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03/13/2011 11:31:47 PM · #1
I have done a few short exposure star trail shots, but how the heck do i do ones that are extreamly long, i can only do up 30 min max...?
03/13/2011 11:33:56 PM · #2
The standard strategy is to combine many shorter exposures. That's actually "best practice" however keep in mind it is *not* DPC-legal, even in Advanced.
03/13/2011 11:35:03 PM · #3
Kirbic is right...but are you sure that cam doesn't have a 'bulb' setting?
03/13/2011 11:35:59 PM · #4
Originally posted by kenskid:

Kirbic is right...but are you sure that cam doesn't have a 'bulb' setting?


Yeah, i can use bulb, up to 30 mins.
03/13/2011 11:36:26 PM · #5
Originally posted by kirbic:

The standard strategy is to combine many shorter exposures. That's actually "best practice" however keep in mind it is *not* DPC-legal, even in Advanced.


Oh so like 3 30 min exposures, and combine in photoshop?
03/13/2011 11:39:04 PM · #6
Originally posted by hojop25:

Originally posted by kirbic:

The standard strategy is to combine many shorter exposures. That's actually "best practice" however keep in mind it is *not* DPC-legal, even in Advanced.


Oh so like 3 30 min exposures, and combine in photoshop?


Yep, although I'd recommend keeping the individual exposures shorter, perhaps 10 minutes or so as a maximum.

ETA: Make sure that your camera's long-exposure noise reduction is set to "off." You'll need to start the next exposure immediately after the previous one.

Message edited by author 2011-03-13 23:40:21.
03/13/2011 11:43:53 PM · #7
Originally posted by kirbic:

Originally posted by hojop25:

Originally posted by kirbic:

The standard strategy is to combine many shorter exposures. That's actually "best practice" however keep in mind it is *not* DPC-legal, even in Advanced.


Oh so like 3 30 min exposures, and combine in photoshop?


Yep, although I'd recommend keeping the individual exposures shorter, perhaps 10 minutes or so as a maximum.

ETA: Make sure that your camera's long-exposure noise reduction is set to "off." You'll need to start the next exposure immediately after the previous one.


Ah righto! Thanks very much :-)
03/13/2011 11:48:44 PM · #8
Also, if you are looking for long trails realize two other things will affect them. First, the direction your camera is pointed. The further away from north the better. (although now I'm trying to guess in my head wither south is better than west or east). Second, the more telephoto you have the longer the trail will look. A really wide shot will take longer for the trails to look substantial.
03/14/2011 08:16:21 AM · #9
Originally posted by DrAchoo:

...although now I'm trying to guess in my head wither south is better than west or east...


The maximum "velocity" of star movement will be along a line 90 degrees south from the North Star. So for the Northern Hemisphere, a line whose elevation is 90° minus the elevation of the North Star. The line "rises" approximately in the East, and "sets" in the west.
The cool thing about star trails is that you can create all sorts of shapes, from circular patterns North Star is in-frame) to arcs, arches across the horizon (camera pointed S in Northern Hemisphere), and nearly straight lines.
03/14/2011 09:35:35 AM · #10
Originally posted by DrAchoo:

Also, if you are looking for long trails realize two other things will affect them. First, the direction your camera is pointed. The further away from north the better. (although now I'm trying to guess in my head wither south is better than west or east). Second, the more telephoto you have the longer the trail will look. A really wide shot will take longer for the trails to look substantial.


The more towards the equator you point the longer the trails. If you're in the northern hemisphere point south, if you're in the southern, point north, and if you're on the equator, point straight up :)

ETA: Just realised I was late answering this one :)

Message edited by author 2011-03-14 09:36:38.
03/14/2011 04:30:44 PM · #11
I just found this video. It takes a long time to load, but it has a lot of good information on star trails.

