Solar Balloons

•July 26, 2014 • Leave a Comment

Solar hot air balloons are a great addition to any outreach event. You can purchase one online for as little as a few dollars or make your own using thin trash bags or sheets of polyethylene.

The heated air inside the balloon expands, making it less dense than the cooler ambient air. This causes the balloon to float. While conducting science experiments, kids can learn the basics on how the balloons generate lift, solar radiation, and solar energy.

Most balloons I’ve seen are shaped like long, slender tubes (sealed on both ends), tear drops (your typical hot air balloon) or tetrahedrons (also referred to as tetroons). But don’t let that deter you from making unique designs of your own!

The best time to launch is in the morning on a calm day while the ambient air is cool.

Materials needed for a tube-shaped balloon

5-7 thin black trash bags (0.3-0.4 mil)
Lightweight, strong tape
Lightweight string tied to a rubber band on one end, a piece of cardboard on the other


Step 1
Cut away the ends of all but one of the bags.

Step 1

Step 2
Starting with the bag that has the uncut end, overlap two bags by placing the end of one bag inside the other by an inch or two.

Step 3
Tape the seam. I used black duct tape that I split in half lengthwise. Cellophane tape would have been better because of its light weight. I’ve read where other people use masking tape.

Step 3

Step 4
Continue steps 2 and 3 for the remainder of the tube.

Step 5
Prepare the tie-down string by tying one end to a rubber band, the other to a piece of cardboard

Step 5

Step 6
Fill the bag with air using a hair dryer or fan.

Step 6

Step 7
Seal the open end with the rubber band.

Step 7

Step 8
Wait for the Sun to warm the air inside of the balloon, then watch it float!

Step 8

Step 8a

Step 8b

For more information about this topic, visit

Solar-powered Robotics for Outreach

•July 24, 2014 • Leave a Comment

Are you looking for a fun way to incorporate solar power into your outreach events? I ran across a robotic kit from Edmund Scientifics called Solar Space Fleet and had a blast using it at my last outreach event.

Per their webpage -

Transform and Power Your Own Space Command

The Solar Space Fleet Kit is an innovative solar powered science kit that can transform into seven different lunar modules and energized via direct sunlight or micro rechargeable battery.

For just under $26.00, the kit includes an easy-to-follow, 46-page instruction manual, decals, a solar panel, rechargeable battery, battery module and all the parts to build 7 different robots. Not included are AAA batteries (2 are needed for the battery module when not using solar energy), a utility knife and/or diagonal cutters to remove burrs before assembly, and little helpers keen to assist you!


First up is assembling the landing gear, front wheel, solar module and battery module. Next are the gear boxes.

The individual robots share parts, so each will need to be disassembled before building another module. A few examples are shown below. The robots’ actions vary with each module: spinning, turning, walking, or rolling forward.

Edmund Scientifics has several educational toys to choose from that are geared for alternative energy. Make sure to check them out and see what you’d like to include in your outreach program!

2014 Mar 20 – June 20, Solargraphs

•June 22, 2014 • Leave a Comment

The final three pin-hole cameras for my solargraphy experiments were taken down late Friday, the night before summer solstice. One of the cameras (positioned upright for a landscape view) was angled too low and very little of the Sun’s path could be seen. The other two were positioned on their sides to catch sunrise and sunset each day.

2014 0320-0620

When comparing the camera’s view to the processed photographic paper, you’ll notice that the view is mirrored.

2014 0320-0620 camera 2

All seven pin-hole cameras were reloaded with Ilford Multigrade IV RC Deluxe MGD.44M Black & White Variable Contrast Paper and positioned in their new locations in time for sunrise on June 21st–summer solstice. I’ve adjusted their angles to include a higher arc in the sky. This set will stay up until winter solstice on December 21st. Fingers crossed!

Related topics:

Solargraphs, how to make 6-month exposures by Justin Quinnell
Tarja Trygg´s website of The Global Project Of Solargraphy

Making a Solar Shade for your Scope

•June 17, 2014 • Leave a Comment

Solar-shade-1Observing in direct sunlight has its challenges, especially when using a narrowband solar filter. Stray light around the eyepiece affects the dark visual adaptation needed to pull out the faint limb details, similar to stray light affecting your nighttime view of deep sky objects.

To improve contrast and reduce glare, I incorporate the use of both a solar cloth (pulled over my head and eyepiece holder) and a solar shade that fits snuggly over the optical tube assembly (OTA). Both are fairy easy to make and you can even purchase manufactured versions of them. Dark Skies Apparel makes unique, top quality observing hoods and solar observing vests designed with pockets to hold spare eyepieces, pencils and glasses.

Here’s how to make the solar shade pictured above.

Materials needed

  • large black foam board, 20 x 30 x 3/16 inch
  • white pencil and #2 graphite pencil
  • compass
  • tailor’s tape
  • measuring tape
  • utility knife
  • scissors
  • piece of cardboard or paper


Figure 1

Figure 1

Figure 1
Create a template for cutting out the hole of the foam board that will fit over your OTA or filter. To do this, determine the radius (r) of your OTA or filter. Start off by measuring the outer circumference (c) of your OTA or filter (in most cases, it will the energy rejection filter, otherwise known as ERF). Mine was 28.5 mm.



Figure 2

Figure 2

Figure 2
r = d/0.5
d = c/3.14
Diameter (d) = 28.5/3.14 which means that d = 9.1 mm. Radius would then be half of that, 4.5 mm. Set the compass to equal radius.




Figure 3

Figure 3

Figure 3
Create the circle template with the compass and cut out the circle just inside the line with a pair of scissors.






