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Author Topic: Transit of Venus  (Read 2859 times)

bob

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Transit of Venus
« on: June 06, 2012, 01:24:22 am »

Here is one from the start, one in about the middle and one near the end (we saw about 1/2 of the transit). I've got a bunch more, took one at least every 5 minutes for 3.5 hours however they are in raw format and need converting before uploading.. Figured I'd put up a sample..

http://pix01.com/7y%40i7f9
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Scolex

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Re: Transit of Venus
« Reply #1 on: June 06, 2012, 01:46:03 am »

I was expecting large format with the mention of raw  :'( cool none the less
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Sean

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Re: Transit of Venus
« Reply #2 on: June 06, 2012, 08:20:18 am »

I think I will catch it next time around.

I sometimes wonder when the earth will plunge into the sun.

that would be a real warming trend.
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bob

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Re: Transit of Venus
« Reply #3 on: June 06, 2012, 11:05:19 am »

I was expecting large format with the mention of raw  :'( cool none the less

There are a lot of factors that go into what you see, so I thought I'd explain them.

First, I really don't know how to handle raw images, it's the first time I've ever tried them. It appears they are vendor specific formats. I had to convert them once with the vendor software into a jpeg, then the pix01 upload converts them again.

Second, they are taken with a telephoto. Even though the zoom is 30x, that's pretty trivial compared to a telescope so the image is only about 1/8 of the sensor size.
Do you ever notice when TV stations point their camera at the moon and zoom in as far as possible and you see a nice picture but they are really lacking in detail. It's because there is really only so much you can do with a camera lense.

Third, even the best camera optics are a compromise compared to even a modest telescope. I built a telescope specifically for a solar eclipse years ago that has a 4.5 inch mirror and a 900 mm focal length (I was aiming for a 1/2" image on 35mm film). It was pretty small but it's way better than any camera lense for shooting an eclipse and the transit is dealing with the same size object (the sun).

Fourth, my solar filter was not a professional unit, just a piece of filter material taped over the lense.

Finally, I was using a tripod. Ideally I would have been guiding on the sun because of it's apparent motion across the sky ;)

I don't have a way to hook a digital camera to my telescope and I never got around to getting a good solar filter for it so I did it with the camera knowing the limitations and I actually am pretty pleased with the results :)
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glynor

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Re: Transit of Venus
« Reply #4 on: June 06, 2012, 11:33:28 am »

I sometimes wonder when the earth will plunge into the sun.

that would be a real warming trend.

According to current stellar research, it should happen in roughly 7.9 billion years.  That's when the sun will have used up most of the Hydrogen in its core and will begin depositing helium "ash" into the core instead (still fusing hydrogen in an outer shell of the core).  At that phase, it is likely that it will have expanded as a Red Giant to envelop the Earth.

Of course, life on Earth would be extinct long before then.

~1 million years: likely to have undergone a supervolcanic eruption large enough to erupt 3200 km3 of magma; an event comparable to the Toba supereruption 75,000 years ago.
~100 million years: likely to have been impacted by a meteorite comparable in size to that which triggered the K–Pg extinction 65 million years ago.
~600 million years: As weathering of Earth's surfaces increases with the Sun's luminosity, carbon dioxide levels in its atmosphere decrease. By this time, they will fall to the point at which C3 photosynthesis is no longer possible. All plants which utilize C3 photosynthesis (~99 percent of species) will die.
~1 billion years: The Sun's luminosity increases by 10%, causing Earth's surface temperatures to reach an average of 47 °C (117 °F). The atmosphere will become a "moist greenhouse", resulting in a runaway evaporation of the oceans. Pockets of water may still be present at the poles, allowing abodes for simple life.
~1.5-1.6 billion years: The Sun's increasing luminosity causes its circumstellar habitable zone to move outwards; all life on Earth dies.
~3.3-3.5 billion years: 1% chance that Mercury's orbit may become so elongated as to collide with Venus, sending the inner Solar System into chaos and potentially leading to a planetary collision with Earth.  Also, the Earth's surface conditions will resemble Venus's today.

So... You know, make your plans now.  ;) ;D
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glynor

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Re: Transit of Venus
« Reply #5 on: June 06, 2012, 11:39:29 am »

It appears they are vendor specific formats. I had to convert them once with the vendor software into a jpeg, then the pix01 upload converts them again.

Yes.

They are quite literally the raw data outputted out of the sensor on your camera, with no manipulation whatsoever.  It is what your camera's sensor "sees".  And, yes, they are vendor specific (often even model specific).

