• Posted on: 14 February 2019
  • By: tihomiry

Removing the DSLR build in IR-cut filter will give you at least 50% more sensitivity for hydrogen alpha emissions of the nebulas. Also the camera will be more light sensitive at dark allowing you to shoot more faint objects.
You can as well do IR photography with IR pass only filter. This is a lot of new horizontals for advanced and scientific photography. If you consider such move, my advise is to buy some second hand DSLR and find service that can remove the filter. You do not need the modern movie options and high number of pixels as the sharpens will increase due to the fact that the build in anti-aliasing filter is at the same glass as the IR-cut filter.
With the modded photo camera you will need external IR-cut filter in order to shoot daytime in true colors. Without the IR-cut the images will look reddish and more blured. The manual white balance will not be able to fully correct the colors as the silicon sensor is highly sensitive to IR light.
When shooting astrophotography you will also need to do manual white balance or post-processing of the RAW frames. The stars will look with less color and if you use lens optics, the IR light will not focus at the exact point with the visual light. Most lens will also not able to focus infinity unless blank glass is inserted in place of the removed filter. To workaround that, I did some modification to the objectives that I am using. My telescopes has a lot of focus tolerance and do not suffer from this issue.
Mirror lenses are more suitable for large specter range photography.
Despite begin harder to shoot whit such DSLR, possessing it is a nice experience.

More from me on this topic you can read at:
English: http://planetarium-gb.eu/pentax_astrophotography.pdf
Bulgarian: http://planetarium-gb.eu/data/Ast_Ph_Tihomir_Y.pdf

Nowadays we are so into the globalization and technologies, that I can submit observation plan to a remote, professional observatory at the other part of the word!

This is a comparison of my not modified Pentax k5 DSLR and the same, but modified one without IR-cut filter.

Astrotracer is a great way to take advantage of the Pentax DSLR camera in-body shake reduction mechanism. It is available since Pentax k5 and track celestial bodies by moving the sensor. Here is what is it ablout:

Staying at my home inspires me to make some documentation of my experience. I got a dedicated drive for my astrophotos and start reorganize them by objects. Here is an article of the most recent process I use on my photos. Enjoy: )

For a few months from now Betelgeuse (Alpha Orion) dim so much, that it looks as bright as the stars in the Orion belt. This is not so disturbing and does not mean that cataclysmic events are happening with it.