The picture clearly shows a curved horizon.
I'm interested in how you determine how to reach the altitude you want with a balloon
You know the lifting ability of helium. It's fairly easy to calculate the lift based on total weight and amount of helium used and the type of balloon.
I aim for an accent rate of 5 m/s. That way, I ensure that the balloon will actually burst, but not burst too soon, while going as high as possible.
Try this calculator http://habhub.org/calc/
My normal payload is CA 1200g, but the next launch will have an extra camera for raw format images which adds to the weight in both camera and batteries. Probably 1850 g this time.
Thanks. I was wondering about filling 4 balloons. Fill one as normal the one below that to 80% the one below that to 60%, the next and last to 40%
For what purpose may I ask?
Also, you don't fill balloons to 100%. Even given the flexibility of the material, the balloon expands quite violently during its ascend
I would think the system I described would get the most altitude. The 100% just means to fill it as you would a single balloon. The other's below would be expanding and more buoyant by the time the first one pops, and then the second, and so on.
Or am I missing something here?
It would only make the lifting ability worse with the added weight of the additional balloons.
The lift doesn't amount to the size of the balloons but the amount of helium they contain. Helium is lighter than the atmosphere so it will keep ascending until there is no more atmosphere. There's an upper limit to the altitude you can gain with helium. You won't go much higher than 40km, the atmosphere is simply too thin.
The amount of helium in the balloon decides how fast the balloon ascents. A lot of helium and the balloon ascents quickly, but pops at a lower altitude (lesser space in the balloon for expansion), too little helium and it ascends slowly, but might not burst at all.
Hydrogen would allow you to go higher, but on a low budget level, hydrogen is dangerous as hell since it reacts with oxygen.