Astrophotography Shooting Tips

piercingperceptions · November 1, 2008

I was wondering what is the best way to get a picture of stars or the northern lights. I am going to alaska over Christmas and want the chance to get some good star pictures. All the times I have tried before I have either had the stars blurred due to the earth moving or it has been very under exposed.

Any tips?

I am shooting with a Canon 50D.
Probably using a 24-105mm f/4L
Tripod of course

I really want a clear shot of the stars. Thanks for the help!

pathfinder · November 2, 2008

Welcome to dgrin.

Shooting stars can be easily done with most cameras that allow manual control of aperture, shutter speed, and ISO. Auto modes usually do not work well, although some P&S has a night scene or star shot mode.

Put your camera on a firm, solid tripod, turn Autofocus off, and start with ISO 100, aperture of f4 or 5.6, and a shutter speed of 20 to 30 seconds. Shoot a frame and look at the image on your LCD, and adjust your exposure as needed.

This was shot several years ago with a 10D at ISO 100, f4 and 30 seconds, fixed tripod.

Try to keep your shutter speed less than 20 seconds if possible, by raising your ISO, as longer shutter speeds than 30 seconds will show star movement. Here is a closer look at that shot of Orion shat was exposed for 30 seconds

If you need to use longer than 30 second exposure that are perfectly sharp, you need some kind of equatorial astronomical mount that aligns and moves the camera with the movement of the stars across the sky.

This was shot in Moab at the shoot out at ISO 1600, f5.0 at 30 seconds, fixed tripod.. It was a bright full moon lit night.

I would suspect that the Northern Lights require a shorter shutter speed if you want to capture them sharply, but I have never shot them so will wait for someone who has to answer that question.

Candid Arts · November 11, 2008

pathfinder wrote:

Welcome to dgrin.

Shooting stars can be easily done with most cameras that allow manual control of aperture, shutter speed, and ISO. Auto modes usually do not work well, although some P&S has a night scene or star shot mode.

Put your camera on a firm, solid tripod, turn Autofocus off, and start with ISO 100, aperture of f4 or 5.6, and a shutter speed of 20 to 30 seconds. Shoot a frame and look at the image on your LCD, and adjust your exposure as needed.

This was shot several years ago with a 10D at ISO 100, f4 and 30 seconds, fixed tripod.

Try to keep your shutter speed less than 20 seconds if possible, by raising your ISO, as longer shutter speeds than 30 seconds will show star movement. Here is a closer look at that shot of Orion shat was exposed for 30 seconds

If you need to use longer than 30 second exposure that are perfectly sharp, you need some kind of equatorial astronomical mount that aligns and moves the camera with the movement of the stars across the sky.

This was shot in Moab at the shoot out at ISO 1600, f5.0 at 30 seconds, fixed tripod.. It was a bright full moon lit night.

I would suspect that the Northern Lights require a shorter shutter speed if you want to capture them sharply, but I have never shot them so will wait for someone who has to answer that question.

Also looking for ideas on how to do this. Every time I've tried astrological photos, the photo is always underexposed and you can't see the stars, or you can see the stars but they all have the movement too them. I love the Moab photo, but these will be black skies, and I'd love for it to be a complete black sky with the stars bright but with no movement. I have a couple ideas to try with editing software, but I gotta wait till I can see the stars again to try.

Northern Lights...I have seen some amazing pictures of them, living in AK for 23 years, but really need to figure out how to actually shoot them. I would imagine try and get the widest apeture possible to get the shortest shutter speed, and bump the ISO if needed. I know Canon is notorious for having noisey blacks, so I'm wondering how high I could go before it's visible...

ziggy53 · November 11, 2008

For longer exposure astronomical "star" photography you really need an equatorial (EQ) type mount and a method of tracking. Polar alignment is an important part of the process and many people find that difficult to do.

There is a relatively inexpensive device in the following thread, but we haven't heard from Nik whether it works or not:

http://dgrin.com/showthread.php?t=109155

Otherwise, what some people do is attach a "piggyback" mount onto a larger telescope which has an EQ mount and tracking motor.

If you really want to go cheaply you can even make the "barndoor" mount described in the thread, but alignment is especially tricky. Tracking in that case can be entirely manual.

Here is a link to aurora photography and some hints:

http://www.ptialaska.net/~hutch/aurora.html

The "trick" to long exposure digital photography is to turn on the "long-exposure noise reduction". Realize that there will be the time required for the image exposre and then there will be an equal time for the "dark frame" exposure, which is needed to remove the dark noise. Canon cameras are often used for long exposure work and the dark noise is really no problem with the NR turned on. Do make sure you have fully charged batteries as long exposures on many cameras sump the batteries pretty quickly. I believe the Canon 1D/1Ds cameras use a shutter latch so that current drain in long exposures is considerably less for those cameras.

piercingperceptions · November 11, 2008

ziggy53 wrote:

For longer exposure astronomical "star" photography you really need an equatorial (EQ) type mount and a method of tracking. Polar alignment is an important part of the process and many people find that difficult to do.

There is a relatively inexpensive device in the following thread, but we haven't heard from Nik whether it works or not:

http://dgrin.com/showthread.php?t=109155

Otherwise, what some people do is attach a "piggyback" mount onto a larger telescope which has an EQ mount and tracking motor.

If you really want to go cheaply you can even make the "barndoor" mount described in the thread, but alignment is especially tricky. Tracking in that case can be entirely manual.

Here is a link to aurora photography and some hints:

http://www.ptialaska.net/~hutch/aurora.html

The "trick" to long exposure digital photography is to turn on the "long-exposure noise reduction". Realize that there will be the time required for the image exposre and then there will be an equal time for the "dark frame" exposure, which is needed to remove the dark noise. Canon cameras are often used for long exposure work and the dark noise is really no problem with the NR turned on. Do make sure you have fully charged batteries as long exposures on many cameras sump the batteries pretty quickly. I believe the Canon 1D/1Ds cameras use a shutter latch so that current drain in long exposures is considerably less for those cameras.

Thank you very one for your help!! I can't wait to get a clear sky and to try!

pathfinder · November 11, 2008

I did use the noise reduction feature in the shot of Double Arch with the 1DsMkii.

I did not use it with 10D, I believe. It definitely makes shooting a slower process as the noise reduction takes as long, or longer, than the timed exposure itself.

BeckmannPhotos · November 13, 2008

I am taking a night photography class right now and picked up a handy rule of thumb for getting star points vs. star trails.

Shutter Time (s)=600/focal length

So if You are shooting with a 20mm effective focal length, you can expose for up to 30 secs. before you start getting noticable star trails.

I have tried this several times and it works great as a guideline/starting point. While it isn't perfect, it gives a good idea of where to start. Obviously if you go to 31 sec. on the above example, star trails will not all the sudden appear.

Keeping all this in mind, you want to shoot and bracket using your ISO instead of exposure time.

Candid Arts · November 13, 2008

I've read this elsewhere too, how do you figure in the aperture to this equation?

BeckmannPhotos · November 13, 2008

The aperture doesn't figure into the star point/trail equation, it will just change the brightness and starring effect that you get.

Candid Arts · November 13, 2008

BeckmannPhotos wrote:

The aperture doesn't figure into the star point/trail equation, it will just change the brightness and starring effect that you get.

Got it. Makes sense. Duh..

Thanks.

OhEddie · November 14, 2008

Astronomical Photography or Astrophotography is the proper term.

Here are a couple of links...

http://en.wikipedia.org/wiki/Astrophotography

http://www.astropix.com/

Enjoy the night

Astrophotography Shooting Tips

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