Figures 4 and 5
If you don’t have a compass, fold a sheet of paper in half both vertically and horizontally. The center of the paper will be marked where the folds cross when you open the paper back up. Place the end of the tailor’s tape at the center cross and mark the radius measurement on the paper with a pencil. Continue marking the radius until a complete circle is created onto the paper.

Figure 4

Figure 4

Figure 5

Figure 5








Figure 6

Figure 6

Figure 6
Use the measuring tape and white pencil to mark the size of the solar shade on the foam board. Mine was 16 x 12 inches, but you can adjust if needed for your preference. If it’s too large, the wind will become more of a factor. Too small, it fails to serve its purpose.




Figure 8

Figure 7

Figure 7
Use your circle cut out and white pencil to outline the OTA fitting onto the bottom of your foam board. It should be nearly 2 inches from the bottom edge.




Figure 7

Figure 8

Figure 8
Just inside the line, use the utility knife to cut out the circle. You may want to place a cutting board or something similar behind the foam board to protect the table surface.




Figure 9

Figure 9

Figure 9
Align your telescope so that the Sun can be seen through the eyepiece, then push the solar shade onto the OTA and swivel it to the side of the telescope where you’ll be observing.

Sharpening Pastel Pencils

•June 16, 2014 • 2 Comments

Sharpening pastel pencils can be tricky. The pastel center breaks easily and before you know it, you’ve sharpened the pencil nearly to the nub in one sitting! Here’s a tip to prevent breakage.

While using a sharpener, applying pressure to shave the wood leads to breaking the pastel easily within it, so use an artist’s or utility knife to expose the pastel first. The wood should be whittled smooth to prevent snagging. Try to make the wood circumference slender so that it fits easily in a normal-sized pencil sharpener. This especially holds true for larger pencils like Conte’. If you like, you can use the knife to roughly sharpen the pastel tip prior to using the sharpener. Next, use the smaller hole of the pencil sharpener to shape the tip and then finish it off in the larger hole for a precise point.

Good luck and please let me know if you have your own tips on sharpening pastels so that we can share them with others!

Whittle pencil wood to expose pastel

Whittle pencil wood to expose pastel

Wood should be slender and smooth so that it can turn easily without snagging in a regular-sized pencil sharpener

Wood should be slender and smooth so that it can turn easily without snagging in a regular-sized pencil sharpener

With minimal pressure, gently sharpen first in the smaller-sized sharpening hole, then finish off in the larger-sized one

With minimal pressure, gently sharpen first in the smaller-sized sharpening hole, then finish off in the larger-sized one

2014 06 04, Barocius along the Terminator

•June 15, 2014 • 4 Comments

2014 06 04, 0245-0449 UT Barocius along the Terminator
Erika Rix, Texas

102mm f/9.8 refractor, LXD75, 12mm Burgess, 2x Barlow, 167x
78F, 56% H, Antoniadi I with moments of II near end of observation, T 5/6

Barocius (center crater along terminator)
Type: crater
Geological period: Nectarian (From -3.98 billion years to –3.85 billion years)
Dimension: 85 km
Height: ~3500 meters
Damaged circular formation on the SE slope of Maurolycus.
Rukl map: 66 Maurolycus

The Moon’s southern terrain used to intimidate me, but these days I welcome the challenge to sketch larger sections of it during my observing session. Drawing highlights rather than shadows saves time. This is especially true along the terminator, since using black paper means that the shadowed area of the Moon is already completed for you!

If you want to tackle large, complex areas while lunar sketching, make sure to increase your drawing area. If it’s too small, you’ll have a difficult time filling in the details with a sharp stroke. My sketch area was a little smaller than normal and it’s painfully obvious by the soft, blunt appearance of the final sketch.

Eyepiece sketch on black Strathmore Artagain paper, white Conte’ crayon and pastel pencil, black and white charcoal pencils. Sketch has been flipped so that north is up, west is to the left.

Solargraphy Experiments

•June 14, 2014 • 1 Comment

I dabbled in solargraphy years ago and decided to delve a little further into it for the vernal equinox. There are several websites with instructions to build your own camera. This set of instructions from Justin Quinnell closely follows my method. I drilled a hole in my cans and film pots rather than using a craft knife, and then filed the ragged edges of the hole with sand paper.

The first trial covered one solar day. The film pot was strapped upright to a fence and then tilted slightly upward to catch the height of the Sun’s path. Processing was simple – remove the film from the canister in a darkened room, place in a scanner and scan at high resolution. It was then inverted in Photoshop. This example shows both the scanned and inverted versions.
test camera 2014

photo paper
The paper I used is Ilford Multigrade IV RC Deluxe MGD.44M Black & White Variable Contrast Paper (8 x 10″, Pearl, 25 Sheets) and results in a cooler green/blue hue.

The smaller the hole, the crisper the sun paths are imprinted on the paper. I used a sewing needle. Make sure to hold the aluminum square up to a light to see if the needle actually went through it before attaching it to your camera.

IMG_4768 I made several cameras and put them up at various locations on March 20th, 2014. One or two of the cameras will be left until autumnal equinox for a 6-month exposure. A few others will be taken down on summer solstice.

I processed a few last night to test the locations and positions of the cameras. This is an example of solargraphy with a tin can pin-hole camera. The upright placement of the camera results in a landscape view. After inverting in Adobe Photoshop CS6, the exposure and gamma settings were adjusted to enhance the tone. The dragon figurine was included in the shot to test special effects. Although it didn’t quite turn out how I envisioned, it was a fun experiment.

20140320 collage

Here is an example of solargraphy with a film canister pin-hole camera. The horizontal placement of the camera results in a portrait view. The camera was tilted slightly upward.

20140320a collage