Let’s go back to the topic. The camera is important piece of equipment since it’s capturing the light. Not all the cameras preforms the same but there are some common setting that it’s good to setup before we go out under the stars.

The very first thing is the photography mode of the camera. Here we have just one choice – M (Manual) mode because of one simple reason: DSLRs are not meant to be astrophotography cameras but daylight cameras. So the longest exposition that automatic modes enables us it’s 30s. But that’s far not enough for deep-sky astrophotography. We need longer exposures and the M mode has a “bulb mode”. That means that the exposition is as long as the shutter is pressed on a camera. Of course, we cannot hold the button on a camera for 5 minutes so the wire trigger is necessary.

We select M mode

The second thing is mirror lockup. Almost all the DSLRs enables lockup function. Mirror lockup means that the mirror in the camera, which reflects light to the viewfinder, locks up some seconds before the start of exposition. And why is that so important? Because if you are using telescope with long focal length, then every single tiny movement is noticeable on a picture. And when the mirror “jumps up” it shakes the system and bright stars get tails and that’s what we obiously don’t want to have on the pictures. So the mirror lockup function triggers the mirror some seconds before the start of exposition so the system can settle down before the exposition is started.

Enable the mirror lockup function

Next important thing is ISO speed. This one is still a hot topic among astrophotographers since some claims that lower ISO is better and others who prefers higher ISO settings. Anyway, two years ago I have made a test on Youth Astronomy Camp which revealed that Rebel XT preforms the best at ISO 800.

Selecting the ISO 800

For additional processing it’s the best that we use uncompressed data so the RAW mode is the right decision. If you prefer having JPGs also, then you can select RAW + JPG.

RAW (uncompressed) format

Another not so important thing is LCD brightness. I strongly recommend to set this as low as possible because in the night our eyes are adapted to the dark and if you want to check for example the sharpness of the images on LCD with the full brightness then you’ll get blind for some minutes.

The last but not the least function is information LCD illumination. This function enables you to see the settings specified in the dark. Just press the button.

Info LCD illumination

Thank you for reading. So far we have chosen the object and specified all the camera settings.

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

• Canon Rebel (300D)
• Canon Rebel XT (350D)
• Canon Rebel XTi (400D)
• Canon Rebel XSi (450D)

The first Canon Rebel was published in 2003 and since then the astrophotography began also more popular and reachable to everyone.
There is a lot of reasons why Rebels are so popular. I’ll try to emphasise the most important:

1. PRICE
   Until the announcement of Canon Rebel there were no other cameras for the reasonably good price delivering all the specifications that are needed for astrophotography. There were only a few astronomy CCD cameras available for high prices. With the Rebel everything changed. It has all the main features needed for astrophotography and it is providing excellent picture quality for low amount of money.
2. SENSOR SIZE
   The Rebels’ sensors are the APS-C size (22.7 x 15.1mm) witch works pretty well for astrophotography because it covers a large area on the sky with any optical instrument.
3. PREVIEW ON LCD
   We are always able to check the focus, the object, field of view etc. on the LCD. It’s one of the most useful things and here DSLRs beats even much more expensive CCD cameras.
4. HIGH SENSITIVITY
   The ISO setting ranges from ISO100 to ISO1600 and more. The picture quality is still OK at high ISO settings and with combining we can get practically noiseless images.
5. PICTURE QUALITY
   Picture quality is just outstanding for this price. At high ISO setting and long exposures the pictures are still useful.
6. DAYLIGHT PHOTOGRAPHY
   The camera you use for astrophotography can still be used for daylight photography unless you modified it. That saves you a lot of money since you don’t need two cameras – one for astrophotography and another for daylight photography.
7. DIGITAL FORMAT
   It’s quite obvious that images from digital camera are in digital format, isn’t is ? Digital pictures are much more fond for post-processing then scanned film.
8. MODIFICATION
   With modifications we can get out even more from Rebels – if we remove the filter in front of the CMOS sensor the camera becomes much more sensitive for H-α part of spectrum and we are able to get more information with shorter exposures.
9. VIEWFINDER
   Viewfinder is extremely handy when we are positioning the camera to deep-sky object. It saves us a lot of time. With the CCDs we are forced to take multiple exposures just to specify the right location and angle of the camera and that’s really time-consuming.
10. CONNECTIVITY WITH PC
    All the Rebels can be remotely controlled with a PC. They comes with the most basic software but on the web you can find a software that turns your Canon Rebel to the fully remote camera!

Of course, there are not only advantages of DSLRs. They have many cons and their quality is not on the same level as CCDs but with some skills we can turn them for really good astrocameras.

Thanks for reading!

Only 10 years ago we’d found astrophotography as pretty expensive. The reason is that the cameras for serious work costed a fortune! Anyway, it was Canon 300D which completely changed everything in 2003. Now it’s only 6 years from that and we all are using DSLRs for astrophotography. Let’s take a look at it:

Canon 300D was the first very good DSLR. It’s price wasn’t too high and the picture quality was great comparing to other cameras. Firstly became very popular for daylight photography but very soon some astrophotographers figured out that it’s possible to get very nice picture with it. The main advantages are that we can set the high ISO level without suffering too much noise, we can always check the focus on LCD screen, we get digital images which we can post-processed with the computer and many more.

But that wasn’t enough for some of astrophotographers. If we take long exposures (above 1 min) that means that the sensor is on all the time and the temperature increase. And when the temperature increase the noise becomes annoying on pictures. This problem can be solved with cooling and some astrophotographers started to modify their Rebels to improve the image quality.

It’s not only the temperature which makes 300D worse that it could be. There is also a filter in front of the CMOS sensor which blocks almost all the light in H-α part of spectrum. That’s the problem because almost all the nebulas in the space consists of this element and when we are capturing we loose almost all the light we want. It’s like looking at Andromeda’s galaxy with sunglasses.
This problem can be solved also. All we have to do is to remove the filter in front of CMOS and replace it with some other or clear-glass. The only way to do this is to disassembly our camera or let someone do that.
For example, the Hutech is the company that produces replacement filters, they can replace filter instead of you, and what is more, you can buy the modified camera at them.
However, Teleskop-Service offers the same in Europe.

On the end I’m presenting you one picture that was captured with “the king of DSLRs in astrophotography”, Canon Rebel/300D/Kiss.
It’s picture of Veil nebula which is located in Cygnus. The exposure was 12 times 5 minutes post-processed in Photoshop and Iris. The telescope was Takahashi FSQ-106 and mount Celestron CGE. I’m sure you like it!

Veil Nebula @ Marjan Žagar & Primož Cigler