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Welcome to Rob Walrecht Productions


Astronomy has never been more fun!
Do you want to be able to recognise the stars and constellations? Do you want to understand the Universe? Do you want to be able to understand, visualise the huge distances within our Solar System and beyond, and the emptiness of the Universe? Then you have come to the right people.

The Planisphere is your perfect guide to the stars. It is also very useful as a premium and even available in a personalised design, for businesses and organisations. See under Business.

And there are more exclusive astronomy products, like the Table Planetarium and the Solar System scale model: your own Planet Path!

The Planisphere
Read more about what the Planisphere offers you.


Happy New Year!

Please find our New Year card here.



Stargazing - with a planisphere

The eclipse takes just a few minutes but on clear nights it would be a shame not to look at the stars from your location, somewhere in the United States.
So don't forget to take along a planisphere
for 40° north!

The planisphere

The planisphere is still the best Guide to the Stars, no app can really compete (see below). We have high quality English languages planispheres for the entire populated world, among them one for 40° north.
We also have planispheres for that latitude in other languages, like one in Spanish.

During a total eclipse you can see other stars!

When the Sun is totally eclipsed you see the brightest stars, in the middle of the day! So even that event is a great one to use your planisphere. Below is a picture of the planisphere for 40° north set for 21 August, at noon, Nebraska (DCT).
Of course you must set your planisphere for the moment the eclipse starts at your location and if necessary adjust it for the time difference between that location and the center of the appropriate time zone. It's all explained on the back of your planishere!








 

Click to enlarge




Which stars can you see?

When you click on the image above you will see a part of our English planisphere fork 40° north, set for 21 August, noon, in Nebraska. I have placed an image of the Sun on the correct position, which is shown by the ecliptic (the Sun's path against the background of stars). The ecliptic in our designs consist of little dots and strokes, one for the position of the Sun on each day of the year (at noon). The strokes are to mark the 1st (with the month number next to it), the 11th and 21st of the months.
Ignore all the objects for binoculars (basically the M-numbers and other codes, they will not be visible at all) but concentrate on the very brightest stars (the biggest dots in the planisphere) like Sirius, Procyon, Betelgeuse, Rigel, Capella etc. I don't know exactly which stars you will be able to see as it depends on some factors.
But it will be nice to do your own research: which stars can you see, and down to which magnitude (brightness) can you go? If you do this I will be very intersted in your results! I would like to mention this on this site.
The red north-south line is the celestial meridian, a great circle passing through the celestial poles, the zenith (marked 'Z'), and the nadir (opposite the zenith). I also use this to show the declination, one of the two celestial coordinates used to give the celestial positions of objects, comparable to latitude on Earth. The other part of the system is right ascension, comparable to longitude on Earth. See this page for more information.



New Pluto Globe!

Wonderful 6 inch globe is very instructive

I have most of the wonderful series of planetary globes brought out by Sky & Telescope, the American publisher of one of the most important (amateur) astronomy magazines. There already were globes for Mercury, Venus, Earth, Mars (2) and the Moon (also 2) - all with a diameter of 12 inch (ca. 30 cm.). See also the (Dutch, sorry) item about the scale model scale model about the 'Small Worlds of the Solar System' (Pluto, Eris, Ceres etc.) that I use in my lecture about this subject and that is based on the (also great) S&T Earth Globe.
And now there also is a Pluto globe! Smaller (6 inch, ca. 15 cm), but beautiful! Only with a globe can you see what part of the dwarf planet is now known very well, reasonably well and not at all. I am very glad to have it now and I hope Sky & Telescope will also bring out globes of the the four large moon of Jupiter and some moons of Saturn. I know there are files for globes of the Galilean moons, published by USGS, because I have downloaded these files some years ago. So Sky & Telescope: I'm pre-ordering them now!

























The new catalogue

Our new catalogue is ready, finally showing ALL our products again. It also has English explanations.You can download it here. It has Dutch and English text and explanation (in light blue).


Astronomy apps for amateur stargazers

Someone asked about other teacher's experiences with using astronomy apps* in astronomy courses. Naturally I don't like this idea for commercial reasons (...) but I also have a problem with the apps as an astronomy teacher and enthusiast. This is what I wrote back. I understand that others may totally disagree, but as a grandpa I see things happening in my small part of the Universe that make me sad and I'll make sure our two 'sunshines' will experience different aspects of nature!
 
... I don’t have any experience with these apps, but what I hear is that they are not always correct and clear enough, for instance with stars shown that are actually below the horizon. The complaint that strikes me most is that they don't provide the necessary overview needed to be able to learn how to recognise constellations and stars.
 
