The Star Trail thread

dgrits · August 11, 2008

My first attempt at getting star trails... and although its almost a decent shot, I did learn a few things...

Any constructive criticism welcome!

Dan

hawkeye978 · August 11, 2008

I wonder how a tight crop would look centered on the tree. It has some great character and you could retain most of the trails while making it the subject.

SaltWaterHippo · August 11, 2008

Hey. I'm a newbie with star trails aswell, I had my first attempts a month or 2 ago. I think it looks good with the black outline of the trees/bushes. Where was it taken from? I'm not sure what the golden and white areas are, Do you know if its light pollution? Maybe if you shot in a darker place you'd get more stars and your trails wouldnt be as faded? I'm just speaking from ignorance, I need to experement more myself before I can be more informative

dgrits · August 11, 2008

Thanks for the replies!!

I tried a center crop and I think it does work better... Thanks!

As for the light pollution, thats the nearby town reflected off some low clouds. (A clear, 'low humidity', night here in South Georgia is like a new 5D left on the doorstep... possible, but not very likely!

As for the lessons learned... I think a fewer number of exposures, longer in duration will make a better picture. This one is 6 pics at 5 minutes each, stacked in CS3. I think next time I'll try 3-5 at 15-20 minutes each. (all are ISO 100, and I may up that, too...)

Thanks tons!!

Dan

davidweaver · August 11, 2008

20-25 minutes? Did you use in-camera noise reduction? Shot to the northwest I think so what is causing the glow? Overall I like it. I'd try for 40 to 120 minutes but it is tough on batteries.

philiphutson · August 11, 2008

dgrits wrote:

Thanks for the replies!!

I tried a center crop and I think it does work better... Thanks!

As for the light pollution, thats the nearby town reflected off some low clouds. (A clear, 'low humidity', night here in South Georgia is like a new 5D left on the doorstep... possible, but not very likely!

As for the lessons learned... I think a fewer number of exposures, longer in duration will make a better picture. This one is 6 pics at 5 minutes each, stacked in CS3. I think next time I'll try 3-5 at 15-20 minutes each. (all are ISO 100, and I may up that, too...)

Thanks tons!!

Dan

The only reason to do multiple shots and stack them is to reduce noise. If your going to stack, take shorter shots like thirty seconds with 5-10sec delay between shots (you'll have to experiment with the pause between). You want some kind of delay between the shots to let the components cool down. I've been happy with my single long shots (or at least happy enough not to want to spend time on stacking them by hand in photoshop). On the Utah trip we did 30 min exposures and with long exposure noise reduction the noise became black pepper specks on the image.
-Philip

Oceanlights · August 11, 2008

It is nice. But more that those stars, I love that tree. It is so much... ahh.. amazing and looks so scary too.

Nice work:

dgrits · August 11, 2008

philiphutson wrote:

The only reason to do multiple shots and stack them is to reduce noise. If your going to stack, take shorter shots like thirty seconds with 5-10sec delay between shots (you'll have to experiment with the pause between). You want some kind of delay between the shots to let the components cool down. I've been happy with my single long shots (or at least happy enough not to want to spend time on stacking them by hand in photoshop). On the Utah trip we did 30 min exposures and with long exposure noise reduction the noise became black pepper specks on the image.
-Philip

What I discovered... in a few of the shots I made some adjustments, and when the exposure is right, the noise was pretty minimal. If I had to try to recover anything from the shadows, the noise increased exponentially. Next time, (probably wintertime before I get another clear night) I'll make those adjustments and see if it helps keep the trails brighter.

Oceanlights wrote:

It is nice. But more that those stars, I love that tree. It is so much... ahh.. amazing and looks so scary too.

Nice work:

Thanks!! That tree is the subject of quite a few shots... mostly sunrises and fog pics... if you're interested, I'll post them.

Thanks again, everybody, for the comments and suggestions!

Dan

DaddyO · August 12, 2008

The tree in the foreground is a nice addition. Too bad about the lightdome.

Crashmaster provided this link in his star trails image located at
Other Cool Shots. Easy way to stack star trail photos. An action
for photoshop.

http://www.schursastrophotography.com/software/photoshop/startrails.html

Crashmasters shot. Hope this link works as I rarely point to threads.

http://dgrin.com/showthread.php?t=96158&highlight=star+trails

crashmaster · August 12, 2008

thanks DaddyO, I was just about to reply with the links.

