Understanding Star Trails

[Francis247]

Try taking some star trails at the playground near my house to help photographers to understand more about taking star trails. Was pointing in the direction of the Orion constellation.

The photo consist of 3 Darkframes and 48 Frames taken with 1 min exposure and compiled using software.



The attached video can help to understand the effect of passing cloud which can be observed at Frame 7 (approximately 7 secs) to Frame 20 (approximate 20 secs).



Sorry for the poor quality video. After using a conversion programme, the quality drops.

[epileatheral]

Hi Francis,
How long do we need to keep our shutter open to get trails like this?

And.. do you know how to locate the North Star?

[mdzmr]

Originally Posted by epileatheral Hi Francis, How long do we need to keep our shutter open to get trails like this? And.. do you know how to locate the North Star?

I don't think so you able to locate the North Star in Singapore.
Its near horizon

[Francis247]

Originally Posted by epileatheral Hi Francis, How long do we need to keep our shutter open to get trails like this? And.. do you know how to locate the North Star?

Hi there,

I took a total of 48 shots with 1min exposure each. That is around 48 mins in total.

To locate the North Star aka the Polaris, you need to find the Big Dipper, but the problem is that in Singapore, we cannot really see the Big Dipper unless you are more towards the North of the globe.


I think this link will help you to understand.
Use the Big Dipper to locate Polaris.

[epileatheral]

Finding the north star..
Here's what I found while googling..

http://www.physics.ucla.edu/~huffman/finddip.html

[billycadiz]

Hi Francis, 48 shots with 1min exposures? Does it means time lapse?how bout 'coz some websites teach about locking it on bulb mode for 30 minutes, but some don't agree with it for it will damaged the shutter. Which is which, I want to try but the suggestions on the website are really confusing. TIA!!

[Francis247]

Originally Posted by epileatheral Finding the north star.. Here's what I found while googling.. http://www.physics.ucla.edu/~huffman/finddip.html

Yap, that's good info also.

[Francis247]

Originally Posted by billycadiz Hi Francis, 48 shots with 1min exposures? Does it means time lapse?how bout 'coz some websites teach about locking it on bulb mode for 30 minutes, but some don't agree with it for it will damaged the shutter. Which is which, I want to try but the suggestions on the website are really confusing. TIA!!

Hi there,

There are 2 ways to do Star Trails, actually maybe more.
But I will just talk about these 2 which I tried before.
I did a short write-up in this post, but was not yet complete. Really need to find time to sit down and do a proper job.

One is the Conventional Way which is the Manual Long Exposure aka Bulbing for some.
This is the way which you mentioned, Locking it on Bulb Mode for 30 mins exposure. Here was my results taken years back.

20th July 2006

#1.

Setting
Focal Length : 22mm
ISO : 100
Aperture : f8
Exposure Time : 479.5 secs
White Balance : Tungsten

#2.

Setting
Focal Length : 22mm
ISO : 100
Aperture : f8
Exposure Time : 479.5 secs
White Balance : Tungsten

#3.

Setting
Focal Length : 22mm
ISO : 100
Aperture : f8
Exposure Time : 599.5 secs
White Balance : Tungsten

The other way was to use the Software aka Startrail.exe. That was what I used for this shot. It is like a time laspe concept like you mentioned actually.

Hope that answer your question.

[mdzmr]

You also can go to www.skyandtelescope.com
here i add in a star chart with a highlighted in red circle showing the Polaris or the north star which is near to the horizon in singapore

[Francis247]

This link is useful also.
http://web.singnet.com.sg/~ngkguan/astro10.htm

[epileatheral]

Oh... so Francis, for the first shot, you actually shot multiple images of 1 min and combine them together using post processing?
Or was it multiple exposure?

[Francis247]

Originally Posted by epileatheral Oh... so Francis, for the first shot, you actually shot multiple images of 1 min and combine them together using post processing? Or was it multiple exposure?

Yap, I shot multiple images of 1 min and combine them together using post processing.
The Youtube Video (sorry about the poor quality) is actually a time-lapse of the whole 48 mins.

[epileatheral]

Oh.. I can't view youtube in my company. Will view it later at home.
Hmm.. I wonder if I can exploit the multiple exposure function in my camera...

[billycadiz]

wow! thank you guys!