Digital Astrophotography And Imaging

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There have been remarkable advances in digital photography over the past few years. Almost everyone now has a digital camera and photographic film is disappearing.

For amateur astronomers, there has been a revolution is observing methods.

Digital photography (or imaging as it is more usually called), has brought capabilities within the reach of amateur astronomers that were previously available only to professionals.

Nowadays, every astronomy magazine you pick up and every website you visit, contains numerous, often excellent images of night sky objects.

Let us examine some of the key aspects of digital astrophotography and imaging.

Sensitivity

Modern digital cameras and imagers are much more sensitive to light than the human eye. It its therefore possible to capture digitally, much fainter detail than you can see yourself, through a telescope.

Ease Of Use

Previously, photographic film was used for astronomy imaging. Digital technology is so much easier to use.

This is mainly because you can see immediately on a screen what you are capturing, allowing you to adjust the set-up to improve the results.

Also, there is no cost for film or processing, of course.

Recording And Publishing Images

Digital astro-imaging allows us all to easily record our observations acurately.

Previously, most amateurs had to rely on sketchbook drawings and written notes. This was perhaps good for sharpening your observation skills, but could be innaccurate, to say the least.

Also, digital images can be easily published on screen or website for other people to examine.

Stacking And Enhancement

By using freely available software, you can enhance your images by “stacking” multiple frames that are captured by the devices. This often produces a remarkable enhancement in the final image.

I use the free stacking software called Registax. It is a wonderful piece of work, to be provided for free to amateur astronomers.

Let’s say you have captured an image of an object with a webcam. The image will be saved as a video file on your computer.

What you do is load the video file into Registax and then select one or more “alignment points”. For example, if the image is of an area of the Moon, you would use a crater for alignment.

The software then analyses each image frame and uses the alignment points to stack them. It then combines the frames, by using the best parts of each.

This process can compensate for telescope tracking errors and variations in seeing conditions, producing a final image that is far superior to the individual frames that were originally captured.

Equipment And Cost

The cost of imaging equipment has reduced dramatically.

You can get excellent results with bright objects like the Moon and planets, just by using a decent webcam costing about £50, attached to a telescope.

It is even possible to capture some images with a simple, fixed lens digital camera that most of us have.

However, for deep-sky objects which are much less bright, you will need either a digital slr camera, or preferably, a specialist CCD imaging device intended for astronomy. Each of these options will cost a few hundred pounds or dollars.

Summary

In some ways, it is a shame that digital imaging is taking over from traditional “eye at the eyepiece” observation.

However, digital astrophotography and imaging brings remarkable capability to the amateur astronomer and I think that the new technology should be embraced.

With a modest telescope and relatively inexpensive digital imaging equipment, you can now produce images to be proud of.

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