Tuesday, January 30, 2007

Astrophotography with DMK camera

Other than planet/lunar/solar imaging, the DMK can be used to do some simple deep sky imaging as well, recently The Imaging Source has released a long exposure firmware for their excellent high frame rate 1394 cameras, and it further improves its capability for deep sky imaging.

In order to keep the exposure short, one will want to use fast telescopes. DMK cameras have very small CCDs like 1/4" or 1/3", and they come in a package with c mount, the natural choice would be c mount lenses. In ebay, we have a lot of good quality c mount lenses available at very competitive price, to give an example, a 75mm f/1.8 prime lens could cost as little as $20 - $30 USD, don't get it wrong, those were good quality lenses, made in Japan! Notable brands are Cosmicar (Pentax), Fujinon, Compustar, to name a few.

With the small CCD chip, these lenses are far more compact than DSLR lens, and it makes everything so portable. The downside is, you have a very narrow field of view unless you have really short lens, like 4mm.

These lenses come in two mounting, one is C mount and another one is CS mount. With CS mount, your lens got to mount closer to the CCD, so if you got a CS mount camera, you can use C mount lenses with a very short extension ring (too short that I won't call it an extension tube).

Here's my collection of c mount lenses:

They are:-

Cosmicar 150mm f/3.2
Fujinon 75mm f/1.8
Fujinon 25mm f/1.4
Cosmicar 8mm f/1.5

and also a Vivitar 1.5x convertor.

In addition to them, I will also use my Borg 45ED II with a 0.5x binoviewer corrector with an extension tube. One may even use moving primary SCT with a f/3.3 reducer, I'm going to try it with my C5.


Астроблог said...

Hello, i`d like to ask you about using this camera (IS DMK 21AU04) for guiding. For astrofotography I use Synta 254mm newetonian scope and Synta 80ED as guide telescope.
Thank you in advance.

Oldfield said...

Thank you for your visit.

PHD guiding seems to be good and it supports DMK, all you need is a small hardware box like the one from Shoestring Astronomy to deliver guiding signals from your PC to your mount.