Star trails video.
03/14/2011 05:46:34 PM · #12
Playing around with star trails the other night and after about 30 mins ended up with these colour blotches in the top corners of the photo. Any idea why?

eg: ' . substr('//images.dpchallenge.com/images_portfolio/115000-119999/119747/120/Copyrighted_Image_Reuse_Prohibited_940687.jpg', strrpos('//images.dpchallenge.com/images_portfolio/115000-119999/119747/120/Copyrighted_Image_Reuse_Prohibited_940687.jpg', '/') + 1) . '

Message edited by author 2011-03-14 17:47:38.
03/14/2011 06:15:21 PM · #13
Originally posted by adamelliott111:

Playing around with star trails the other night and after about 30 mins ended up with these colour blotches in the top corners of the photo. Any idea why?

eg: ' . substr('//images.dpchallenge.com/images_portfolio/115000-119999/119747/120/Copyrighted_Image_Reuse_Prohibited_940687.jpg', strrpos('//images.dpchallenge.com/images_portfolio/115000-119999/119747/120/Copyrighted_Image_Reuse_Prohibited_940687.jpg', '/') + 1) . '


Its the heat building up inside the camera, my D200 does the same thing. If you want to get super serious then you can get a cooler & try to keep the camera cooled down. This is why I only attempt long star trails in the winter. It only gets down to about 10 degrees here but it certainly helps.

You can either crop them out or desaturate the purple, or do a colour change on purple
03/14/2011 06:32:00 PM · #14
Originally posted by adamelliott111:

Playing around with star trails the other night and after about 30 mins ended up with these colour blotches in the top corners of the photo. Any idea why?


That's one reason why "best practice" is stacked shorter exposures. You will still get some of the "sensor heating" but it will be much less prominent. Take some dark frames before and after your image series, and you can get rid of most of the heat artifact.
03/15/2011 04:04:10 AM · #15
This is technically called amp glow, and it should be noted that the D80 is well known for its susceptibility to it. As Fritz said, shorter exposures are your only defense, but you'll find that after you do a bunch in a row it'll still start to appear. The cold weather comment is dead on, but with my D300 (which people find has better amp glow performance) I've not had any problems shooting at around 50 degrees for stacking 30+ minutes of exposures.
03/15/2011 04:51:27 AM · #16
Originally posted by hojop25:

Originally posted by kenskid:

Kirbic is right...but are you sure that cam doesn't have a 'bulb' setting?


Yeah, i can use bulb, up to 30 mins.


Hi Josh,

Thinking about what you said, of the 30 minutes, is that as much as it can go?
Are you using a wired or wireless remote trigger?

Just asking because on Nikon cameras if you use a wireless remote and bulb, it will limit the exposure to 30 minutes.
Funny thing though, found once an answer from Nikon in an official forum that the workaround is holding the shutter button for more than 30 minutes :P

Anyway, with a wired remote trigger you can go for as long as the battery holds.

For star trails, I also advise lots of exposures and then stack them together.

There's a handy software called Startrails (www.startrails.de) that will stack all your photos.
Just use 30 seconds exposures and keep the shutter button pressed on the wired remote.

Also, remember to take the photos in jpg, or your workflow will be very painful.

Here's one of 200 stacked 30 seconds exposures:

' . substr('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', strrpos('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', '/') + 1) . '
03/15/2011 05:15:03 AM · #17
Originally posted by sarampo:



There's a handy software called Startrails (www.startrails.de) that will stack all your photos.
Just use 30 seconds exposures and keep the shutter button pressed on the wired remote.

Also, remember to take the photos in jpg, or your workflow will be very painful.

Here's one of 200 stacked 30 seconds exposures:

' . substr('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', strrpos('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', '/') + 1) . '


It's super easy to do this in PS as well. Load as layers from bridge and change the mode to lighten on all of them but your "background" scene. Delete/alter as necessary.
03/15/2011 07:17:32 AM · #18
i use a photoshop action that i downloaded from here:
//www.schursastrophotography.com/software/photoshop/startrails.html

i just checked the link but it said the domain expired 3/5/11 and it forwards you to a different page.
i was able to press the stop button on the browser before the page was redirected though. you can then click the link to download the photoshop action.
03/15/2011 07:28:09 AM · #19
Thanks alot guys! Very helpful! :-)
06/25/2011 06:24:05 PM · #20
Originally posted by sarampo:

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' . substr('//www.dpchallenge.com/images/user_icon/21.gif', strrpos('//www.dpchallenge.com/images/user_icon/21.gif', '/') + 1) . ' sarampo Why is there a gap in the trails, did you miss an exposure?
I tried to take some pictures of star trails last night, I should have read this thread first as they are a bit wrong.
I have a cable shutter and left it on for 10-20 mins, the first exposure was pretty cool, so i left it on for longer but it came out over exposed. I guess the way around this is to do shorter exposures and stack them.