Try 30 sec exposures at 800 ISO, full open aperature, then lock open the cable release and let it run until the battery craps out or you fill up your card. No reason to shoot in anything other than M Jpeg res, and you can get alot more images. Then just run your images per the instructions on Chris Schur's webpage after you download the PS action from the same site.

Clouds, even very thin cloud or extremely high humidity will drastically limit the number of stars visible. Alot of light pollution will do the same thing.

One very cool trick you can use to illuminate a foreground landscape is to start shooting abouyt 15 min before the moon sets to effectively light up your foreground, then acquire the rest of the trails after the moon sets which will give you alot more stars visible. If you want to get really trick, then you could layer mask in the quality star trails that were captured after the moon set, but still have your foreground subject illuminated.

This run ran for a few hours, started about 20 min before the moon set. There is a little pincushion distortion because of the Tokina 12-24 lens I used at 12 mm with a 40D

good luck, have fun with it, its a pretty cool trick with a DSLR.

dgrits · August 12, 2008

crashmaster wrote:

Try 30 sec exposures at 800 ISO, full open aperature, then lock open the cable release and let it run until the battery craps out or you fill up your card. No reason to shoot in anything other than M Jpeg res, and you can get alot more images. Then just run your images per the instructions on Chris Schur's webpage after you download the PS action from the same site.

Clouds, even very thin cloud or extremely high humidity will drastically limit the number of stars visible. Alot of light pollution will do the same thing.

This run ran for a few hours, started about 20 min before the moon set. There is a little pincushion distortion because of the Tokina 12-24 lens I used at 12 mm with a 40D

Thanks! I'll try those settings next time... You are right about the humidity/clouds. Its a shot-killer in this part of the country! It may be months before we have another low-humidity, moonless night here again.

(btw, that's the same lens/body combination I used)

Thanks for the suggestions!!

Dan

8zil · August 13, 2008

the original picture posted is great, as is the one of the truck in the foreground, I am also begining to experiment with these pictures but I am having a hard time learning the aperture to be used, somehow i try to close it and end up with very few stars, then again is difficult to find a place in holland without light pollution, can't wait to get back to Mexico and drive somewhere with no humans around....

it might have been already answered but, what causes the yellow glow? I like it, i think it adds a lot of character to the picture.

crashmaster · August 13, 2008

8zil wrote:

it might have been already answered but, what causes the yellow glow? I like it, i think it adds a lot of character to the picture.

Its light pollution from a city, or a "light dome." Can look cool, but very bad for astronomy. There are very few places now in the US where there are absolutely no light domes along the horizon for 360 degrees, and all of those places are found out west. The last truly dark skies in the country are a rapidly dwindling resource.

HFMarshburnJR · August 21, 2008

I hope you don't mind, but I have read through several threads on star trails and I keep seeing everyone recommend going to a higher ISO for these kinds of shots. Everything that I have read and that I have practiced is counter to that. By upping the ISO, depending on your own camera's low light capability, you are actually introducing more noise by doing that. I also saw a comment that rationalized this approach because "...what we are trying to do is catch a lot of light fast...".

My apologies, but for this type of photography, that just isn't right. You are trying to catch a lot of light, but longer exposures at wider open aperatures will do that just fine. And since your camera handles noise the best when you are shooting at its base ISO, I would suggest that you go there for your first tries.

Also, the image put forth by the original poster appears as if it was shot at too small of an aperature, since only the brightest stars have been captured. I also see evidence of noise caused by amp glow (the purple glow in the background), which is a side effect in most digital cameras on the market today. For my Nikon D70, noise from the amp began gtting really bad in any exposures over 5 mins. I would combat this by making sure that none of my exposures were longer than that, and I would stack however many images I ended up with to get the final composite exposure. My D3 handles light and noise a lot better, so I can extend the exposures before noise from the amp becomes an issue.

One last thing...for what it is worth...I am actually taking a small group out to learn more about star trail photography this weekend. As a primer, I provided the following writeup on my workflow for the participants to give them something to think about before we get out into the field. This is the writeup I gave them :

______________________________________________________________

1. Start by setting your camera up before you leave for the field - I do the following gross checklist before I get in to where I am going to be setting up - And I usually do it earlier in the evening, when I am more alert
a. Set the ISO to your camera's base level
b. Select the lens you are going to use.
c. Set your lens to manual focus
d. Set your shooting mode to manual, set shutter speed to bulb , Set your aperature to wide open - 1 stop.
e. Attach your remote shutter release/intervalometer to your camera. Set up your intervalometer for the exposure you plan on running your test exposure to.
f. Format your memory card
g. mount your camera on your tripod
h. If you are going to use a spirit level, mount it to your camera or tripod
i. Put a small flashlight in your pocket
You are ready to go to the field

