Astronomy Notes

I’m sure that some of your know what does DSLR stands for. It’s Digital Single Lens Reflex. Let’s straight into the topic this time.

Dual Use
As you see from the left image, DSLR is just like a conventional camera. Therefore, it’s able to take both your family’s photos and astrophotographs. It’s more valuable!

Larger Chip Larger FOV
What does you get this time? This is maybe the greatest advantage over CCD imager. It has larger chip, thus it typically has more pixels in the chip. What can you do with this? You may print a poster! If you want to get the CCD imager which is as large as the CCD of DSLR, you need USD3k-6k. Let’s take SBIG’s ST-2000XM as an example, it costs USD2695 during the offer period! If you are concerned about the pixels, it does only have nearly 2 mega pixels but Canon EOS20Da has 8.2 mega pixels. However, don’t judge it just by the pixels. Everything has its advantages and disadvantages. (I suddenly remembered that we can print larger photos just by doing mosaic. This will be explained in Sunday)

Cheaper in the same chip size range
Just by comparing the Canon EOS20Da and ST-2000XM, you will know why I say so. Sure, it doesn’t mean that ST-2000XM is not a good buy.

Convenient
DSLR can be operated with batteries and the man’s hand. It does not need a laptop to control it. It does also take all colours in one step (this can be a disadvantage though, you may refer to The Best Imager: Monochrome CCD to know the pros of monochrome CCD).

However, DSLR usually producees more noises. It has to be modified in order to be cooled using the devices like the astrophotographers usually use. If the DSLR is not specially designed for astronomical use, it cuts the lights which is considered important by astronomer but unwanted by the public.

This Sunday, I am going to write about the CCD imager. Stay tuned!