Amateur Astronomer Captures Rare Glimpse Of Infant Solar System

The photo above was taken by Rolf Wahl Olsen, ‘amateur’ astronomer from New Zealand. The word amateur should be used lightly, as these are the first shots taken of the planetary disk surrounding the popular star Beta Pictoris (β Pic). Olsen took the pictures using a 10-inch telescope from his home. Here are the mind boggling equations he used to get his picture!

First I collected 55 images of Beta Pictoris at 30 seconds each. The dust disc is most prominent in IR so ideally a better result would be expected with the use of an IR pass filter. Since I only have a traditional IR/UV block filter I just imaged without any filter, to at least get as much IR light through as possible.

Next step was to capture a similar image of a reference star under the same conditions. For this purpose I used Alpha Pictoris as the paper suggested. This star is of nearly the same spectral type (A7IV compared to Beta’s A6V) and is also close enough to Beta in the sky so that the slight change in telescope orientation should not affect the diffraction pattern. However, since the two stars have different magnitudes I needed to calculate how long to expose Alpha for in order to get a similar image which I could subtract from the Beta image.

The magnitude difference between the stars is 3.86(Beta) - 3.30(Alpha) = 0.56

Due to the logarithmic nature of the magnitude scale we know that a difference of 1 magnitude equals a brightness ratio of 2.512. Therefore 2.512 to the power of the numerical magnitude difference then equals the variation in brightness.

2.512^0.56 = 1.67, so it appears Alpha is 1.67 times brighter than Beta. This means that exposure for Alpha should be 1/1.67 = 0.597x that of Beta. I took the liberty of using 0.6x for simplicity’s sake…

So I collected 55 images of 18 seconds (30 x 0.6) for Alpha.

You can see more of his work at his site and read more on this story on Discovery!