Why is it dark at night?

Well, why IS it dark at night? Here's a nicely-done video that explains why, using a lot fewer words than I could.
http://www.youtube.com/watch?v=gxJ4M7tyLRE

Neil Armstrong

NASA sent the following press release out today.
********************************
FAMILY STATEMENT REGARDING THE DEATH OF NEIL ARMSTRONG

 

 

WASHINGTON -- The following is a statement from the Armstrong family regarding the death of former test pilot and NASA astronaut Neil Armstrong. He was 82.

“We are heartbroken to share the news that Neil Armstrong has passed away following complications resulting from cardiovascular procedures.

Neil was our loving husband, father, grandfather, brother and friend.

Neil Armstrong was also a reluctant American hero who always believed he was just doing his job. He served his Nation proudly, as a navy fighter pilot, test pilot, and astronaut. He also found success back home in his native Ohio in business and academia, and became a community leader in Cincinnati.

He remained an advocate of aviation and exploration throughout his life and never lost his boyhood wonder of these pursuits.

As much as Neil cherished his privacy, he always appreciated the expressions of good will from people around the world and from all walks of life.

While we mourn the loss of a very good man, we also celebrate his remarkable life and hope that it serves as an example to young people around the world to work hard to make their dreams come true, to be willing to explore and push the limits, and to selflessly serve a cause greater than themselves.

For those who may ask what they can do to honor Neil, we have a simple request. Honor his example of service, accomplishment and modesty, and the next time you walk outside on a clear night and see the moon smiling down at you, think of Neil Armstrong and give him a wink.”

Partial Solar Eclipse

Amazing; over 4 months without a post. A combination of health, equipment, weather, and other issues meant that I've done very little photography so far this year. The upside is that I've had plenty of chances for visual stuff, but that doesn't produce anything to post.

This solar eclipse was seen an an "annular" eclipse in much of the country, but not here. An annular eclipse leaves a donut-shaped ring (an annulus) of the sun visible around the edges of the moon, and happens when the moon is far enough away that it's apparent diameter is smaller to us than that of the sun. The series of shots above were all shot at 1/8000th of a second at F45 through a proper filter. Notice how the disc of the sun appears dimmer as the moon covers it. It doesn't get bright again in this series, since toward the end, it was very close to the horizon, and was shining through more air to get to me, acting like an additional filter. The sun set before the moon completely uncovered it. This series covers about 90 minutes, while the entire event took about two hours.

By the way, if you have been looking at MSNBC this past week, you may have noted that they have been calling it an "annual" eclipse on their front page the entire time. It is NOT an annual event; they are relatively rare. It's one thing to be a copy writer and make the mistake, although I have no idea why someone with no astronomy knowledge would be asked to WRITE that article. But it's inexcusable for no editor with understanding of the subject to have ever seen the article. Even worse to leave it up for a week, in the face for the flood of complaints. Nice one, NBC. What else are you telling us that's just as ill-informed?

If you were outside looking at the eclipse, or just outside at all, you may not have noticed much looking around. It certainly would not have looked like the light from the sun had fallen by 80% or more. The picture at left was shot at ISO 100, 1/60th of a second at F10, just about ten minutes into the event. That would be when the first image in the composite was taken.

This was taken about an hour later, at the peak of the event, with the exact same exposure. Our eyes will accommodate the different light level, but people are often surprised to see just how much our eye will adjust. To most people, it looked exactly the same when both shots were taken.
If the effect is familiar, it's because low-budget TV and movie producers use the same trick to simulate "night" shots made in broad daylight, with a neutral density filter.

There were news articles about how solar filters were sold out at at every shop that carried them; that is great news, since it shows some interest. But there are other ways to look at the sun without ruining your eyeballs.

My daughter is showing a very simple solar projector here. It has the advantage over looking through a filter or welding mask in that it will even show sunspots, which makes it interesting anytime at all. Try drawing a sketch of what you see if you do this, then look again a few hours later and the spots will have all moved. Many people make quite a hobby of tracking sunspots, and it can get addictive.

It goes without saying that you don't ever look at the sun. ESPECIALLY if you have a pair of binoculars around. Also, be very wary for onlookers who will see you looking at the sun and who may unwittingly grab the binoculars and try and take a look for themselves. Don't use the binocs for looking at anything ELSE, either-the eyepieces can potentially become very hot, and could even crack as a result. You don't want that near your face.

M32 & M42, up to two hours stacked

So here is the same shot as in the previous post, with another hour added to the stack. Since it needs to be stretched less to achieve similar brightness, there is less "stress" visible in the image; the background is beginning to become an even black, etc. I expect this to take a total of 5 hours in the final stack to really work well, but I want to post the individual steps along the way. It takes 3-4 hours of shooting get 1 hour's worth of usable subs.

