Do you want katana sharp lunar images? Here are the three sharpening stones:
Weather degrades lunar resolution
Earth’s atmosphere constantly boils with activity, it’s amazing we can see anything at all! The real skill is being able to read the weather—not necessarily how you image the Moon. All things being equal: you need to be able to distinguish between poor, average and excellent seeing conditions. You will have an edge over someone who neglects this skill.
You can have the best gear in the world, but if you set up shop during a hurricane, your images will be softer than a snail’s forehead.
You want katana sharp images, right? Don’t photograph the Moon during poor seeing conditions.
Ha! Did you think it was that simple? Turbulent weather is only part of the equation. The other part is called ‘transparency’. Earth’s atmosphere contains all sorts of junk…car exhaust…volcano puke…dust…dirt…all kinds of shit. As you can guess, this “shit”, has a tendency to smear lunar images.
**Secret Knowledge: Thunderstorms temporarily scrub away disgusting atmospheric pollutants. **
You can’t control the weather (I hope). Do you know what you can control? Focus!
Focus (0 magnification)
Magnify Image (10x) —Focus
Zoom in as much as you possibly can. Keep in mind—zooming in on the camera will exaggerate atmospheric turbulence. The image may be blurred, depending on the seeing and over all restlessness. Your ability to finely focus will be tested, again, depending on the atmosphere’s mood.
Don’t be afraid to spend some time to achieve an optimum focus. If you happen to be using a catadioptric telescope, make sure not to twist the focus knob too much at once, doing so will ensure that you slightly de-focus the image. Don’t twist your knob too much! Got it?
Periodically check your focus. You may discover that you didn’t do such a great job. Maybe the weather calmed down, maybe you twisted your knob too much, who knows. The point is: check your focus.
Got that? Check your focus.
Truth be told: the Moon is pretty damn bright.
Mind your exposure! Too much light will wash out lunar detail
It would be a shame to take advantage of premium weather, only to over expose all your precious photographs. Wouldn’t that make your eyes bulge out of your face? Don’t let that happen.
Generally speaking—exposing the Moon is pretty straightforward.
For example: if the Moon fills the frame, and it happens to be full, do not expose any longer than 1/100 sec. (ISO 100). If the moon has entered either of its quarter phases, you can get away with a longer exposure time.
If you compare the three full Moon images I provided, you’ll see the difference a change in exposure can make. A little change in exposure has great consequences over lunar images.
The same principle applies to lunar crescent phases.
I recommend starting at 1/100 sec. (ISO 100, prime focus) and adjusting your exposure as you see fit (depending on personal choice and lunar phase).
If you’re imaging the Moon with a wide-angle lens, the exposure must be quicker compared to an image taken at prime focus.
Fill the frame as much as possible.
If possible: set your camera’s ISO to 100. Noise degrades lunar resolution as bad as undesirable weather.
** Bonus Tip** Take as many images as possible. Magnify each photograph and check for overall resolution issues—you’ll notice some parts of your images may be sharper than others.**
This three-step process will hone the edge of your lunar images, resulting in lacerated eyeballs.
As for post processing, feel free to apply an unsharp mask, but watch out for artifacts—it’s very easy to ruin a viable photograph. The image at the end of this post is at the threshold of being overcooked.
I’ll discuss more about post-processing (when I’m less lazy).
There are many ways to image the Moon. Don’t take what I have to say as absolute gospel. If you have any questions: feel free to leave a comment (or email me) and we’ll try to solve any issues together.