How to shoot the night sky (astrophotography)

[jgomez65]

Several people asked me to post a simple tutorial on how I took some nigh sky pictures. I am not an astrophotographer in any way, shape or form, nor do I have any expensive equipment. I simply read several tutorials, picked a dark spot on the beach and tried to do my best.

Anyway, here is how I did it.

1. What you need:
You need a camera that has manual exposure mode. Most SRL camera come with a feature called Bulb which does exactly that.

You will also need a remote control or a shutter release cable in order to minimize shaking the camera when taking the pictures.

You will definitely need a tripod

2. Selecting the spot to take your picture
The darker the place, the better it is. Taking stars pictures in your back yard is possible, however for better results select a place away from city lights. Those lights tend to pollute the image and make the stars less visible.

3. Camera settings
First, try to use a lens with a large aperture. In my case I used a Sigma 28 mm lens at f/3.5

Next, set your camera at a high ISO. I tried with both 1,600 and 800 ISO and I got good results.

Finally, in order to avoid the star trail (that is avoiding capturing the movement of the stars as the earth rotates) you have to use the RULE of 600 which is very easy:
Divide 600 by the focal length of the lens you are using. In my case I divided 600/28 = 21.42 ( I can leave the shutter open for 21 seconds and avoid capturing the star trail)

Finally, put your lens in manual focusing and turn it to infinity focus (that would be the symbol at the end of the numbers on your lens)

4. Taking the pictures
Set the camera in your tripod and take at least 5 consecutive images at the stars using the correct exposure time (using the RULE of 600) Do not move the camera to a different spot or change the settings unless you are done with that series of pictures.
Tip: Every time I am done with a set of pictures, I place my hand in front of the lens and take another picture. That way I know that the picture where everything is black is where the series end.

5. Editing the images
Don’t be disappointed if you don’t see any color in your images. This is normal. You will need to bring the colors up in PS or any other editing software.

The first step is to stack the images. That is to superimpose one image on top of the others (not all the images, but pictures belonging to the same series). You can do this with a free software called Deep Sky Stacker. Just use the default settings on the software.
The final image will be a large TIF file that you will use to bring up the colors in Photoshop.

Next open your TIF file in Photoshop and edit the curves and levels. You can follow this easy tutorial on this video:
YouTube - ‪Curves and Levels - Easy 123 - Photoshop Astrophotography Tutorial‬‏

I also edited the blue, red and green colors in the level in order to make the nebula more visible.

That’s it.

Here is the original image and the final result:

Original:



Final image:

[Izzy]

Thanks for posting this. I will have to go out and give it another try.

[goose129]

Two Questions:

1. Do you do the dark, light, flat and/or bias frames with DSS?

2. I understand the 600 factor to obtain a starting exposure, what I can't wrap my head around is why. I mean if I can shoot a 30s exposure with a 18mm lens, why can't I make the same exposure with a 35mm or 50mm or whatever? How does the focal length effect streaking?

[jgomez65]

Originally Posted by goose129

Two Questions:

1. Do you do the dark, light, flat and/or bias frames with DSS?

2. I understand the 600 factor to obtain a starting exposure, what I can't wrap my head around is why. I mean if I can shoot a 30s exposure with a 18mm lens, why can't I make the same exposure with a 35mm or 50mm or whatever? How does the focal length effect streaking?

1. With the DSS software I just use the default settings. Nothing more.

2. For the second question, look at it from this point: the closer you zoom in on an object in the sky, the faster the object will move across the lense. This doesn't occur with the moon too much because it is relative close to Earth, but for other objects that are far away such as galaxies, planets and stars it will happen very fast. The rule of 600 is just a safe way to avoid the trail.

[gturner]

Thanks for this - well timed as I have a trip to the area of South Africa that they are looking at building the km2 array. Just about the best night skies you could hope for.

[hduguid]

[QUOTE=jgomez65;1278737
The final image will be a large TIF file that you will use to bring up the colors in Photoshop.

Next open your TIF file in Photoshop and edit the curves and levels. You can follow this easy tutorial on this video:
[url=http://youtu.be/WnPII6YdVBc]YouTube - ‪Curves and Levels - Easy 123 - Photoshop Astrophotography Tutorial‬‏[/url]

I also edited the blue, red and green colors in the level in order to make the nebula more visible.

That’s it.

Here is the original image and the final result:

Original:

Ok, I've tried this and have stacked, but I haven't figured out yet how to bring up the color in PhotoShop, as you indicated in your comparisons.
Looked at the video, but....
Oh, BTW, I've PS-elements.

Any further steps you can provide?

[Tzetsin]

Hey, thanks for this. I've done many many night sky shots, but have never thought to stack multiple exposures. I'll have to give that a go.

[bdbolin]

Great tutorial, the 600 rule is awesome to know. I have been out and tried night shot before and always managed to get star trails (which are cool when you want them). lol

[jgomez65]

Ok, I've tried this and have stacked, but I haven't figured out yet how to bring up the color in PhotoShop, as you indicated in your comparisons.
Looked at the video, but....
Oh, BTW, I've PS-elements.

Any further steps you can provide?[/QUOTE]

I am not sure about PS Elements, but in the regular PS you can bump the colors in many different ways, using a combination with the Color Balance, Channel Mixer, Saturation, Vibrance, etc

[Andrew435]

This is awesome, I'm going to have to try this technique! I've always wondered how this is done!