While most photographers would try and get a ten minute exposure to bring out the lower half of the nebula (which is FAR fainter than the upper half, I have found that my method of dealing with light pollution (which essentially limits my exposures to 30 seconds) is turning out to be a way to show bright nebula with the dynamic range adjusted. A normal photograph that brought out this much of the lower "jaw" of the fish's mouth would have the area at the top around the Trapezium totally blown out. One I complete this photo after another 3 nights of shooting, I should be able to not only capture the fainter regions, but still show detail in the very bright regions, and probably still resolve the Trapezium in the center of the brightest areas. The downside is that it does take many nights, and many hundreds of individual photographs, aligned of several nights of work. I've started calling the process "speckle stacking", since it really is a weird variation on the "speckle imaging" used by modern giant telescopes, but with exposure in the seconds, not milliseconds. It's a very low-tech way to take advantage of the pro's high-tech method.

I have an idea what may be causing the banding on the left and right images-I'll know after my next photo shoot if I am right.

And finally, full circle

When I decided to get serious about learning to shoot astro, if was February of this year, and Orion was still reachable in the early evening. So here is a good comparison between then and now-this shot is 55 minutes exposure, no multi-night shooting, just using what I have learned over the year. M42 is the perfect nebula to start learning with, but the level of detail in there just keeps going forever; there is no risk of getting bored with it.

I still have all the problems I started with, just in lesser degrees...vignetting is still a serious problem, and even the use of a good light box won't eliminate it. I'm still only able to use roughly half the subs I shoot, and I'm still spending more time tinkering than shooting. This shot from tonight is just going to be a foundation for more exposures; that will take care of the darkened corners and the trademark Canon DSLR banding visible up the left side, while each night's shots will bring out more and more detail inside the "fish's mouth".

It's still been a good year for learning-here's a reminder of what I was getting 10 months ago of the same target.

Running Man Nebula

This nebula lies just above the Great Orion Nebula, which means that I'm actually getting around to regions I was trying to shoot when I started this thing 10 months ago. When you look at Orion's sword, the Great Nebula is the middle clump of stars, while this is the top clump. It's been given three catalog numbers, since there are actually three separate areas of glowing gas that just overlap from our point of view. So say hello to NGc 1973, NGC 1975, and NGC 1977. Most people just refer to it as the Running Man.

Please forgive the satellites...that's the price we pay for cable TV and global telephone service-the geosynchronous orbits of most comm satellites carries them right smack through Orion's belt. Actually, each satellite seen in this area is stationary over our heads; the appearance of motion is caused by the telescope moving to track the stuff in the background. The software used to stack photos usually discards satellite tracks as noise, unless they are very bright, which is what happened here. Only 5 minutes exposure, so I couldn't toss the subs with streaks in them.

M38

M38 is an open cluster in Auriga, a constellation you have probably never heard of. If you find the Pleieades (an easy task) with binoculars, then start looking around a few fields of view north, you will find this and nearby M36 without much effort.

Like most open clusters, photographs don't quite capture the beauty like the view through a small scope or binoculars does. This cluster is famous for its odd shape, which is not that evident in this photo, and is completely impossible to notice with larger scopes. With a low-power eyepiece in my own scope, it is breathtaking, though.

Weather

No posts today-by the time I finished last night, it was 37 degrees and 98% humidity. My gear is still not dry, and I can't feel my fingers a day later. And yet the daytime weather was beautiful...California does this in the gaps between summer and winter. The clouds from the upcoming storms are also starting to appear, so the scope is going back in the newly-completed Telescope Shed; my custom-built 16'x16' centerpiece of the newly christened Observatorio Astronómico de El Rancho Titanico, ready for hosting Star Parties, Bar & Bat Mitzvahs, weddings and circumcisions. All with an Astronomy theme, of course.

NGC2024, the Flame Nebula

Orion is coming back...this is the Flame Nebula, next to the left-most star in Orion's belt.

Very early stack here, only 20 minutes, and this is a fairly faint nebula. But the real news is that the stack is made of 10 two-minute exposures; a serious victory in my year-long battle with cheap equipment.

I had expected that when and if I could start shooting longer subs, everything would be a piece of cake, but after shooting just a few items, it's not so clear now. My traditional method of stacking hundreds of short exposures may not be they way you'd want to do it with good equipment and a dark sky, but it does allow me to vastly improve the results with cheap stuff and loads of light pollution. And since the key to making it work is having scores, if not hundreds of individual exposures, the longer subs actually can be a disadvantage when shooting relatively bright objects. In particular, stacking huge numbers of subs allows the removal of more of the pollution. This shot is very grainy and noisy, but that just takes more exposure time to fix. What appears to be a blown-out background or a gradient problem in the upper left is actually caused by more nebulosity. Like I said, this shot is from an early stage in the process.

