Webcam Tips

Ok, so I haven't exactly been doing webcam astrophotography for very long but there are some key things that I've figured out pretty quickly.

1. Set up your equipment so that you'll be comfortable
You could be outside for several hours and there are enough things to be doing without grappling with your equipment. Make sure that you have your laptop on a table at a good height and your chair positioned for easy access to both the laptop and the eyepiece. I try to position the telescope at a height that makes it possible to use an eyepiece without needing a diagonal. This minimises the amount of focussing when switching between eyepiece and webcam, which in turn makes it easier to get the target in the field of view of the webcam.

2. Get an UV/IR blocking filter for use with the webcam
It makes for a better image, makes it easier to focus the target and also eliminates the worry of getting dirt onto the webcam chip.

3. Spend the first couple of observing sessions just getting used to the webcam and settings
Try things out, get used to having the extra equipment around and take some videos so that you have something to practice post-processing on.

4. Tend towards under-exposing rather than over-exposing
The default webcam settings will probably over-expose the image. This is fine while trying to locate the target but once found it's best to turn down the gain and/or increase the shutter speed. Increasing the frame-rate is also beneficial.

5. Focus is crucial
If the target isn't focused properly then the final image will suffer for it. Once you've got the right webcam settings, spend a few minutes finding the best possible focus.

6. Get a good number of frames to process
My webcam takes videos at 15 frames/sec and I aim for 4 minutes of material which means around 3600 frames.

7. Let your telescope reach thermal equilibrium before observing
Sometimes it can be a pain thinking about it in advance but it does make a difference if the telescope has been sitting outside for an hour or so before you start taking videos.

8. Get decent alignment on your finderscope
It's never going to be perfect but if you're searching for the target with the telescope than you'll have problems finding it in the webcam. If it's on the cross hairs of the finder than it should be in the field of view of an average eyepiece.

9. Watch how the target moves across the field of view
Getting the target in the field of view of the webcam when using a Barlow is not always easy. I've had most success by positioning the target on the edge of the telescope field of view so that it will move through the centre of the field of view a few seconds later. This gives me enough time to switch the eyepiece for the webcam and wait for the target to appear. This is the only way I've been able to find Mars with a 5x Barlow.

These simple techniques have greatly improved my webcam imaging as we'll see in my next post.