How to clean Astronomik filters properly
When cleaning optical surfaces, it is usually essential to handle them with extreme care to avoid scratching or damaging the coating. However, Astronomik filters have an exceptionally hard coating that is extremely scratch- and moisture-resistant and will not degrade over time. This makes the cleaning process much easier and less stressful.
Here are some tips for cleaning Astronomik filters properly. By following these steps, you can keep your Astronomik filters in pristine condition without fear of damaging them.
Recommended cleaning tools
- Soft brush: Ideal for removing loose dust.
- Microfibre cloth: Great for gently wiping away fingerprints or smudges.
- Lenspen: Useful for persistent small stains.
- Optical grade cotton cloth: Used with isopropanol for thorough cleaning.
- Isopropanol (pure, from the chemist): For persistent stains.
Removing dust
Use a soft brush to gently remove dust from both sides of the filter. This simple step is usually enough to keep your filter clean.
What to avoid
- Manual bellows or untreated compressor air: These can blow more particles onto the filter or deposit water and oil droplets. This will not damage your filter, but there will be a lot more dirt to remove.
Removing fingerprints and smudges
To remove fingerprints and similar residue, wipe the surface with a high quality microfibre cloth, applying light pressure and moving in straight strokes. It is helpful to mark one side of the cloth for handling and the other for cleaning to avoid transferring grease back to the filter. Wash the cloth regularly to remove accumulated oils.
If fingerprints persist, dampen a piece of optical grade cotton cloth with pure isopropanol (from your local chemist, choose the best grade of purity) and gently wipe the filter’s surface. A small bottle of 100ml will last forever.
For small, stubborn stains, a lenspen is a handy tool.
What to avoid
- Distilled water: It evaporates slowly and can seep into the filter frame by capillary action.
- Special optical cleaning solutions: The generally unknown chemical composition can be harmful to the filter or cells and cause irreversible damage.
Safe handling of isopropanol
Isopropanol is a volatile, highly flammable liquid with a strong disinfectant odour. It forms highly flammable vapour-air mixtures and may cause dizziness or irritation of the eyes and mucous membranes upon direct contact. Always ensure that your work area is well ventilated and follow the safety instructions on the accompanying pharmacy data sheet.
