Following up with the pictures of the moon taken with a Nikon camera on a 114mm Newtonian telescope, I have recently bought a quite cheap CCD camera. There are a few advantages and a few drawbacks.
Here are the qualities of the CCD:
very easy to mount directly on the telescope
directly exposed to the object without any extra lenses
instant results on the computer screen with a large view of objects in full screen
need to have a computer around (along with the brightness of the screen that can have an impact on your night vision)
no possibility of playing with contrast/exposure time since it is a cheap camera, you have to rely on the automatic settings, some more expensive ones do have these kinds of settings, but that’s definitely another budget
And here are the qualities of a full camera:
playing with contrast/exposure time depending on the object you’re trying to take – the moon and a deep sky object will definitely not want the same settings
mounting the camera on the telescope is not difficult but needs some precautions
having to go through at least an eyepiece and a refractor can create a lot of chromatic aberrations and distortions, as seen on the pictures in that post (look out for a blue halo around the moon or around the craters, for instance) compared to the ones in this current post.
the weight of the camera can be an extra load on the telescope’s mount, especially if the mount is already reaching its limits with the tube on its own
So finally, here are two sample pictures taken on the same telescope:
Note that those pictures were taken from my balcony, right in the middle of the city, and all astronomers know that this is the worst setting to do any kind of viewing and especially any kind of photography. The thing is that you won’t realize what this really means until you see this video (2Mb):
See the wobbling? That’s the air heated unevenly that moves around. It somehow totally reminds me of what you see when you look at the bottom of a very very still pool filled with water, look at this one:
Isn’t that simply amazing?
Recently I was asked how many times you should hear a word in a foreign language before it really sticks into your mind.
Sometimes, hearing/reading one word one single time in the right context will imprint it into your mind forever. And sometimes, you will repeat one word 100 times and it will not stick. Spaced repetition is a powerful way to get the words to stick while reducing the number of times you are exposed to each word, but it is not magical either. With the wrong context, you may also fail with spaced repetition.
I learned one thing from decades of studying, it is that context is everything. That’s why trying to immerse yourself in a certain context while learning a language is important. The best of all is to simply be in the country of the language you’re learning. But as it is not always possible, here are a few tricks.
When I use Anki to do spaced repetition, I listen to some music in the language I’m learning while repeating the words. This switches the brain into the mode “oh, that’s this language, okay!”, as well as cheering you up and setting up a mood. You might even want to tap your feet with the rhythm while learning words. And on all my cards, I have an image of something that is characteristic of the country/ies where that language is spoken, as well as some sentences in which the word is used – because learning a word by itself is boring, and learning it within a sentence makes it more interesting. I will make a post later to explain how I did it technically. Associating a picture with the word also helps quite a bit, especially for physical objects.
Teachers know that bored students don’t learn anything. That’s why teachers who make their classes very emotionally alive are more successful than others. There are some very serious scientific studies on this but I’m sure you have in your own experience that teacher who stood above all others because his classes were so lively, funny or exhilarating.
And of course it all depends on the language you’re learning and the language(s) you already know. The learning curve of Japanese or Arabic is obviously much greater for a native monolingual English speaker than the one of German for someone who knows Dutch and Danish.
So there is no “number of times for a word to stick”, it’s all about context!