Lightroom has a very nice RAW converter, as does Photoshop.  MC handles some kinds of RAW file formats as well, though I don't think you can manipulate them or convert them.
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KingSparta

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Re: Transit of Venus
« Reply #6 on: June 06, 2012, 12:41:41 pm »

From Wiki: Toba catastrophe theory

>> "This change in temperature resulted in the world's human population being reduced to 10,000 or even a mere 1,000 breeding pairs, creating a bottleneck in human evolution."

If that was true, I wonder how many people like humans were on earth before the eruption?

Interesting reading, I always liked information about universe\space science

for me Carl Sagan always made this exciting to learn.

Toba catastrophe theory

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

Cretaceous–Paleogene extinction event

http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event
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bob

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Re: Transit of Venus
« Reply #7 on: June 06, 2012, 03:26:46 pm »

Yes.

They are quite literally the raw data outputted out of the sensor on your camera, with no manipulation whatsoever.  It is what your camera's sensor "sees".  And, yes, they are vendor specific (often even model specific).

Lightroom has a very nice RAW converter, as does Photoshop.  MC handles some kinds of RAW file formats as well, though I don't think you can manipulate them or convert them.
Of course, my version of Elements is one rev too old to use the plugin that works for my new camera :-(
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glynor

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Re: Transit of Venus
« Reply #8 on: June 06, 2012, 03:44:59 pm »

Of course, my version of Elements is one rev too old to use the plugin that works for my new camera :-(

The reason that photographers like RAW file formats is that ALL Digital Cameras apply all sorts of "wizardry" to the raw image data captured by the sensor before they output that JPEG or TIFF file.   They have to.  The raw sensor data isn't "right".  Just like a printer or a monitor, it has certain sensitivities to certain bands of the light spectrum, which vary with wavelength.  Plus, almost all raw sensor data is VERY soft.  All digital photos need some amount of sharpening.

The sensor sees what it sees, and has certain performance characteristics, which they model, and then they have algorithms built into the CMOS of the camera that add sharpening in this amount and shift the color from this to this, and remap pixels from this scale to this scale, and so on and so forth, to make the JPEG you get in the end better approximate what you "saw" with your eye through the viewfinder.

So, you need to process them.

The question becomes, do you want them to be processed automatically, or by hand?

In many cases, the automatic processing is just over-the-top.  This is one of the big reasons that you don't see many pro photographers carrying around Sony DSLRs.  They go bat-crazy on the sharpening and color saturation (or they used to, last time I cared about that world).  Canon and Nikon tend to be the most "respectful".  The other, more consumer focused cameras, tend to just try to make pictures reliably what "regular people like and want".

But even if the processing isn't over the top, is it right for what you were shooting?  Those automatic schemes can be controlled somewhat on the camera (usually via different "scene modes", you know for night, and daytime, and indoor, and portraits, and whatnot).  It isn't like those modes are flipping between different sensors!  They're just tweaking the post-processing filtering systems used (and setting different aperture, exposure, and iso settings).

The problem is that if it is wrong, or too much, or bad, you cannot "undo".  If all you have is the already-altered JPEG, you're stuck with it.  You can modify what is there, but you can't "undo" the damage done by the automated filters.  Once image data is destroyed by a sharpening system, it is destroyed, and there's no going back.

Using RAWs and a nice RAW workflow system (like the one in Lightroom, which is really superb), lets you apply those filters yourself.  Applying just the right amount of sharpening, but not too much.  Just the right color balance for that particular composure.  And, it lets you do it in a non-destructive way, because you always still have the RAW image data there, you're just interpreting it differently.  Now, that doesn't mean you have to hand tweak every single photo.  A good tool will let you define your own presets (and even gives you ones specially designed for your camera's sensor), and then tweak them just slightly as needed to "fix" a slightly oversharpened or underexposed image.

It is fantastic for saving a shot that otherwise would have been ruined on a consumer DSLR.  And, more importantly, you can always undo.

Make sense?
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bob

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Re: Transit of Venus
« Reply #9 on: June 06, 2012, 04:23:16 pm »

...
Make sense?
Yes, and it's pretty cool!
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bob

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Re: Transit of Venus
« Reply #10 on: June 06, 2012, 04:26:38 pm »

...
In many cases, the automatic processing is just over-the-top.  This is one of the big reasons that you don't see many pro photographers carrying around Sony DSLRs.  They go bat-crazy on the sharpening and color saturation (or they used to, last time I cared about that world).  Canon and Nikon tend to be the most "respectful".  The other, more consumer focused cameras, tend to just try to make pictures reliably what "regular people like and want".
...
The Samsung phone cameras like the Nexus S I'm using are REALLY over the top in color saturation.
Fuji did that a lot with their film as well, it was overbalanced to the red/brown tones.
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