This question is difficult to answer in simple terms as there are a number of variables that factor into the equation.

Obviously we want to see you succeed in your observing runs, and we want you to have confidence that you are not wasting your time in your endeavor. To that end will we do our best to give you some simple guidelines and a couple of test cases to help you determine if your equipment is up to the task.

Remember... Patience, skill and perseverance are far more important than deep pockets in a search of this nature.

If the FAQ proves to be too nebulous and you are looking for a definitive "Go/No Go" then check out our test cases. They should help you determine with just one image if you can pull it off.

Bigger is better and the benefits are obvious (my favorite is "shorter exposure times"). What we really want to know here is how small is too small?

We've seen images from both a 12.5" reflector and 5" refractor that show enough whispy nebulosity from our test cases to be convincing. We are looking for examples from more modest systems, but these are our bench-marks for now.

Remember, what is practical and what is possible are rarely the same (we're leaning toward practical), so if you feel you can get it done with something less than our bench marks then by all means give it a go. We are rooting for you!

Bit depth is the first measure we look at. 12-bit is the minimum, and 16-bit is better.

Consistent dark fields are also important. If the amount of noise in your images is variable, the light echoes will be much harder to detect. To that end, the ability to consistently set your camera's operating temperature is a must.

Those are the only hard requirements we have for you. Larger chips allow for larger field sizes, more efficient chips allow for shorter exposures, and so on.

You should have a reasonably consistent point spread function. Every element of your system will influence this but the biggest factor will be seeing. Disregarding seeing, you want your PSF to be minimal.

A filter helps. Specifically a filter that cuts off beyond 700nm

• Anstronomik IR-Cutoff Filter
• OPT IR Blocking Filer
• Baader 1.25" UV / IR Blocking Filter

Test #1 - IC 426 in Orion

• Using this lovely finder image, locate and image IC 426.
• Right ascension: 05h:36m:28.00s, Declination: -00°:16':36.0"
• We will be posting data referencing this image and calling out details that you should be able to make out in your own images.
• A closer look at IC 426 can be found here.