Easy Deep Sky Astrophotography - No Telescope Required

Easy Deep Sky Astrophotography - Without a Telescope

Messier51 sRGB.jpg


Have you ever wished you could photograph the deep space treasures like the one above? This one was imaged by the Hubble space telescope and shows the beautiful and iconic Whirlpool Galaxy.

This guide isn't going to give you pictures like this or like the fantastic images you see in magazines, but it will show you that you can still photograph dim and small deep space objects with no more than your DSLR camera. This guide doesn't use or need a telescope, mount, guiding systems or expensive software that often puts many people off starting out in astrophotography. You also won't need much skill or knowledge to achieve results I hope you will be pleased with. My hope is that with this guide, people armed with just a camera will go out and have a go at astrophotography. It can be so rewarding to see these distant, faint objects appear in pictures that you have taken. If you get any good pictures send them to me and the best ones will be included in the DSLR on a tripod image gallery.

Part 2 on stacking your images using free software Deepskystacker (PC) and Regim (Mac) with video tutorials can be found here:

Part 2 - Stacking Your Astroimages

Part 3 - Processing Your Astrophotographs


What Can You Expect To Achieve

Here is an example of the Globular Cluster Messier 3 taken using just a DSLR on a standard tripod. This image was taken at 200mm focal length and gives you some idea of the kind of picture you can achieve with a 'bright' deep space object.

M3 200 12800 343fr finished1.jpg

Messier 3. ISO 12800 (Hi2), 343 frames at 2sec, 200mm focal length


The Target

To demonstrate how it is possible to get a decent image without any expensive equipment (except a DSLR camera of course) this guide is going to image a small and distant galaxy with a unique and easily recognisable shape, the Whirlpool Galaxy or Messier 51. 

To further demonstrate how easy it is for anybody with a DSLR to photograph these "faint fuzzies" the image is going to be taken under a full moon lit sky in a city location where at best the light pollution allows naked eye visualisation of magnitude 4 stars (under a dark sky, magnitude 6.5 stars are visible). I would be hard pressed to be able to see M51 through my telescope under these conditions.


The Guide

This guide will be split into 3 parts. Part 1 will be getting the pictures, part 2 is what to do with them once you have them and part 3 will be basic processing to bring out some more detail in your final image.

So lets get started and I hope you enjoy the guide. Please send me any pictures you manage to get.


Part 1 - Getting the Pictures


Setting Up the Camera

I have the "wrong" camera for astrophotography. I use a Nikon D3100 but the same principles apply to all DSLR cameras. I would recommend a Canon DSLR if you are starting out as these produce 'true' RAW files, don't eat stars (google Nikon and star eating) and most astrophotography software is designed for Canon cameras.


Before you go out make sure your camera is fully charged and the SD card is empty. You are going to take a LOT of pictures and you don't want to end early.

Manual Mode

Set Manual mode on your camera

Set the Camera to manual mode so you have full control over the settings.

Aperture

Set the aperture as wide as you can possibly go, that is the lowest f number you can get.

ISO

Set the ISO to the maximum your camera can achieve. Without a tracking mount your exposures are going to be short so you really need to try to catch as many precious photons of light as you can in this short time window. An ISO of 800 is probably too low for many of the objects. This guide used 6,400 and 12,800 to take the images.

RAW

You'll need to make sure your camera is recording in RAW format.

Noise Reduction

Nikon cameras have a noise reduction setting, I would recommend you switch it off.

Focus

Set the camera to manual focus. 

Image showing the camera settings


Attach a Remote Shutter Release

You could get away without needing a remote shutter release by setting the camera's timer mode. But, you are going to be taking a lot of pictures and it will be much easier and far more relaxing if you can activate your camera using a remote control. These are pretty cheap to buy and well worth the money because you need a really steady camera to avoid blurry shots and the best way to achieve this is by not touching the camera once it is set up in place.


Choose Your Focal Length and Exposure Time

Your focal length is the amount of zoom. If you have a standard kit lens these are usually 18-55mm. So go ahead and crank it up to 55mm. If you have other lenses you can go up higher on focal length to achieve more zoom. Now, here is the problem.

Planet Earth is spinning and as it turns the stars seem to move across the sky. As we aren't tracking the stars as they move then the stars will tend to blur into long lines instead of starry pinpoints. this is known as star trailing. Star trails can make beautiful pictures like the one below but for this purpose we need the stars pinpoint and in focus. So how do you do this. The answer is the rule of 600. You can find more information on what this is by clicking the link. Basically, this rule tells you how long your exposure can be at different zooms (focal lengths) before star trailing becomes noticeable. 

Star trails over the ESO 3.6-metre telescope.jpg
Star trails over the ESO 3.6-metre Telescope, which hosts HARPS, the High Accuracy Radial velocity Planet Searcher, the world's foremost exoplanet hunter. This image comes from Your ESO Pictures Flickr Group, where anyone can submit photos connected with ESO.


For a kit lens set to 55mm on a standard non-full frame DSLR this time is about 7 seconds. So if you are using 55mm of zoom then set your exposure time to the nearest setting below 7 seconds you can get. For most cameras this would be 6 seconds. If you are using more zoom then you can use the rule of 600 to calculate how long you can expose for. 