2. Upon arriving at your shooting location
a. Walk around for a few minutes with all lights turned off. Allow your eyes to acclimate to the darkness. Determine what you believe you want your composition to be and where you will need to set up in order to achieve the desired comp. Think in three dimensions!!! (e.g. The composition above worked for me because I was able to get the spin of the stars around the tip of the windmill - to achieve that , I needed to lower the tripod in order to obscure Polaris from the shot)
b. Set up your tripod
c. Set your focus to infinity on your lens - not all the way past infinity to the stops on the lens, but to the infinity mark, or wherever you think you have the clearest focus through the viewfinder (Use the small flashlight in your pocket now - it will be a big help!!!)
c. Take a test shot - On a moonless night, like last night, I start with a 3-5 minute exposure at F4. After the exposure is complete, review it on your LCD screen and determine if you are getting a light-enough image. If you feel like you need to adjust, do so and run another test to make sure you are in the ball park. Once you get an exposure you feel like you can work with, you are ready to run your series.
d. NOTE: From this point forward, life is easier if you are using an intervalometer, where you can program an exposure time and a number of images to be taken and then let the camera do it's thing. If you are doing this with just a remote shutter release and a stopwatch, then you have to stay awake - which is tough if you aren't a "night person". You want the exposure time for all of your images to be approximately the same length so that post processing and stacking of your images can be facilitated in a more consistent and easy manner.

Why multiple images? Most of our digital cameras begin introducing considerable amount of noise anytime you are looking at exposure times in excess of 1 minute. They also tend to lose the black color in the night sky after an extended period of exposure. My best results in this type of photography have come back with exposure times for individual images in the 3-5 minute range. So I tend to try and make that my base - I make all adjustments for local conditions off of that.

At the end of the night's shooting, before you put your camera away, and before you turn it off, put the lens cap back on and take one last exposure at the exact same settings that the rest of the shots were taken at. This can be used to cancel out noise IF you have a major noise issue with your final stack. Do a search on "dark frame subtraction" and "potography" and you will find all kinds of references to how to use this exposure in your final processing.

OK...now you have your exposures. The onlything left is your post processing to get your final image. My workflow looks something like this:

1. Import raw files into Adobe Bridge. Do a bulk process on these files using Image Processor to create JPG files to be used in Image Stacker.
2. Use Image Stacker Software (Image Stacker Software
to create the star trail stack. Use the "Brighten" blend mode.
3. Bring the finished stack into Photoshop for final touch-up and processing
4. Voila'

OK...I admit it...After taking that long to type this up, it is pretty involved...but it isn't hard. You can do it. The next time you want to give it a try, drop me a line...If I can, I will be glad to tag along. Maybe we can put a small group together and give it a go. It is always more fun to have someone to talk to while the camera is doing it's thing.

_______________________________________________________________

Now...after I get down off my pedestal...this is something that I am passionate about...and I freely admit that there are a 1000 ways to skin the proverbial cat. But this method has worked for me very well. To prove it, I leave you with an example of my work. If you want to see any more, please feel free to go o my gallery at this location:

http://lemmingswalk.smugmug.com/gallery/3398254_B5ccm#190030899_UmsKQ

HFM

davidryan · August 22, 2008

I don't know if anyone mentioned this here in this thread but I was told and have come to find out (and agree) that shots after 2AM will have the least amount of light pollution if you are near light sources like cities and towns. Humidity does not become such an issue if there is a light wind and few lights polluting the scene.

Also, if you are taking multiple shots (and I too recommend this) do not allow time between shots-- when you stack your shots in ImageStacker there will be dashed star trails instead of one fluid line. Those stars that don't look like they move really do, and they move much faster than you'd think!

Here are some examples of my own star trails...

Polaris and the Academy

My in-laws ranch, the place that is in the middle of nowhere and therefore makes it a great star-trail place...

And though it never went into a star trail final shot-- a video of just how quickly the stars really move-- a thunderstorm, shot in 30 sec intervals.

