Seriously Terrible First Attempt (Star Trails)

So I've been wanting to try this all week and I got home tonight and saw at least some broken clouds...

Nearly full moon overhead and lots of clouds equals this crap. lol

One question I have. It's possibly hard to see at this size but there are gaps in the star trails where the camera shut down one image and started the next. I shot this at 40mm so do I need to shoot it wider for the gaps to not be there? (First gap is just my mistake of also including my first test shot in the series).

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I can see random gaps that look like they're caused by clouds and you obviously have plenty of cloud around.
Are the gaps that you are talking about evenly spaced across all of the trails ? If they are and the gap is about the same length as the trail part, that's probably caused by the camera taking a dark frame. Look for a setting called something like "long exposure noise reduction" and turn it off.

Steve.

PS. I like the result. It makes a nice change. An astro-abstract.

that looks interesting, i wouldn't trash it...

SteveInNZ wrote in post #9495334
I can see random gaps that look like they're caused by clouds and you obviously have plenty of cloud around.
Are the gaps that you are talking about evenly spaced across all of the trails ? If they are and the gap is about the same length as the trail part, that's probably caused by the camera taking a dark frame. Look for a setting called something like "long exposure noise reduction" and turn it off.

Steve.

PS. I like the result. It makes a nice change. An astro-abstract.

Yeah there were clouds last night and they moved a lot more than I expected. I just started the camera and went inside to work on other things. So I didn't really see what the clouds were doing till I combined them. Noise reduction was not turned on. The gaps are all the same size but not the same distance as the actual recorded star trail. I'll get a 100% crop soon.

RadAL wrote in post #9495605
that looks interesting, i wouldn't trash it...

Thanks

Here's the 100% crop.

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Here's a little :03 video I made of the stills.

http://www.youtube.com​/watch?v=9ebLN40Ci-s

What I have seen from the few star trails I have done, is that the gaps are more evident further away from the centre of the "startrails circle", the centre being the celestial south pole (I think that's its name) in the southern hemisphere. I imagine that it is the same for the northen hemisphere .
To reduce the size of the gaps, take pictures of stars that are closer to the celestial pole. To have the same length (distance) of trail, you would need more exposures, that would however show more of a curve.
To reduce the number of gaps, one need to keep the shutter open for longer, instead of having 120 x 30 second exposures, rather have 10 x 6 minute exposures.

good reading :

http://www.fredmiranda​.com/forum/topic/72576​9/0

qoutes from the page below, the effect/application of focal length:

http://www.brighthub.c​om …y/articles/4281​7.aspx?p=2
"•Wide shots having a foreground: These are usually the most spectacular looking images, as the star trails are in context to an appealing foreground. You can experiment depending on your surroundings (a lake, a monument, your tent, etc.) and choose a wide enough focal length to accommodate it. Try to get the Pole Star in frame, as all other stars would be rotating around this one."
"•Zoom in for an abstract effect: Zooming in and filling the frame with only the star trails gives an artistic effect"

a lot of patience required as we learn by trial and error

Thanks for the feedback and links Casper.

I would like to try shooting stars, but with my 50d only lens choice I have is 50mm or 28-125mm.Is it possible? If so what would be the proper settings?

Twhit, you can use your 28-125 no problem. I used my 28-75 on the example in this thread. My shots were done at ISO 400, 28mm, f/5.0 and 25 seconds. I have a lot of light pollution near my house though so your settings may vary a little.

My next attempt I'm going to shoot closer to 18mm with my 10-20 and see if it comes out any better.

Thanks,if it ever stops snowing and raining I'll give it a try! Do you know what mode AV or TV ?

I use M