Do I need an IR filter?

[cuivenion]

I'm using a webcam (PS3 Eye) that is CMOS based for both lunar/planetary and DSO imaging. I understand an IR filter is necessary for the former but do I need it for DSO imaging?

I'm using a Skywatcher 130p on an EQ5 to take the images.

[Astrosurf]

I wouldn't use a webcam for DSO imaging. Some I believe you can convert to long exposure, but I'm not sure about the PS3. DSLRs are best for DSOs. I was advised to use a UV/IR filter with my old webcam for planetary.

Alexxx

[Cornelius Varley]

For converted webcams an IR filter is a must. Webcams can see iR wavelengths which need to be filtered out. IR light focuses at a slight different point to visible light and without the filter the image will be a light fuzzy and will have a slight pink tinge to it. Unfortunately, most webcams aren't sensitive enough for DSO imaging without further modification to increase exposure times. With the advent of cheapish astro cameras that are capable of DSO imaging, electronically modifying existing webcams for DSO imaging seems to have disappeared. Thre Philips range of TouCam Pros and Logitech Quikcams used to be favourite for this mod.

[cuivenion]

Hi, thanks for the replies. It's just a project for fun, I'm not expecting to much. I've already got a half decent shot of M57, and I've added a peltier which has dramatically cut down on the noise, so I'll have to give it another go when I get the chance. I'll be on the lookout for for a cheap IR filter then.

[sharkmelley]

Yes, a full spectrum sensor requires an IR filter for both planetary and DSO when using refractors or any scope with extra lenses.  This is because lenses are not generally designed to bring IR to focus in the same plane as visible light.  This defocused IR leads to star bloating in DSO imaging and general burring in planetary imaging.

Mark.