Processing Sky Dust

Removing Sky Dust from a Collector with Water,
mounting on microscope slides.

This procedure will remove sky dust from a nylon collector using spray bottles filled with water.
It's simple, easy, and uses materials found in every home.

Click HERE to open a printer-friendly PDF version of these instructions.

1. Gather and prepare your materials first.
   • Prepare the filter (photo).
     • Cut both ends from a coffee can.
     • Cut the center from the plastic coffee can lid leaving a quarter inch lip around the top.
     • Tuck a 3.5-inch basket-style coffee filter into one end of the coffee can. Fold a half-inch of filter over the rim of the can (photo).
     • Snap the cut plastic lid over the rim of the can to hold the filter in place (photo).
   • Prepare cardboard sheets.
     • You will need two sheets of single-ply cardboard for each filter. A good source is the front and back of cereal boxes.
     • Use kitchen shears to cut the cardboard panels (photo).
   • Prepare the glue mixture.
     • Mix an equal amount of water with any brand of white glue (photo).
     • This step is best done just before you cut the filter in step 5, below.
   • Gather quart-size plastic zipper bags, kitchen shears, pump spray bottle(s), fine tip indelible markers, microscope slides, masking tape, white glue, razor blade or sharp craft knife, and pencils.
     • The quart-sized plastic zipper bags are used to store anything that might otherwise get contaminated.
     • Use pencil to write identifications around the rim of dry filters before they are used. Pencil won't bleed, and it's nearly impossible to write on wet filters.
     • Use indelible marker to label plastic zipper bags.
       
2. Carefully peel the tape from the nylon collector (photo).
   • Place a finger on the nylon and peel the tape toward the pool end of the strip.
   • Try not to disturb the collector.
     
3. Lift the collector from the kiddy pool and hold in position for rinsing (photo).
   • NB - this takes four people!
   • Have two people hold the collector as shown in the photo. One end must be lower than the other.
     
4. Rinse the sky dust into the filter (photo).
   • Have a third person hold the low end of the collector over the coffee can filter with one finger and the other thumb (photo).
   • The forth (or more) person rinses the collector with a spray bottle filled with clean water (photo).
   • Rinse systematically down one side from top to bottom. Then do the other side.
   • Finally rinse the bottom fold toward the coffee can filter.
     
5. Remove the filter and sky dust from the coffee can holder.
   • NB - wash your hands first!
   • Write the identification data on a plastic zipper bag with an indelible marker.
   • Carefully pry the plastic rim from the coffee can filter holder.
   • Lift the filter by its rim so that it forms a little pocket (photo).
   • Slide the filter into the labeled plastic zipper bag (photo).
     
6. Cut and mount a strip from the center of the filter.
   • Place three microscope slides side-by-side on the unfinished side of a sheet of cardboard.
   • Use two strips of masking tape to tape the ends of the slides to the cardboard.
   • Carefully lay the still-damp filter flat on the unfinished side of a sheet of cardboard (photo).
   • Use kitchen shears to cut a two-inch wide strip from the center of the filter. Cut the filter and cardboard together (photo).
   • Smear a thin layer of the white glue mixture prepared during step 5 on the slides (photo).
   • Carefully lay the cut filter strip on the slides, dust side up, so that the strip passes over the center of the slides. This will leave a half-inch of each slide end uncovered (photo).
   • Discard the cut cardboard.
   • The glue will be on the down side of the filter and will wick up as it dries. This will glue the dust to the filter without covering it with a confusing film.
   • Set the slides in a protected place to dry. Avoid contamination by providing a raised cover.
     
7. Separate the slides for viewing.
   • When dry, use an indelible marker to label the end of the slides with an identification mark.
   • Use a razor blade or sharp craft knife to cut the slides apart.
   • Place the slides in a labeled plastic zipper bag until ready to observe. Be careful not to cause one slide to scrape the surface of another.

For participants interested in collecting with greater precision and resolution, please contact us for procedures using vacuum-pump filtration and sterile forensic tape.