<object width="425" height="318">

<embed src="http://www.smugmug.com/ria/ShizVidz-2008080703.swf" flashvars="s=ZT0xJmk9MjQwMDc3OTE2Jms9a1k4dTQmYT0xMDM1MjY2X2c2QnlMJnU9cnlhbnNmb3J1bQ==" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="318"></object>

schmoo · August 22, 2008

bow

This is turning into quite the Star Trail Thread! I am so impressed by the work I'm seeing here. I love star trail shots and would love to shoot them more but I live in such a crowded, humid place of the country.

snowalker · August 22, 2008

rainy stars
crashmaster
How it's posible the car is not overexposed after "a few hours"?

crashmaster · September 2, 2008

snowalker wrote:

crashmaster
How it's posible the car is not overexposed after "a few hours"?

All exposures were 30 sec, so the pixels do not reach saturation or even approach the full well depth.

Remember, although I am stacking several hours worth of images it is not a "sum" combine.

There was quite a lengthy post about using a low ISO and longer exposures to do star trails and thats fine if you want to do that, however doing that may blow out any illuminated objects in the foreground depending on the light source, so take that into consideration. Using long exposures will also require dark frame subtraction as significant heat builds up in the chip which results in more noise. With these uncooled CMOS sensors, dark frame subtraction works just OK, IMO, and it must be done properly.

For dark frames to be most effective, they need to be taken at the same exposure time and ISO setting as the light images and preferably at the same ambient air temperature as the light images. For example dark frames that were taken at an ambient air temp of say 70 degrees, will not work well with light images taken at say 50 degrees. Also, for dark frames to be most effective at subtracting noise from light frames, you should take around 10 of them and do a median combine to create a master dark, then subtract the master dark from each one of your light frames. Software such as Images Plus or Ray Gralak's Sigma work very well for creating your master dark frames.

In addition, shooting at cooler air temps will result in less noise in the light frames. When using these chips for long exposure astrophotography it can be quite challenging sometimes to get even a semi smooth image without substantial use of noise ninja in addition to quality dark frames. The sensor in the 20D has a "river" of dark current that pops up during long exposures and can be quite a challenge to remove even with quality dark frames.

There is not a right or wrong way to do DSLR star trails. For myself, I like to use a high ISO, wide open aperature and short exposures with no delay between shots. Its simple, effective and captures some quite dim stars without requiring long exposures or dark frame subtraction. I feel the chip in the 40D that I use is fairly clean even at high ISO so thats what I do, to each his own though.

Like I said, no right or wrong way to do this really, just experiment, try out a little of everything and see if you like the results.

jamesl · September 2, 2008

Wow! Some amazing stuff on this thread! As mentioned, there are a lot of different ways to shoot star trails, and most will give great results. Myself, I prefer the short 30 second exposure route with a wider open aperature and low ISO. I shoot large jpg so that the write time to the card is shorter, and more files can fill my card.

Here's a few I've done:

2 1/2 hour of 30 second exposures with my Canon 10D and 20mm lens. Aperature was at 2.8. I took one exposure early on to capture the sunset colors. This looks much better in print, as you can really see the star trails.

Same as above. I had to clone out a few plane trails. Also, the full moon was behind me, and that really lit up the landscape.

Here's an instance where I should have shot at a higher ISO to get better trails. Also, some light clouds came in and made it tough to get a good shot.

Again, a higher ISO probably would have helped, and clouds kind of messed things up.

Keep the star trails coming!

James

DaddyO · September 2, 2008

Sweet images James. Well done.

Crashmaster. Appreciate the read in your last remarks and others you
have posted concerning this topic. Michael

crashmaster · September 2, 2008

Great stuff james, very nice work! The second shot is simply awesome! Zion perhaps?

Anyway, I used to be quite a star trail junkie in the film days with my Canon FTb and film.

When I was out astroimaging on dark moonless nights with my dedicated CCD camera on a telescope, I would set up the SLR on a tripod and open the shutter for the whole night exposing some gas hypered film. Of course, one flashlight in the lens or car headlights starting up would ruin an all night exposure and I wouldnt realize it until I processed the film. I dont miss those days........really

Another trick I did was to take hours upon hours of astro images tediously hand guided over the course of a night. Then I would pack up in the morning and go home, get ready to process the hard won images of a long nights work, but shocked to discover that I shot all night without film in the camera:dgrin That kind of stuff makes you want to slit your wrists!

Like a I said, I sure dont miss those days........at all.

schmoo · September 2, 2008

crashmaster wrote:

Great stuff james, very nice work! The second shot is simply awesome! Zion perhaps?

