Astronomy without a telescope
Despite the fact that I've been interested in astronomy for over a quarter of a century, in all that
time I never bought a telescope. I did make long exposure shots of the nightsky with my camera, the
Panasonic DMC-FZ50. I especially selected the Panasonic on that ability to make photo's with exposures
longer than a handful of seconds.
Orion, taken from my balcony, with an exposuretime of 15 seconds.
Buying a telescope
Like many things in life, with telescopes, the possibilities are endless and confusing. There is a reason
why you can find more than a few sites with advices on selecting your telescope. These were my considerations:
1. I want to see much more then with binoculars. Wow me!
2. In Gouda, and certainly in my street, light polution is a problem. So a very expensive telescope would
certainly be overkill.
3. It must fit in my car, so I can take it to places with less light polution and astroparties.
The solution was a Dobson telescope: simply said, it's a large tube with two mirrors without fancy
motors or heavy tripods. You can rotate this Dobson left and right and the telescope can rotate upward
and downward. And it isn't that expensive anymore. My telescope was 300 euro's with 30 euro's for shipment.
So I bought a 200 mm GSO Dobson in february 2008.
The 200 mm GSO Dobson after assembly. Any resemblance of the assembly of the rockerbox (that black thing
where the telescope rests on) with an IKEA cupboard, is purely incidental.
And don't forget the eye pieces
Anyone who thinks that his wallet can remain closed after this, is mistaken. Oh sure, the telescope works
fine with the 25 mm eye piece that comes with it, but other eye pieces are almost essential. Like a
wide field eye piece, to make finding objects easier. Or a smaller eye piece, to bring your objects
closer (with more detail). I also bought a zoom eye piece, so I don't have to change eye pieces if I
want to get more detail or a wider view.
The St.Janskerk in Gouda, about 1.5 km from where I live, through a 25 mm eye piece and a 42 mm wide field
eye piece. The 42 mm eye piece gives you an oversight of the object you want to see, but nog as much
detail as the 25 mm eye piece. The 8 - 24 mm zoom eye piece (not shown here) even makes the nails in the
bell hammer visible.
Astrophotography or not?
There is one thing you can't do very well with a Dobson telescope: astrophotography. The problem is
that the Earth turns and therefore the sky you are watching, seems to move. So faint objects
will smudge on your pictures. Other, more expensive, telescopes have motors that move the telescope
along the Earths rotation and that allows you to get a steady shot.
Yes I will!
But upon seeing the moon and planets through the telescope, I wished I could take photographs anyway.
So I tried holding the camera behind the eye piece. It's not easy this way. It's a bit hard to get
things in focus. Plus you have to keep absolutely still. But I got it working anyhow. For example
the light from the moon is so strong, that exposure times can be kept very short and the image can be
quite sharp. The planets, like Saturn, are harder to do, but still possible.
This image of the moon was taken in daylight through a 42 mm wide field eye piece. You can see the moon,
the blue sky and a shadow of the secundairy mirror (which hangs at the top of the telescope tube) is the
center of the blue "donut".
A moon crater on the division between night and day. I made this through a 8-24 mm zoom eye piece.
It was difficult to get the entire image focussed, but it shows why the moon is such a beautiful object to
see.
Half moon, seen through my 25 mm eye piece. There's just some incredible detail visible.
Jupiter at 100 ISO
October 13th 2008 20:53, 8 - 24 mm zoom eye piece (at 8 mm).
Jupiter through the 8 mm zoom eye piece. Not zoomed in with my camera this time.
A day before full moon
September 14th 2008 0:56, 42 mm wide field eye piece.
Full moon is so bright and there is almost no shade, because the sun is almost perpendicular to the surface.
Only on the edges you can see some shade in the craters. This image was made with 1/640th of a second
shutterspeed.
Oceanus Procellarum, the Ocean of Storms. The bit dull crater within is Kepler, the bright crater upperleft,
is called Aristarchus.
Jupiter and it's four brightest moons
September 6th 2008 9:15pm (CET), 25 mm super plösl eye piece.
Jupiter is so bright and its four brightest moons aren't as much. It's hard to get them all
nicely exposed. Nevertheless, when you watch Jupiter and the moons (from left to right: Europa, Io,
Callisto en Ganymedes) through the telescope, it's bit like it's Christmas there.
Saturn.
May 7th 2008 11:45 pm (CET), 25 mm super plösl eye piece.
Saturn. You can really see the rings of "The Lord of the Rings". It was difficult to make a sharp image.
With my eyes, I could see it much sharper. I could even make out some of the clouds and Saturn's
moon Titan was not hard to see.