What is the ideal ISO?
Do you need to toggle with the exposure compensation?
Do you keep colour setting as standard or vivid or something else in camera?
The only other problem I had is condensation/dew on the lense, Any one know what can be done about this (I am in southern Hem and it is winter now)?

Thanks
Caz
' . substr('//images.dpchallenge.com/images_portfolio/110000-114999/114565/120/Copyrighted_Image_Reuse_Prohibited_958550.jpg', strrpos('//images.dpchallenge.com/images_portfolio/110000-114999/114565/120/Copyrighted_Image_Reuse_Prohibited_958550.jpg', '/') + 1) . ' Edited version of this ' . substr('//images.dpchallenge.com/images_portfolio/110000-114999/114565/120/Copyrighted_Image_Reuse_Prohibited_958551.jpg', strrpos('//images.dpchallenge.com/images_portfolio/110000-114999/114565/120/Copyrighted_Image_Reuse_Prohibited_958551.jpg', '/') + 1) . '

Message edited by author 2011-06-25 18:36:15.
06/25/2011 06:35:54 PM · #21
Originally posted by supanova:

Originally posted by sarampo:

' . substr('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', strrpos('//images.dpchallenge.com/images_portfolio/105000-109999/105457/120/Copyrighted_Image_Reuse_Prohibited_833992.jpg', '/') + 1) . '


' . substr('//www.dpchallenge.com/images/user_icon/21.gif', strrpos('//www.dpchallenge.com/images/user_icon/21.gif', '/') + 1) . ' sarampo Why is there a gap in the trails, did you miss an exposure?
I tried to take some pictures of star trails last night, I should have read this thread first as they are a bit wrong.
I have a cable shutter and left it on for 10-20 mins, the first exposure was pretty cool, so i left it on for longer but it came out over exposed. I guess the way around this is to do shorter exposures and stack them.

What is the ideal ISO?
Do you need to toggle with the exposure compensation?
Do you keep colour setting as standard or vivid or something else in camera?
The only other problem I had is condensation/dew on the lense, Any one know what can be done about this (I am in southern Hem and it is winter now)?

Thanks
Caz


ISO - 100 (Crucial...you DON'T want noise).
Aperture- about 5.6 to 8 depending on how much ambient light is available.
Standard settings (I don't change to vivid or comparable options on Canons)
Southern hemisphere also but I don't have the dew issues. Somebody else can help you here. Although on cold nights keep spare batteries in bra to keep them warm.
Shooting over water will double the amount of light in your image. Think of it as a big reflector. (so cut the light via your other settings if you want the longer time frame)
Don't allow the moon to creep into your frame.
Do have some moon as on black nights I have done 30 min photos and it stays black even with all the stars in the sky(these shots were done 60kms from nearest town so no ambient light around)
I do not stack so I can't help you there.
06/25/2011 06:38:43 PM · #22
I'm no expert but try to judge your exposure by putting you ISO so it gives you a reading of 30 secs, and then judge what exposure time you need from there if your ISO was at 100.
06/25/2011 07:01:40 PM · #23
Originally posted by Adz:

I'm no expert but try to judge your exposure by putting you ISO so it gives you a reading of 30 secs, and then judge what exposure time you need from there if your ISO was at 100.


Your meter is useless for night photography. Don't try to work any math to figure out what is the right exposure. Any lightsources in the metering area are going to fool the camera.

For startrails, layering the individual pictures with a blending mode of lighten does everything you need to do. After that, it's standard image tweaks.
06/25/2011 07:05:45 PM · #24
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I havent tried the short bursts and combining them. But this one came out good, should have left it on for another 10-15 minutes.
06/25/2011 07:16:11 PM · #25
Short shots combined is definitely the way to go. Highly reduces noise. Plus it's much easier to remove annoying things like planes running through your scene. Here are a couple I have done in the past few weeks with 200+ 30 second shots. Then I combined with the free tool StarStaxX

//www.flickr.com/photos/giantmike13/5830459831/
//www.flickr.com/photos/giantmike13/5825983701/

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