There is a limit on this though. At higher magnifications (or focal lengths) the time you can expose for becomes shorter. Too short an exposure and you won't have enough time for the sensor to pick up any photons from your target. I would say the maximum useable focal length is 300mm which for most non-full frame DSLR cameras would give an exposure time of about 1.3 seconds.

For the image above the focal length was 200mm with an exposure time of 2 seconds.


Focusing the Camera

This is crucial to your final result. Poor focus will result in a poor final image and most stacking software programs won't stack poorly focused images anyway. Spend some time getting this right. The easiest way to do this is to set your camera at the focal length (the zoom) that you are going to take your pictures at. Now point the camera at a bright star in the sky on the tripod. Once you can see the star in the viewfinder switch to liveview, if your camera has it, and zoom in on the star (zoom in using the digital zoom, don't change the focal length). Now focus as tightly as you can on the zoomed in star. If you don't have liveview don't worry you can still get great focus. You'll need to take a few shots of the night sky adjusting the focus back and forth until the stars are pinpoints and you can see lots of them when you review the image after taking the picture.

Now you are all focused it's time to frame your object.


Framing the Space Object

Consult a sky map to identify which part of the sky you need to point your camera at. If you are following along for M51 then you can use the Big Dipper page in the constellation guide on this website.

Once you know where you are pointing then put your camera on it's tripod. I use the cheap, portable and versatile Joby Gorillapod for this. You can purchase one from Amazon by clicking on the picture below if you wish (I would receive a small commission for this at no extra cost to yourself).


Take a few shots and make sure you are happy that you have the stars in your picture that surround the deep space object you are imaging. You may be lucky and be able to see the object itself for brighter objects like star clusters and some nebulae. If you are having trouble orientating yourself zoom out and take a shot (but don't alter the focus you have set). By zooming out it usually becomes much clearer as to where the camera is pointing because usually a few bright stars are then visible to guide yourself by.


Capture Your Images

All set, so sit back enjoy the night sky and take around 300-400 images (or upto 30 minutes of total exposure time if you have longer exposures). Check every 50-100 images that you still have the object in frame. If it has moved out of frame make a small adjustment to compensate and carry on shooting. If you find that all you are getting is a white picture then you 'll need to turn the ISO down. This can happen in particularly bright skies at low magnifications. Once you have captured these images move on to some calibration images. From here on the images that contain the picture of the deep sky object and the stars are called your 'Lights’.


Calibration Frames

Now take 20 'Dark' frames. You do this by simply putting the lens cap on the camera and leaving all the settings exactly the same. Next take 20 'Bias' frames. These are taken by leaving the camera's lens cap on and changing only the exposure setting to maximum speed. For my camera this is 1/4000th second. If you wish to collect flat frames do this now, but for the purpose of this guide we are going to leave them out.

That's it all done. Now all you need to do is load the pictures into a stacking software like the free DeepSkyStacker (PC) or Regim (Mac) and then a bit if tweaking in image software like Photoshop (expensive), GIMP (free but 8-bit at present) or even iPhoto. The next couple of weeks will cover these aspects in detail.


Examples

Here is the Whirlpool Galaxy, Messier 51 taken under a full moon with city light pollution. It's not the greatest picture of this galaxy, but to think it was taken using only a DSLR on a normal static tripod, it is quite amazing that detail can be seen like the spiral structure.

M51 200mm 12800 343fr.jpg

M51 at 200mm with more structure detail.

This one at 300mm focal length shows more structure detail.

The Whirlpool Galaxy at 300mm focal length. This one is 715 frames stacked on a moonless urban location.

M51 300 715 closeup.jpg

Messier 51 at 300mm focal length.


If you have the usual 18-55mm kit lens you can still image deep space objects, but the small ones like galaxies will appear small. Still even at this scale they are still recognisable.

At 55mm the deep space objects are really small, but still can be seen. The image below shows the scale at 55mm.

M51 324fr 55mm 6400 labelled.jpg

324 stacked frames at 55mm, ISO 6,400


This image is zoomed in showing the Whirlpool Galaxy from the above image. As you can see. The galaxy is a smudge with little detail as the whole galaxy is only a few pixels wide at 55mm focal length.

M51 324fr 55mm 6400.jpg

The Whirlpool Galaxy 55mm zoomed in



For more deep sky images without using a telescope or tracking mount check out the DSLR with tripod Deep Sky Astrophotography picture album here

So go out have a go and let me know how you get on. This technique should be able to image all of the Messier list objects (Click the link for more information on what the Messier list is). This is a great way to start out in Astrophotography very cheaply if you own a DSLR camera already. See if you can image the entire Messier catalogue and please send me your images or post them on my Facebook page.


My Equipment

Here is the equipment I use:

DSLR equipment.jpg


Nikon D3100 DSLR Camera with 18-55mm kit lens

Nikon 55-300mm Telephoto lens

Joby Gorillapod tripod

Remote Shutter Release


All the equipment required is listed below. If you purchase anything I will receive a small commission at no extra cost to you.



Looking for Part 2: Stacking Your Images

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Related Posts: Astrophotography

Liked this? Try: How to Image Jupiter Cheaply With An Iphone

Or Visit the DSLR on a Tripod Deep Sky Astrophotography Album

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