The technology of webcam astrophotography is only a few years old. In this time it has rapidly developed from short-exposure 6-bit per channel black-and-white images to long-exposure 16-bit images in full color. This new technique is competing well with conventional astrophotography. Increasing numbers of amateur astronomers are turning to webcams to display their excellent images.
The great news is that you don’t need a lot of money to take up webcam astrophotography. The price of a webcam with a CCD chip (the chip is essential) is roughly equivalent to that of a reasonable eyepiece. In fact webcams are much cheaper than many conventional cameras and CCDs. You can download software free for the purposes of controlling the camera and processing the images. The only other things you need are a tracking telescope and a computer.
It is fairly easy to get started with webcam astrophotography. You just need to remove the lens off your webcam, and point it through your telescope where the eyepiece would normally go. The software that is provided with your webcam can be used to take AVIs. But to convert AVIs to images you will need to download free imaging software such as Registax or K3 CCD Tools, which are easy to use.
A Barlow lens is the best method of magnifying your webcam images, but you can capture AVIs using prime focus (without eyepieces or a Barlow) – you only need your telescope and webcam. The prime focus method is only suitable for the Moon, Mars Jupiter and Saturn. Whatever your telescope’s focal ratio is (say f/8) that’s what the focal ratio of your AVIs will be.
After trying webcam astrophotography and deciding that you want to continue it is a good idea to invest in high-quality 2x and 3x Barlow lenses. With a 2x your AVIs will be captured at f/20, and with 3x they will be captured at f/30 – that’s if your telescope has a focal ratio of f/10. You do not need to buy any other lenses, filters or software.
You definitely need a webcam with a CCD chip. Some good examples of astronomical webcams are Phillips Vesta Pro, Phillips Toucam Pro and Logitec Quickcam Pro 3000 or 4000.
You do not really need any special telescopes to do webcam astrophotography. However, webcams are especially suited to high magnification imaging of the Moon and the bright planets. This means that a telescope with a longer focal length is preferable. Because a webcam’s imaging chip is very small, objects tend to drift out of the field of view fairly rapidly. A clock-driven telescope can greatly assist with combatting this problem.
Apart from Registax, Astrostack is a good free webcam image processing program. Adobe Photoshop, which is fairly pricey, can assist with fixing up images.
Webcams have the advantage of utilizing USB Plug-and-Play technology which makes them easy to install on your computer, and image download times are fast. The great thing about webcams is that they provide real-time feedback. This allows you to adjust focus and exposure as you go to get the best results. Also there are no hassles or costs associated with film developing.
With webcam astrophotography you can create nifty animated images and movies of changing astronomical events such as the movements of Jupiter’s moons, or watch lunar eclipses of stars and planets. Because of the digital nature of webcam images they can be printed, posted online, or emailed with no need of developing or scanning. Because webcam images are in color you do not need to spend time with the hassle of tri-color. Also, a webcam can take multiple individual exposures of an object in a night, without you having to do anything.