Anyway, I used to be quite a star trail junkie in the film days with my Canon FTb and <gasp> film.<img src="https://us.v-cdn.net/6029383/emoji/rolleyes1.gif" border="0" alt="" >

When I was out astroimaging on dark moonless nights with my dedicated CCD camera on a telescope, I would set up the SLR on a tripod and open the shutter for the whole night exposing some gas hypered film. Of course, one flashlight in the lens or car headlights starting up would ruin an all night exposure and I wouldnt realize it until I processed the film. I dont miss those days........really

Another trick I did was to take hours upon hours of astro images tediously hand guided over the course of a night. Then I would pack up in the morning and go home, get ready to process the hard won images of a long nights work, but shocked to discover that I shot all night without film in the camera:dgrin That kind of stuff makes you want to slit your wrists!

Like a I said, I sure dont miss those days........at all.

<img src="https://us.v-cdn.net/6029383/emoji/eek7.gif" border="0" alt="" >

:bash

And James, excellent star trails! I love the work showing up in this thead. It's so inspiring, and quite cosmic.

</gasp>

CatOne · September 3, 2008

Hadn't done one before but did a couple this week.

Here's one from Schulman Grove in the Ancient Bristlecone Forest at 10,500 feet.

It's a 30 minute exposure, at ISO 400, and it's evident at 100% that the 1Ds Mark III *really* needs the long-exposure NR enabled. :cry

At this size it's not so noticeable.

coscorrosa · September 3, 2008

CatOne wrote:

Hadn't done one before but did a couple this week.

Here's one from Schulman Grove in the Ancient Bristlecone Forest at 10,500 feet.

It's a 30 minute exposure, at ISO 400, and it's evident at 100% that the 1Ds Mark III *really* needs the long-exposure NR enabled. :cry

At this size it's not so noticeable.

Whoa, that's an awesome shot! On my 1D MIII (not Ds) the noise really shows up after a few minutes (even at ISO 100). I'm going to have to try out some of these star trail shots, there's a bunch of great examples in this thread.

schmoo · September 3, 2008

It's official! I changed the title of this thread slightly and added it to the sticky.

Come one and come all, show us your stars!

crashmaster · September 4, 2008

CatOne wrote:

Hadn't done one before but did a couple this week.

Here's one from Schulman Grove in the Ancient Bristlecone Forest at 10,500 feet.

It's a 30 minute exposure, at ISO 400, and it's evident at 100% that the 1Ds Mark III *really* needs the long-exposure NR enabled. :cry

At this size it's not so noticeable.

That is fantastic!! Love the Milky Way coming out of the top of the tree.

mushy · September 4, 2008

CatOne that shot is stunning! Especially for a 30 min exposure, I always shoot much longer thinking I need to!

This isn't a star trail but a night time shot all the same

ISO 3200, 33 Secs, F4, there is plenty of noise but it looks fine at this size:D
I'm off to the middle of nowhere next weekend and will be experimenting with setting from this thread!
Thanks all

HFMarshburnJR · September 4, 2008

Let me see if I can contribute again. This is the one that got me hooked. It is an effective 3 hr exposure consisting of 18 stacked 10 minute exposures. The first three had the benefit of a setting half moon, and wer shot at F5.6, ISO 200 with a Nikon D70 and a 14mm F2.8 lens. Once the moon set, I opened up the aperature to 2.8 for the remainder of the shoot. Black frame was shot at the end of the shoot. All images were stacked in Photoshop CS3.

This was my first star trails effort. Enjoy.

jamesl · September 5, 2008

crashmaster wrote:

Great stuff james, very nice work! The second shot is simply awesome! Zion perhaps?

Yup, Zion.

I shot that with my good friend Luben Solev from the UK. We tried a few star trail images while we were in Zion, but this one came out best. Those are the Towers of the Virgin, and the view is from right behind the visitor center.

James

Ratty2austin · September 5, 2008

Mind if I share some of mine?

I have been fascinated by star photos ever since I learned to take them with my old Minolta X700 film camera... but with the digital, it was much easier! (did not have to wait for my film to get back to find out the settings were off

)

anyways,

with my old 300D near Rampart Lakes- Snoqualmie pass, WA

and this one was taken with my 40D (touched up with photoshop) in Death Valley

thanks for letting me share, and I really like the ones you all have posted as well! I think the Earth's rotation star photos are really cool!

schmoo · September 5, 2008

Ratty2austin wrote:

thanks for letting me share, and I really like the ones you all have posted as well! I think the Earth's rotation star photos are really cool!

I love the number of stars in that one, whoah. This looks like something out of an astronomy textbook!

This thread is now open for anyone to post their star trails. Thanks for contributing (which is more than I have done

)

The Star Trail thread

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