Collimating a Laser collimator

Ever wonder if that inexpensive laser collimator is really doing what it should? I never really trusted them, therefore I put mine on test one day. The first thing I had to build was V-shaped holder made out of wood, to prevent the collimator from moving around during tests.

V-shaped holder

Next I nailed the holder on to the wooden table to stabilize it and put the turned on collimator in v-shaped notch. 5 meters away (farther is better) where the laser beam was shining on the wall I attached a white paper for markings. Now rotate the laser collimator and see if the beam is making a circle or it stays a dot. If it stays in one place, your collimator is in perfect alignment. As you can see from the markings on the picture, my laser beam was making a circle. Using the two small allen adjustment screws at the back of the collimator move the beam so that it is pointing in the center of the marked circle and rotate it again. Repeat this until the beam remains in place while rotating the collimator. It took me about 5 iterations.
That’s it. You have successfully realigned you laser collimator, now use it with confidence for aligning your telescope optics.

Black markings on paper clearly show that my laser beam was making a circle.

V-shaped holder in action, preventing the collimator to move around.

Matcha muffins


  • 200 g all-purpose flour
  • 80 g white sugar
  • 10 g baking powder
  • 10 g matcha green tea powder (for cooking use lower grade matcha)
  • 75 g melted butter
  • 2 eggs
  • 200 ml milk

Preheat oven to 160 degrees C. In a large bowl, mix together all the ingredients and put the mixture into the muffin cups. Bake for about 20 minutes. From the above ingredients I got 18 muffins as I like them to be smaller.

Nom Nom Nom

Yes they are very green, looks dangerous but very tasty.

Simple solar panel circuit

I got tired of replacing and recharging batteries every week therefore I bought a small (7cm by 7cm) solar panel that would charge batteries and power the weather station. Before mounting it on the roof of the shelter I measured its output voltage and current. The peak current was 70mA and the voltage of 6V, that is more than enough to cover the 10mA needs of the weather circuit.

Solar panel

The panel is connected to the batteries using Schottky diode on the positive lead that prevents battery discharge at night. This one-way valve allows current to flow from the panel to the battery, but does not allow current to flow backwards out of the battery through the solar panel. In this design I am continuously trickle charging the battery when sunlight is present.

Simple wiring diagram

Update: It works. So far a month on solar power.

Venus transit

In anticipation of this rare we headed on an higher local hill with a clear view to the east, as the event was already towards the end at the sun rise. We had seven telescopes ready to observe and photograph the transit, but unfortunately the clouds and fog had other plans and blocked our view for the whole time. This was also announced as public observation which brought around 100 people on the place.
It looks like we will have to wait a few years until 2117 for a new opportunity to catch it.

Telescopes with solar filters attached waiting hopelessly for the Sun to appear.

Belgrade Star Wars convention

While walking around Belgrade last week I accidentally saw a poster for the Star Wars fan convention. This is their second one, the first was held last year in June. There was no entrance fee and as the saga fan I had to attend it. While my short visit there few people were in customs, but what surprised me the most was the room full of people listening to the lecture about the audio effects in SW. There were also other lectures like cgi, special effects… I went around booths and they were showing some hand made stuff, books, legos, recreations of the movie scenes, other memorabilia.

Movie scenes recreation

Millenium Falcon

Few more pictures in gallery.