In my own astronomy course for teachers I have tried to use table planetariums and other models and equipment to help the students understand – or better visualise – the three-dimensional character of the space around us, with all the imaginary lines and points we came up with. They were all unsatisfactory.
I already (naturally…) used my planispheres as an important part in this course, as people want to find their way among the stars. I had made some sets of ‘Questions & Assignments’ which my students liked, about the use of the planisphere and things like time and coordinates.
 
When brainstorming about the problem (which I usually do at night…) I realised that I could build on those sets and use them to help people develop some directional, special awareness. All this with the use of the planisphere! This has been a massive success and I now give this part of my main course as a separate course to ‘normal’ laymen and whoever likes it.
 
Another thing that bothers me as an astronomy teacher is that the apps tend to strengthen the superficiality and short attention aspects, the ‘Big Mac attitude’ of today’s young people that will never satisfy them as much as a fine dinner with family and friends. Playing a board game with friends or family is also quite different from playing on your computer day after day.
The same is true for the planisphere: it can lead to someone exploring the night sky him or herself, of course with family and friends. They may never forget the first night they did this. They will learn how to recognise and find constellations and stars – and remember that. It may lead to astronomy as a during passion. I doubt whether a quick glance at a cell phone will lead to that.


*) I don't have a fundamental dislike of apps. I think they are great for people like myself, who know the starry sky but want a quick update before a presentation or something like that. And in fact I want to make my own Solar System app once, if I can find someone who can make such a thing for me.



Asteroid Day - 30 June 2016

Activities in Amersfoort, The Netherlands

30 June will be the second Asteroid Day, with events about these intriguing but potentially lethal Small Solar System Objects. In Amersfoort we will host an event in the local observatory. It will be my lecture Small WOrlds of the Solar System, adapted to contain more information about asteroids (the basic lecture is about the dwarf planets Ceres and Pluto, protoplanet and asteroid Vesta and the Rosetta Comet. It's in Dutch.


Transit of Mercury on 9 May 2016

Small planet moved across the Sun's disc

On 9 May Mercury moved exactly between the Earth and the Sun. We call such an event a transit. The smallest planet has an orbital period ('year') of almost 88 days. Still,  the chance of a transit is not that great: 13 or 14 per century. That's because Mercury's orbit is tilted bij 7°: only when the small planet, the Earth and the Sun are on one line can we see Mercury pass in front of the Sun.













Picture and video

Bob van Slooten from my own town Amersfoort took the picture above around the 'maximum', or the moment the centre of Mercury's disc was nearest to the centre of the Sun's disc. Click on the picture to see it larger.
My wife Marja and I watched the event with our 8 x 40 binoculars, of course fitted with special SOlar Screen filter material (see below).
On the internet is a video by ESA, made from images by the Proba 2, a satellite the size of a small refrigerator that monitors the Sun in extreme UV.


Left: my filters for our binoculars and videocamera.
They were made with foamboard, the kind used for photo's. It's easy to work with, you can stick the solar screen between two layers.
The white rings are made from foam rubber and fit netaly in the eye pieces.






Eclipse Glasses!

To observe the Sun with the naked eye safely

You can find this item here. Then scroll to the bottom of the list.
For large orders (50+) please send an e-mail to us: info@walrecht.nl.


Special sets of planispheres

For people who want better coverage

We offer several sets of planispheres, like the Europe Set, North America Set, World Sets (several) and Pacific Set. You can find them here. They are basicaly in English but we can swap any latitude version for one in another language, when it is available.


Special offer: Solar System scale model

English and American Solar System scale models now very cheap!

In 2003 we prublished three Solar System scale models (scale 1:100 billion) consisting of 16 cards, full of information AND the distances to the Sun and the sizes to scale.
The Dutch scale model was very succesful and was recently brought out in a new design and set up (a basic set and a supplemental set, see the Dutch page for pictures).
The English scale models (English with metric information, and US with miles, inches etc.) were never a success, like the English BIY Star Wheel and Sundial, because we don't have partners for these products in other countries.
However, they are still very usefull to teach young and old about the distances within and the emptiness of the Solar System - and beyond! Granted, Pluto is no longer called a planet but a dwerf planet, and many other ice dwarfs were discovered after the publication of the products. Therefore there are new cards available for many ice dwarfs that were discovered after 2003, a few of them are now also dwarf planets. These extra cards can be dowloaded for free here.


Brochure 'Bombardment of the Earth!'

Free (Dutch!) brochure with orders of planispheres and books

Since last October we give a free Dutch brochure, Bombardement van de aarde (Bombardment of the Earth!) with each order of planispheres or books. If you are not a Dutch or Flemish customer but understand Dutch, you can get one for free as well. However, you would have to let us know as a remark on the order or by e-mail. This is, as long as we have stock of the brochure.
For businesses: we can produce a version in your language, if we have the translation (an English translation can be made).