 

[pixmedic]

SCIENCE!

 

[tris_d]

.......and everything else is based on brightness.

Fail.

You failed to articulate yourself. What are you doing, trying to outsmart me or something? Don't you have anything better to do? -- The only thing that was not mention and does not relate to brightness is 'gravitational lenses', which is terribly uncertain method.

 

[Helen B]

If you want to use the brightness of the candle to measure distance (or relative distance) it isn't the image brightness that you should be comparing. You should be comparing the number of photons that pass through a given aperture. You could integrate the brighness value of each pixel that makes up the image of the candle flame.

Number of photons (per surface area per unit time) is what light intensity is, and that's what determines image brightness. More photons - more brightness, right?

Wrong. This is what you seem not to understand. The brightness of the image also depends on the area of the image. Half the photons, half the area: same image brightness. If using an image of the candles you need to take the image area into account. As I said, you need to integrate the brightness of the elements that make up the image.