IR/CUT FILTER

[DAVE AMENDALL]

Hi All, I have a full spectrum DSLR. which I will be using with  my  C11xlt. My question is do I need an IR/cut filter for DSO imaging ?........Dave

Edited October 27, 2020 by DAVE AMENDALL
typo

[tomato]

I think it is generally a good idea, I’m going to use one with a OSC Astro camera.

[michael8554]

I think the way it goes is:

A Full Spectrum mod will pick up the IR that many stars radiate.

On a Refractor the IR will be slightly out of focus compared to the visual band light, so leads to bloated stars.

On Reflectors (including SCTs) all wavelengths are focused, so IR filter is not required.

Michael

[jambouk]

Ideally you don’t want your sensor picking up UV and IR light as well as visible light, but you need to look at what the spectral range of the camera is with its own inbuilt UV/IR cut filter to decide if you need to use an external filter. All filters reduce light transmission and offer another surface to get dirty and put dust bunnies on your final image.

Most targets will appear to emit light in a range of wavelengths, but the image you get of the target in question at specific wavelengths may differ between wavelengths. Take for example the Crab Nebula image below in UV, IR and visible which I edited on my phone and taken from the internet. If you try and merge all three of these images into one image, the resulting image wouldn’t be as crisp or as detailed as if you just imaged in say visible wavelengths.

[DAVE AMENDALL]

Hi Thanks for the input,some useful comments which will help in practice . Processing  gets rid of that rose pink look and the star images show improvement...........Dave