Minnaert Telescopes

[][]These telescopes are a subsection of the old observing gear once used in the observatory. They were stationed on the roof of the Huygens building on pillars specially made for them. This was done in the 80's ish era. They have a 4 cm objective and work with 0.968' objectives.

Originally they were made for the Sonnenborgh observatory in Utrecht, they were designed by Minnaert in the 1950's and also used for student practicals. But since this time they have been modified quite a bit, they got electrical components, straightedges and PVC dewshields.

Some of them even got motorized and works on 6V 50HZ AC, we currently have one of these at the old observatory. []

[]The telescope is pretty easy to handle, as is expected from a student telescope. In the picture on the left you can see the tube and a few numbers. RA and DEC are read from the two disks on the telescope, and the axis can be set with the black knobs(number 3 and 4). The telescope can be focused by screwing the eyepiece holder (number 1) in clockwise or anticlockwise position. The cover screw (number 2) is only there to protect the screw thread (so make sure it always covers it but remember that turning it does not affect the focus.)

In Sonnenborgh one can see that these telescopes have also been used for practicals, as the pillars at the backside of the building have markings on them that allow one to put a telescope on to them. Unlike the Leiden ones, they are more precise. In the observatory they also have two earlier models of the telescope. Clearly very similar but more primitive.

There is a manual written by Minnaert that describes these telescopes, one can find it here

[]One of these telescopes can be found on the desk of the visitors center, it is chained to the monitor but works perfectly. Please make sure that the cap will not get lost.

With this telescope used to be posible to see Pluto (the dog). A small doll is hung in the Hortus and can be seen with the telescope. Open the window to greatly improve the resolution. The first Pluto was stolen and then replaced with a marsbar but a new Pluto has been bought. The 9mm eyepiece which was shortened to fit gives a bigger image than the 25mm one. But you can chose!

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For these telescopes we have a projector, three eclipse filters and a converter for 1.25'' eyepieces. []