Astronomy

My first picture of Jupiter and Galilean moons Ganymede, Europe and Io (moons enhanced).
Figure 1: My first picture of Jupiter and Galilean moons Ganymede, Europe and Io (moons enhanced).
Seventeen years of research on nautical instruments produced various sidelines that were not covered in my PhD thesis. One that fascinated me most was Galileo Galilei's early seventeenth century proposal for longitude finding at sea. Galilei had discovered the first four moons of Jupiter (Io, Europa, Ganymede, and Callisto) in 1610 (see figure 1, for more pictures see the astrophotography page) and soon realised that they formed a heavenly clock that could potentially be used as a reference clock in the determination of longitude by comparing tabulated times of the moments its moons touched the Jovian limb with times from onboard observations.

The set-up at InFINNity Deck when it opened in May 2018 (left to right: Esprit 150ED, C11, Lunt).
Figure 2: The set-up at InFINNity Deck when it opened in May 2018 (left to right: Esprit 150ED, C11, Lunt).
Although a valid method, the success of it depended on the quality of the instruments and the skills of the observer. In my PhD thesis I have shown that observational skills vary between observers due to difference in human visual perception and that in order to become a qualified observer at least some 500 observations are needed. In addition being on board a moving vessel would not have been beneficial to the results achieved with Galilei's method.

Having researched human perception, using the nautical instruments I created through the years, I wondered what kind of accuracy in longitude finding could be achieved using Galilei's method and especially what the differences between two observers would be. For this I decided to build an observatory on top of our library.

The GTT60 mounted between the C11 and Esprit since November 2018.
Figure 3: The GTT60 mounted between the C11 and Esprit since November 2018.
In it the following instruments are currently installed (see figure 5):The telescopes are carried by a 10 Micron GM3000 HPS mount which is sufficiently large to take this load and to add some more equipement.

Initially only the first two telescopes were installed together with a C11 XLT Carbon (see figure 3), but as the mirror-flop was too large on this instrument it was replaced with the EdgeHD version, which has a mirror-lock to minimise this effect.

The GTT60 was added to the array in September 2018 (see figure 4).

The situation as per July 2019 with the C11 EdgeHD installed.
Figure 4: The situation as per July 2019 with the C11 EdgeHD installed.
In June 2019 we decided to part with the Celestron C11 XLT and to swap it for a C11 EdgeHD (see figure 5). Reason for that was the fact that the XLT has considerable mirror-flop, which makes it difficult to keep it parallel to the Esprit. Befriended amateur-astronomer Rob Musquetier wanted to sell his C11 EdgeHD as he is only doing astrophotography using APOs and no longer had use for the C11. Our C11 was acquired by the astronomical society AWSV Metius in Alkmaar and will soon be installed in their observatory.

Local schools
Next to my own research the observatory is made available to the local schools. In September 2018 eight students, in four groups, of high schools Jac. P. Thijsse College and Bonhoeffercollege have started their research. The following year five groups of two students did their research based on data acquired at of provided by InFINNity Deck. The topics of their research can be found at the education page.

Of course the observatory is also used for visual observing and for astrophotography.

Sky conditions and astronomical twilight

For the sky conditions and astronomical twilight at InFINNity Deck see the Astrophotography section.

If you have any questions and/or remarks please let me know.


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