Show Your Astrophotos

[digit]

One of the advantages of RAW files is that they save the "raw" information directly from the camera's sensor with no modification. Most A/D (analog/digital) converters in the sensor array can save up to 12 or 14 bits of information for the red/green/blue channels on the sensor. JPG images can only handle 8 bits of color information (values 0-255) for each color channel. Even if the JPG is saved with highest quality lossless compression, there is information lost when converting from RAW to JPG. My Canon EOS 5D Mark II has 14 bit RAW files. This means that the range of values that can be stored for each pixel's three color channels is 14 bits (0-16383) instead of 8 bit (0-255)--a much wider dynamic range. Those extra 6 bits get lopped off during the RAW => JPG conversion. I always shoot RAW files (and save them as more generic Adobe Digital Negative--DNG files) since RAW images are more forgiving of changes to exposure/brightness/contrast than JPG images. You can "bend" the RAW images more with post-processing without "breaking" them (digital artifacts such as noise or banding showing up in the processed image). I tell people RAW images are more flexible and JPG images are more brittle during post-processing. I can recover details out of the shadows or pull cloud texture out of an overblown sky in a RAW image that could never be done with a JPG because the necessary bits were lopped off during the conversion to JPG.

 

I would expect that those extra bits would also help during image stacking and would provide better detail with less noise. I'd be interesting in hearing your observations of any noticeable differences if you decide to run an experiment stacking RAW versus JPG in one of your lovely nebula images.

 

 

Cheers.

 

-Ken

[digit]

I had the opportunity to do a field trip down to the Windley Key Fossil Reef Geological State Park in the Florida Keys earlier this month during a symposium down at the Rosenstiel School of Marine and Atmospheric Science (RSMAS) at the University of Miami. Famed sedimentary carbonate geologist Gene Shinn was our guide at this park that he helped create. Here's a quick photo of Gene talking to the group out in the quarry where huge quantities of fossil reef limestone had been quarried to build and face many buildings in Miami and the Keys.

 

While arguably not the best example of JPG versus RAW, you can see how much detail can be pulled out of the overblown highlights along the quarry face and some details salvaged from the shadows of this higher contrast image taken on a sunny day. I could probably look for better examples of RAW images being useful but this one is at least fossil related.

 

Direct JPG image on the left and a RAW image with some recovery of highlight and shadow detail on the right.

 

Cheers.

 

-Ken

 

      

 

[Wrangellian]

On 1/21/2019 at 10:37 AM, Ptychodus04 said:

 

Mercury will transit the Sun on the morning of 11/11. That should be cool. I imaged the Venus transit in 2012.

 

I got the Venus Trtansit (thank God, as that's the hard one!) but I missed the last Mercury transit due to forgetfulness and the previous one due to cloud, but I don't have much hope of seeing this one as it's only going to be visible low on the horizon at a time of year that's always cloudy up here! Then I have to wait another 10 years for the next. 

At least I got to see the biggie in 2012. Even then, in June, it was mostly cloudy up here for many days on either side, but they miraculously opened up as if on cue for me to see it.

[Wrangellian]

10 hours ago, snolly50 said:

Those are very nice. It sure is a tricky subject to adequately capture. Of course the Moon in general is tough to image well. When you throw in the cold conditions and the fact that during the eclipse the needed exposures are ever changing - well, it is a challenge, but fun. I have enjoyed seeing your images as well as those previously posted.  

Thanks. I think you and Kris have me beat in astrophotos overall. Tough subject for sure, you really need to know about all the tricks, and having abetter camera that is designed for the job (if there is such a thing) couldn't hurt...

9 hours ago, Ptychodus04 said:

Agreed. It tends to be one of the harder objects. I find it particularly hard to get it into focus where I want. It’s so close that through a telescope, the Moon’s curvature requires a focus change between the center and edges. This makes a full body shot tricky.

 

That surprises me! Wow, ya learn something new every day.

[snolly50]

1 hour ago, digit said:

JPG versus RAW

When I received my 1st DSLR (a hand me down from my daughter who is a much, much better photographer than I am) I shot in jpg. She made quite a bit of fun of me for this practice, basically saying I was not using the camera to full advantage. Of course she was correct. I now shoot only in RAW. In short, its ability to be manipulated post capture to my mind is like getting a do over with better settings for every shot. I have often rescued images that were grossly underexposed and was able to produce a suitable image in spite of my poor judgement in settings or unavoidable environmental circumstance. 

[Missourian]

On 1/24/2019 at 1:56 PM, Ptychodus04 said:

There's a fine balance between light gathering and noise when using a fairly cheap (and old) DSLR for long exposures. This is a single 60 second exposure through the same telescope with the ISO pushed from 200 to 400. You can see the Trapezium area is totally overexposed and there are a ton more hot pixels than in the previous image. I think I also caught a couple of satellites. The streaks are not dashes which would indicate airplane lights. I'm thinking the next imaging test will include the higher ISO and a shorter exposure time.

 

 

Very cool. Those streaks may be geostationary satellites, which happen to lie along ~ minus 5 degree declination as seen from mid-northern latitudes.

[digit]

1 minute ago, snolly50 said:

In short, its ability to be manipulated post capture to my mind is like getting a do over with better settings for every shot.

Yup. The forgiveness of this format was quite the help for underwater photography where exposure is sometimes tricky and do-overs are nearly impossible once you've finished the dive. Also much easier to white balance to remove the blue cast of underwater photos with RAW images.

 

It makes sense to use all the help you can get to compensate for occasional lapses of photographic skills. Rescued iffy images plenty of times and helped make good images better by evening out contrasty photos on days with bright light that are always tricky to shoot.

 

Cheers.

