STEP BY STEP
STEP 1
A common error made when framing a Moon image through a scope’s diagonal is to have it mirrored. Two features give basic orientation during the lunar cycle: Mare Crisium in the east and dark-floored Grimaldi near the western limb. With north up, Crisium should be to the right above the horizontal centre line. Grimaldi should be to the left below the centre line.
STEP 3
DSLRs and other types of digital camera have histogram displays to help get the perfect exposure. The basic rule is to keep the main data block within the edges of the graph, avoiding sharp ‘cliff’ edges at either end. For high frame rate cameras, the control software should display a live levels meter. Keep this between 70-80 per cent of peak.
STEP 5
Multiple image captures need to be registered and stacked. Using freeware Autostakkert (www.autostakkert.com), click Open and select capture file. For close-ups, select surface. Hold Ctrl and left click on a welldefined feature. Click Analyse. Set the ‘Number of frames to stack’ and ‘Frame percentage to stack’ boxes – try 20, 30 and 40 per cent to start.
STEP 2
Take your time focusing. Slowly approach the point of focus from one side and move past it to defocus the image. Then reverse direction and repeat the process. When you’re confident you know where focus is, snap to that position. Get into the habit of checking focus often as temperature variations can move the point of focus slightly.
STEP 4
A monochrome, high frame rate camera works best on the Moon as you can avoid complications due to atmospheric dispersion that can cause colours to misalign. Fitting a red or infrared pass filter restricts the colours entering the camera to avoid this. These filters also stabilise the view as longer wavelengths are less affected by atmospheric seeing.
STEP 6
Select a small alignment point (‘AP Size’) and click ‘Place AP grid’. If shadowed features aren’t covered, lower ‘Min Bright’ and click ‘Place AP grid’ again. You can also add AP boxes by clicking on a feature. Press the Stack button. When processed, the results are stored below the movie folder. These may be sharpened in an image editor.