Astrophotography Equipment

UV/IR cut filter – yes or no – a guiding example

Is it necessary to use an UV/IR cut filter? If yes, is this something you can really see in your results?

It simply happened. I did read it in the past: Use UV/IR cut filters when guiding. I always did it. But why?

Without UV/IR cut

I got my answer when I simply forgot to screw my UV/IR cut filter onto my guiding cam after a change of my configuration. The guiding stars were not really focused, they had little shiny halos. The result was the upper left guiding graph.

With UV/IR cut

When I saw this messy guiding graph I remeber what happend. Just two minutes later I had screwed the filter onto the camera and guiding was resumed. The same equipment, the same sky, the same balance, the same guide stars and the guiding result was completely differnt as you can see on the upper right picture. My guiding was less than one arcsecond and ok so far.

Perfect conditions

I tested some stuff this evening and also forgot to rebalance after adding the guidescope. … This in mind, the guiding was really nice …
One day later, with exactly the same equipment but with a perfect balance and really good seeing the guiding graph was really awesome. Look at the result in the lower middle.


To got an idea of the weight and equipment i used: A Vixen VC200L with an EOS M100 on a HEQ5pro with a 240mm guidescope and a QHY462C. I also got a Pegasus Astro Powerbox Advanced on the VISAC and also a Pegasus Astro Focus Cube.

Lessons Learned

Always use an UV/IR Cut filter. Especially when using a One Shot Color Camera.

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