Getting Started

Planetary imaging has never been easier yet there are a few things to learn. You can learn the easy way or the hard way. The easy way is to find out what other people know. One of the best resources is this Cloudy Nights forum:

Solar System Imaging & Processing

Of course there are also a lot of YouTube videos on the subject. Here are mine.


Introduction

In this first video I give a brief introduction to planetary imaging. With the advent of digital webcams we can now take pictures of planets from our driveway using amateur size telescopes that are much better than was possible using the monster ground-based telescopes of the 1990’s. When we use the optimal Barlow we will end up with a picture of Jupiter that is around x pixels in diameter where x is the size of the telescope in mm. For example, an 8″ scope (around 200mm) will give us a picture of Jupiter that is around 200 pixels wide.

 


Equipment needed

In this next video I talk about some equipment you will need for planetary imaging: camera, computer, telescope, Barlow, and a mount. For the camera I recommend getting a webcam that has been specifically designed for planetary imaging as opposed to using a DSLR or modified Skype webcam. Life is easier if your computer has Windows. Almost any crummy laptop will work for capturing but you will want a more powerful computer for stacking and processing your final images. For the telescope bigger is better. Still, it is amazing what can be done with small telescopes. Check out the pictures people have taken on these forums on Cloudy Nights:

Small bore challenge: Saturn w/ 6″ or less

Small bore challenge: the Moon w/ 6″ or less

Small bore challenge: Jupiter w/6″ or less

Small bore challenge: Mars w/ 6″ or less

Uranus & Neptune – small bore challenge?

Small bore challenge: Venus w/ 6″ or less

The optimal focal ratio is a function of the pixel size of your camera. This post on Cloudy Nights explains.

Optimal focal ratio = 5 x pixel size (in microns)

If your camera’s pixel size is 3 microns then you should try for 5×3 or f/15. It appears that in practice you should use 7 instead of 5 so for the camera with 3 micron pixels you should aim for f/21 instead of f/15. This is only to get you in the ball park.

You can use just about any mount but things get tricky if you don’t have a mount with motorized tracking. An alt/az mount is fine but in the video I show how the equatorial mount is preferred if you want to make animations.

 


DSLR

The purpose of this video is to show you how planetary imaging is different than what you’re used to with a DSLR. The reason we can now get good pictures of the planets (compared to a few decades ago) is due to lucky imaging which relies on getting several thousand frames before the planet rotates too much. A webcam is ideal for this. If you want to use a DSLR you have to get it to work like a webcam.

If after watching the video you still want to try your hand using a DSLR then you might want to check out this link to an eBook showing how.

A Guide to DSLR Planetary Imaging


Which webcam?

In this video I talk about a few webcams which are available and the ones I think are the best. I only consider color webcams but some of the color ones have a monochrome version also. For under $200 the best (and only ) webcam I recommend is the NexImage 5. After that it seems that everyone is going for the webcams by ZW Optical. Visit the Cloudy Nights forum to see what people have to say about the cameras.

 


Which Barlow?

This video probably doesn’t have anything useful (for knowing how to get good pictures) beyond this rule of thumb formula:

Optimal focal ratio = 5 x pixel size (in microns)

I’ve learned from spending a lot of time at the Solar System Imaging & Processing forum that the 5 in the formula should probably be 6 or 7.

More optimal focal ratio = 7 x pixel size (in microns)

For example if your camera’s pixel size is 3.75 microns then you want to get a Barlow that will give you around f/26 (7 times 3.75 equals 26.25).

What you will hopefully find in the video is insight. You will understand why you don’t want a bigger or smaller focal ratio. I also show how I came up with the formula for how big Jupiter is.

Jupiter size (in pixels) = telescope size (in mm)