 

-Ken

[Ptychodus04]

12 hours ago, Missourian said:

 

Very cool. Those streaks may be geostationary satellites, which happen to lie along ~ minus 5 degree declination as seen from mid-northern latitudes.

There’s 2 reasons why they can’t be geostationary. They aren’t in every image and the show up as streaks in the picture. Geostationary satellites would look like stars in the picture because they are orbiting at the same rate as the earth’s rotation. I’m thinking they are a couple of the hundreds of other satellites up there in a lower (faster) orbit.

[Missourian]

3 hours ago, Ptychodus04 said:

There’s 2 reasons why they can’t be geostationary. They aren’t in every image and the show up as streaks in the picture. Geostationary satellites would look like stars in the picture because they are orbiting at the same rate as the earth’s rotation. I’m thinking they are a couple of the hundreds of other satellites up there in a lower (faster) orbit.

 

For a 60 second exposure tracking M42, any geostationary satellites would trail in the image, since they are at a fixed position as seen by the observer.

[minnbuckeye]

18 hours ago, digit said:

advantages of RAW files

 

I am as novice at photography as much as I am at paleontology. I know just enough to get me in trouble! Can someone explain "in the raw"? And does a Nikon D5200 have these capabilities?

[digit]

Yup. The Nikon D5200 can save raw (NEF) images. A quick search turned up this article that might go a ways toward explaining why you might choose to shoot in RAW:

 

https://www.dummies.com/photography/cameras/nikon-camera/why-choose-raw-nef-over-jpeg-on-your-nikon-d5200/

 

 

Cheers.

 

-Ken

[Ptychodus04]

1 hour ago, Missourian said:

 

For a 60 second exposure tracking M42, any geostationary satellites would trail in the image, since they are at a fixed position as seen by the observer.

I understand what you’re saying now. The satellites are tracking with the earth, and I happened to catch them lined up with Orion. The tracking of the telescope on Orion causes the stationary point of light to streak. Makes sense. 

[digit]

It's all relative.

 

 

Cheers.

 

-Ken

[minnbuckeye]

The Moon, Jupiter, and Venus at 33 degrees below zero! Didn't get the perfect setting due to the cold. These are the three shots I made before my fingers said go inside!! 

 

 

 

   

  

[digit]

Yikes!

 

I know professional photographers and videographers who film in arctic climes. Many of you have seen their work on various BBC nature documentaries. Digital camera technology has its advantages over archaic film technology as celluloid film tends to get brittle at very low temps. Batteries also perform poorly at extreme low temps (the electrons don't travel as fast all wrapped up in those thick fur coats). Many photographers who would sit and wait for hours in blinds waiting for a sight of a rare creature or a specific behavior would be bundled up in lots of exposure gear so they don't turn into a block of ice. They would often keep their battery packs in an inside pocket close to their body and use a long external power cable to provide the power to their equipment. Unusual conditions call for unusual solutions.

 

Lovely celestial juxtapositions.

 

Cheers.

 

-Ken

[Missourian]

Some cool lunar photography:

 

 

[digit]

Wow! And those people didn't even flinch with that huge moon sliding right past them.

 

Cool video obviously shot with extreme telephoto.

 

 

Cheers.

 

-Ken

[Wrangellian]

Good opportunity to catch a thin new moon this evening, within an hour or so, for those who have clear skies here on the west coast (like me, miraculously enough this winter)!

Or it's already happening for anyone in the next time zone over?

Go out soon after sunset. I'm going to try.

[Missourian]

Clear skies.... what is that?

[Ptychodus04]

57 minutes ago, Missourian said:

Clear skies.... what is that?

I’m with you there. We’ve had some seriously thick clouds recently... no astronomy for me. 

[Wrangellian]

I guess there's only so much of it to go around. Streaky cloud started to come in almost as soon as I posted above, just because I said we miraculously have clear skies, but I managed a few shots. I looked last night but could not see it, despite perfectly clear skies. Sure, the moon would have been thinner and closer to the sun/horizon, but tonight the moon is high up and plainly visible, yet I couldn't even spot it with binos last night despite my best efforts.

Next month the ecliptic will be at an even higher angle so I might stand a better chance, though it will be setting behind a mountain by then. This month the sun/moon set at a lower part of the horizon which would have made it easier to spot something low like the very new moon, and better pics.

[Wrangellian]

Mercury is up high in the west after sundown for the next few days... Anyone able to get some telescopic shots of it? I've miraculously got clear skies at the moment, but all I can do is telephoto shots.

[Ptychodus04]

On 2/25/2019 at 8:35 PM, Wrangellian said:

Mercury is up high in the west after sundown for the next few days... Anyone able to get some telescopic shots of it? I've miraculously got clear skies at the moment, but all I can do is telephoto shots.

Miles of thick clouds here.

[Wrangellian]

Here are a few shots I got of it a few days ago (the 24th):

First pic was probably with 'incandescent' white balance, so it's overly blue... then I changed it for the subsequent shots (to either 'full sunlight' or 'shadow', I forget which), and it's probably a little less blue than it should be, but looks nicer I think. 3rd shot shows a plane going by Mercury. I got a series of shots as the plane progressed by, but I won't bore you with those. It would be fun to be able to stitch them together in an animation but I don't know how to do that.

Not the easiest planet to spot (tho' easier than Uranus, Neptune, Pluto..) but this time of year is the best, as the ecliptic is at a high angle.

 

[Wrangellian]

I guess it doesn't do so well to shrink them to 50% for posting. They look better at full size.

Here's a few from the following night... I changed the white balance again before the 2nd shot so it's closer to reality, and the last one is an un-shrunk (but cropped) telephoto shot: