DIY Solar filter @RM3 +

1 - 30 Astronomical Events / Activities Challenge

Accomplished on : Fri 15 July 2011

 

 

After the day I bought my telescope, I always think that: 'I've got a scope, I can use it to stargaze, 'moongaze', ..., but not the nearest star to Earth - the Sun. What a waste...'

 

Usually, the price of a solar filter might cost up to RM 150 +-, so observing the Sun through my scope is pretty much impossible in near future...

But after I'm told of a cheap and economic way, I made it straight away with a cost of RM3 + a little materials..

 

Let me share the how to(s) if you wanna make one. I'll try to make this short but informative..

 

 

What you need:

• a solar filter spectacles (you can get it from telescope dealers near you. I got it for RM6) (make sure that you get one which is used for solar viewing ONLY)
• pencil, erasers, ruler
• duct tape
• cardboard (doesn't need to be thick but hard and can be used for a long period)
• scissors
• small rope
• 1-3 hours

 

1. Cut the solar filter spec into two, and take out the thin film of solar filter.

 

2. Trace out the size of of the top part of the scope (let me call it 'head') onto the cardboard. 3. Since the head is round, I made an octagon. Measure the diameter, and the calculation to get the length of each side of octagon is shown below.

4. Align the edges of octagon with origin, draw a line away from the centre, starting from the edge.

5. Cut the lines which you have just drawn until the edge of the octagon. Now, you are able to fold them into the shape of a cap of the head. Remember to test its size on the head from time to time.

6. Since mine is a newtonian, with a secondary mirror at the middle, I cut a hole at the side, avoiding the centre. Paste the solar filter just like this:

7. An advantage of my newtonian, there are screws which holds the secondary mirror at the head. So, I punched holes at the position of the screws, so that the whole thing can be held there tightly. (If yours is a refractor, you may consider to let the cardboard to be longer at 2 sides, punch a hole on each side and tie it at the curve.

 

8. To prevent the diy solar filter to drop off the head, just tie a small rope at the bottom of the screws. 9. Everything looks fine, wrap the edge of octagon with duck tape so that no stray light passes through the tiny holes.

ITS JUST THAT EASY !!!

It has got its first light on Saturday, 16 July 2011.

 

It was very cloudy that particular day, but I only hope that the Sun will be unobstructed for 30 minutes. Just 30 minutes. And my wish was heard..!

 

It's pretty hard to get the image of the Sun as the view will be totally dark, until the photons from Sun falls directly onto your retina..

 

(WARNING: Never look the Sun through the scope, even from the finder scope without a solar filter !!!)

 

The image was pretty reddish-yellow. I was awestruck as I was able to see two sunspots that time, with a cost of RM3 +, which I thought was impossible in near future.

Well, IMPOSSIBLE = I'M POSSIBLE, aren't it?

 

 

Note that the image is much more clearer and bigger and definitely way nicer than the picture shown below.

Last but not least, we should actually consider a better quality solar filter if we planned to use it for a long term. The solar filter in the spec is not suitable to be used for a scope, so take extra precaution when you are using it and please watch out if others, no matter how young or old are using it to observe the Sun. Eyes are one of human's most important asset!

 

What can I do with this diy solar filter?

• sidewalk astronomy at noon !! (ppl usually come out at noon..)
• a wider variety of objects to observe
• definitely can spend more time with my scope!