Since this is the post of equipment for astrophotography I will write it in English, for international usage.

So… The light pollution is becoming more and more annoying thing, not only in Slovenia, but more or less all over the world. Astronomers are the ones who feels that more than any others. The problem is that there are every year less locations for observing and photographing the untouched sky. Well, some manufactures of astronomy equipment decided to produce filters that suppress the light pollution.

On the beggining of summer ’08 I figured out that the situation from my backyard is too bad so I need the solution. On the web I found some filters but no one GOOD review of them. That’s why now I am writing to everyone who would like to know something more about it.

In the end I decided for IDAS LPS filter of Hutec. Because I was pretty sure I will be using just for astrophotography I decided for frontfilter (look at this figure) which can be placed directly in the camera’s body so I can use it with lenses also and not just with the telescope. The version od filter is P2, that means that is the most sutiable for astrophotography in prime focus.

The filter arrived on June and costed approximately 250 eur. The first impression was something like: “250 eur for such a piece of glass?!??”. But after a first-light I changed my opinion. It is worth every single pennie! It works just the best for me, my backyard turned to the very good astrophotography place. It has no affect to sharpness of the image. I use it with my Canon 350D (Baader mod.) and also both sample pictures are captured with this equipment. The telescope was William Optics SuperAPO 80/480 with TeleVue reducer/flattener 0.8x. The picture without filter is out of focus because when I removed the filter I didn’t refocused. Anyway, it represents the affect of filter. Both pictures are captured at the same settings: f/4.8, ISO1600, 120s, RAW, WB(2850, -30), imported and exported with Lightroom.

Without IDAS LPS filter
Astronomy without IDAS LPS-P2 frontfilter

With IDAS LPS filter
Astronomy withIDAS LPS-P2 frontfilter

It’s quite obvius what the filter  does.

I have also measured the Mean of these two pictures. The median value for the picture without IDAS LPS is 118, the median for picture with IDAS LPS filter is 52.

That’s all, hope that this article will help someone.

CS! Primoz