I keep a nice thermometer and hygrometer with me when I'm shooting. When this was done, it had fallen to 36 degrees, which is normally good for telescoping. But the humidity was 97%, which stinks. that is why the bright star-Alnitak, or Zeta Orionis-is so overblown and large. Still, makes for a pretty star.

In the next few days (while it's raining and cloudy, of course) I will be replacing even more of the mount, so in a week or so I could be back with more pictures. And with the return of Orion, I can start re-shooting things I did when I was just starting out, and will finally have some comparisons.

M30, without the moon right next to it...

A darker night, another 30 minutes of exposure. As is always the case here, as soon as I get one thing working another goes wonky; something is causing my flat frames to be heavily asymmetrical, causing the uneven gradient in the background. It'll get figured out eventually. This shot really seemed to suffer in being converted to jpeg as well.

I still say this little jewel is one of the nicest surprises in the sky this time of year...the three rows of giant red stars seem even more pronounced visually than in photographs.

M30

M30 has long been a favorite of mine. In a small scope or even good binoculars, it's a fairly tight globular cluster with two rows of bright red jewels. It can be a bit hard to find, since it's in one of those fairly rare "blank" spots in the sky, where we have an almost unobstructed view out of our own galaxy.

Since getting the replacement parts last week, after that first night it has done nothing but rain and drizzle. I tried to get this last night during a break in the cloud cover, and got all of 2 minutes exposure before the fog settled in. Assuming that one day there might be some good visibility, I can't wait to shoot some real time of this object. Given that I shot 60 dark and 60 flat reference frames, I am not sure where the background gradient came from here; it's possible that there was just too little data to work with in 4 thirty second subs.

M45 The Pleiades

This deserves a much longer exposure, but the moon was only about 20 degrees away...in a couple of weeks it will be in prime position for me to shoot it properly.

The Pleiades have to be the best known star cluster.What makes it so much more interesting to photograph than most open clusters is the large about of blue reflection nebula around it. In this short exposure, there is just a hint around a couple of stars. The nebulosity is actually just a bit dimmer than the moonlight itself, so there isn't a way to bring it out any more in these conditions. If it hadn't been for the dearth of pics the last two months, I may not have bothered posting it-but Tuesday night way like this; since I could shoot something in 30 minutes for the first time ever, that's exactly what I did. When the moon is this close to the target, no amount of baffling and flat frames can make the field even and richly black.

By the way, next time you see a Subaru, look at the badge on the hood. Look familiar? "Subaru" is the Japanese name for the Pleiades; the car company is named after it.

M2

M2 is a few degrees south of M15, a little smaller, and a tiny bit dimmer. It's still very easy to find in binoculars.

Just to the south of M2 are several more globulars-I may be able to catch them in a few days right after dusk and before they dip below the horizon.

This shot is 10 minutes at ISO 3200. The exposure for the last two pictures is not needed in order to get the clusters to show brightly; unlike remote galaxies, these are part of the Milky Way and are much brighter. Instead, I use the exposure time to kill light pollution and moonlight.

At first glance, the last two pics look like there may have been a focus problem. Actually, the focus is essentially perfect. Last night was very clear, but the seeing was awful. Because of wind and turbulence in the air, stars with twinkling madly. Twinkling is actually the effect we see when the image of a star appears to shift around a lot; under magnification, it's much easier to see that the brightness stays the same, but the apparent position moves around. In a longer exposure, that makes stars look blobbish. Even Jupiter was twinkling; it takes some pretty bad air to make planets do that.

M15

I have a lot of favorite globular clusters-and this is one of them, M15 in Pegasus. The moon was so near and so bright that I couldn't even find Pegasus visually-not one single star. After a bit of hunt and peck, I nailed it down, and here is the result. 15 minutes at ISO 3200.

Our neighborhood lost a wonderful but sick 60' eucalyptus last week; because of that, I can shoot in the part of the sky that is actually darkest here. After missing the last two months, I'm feeling pressure to get those early Fall objects while there is a chance. Fortunately, that area is very rich in clusters and galaxies, which don't always take days of effort to capture. Here is the first of them, the Pegasus cluster. This is an easy binocular find when the moon is not nearby.

Last month we also got a new monitor, and it is not calibrated in any sense; it is altogether possible that these next few photos will need to be redone once I get the screen adjusted properly.

Back in the saddle again

Once I got through the weather delays last month, it went from bad to worse...several components that were being used far harder than the original designers intended finally gave out. That included the RA worm gear and the handset controller.

Today I managed to get a hold of a nearly complete EQ-6 mount, probably ten years old, but never sold. Many parts missing, but none that I don't have...and since this is the upmarket version of the mount I have, I was able to replace the entire RA worm gear block. I still have some handset issues (it will no longer power the declination motor, for instance) but that's nothing I can't work around.

