Astronomy and DSLR Astrophotography Blog

A lot of astrophotograpers decide to make a modification of their cameras. The reason is that filter in front of CMOS or CCS sensor blocks almost all the H-α part of spectrum due to balancing the colors for daylight photography. But this is not suitable for astrophotography because almost all the nebulas consist of the Hydrogen and this light is cutted off just some millimeters in front of the sensor. If we remove that filter then we get much better response of the red color.

Since the Canon Rebel is the most common camera used between enthusiastic astrophotographers I’ll try to suggest some good links of step-by-step tutorials which guide you thought the process.

1. Canon Digital Rebel (300D) Modification
   Good tutorial with sample images before and after modification. For Rebel (300D).
2. ash’s Modified Digital Rebel XT Page
   Very nice tutorial for modification of Rebel XT (350D). I have done modification of my Rebel XT with this guide and he survived the operation!
3. Canon Digital Rebel XSi (450D) Modification
   Good guide with pictures and everything well explained for Rebel XSi (450D).
4. Canon Digital Rebel (300D) Peltier Modification
   Guide how attach Peltier cooling element into Rebel. Works good for long-exposure astrophotography.
5. Another Digital Rebel XT (350D) Modification
   Just another Digital Rebel XT mod. Maybe someone finds it useful.

For the end I am presenting one of my images after the modification. The Veil Nebula, NGC 6992:

The Veil nebula (NGC 6992) @ Primož Cigler

equipment 300D, astrophotography, camera, canon, digital, filter, images, links, nebula, rebel, tutorial, veil

The light pollution is becoming more and more annoying thing more or less all over the world. Astronomers are the ones who suffers due to 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 beginning of summer 2008 I figured out that the situation from the point of light pollution from my backyard is so bad that I need the solution. On the web I found some filters that suppress the light pollution but no one good review of them.

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 front-filter (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 of filter is P2, that means that is the most suitable for astrophotography in prime focus.

The filter arrived on June and costed approximately 250 eur here in Europe, in USA it’s a bit cheaper. 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.

The image without Hutech IDAS LPS filter

The image with Hutech IDAS LPS filter

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 whereas the median for picture with IDAS LPS filter is 52.

That’s all, hope that this article will help someone to decide what to buy or not to buy.

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