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How to Modify a Webcam for Astrophotography

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How To Make Your Own Web Cam Astrocamera

This page explains how I modified a Logitech Quickcam Express webcam for astrophotography. It should be general enough to apply to just about any inexpensive webcam. If you enjoy do-it-yourself projects, this is a fun alternative to purchasing a ready made webcam conversion like the Orion StarShoot Solar System Color Imaging Camera IV.

All you need is the type of little web cameras mounted in a ball that sit on your computer. Sorry, I no longer have the original housing, but hopefully you get the idea of how to do the conversion from the description on this page. Even should you opt to buy a ready made conversion, this page will show you what you're basically getting.

To make a device that's great for taking lunar and planetary photographs, you only need an inexpensive webcam version, like the Logitech Quickcam. You'll also need a T adapter like that often used to mate a 35mm SLR camera to an astronomical telescope.

This type of camera will not likely let you take photos of deep space objects, because most web cameras have exposure times only in the fractions of a second. But the moon and planets are definitely within reach with such a device. Add an old laptop to run the camera when in use, a copy of Registax for processing avi files or snapshots, and you'll be in business.

In the years since I made my modified webcam, which still works and gets some use, Celestron has introduced a well priced webcam astrocamera called the Celestron NexImage. The NexImage, now replaced by the Orion StarShoot Solar System Color Imaging Camera IV, comes packaged with a recent version of Registax, a program for Windows that lets you stack images. I have a Celestron NexImage, and can verify its usefulness.

The image at right is an example of what the Celstron conversions can do. I took this image using the NexImage coupled to my ETX90. It caught the Great Red Spot, but also shows the disappearance of the SEB in 2010. Maybe it's my imagination, but I think I see hints of some festoons in the image. The ETX 90 is getting hard to find, but a comperable telescope at a good price is the popular Celestron NexStar 90SLT Mak Computerized Telescope (Black). I rather suspect you could get as good of photos with the Celestron, as I have with my aging Meade ETX 90.

Jupiter And GRS Through ETX90


Astrocam Assembly Diagram


Linux Survey

At left is a diagram of the webcam modifications.

Inside the webcam housing is usually a single circuit card, hosting the CCD array in the center of the card.

If you have machining equipment, you can make a really nifty astro-camera. Not being a machinist, I had to find a simpler way.





I had a simple camera T-mount adapter, like the Celestron 93625 Universal 1.25-inch Camera T-Adapter, which is great for mounting a 35mm SLR camera to a standard 1.25" focuser. This adaptor is just a 1.25" barrel that has a T thread for a mounting.

With a T adaptor for one's particular 35mm camera, this snout allows easy prime focus photography.

I was able to find an old soft-plastic pill bottle that was the right diameter to snuggly fit over the T thread. I cut off the bottom inch or so of the plastic bottle (discarding the top), cut a 1/2" hole in it to allow light to reach the CCD array, and screwed the pill bottle end onto my T thread adaptor.

I also fabricated a simple cover over the back of the circuit card, and hurray, I had a CCD camera for astrophotography.



Astrocam Parts

This image will help clarify my diagram and description.

On the left you see the modified webcam astro-camera. The white part (blackened inside) is the plastic pill bottle end. You can see the hole cut in the bottom to expose the CCD array (the square).

The pill bottle is just the right diameter to tightly fit over the T-threads of the camera to focuser adaptor, shown on the right of the picture.

You can see that with electrical tape and some thin cardboard (like poster board), I fabricated a simple cover over the rear of the astro-camera.



Assembled Astro-camera

At left you can see the assembled astro-camera. The snout slides exactly into a 1.25" focuser.

The USB cable is plugged into a computer during use, and I run the vendor supplied webcam software to make the exposures.

My camera is only suitable for the moon and planets, in that it doesn't have the capacity for long time exposures.



Astro-camera on Telescope

This is a image of the webcam astro-camera mounted to my Meade ETX90. As you can see, it simply slides into the focuser instead of an eyepiece.

If I need more magnification, I insert a barlow lens first, then the webcam.

Individual pictures can be taken with the webcam, and is the technique I used for most of the images displayed on my photography pages (I was still learning).

However, I've found that what works better is to use the astro-camera to take movies (avi files). Small clips of 2 to 4 seconds.

Since the camera takes about 10 images per second, a few seconds gives me plenty of images to work with.

Then I use an image selection and averaging program to combine the frames of a film clip into a single image. This technique helps reduce atmospheric turbulence and pixel gain errors of the camera.

Note, this technique can't really overcome a bad seeing night, but can certainly help reduce the residual turbulence on a good night.



Webcam Astro-camera Result

At left is my best Mars image, taken during the 2003 opposition with my Meade ETX90 and the modified webcam astro-camera.

I believe it to be a rather remarkable photo with such a modest instrument. It is a stack of 48 frames taken from an avi file. For this image I used the Image Stacker program.

I used to use the Image Stacker or the RegiStax program for stacking frames from an avi file. Now I use a Yorick script of my own design, and some ImageMagick tools in Linux.

I've taken a number of pictures with my ETX 90/web cam setup. You can see the gallery at ETX Astrophotos. I've also taken some images through a 60mm refractor, and the detail obtained surprised me. Check them out at 60mm Astrophotos.

Web cams have a small CCD, so the field of view it encompasses is also small. Getting moon images is easy. If I see the moon in the finder, some portion of the moon is also in the camera. I use my handy added slow motion control on the Meade ETX90 to move to the part of the moon I want.

Planets are tougher. I may have the planet in the finder, but I often can't find it in the camera. I've gotten around this with the Meade ETX90 by removing the rear plug and putting in another eyepiece. Using the flip mirror, I can look through the auxiliary eyepiece to center the planet, then flip back to the camera.



Final Comments

If you are interested in constructing such a device, I suggest you try with an inexpensive webcam. I paid (a few years ago) about $30 for mine. I figured if it lasted long enough to give me a bout 3 rolls of film worth of pictures, it was worth the expenditure.

I've been lucky. My little webcam is still working.

To get the most out of your photographs, it helps to keep track of upcoming targets. The moon is one of my favorites. Best moon photos are obtained when your targets of choice are near the terminator. A good planning tool for lunar photography as well as lunar observing is the software package Xephem, shown in some detail at my Xephem Review page.

Jupiter is one of the best targets for planetary photography. It is bright enough (Saturn is kind of dim) and big enough (Mars is kind of small) to make a good target. Some prior planning here is also helpful in order to get a shot of the Great Red Spot, or some transiting Jovian satellite. For my Jupiter observing and photographing guide, I again use the Xephem software package.


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