Tonight I was able to enjoy the luxury-for the first time-of picking multiple targets, and even with the full moon I got some nice subs-once I finish the stacking and processing, there should be a lot of action here. Finally!

For starters, look for a couple of globular clusters in the next day. The tracking is VASTLY improved, and nothing shows tracking problems like globular clusters, so of course that's what I had to start with...

three weeks...

It's not neglect...for three weeks, I have been greeted by a foggy wet marine layer every single night. Across town-no problem. Here at El Observatorio Titanico del Rancho Conejo, no sky. Once I get a clear night; you can bet you'll hear about it here.

Night of the Triffids

This will probably be the last of M20 for me this season, since there are so many other objects I want to shoot. SO my final stack for this image was 260 frames of 30 seconds at ISO 3200, plus over 900 individual reference frames. Another 1500 or so 30 second subs were rejected, for a total of roughly 15 hours of exposure times. That is the secret to doing more with less equipment-add time, persistence, and some OCD.

Compared to the shot posted a couple of days ago, this is far smoother, more detailed, and shows a lot more depth-to me, it's starting to look like a place, not just an object. There are features in the dark clouds that I never actually have seen before, even in the better known professional images. It gives the impression that if I continued adding to the stack, the dusty clouds and globules would just keep appearing around the edges. In reality, the dust clouds DO extend on and on, but without bright stars in or near them, we can only see them in the infrared or infer their presence by the thinning of the background stars. The Spitzer IR images of the area show just how much there is in the area. For all practical purposes, this is about all that can be grabbed with an 8" scope in such light-polluted skies, and it did take a fairly silly amount of time to make. Better equipment would give tighter star images. Better resolution would be possible, but the only practical way to get much more of that is with more aperture. Still, I'm pretty happy with it.

Click the pic for a 1500 pixel view.

Galaxy Zoo-Hubble

Want to be an astronomer, but don't have a telescope or any of the other fancy kit they usually have?

Worry no more-because we are living in a world where data is being gathered at a far greater rate than it can be studied and turned into information. There are many ways that scientists are trying to cope with this, the best known being the BOINC projects that distribute problems involving massive amounts of data around a cloud of regular people's computers. Some problems, however, are not well suited for computers, and that especially includes pattern recognition.

That is where YOU come in. Our brains are far better at spotting subtle patterns than computers are. As more and more photographic data of the universe has piled up, the public has been enlisted to help classify each object being photographed. The best known of those projects has been Galaxy Zoo. Rather than enlist your unused CPU cycles, this project enlists your spare time and brain power. Very cool stuff.

The Hubble Space Telescope has done so much more than the Heritage images most people are familiar with, and it has produced an utterly unimaginable amount of data. Now there is a Zoo project to try and cope with that-the Galaxy Zoo-Hubble project.

If waste even a few minutes a day playing Solitaire, consider taking a look at this-it's a far more interesting way to kill time, plus you'll be doing SCIENCE!

back to M20

Not much time for shooting lately, which is unfortunate-the seeing has been great. Lots of time poured into efforts to improve my tracking quality, and not much to show for that either. Oh well; so it takes a long time to get the pics I want.

This is the stack I started a few days back, but with another half hour added. The nebula looks more or less as bright, but the stars are starting to look far more natural, and the fainter wispy cloudiness at the fringes is starting to come through. With a "short" stack, when the faint stuff is amplified the stars all become bloated white blobs. The more light I add to the stack, the less it needs to be stretched, and the more natural the appearance is overall. I should be able to add another couple of hours to this before it has passed from the summer sky. As I add more subs, I can remove some of the first ones I shot with the potato-shaped stars also.

The Lagoon Nebula, M8, is just about two frames below M20; they are often photographed together, but I can't get any wide angle shots with my setup.

M8, six nights, four hours...

So here we have the results of six nights worth of shooting, sorting, stacking, etc. As I have mentioned before, DSLRs aren't terribly good at picking up the deep reds associated with emission nebulae, in part because those wavelengths aren't very easily visible to our eyes. But use enough exposure time and it starts to become apparent.this is a stack of over 400 30 second exposures, plus the hundreds of reference frames that were shot along with it (to make no mention of the nearly 1000 shots taken that were unusable due to periodic wobble.)

I've put a lot of time into this one, but hey; once you have a really good polar alignment, you hate to move the equipment, you know? Plus, M8 is our summer Orion. As many great things as there are in the summer sky, M8 is the only object that can compete with the Great Orion Nebula for spectacle.

Tonight looks like clouds, but once it's clear I'll be shooting the new supernova in M101. That was also one of the first galaxies I photographed this year, so I am looking forward to seeing if there is any obvious improvement in my skills...

Oh, and to make sure that Google feels the pain, this has been uploaded at 2000 pixels-be sure to click on the pic to see the large version!