Astronomy and DSLR Astrophotography Blog

Dark nebula is a nebula in the galaxy which absorbs the light from the background. There are two types of them in general – one can be seen because they block the light of the emission nebulas in the background. One of the most spectalular of them is Horsehead nebula in Orion. The others block the light which comes from the stars behind them and those are best seen where the density of the stars is the highest – in the Milky Way. Dark nebulas consist of cold materia in the space, which is not hot enough to transmit the light.

In the night from 23th to 24th August I have gone to Bohor to take some photos of Elephant’s trunk, but I had to end taking photos about at midnight because the object passed the meridian and I couldn’t track it anymore. I had to make quick decision which object to capture the rest of the night and I choose the dark nebulas B334, 336-7 in Aquila, near Altair. I had no internet and I hadn’t a clue how this nebula looks like. Some of dark nebulas are really breath-taking and impressive (who doesn’t know Horsehead). Well, mine isn’t so spectacular, but I am pretty satisfied with the result. The next day I have checked the google image search for this nebula and found nothing, which means that I am one of the first who decided to “burn” his CMOS sensor on this object for some hours After all, that counts as well …

Here you go:

Dark Nebulas B334, B336, B337 @ photo: Primož Cigler

Some technical data about the exposure, equipment and so on:

Object: B334
Date and Location: 23. 8. 2009, Oslica, Bohor
Exposition: 26 x 5min
Camera: Canon 350D, Baader mod., ISO 800, RAW
Optics: Orion Optics Europa 20cm f/4.5
Mount: Vixen GP-DX SS2K
Autoguiding: SW 80/400 with QHY5
Processed in: Iris, Ps

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Yesterday evening it was clear outside and the Moon was rising at about 1.30 so I had 2 hours of total dark and this is enough for testing the new autoguiding camera QHY5. The target was M51, the second time. While I was deciding what to capture I realized that I will have to move to better location since from my backyard the southern sky is totally useless because of road lamps.

I managed to make a new cable for QHY5 so now it works with SkySensor autoguiding port. With that I decreased the number of cables from laptop to my mount from 5 to 3. Now I need only USB connection between PC and Camera, Bulb shutter release cable and USB connection with QHY5, which is great. I am planning to buy a new CCD for astrophotography so after that I will need only 2 cables. No more mess around the scope, finally!

So, I have just processed the image, the result is shown below:

Spiral Galaxy M51 @ 26 x 5min, ISO 800, RAW

I have also taken a shot of my equipment, at the “working” state

My Astrophotography Equipment

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Finally I have more time. The exams are almost finished so I have three months of holidays now and I hope that I will take some good astrophotos in this time and post it here. I will also continue with Astrophotography Tutorial but for today I have prepared something more fresh. The last week I have ordered new autoguiding camera for my setup. The previous one, Atik ATK-2HS, was not mine actually so I decided to buy the new one. I have ordered QHY5 from UK, the astronomy store named Modern Astronomy. The shipment to Slovenia costed only 10 pounds and it took only 4 days to arrive.

The first impression was very positive! Even though it is “made in China” it looks very well designed and made. The build quality is on very high level. It is not plastic like Atik, but metallic. The original package comes with camera, T-2 to 1,25″ nosepiece adapter, USB cable and setup instructions. I have also ordered RJ-11 cable for direct autoguiding via camera.

I got impressed when I unscrewed the nosepiece because of the size of the CCD. It seems really huge comparing to tiny CCD detectors in webcams (Atik ATK-2HS also uses ordinary 640×480 one). The resolution is 1280 x 1024, more specification are available at the QHY website.

QHY5 without nosepiece

The best thing is that QHY5 has T-2 thread which perfectly fits to my autoguiding telescope so I can just screw it on.

QHY5 on the autoguiding telescope

As you can notice it has two ports in the back side. One is USB 2.0 port for connection with the computer and another is ST-4 compatible autoguiding port for direct connection with the mount. I am using Vixen SkySensor hand-controller and I though that it is compatible but in fact it isn’t, because Vixen uses it’s own standard for autoguding. The connector is the same but wires are connected differently so today I am going to make a new cable. The camera has also build-in red LED diode which is too bright and could be disturbing in a completely dark so I pasted a black stripe over it.

Back side of QHY5

The camera comes with one A4 paper sheet of instructions how to setup. The drivers are not included, you have to download it from the Modern Astronomy site. The setup is really simple, you just install the generic driver and plug in the camera. Then you have to install additional driver for the autoguiding software you are using, in my case Guidemaster. All the main autoguiding software are supported, including ASCOM platform.

To sum up, I am very satisfied with the purchase. Two days ago I had a first light and everything worked fine. I was planning to capture M102 but ended with just 2 pictures because it clouded. This is 100% crop of one of them as a proof that camera guides OK:

100% crop of M102

I hope you enjoyed the review. If you have any questions don’t hesitate to ask under the comments

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In this part we’ll take a look at some telescope specifications. It’ pretty common question what’s the best telescope for astrophotography. The answer? Such a telescope doesn’t exsist. There are several different telescopes available on the market and every serves its own purpose.

The Newtonians, for example, are very handy and good instruments for astrophotography, though they need to be collimated very precisely and often. On the other hand ED and APO refractors are better, but they are much more expensive. The SCTs are compact and provides longer focal lengths but they are rarely well-made.
So the question is what telescope to choose for deep-sky astrophotography with DSLR camera?

There are several different answers, depending on our object to be captured. Let’s start with the largest: wide-field images of the sky. If you are planning to capture the wide-field images of the night sky you don’t need the telescope but the lens. This is because telescopes are optical instruments with longer focal lengths and that means smaller field of view (FOV) whereas the lenses has a really wide range of focal lengths, from 4mm up to 1200mm and more. The most common target in this range of objects is the Milky Way. This kind of astrophotography is especially appropriate for beginners because the auto-guiding is not necessary and most of the cameras already comes with “kit” lenses which have wide field of view.
One of my images of Milky Way in Cygnus taken with 50mm lens:

Mosaic of Milky Way taken with 50mm lens

Next step are large deep-sky objects. For this objects I recommend the middle-sized APO and ED refractors (80-120mm) or telephoto-lenses. If we have a good mount we still don’t need auto-guiding at this focal length but in most cases it’s better to use it if possible. The most common objects in this range are constellations, detailed locations of Milky Way, large nebula complexes (Orion) and bright comets. The next picture represents Comet Holmes as it was seen 8th January, 2008, taken with Canon EF 70-200 f/4.0 lens:

Comet Holmes with Canon EF 70-200 f/4.0 at 200 mm

Next are middle-sized deep-sky objects. The best focal lengths for them are from 1000 mm to 2000 mm. Newton telescopes and larger refractors has the most appropriate specifications for imaging this type of objects. The auto-guiding is really necessary here because just the best mounts can slew accurate enough to assure the pin-point stars at these magnifications. In this range we find almost all the object from Messier’s catalogue and the brightest NGCs. One of my pictures taken with Orion Optics Europa 8″ f/4.5 are Pleiades.

The last type of object, accessible to amateur astrophotographers, are smaller deep-sky object. They are mostly galaxies and planetary nebulas. Because they are small, we need long focal length to capture the details inside them. The SCTs and other catadioptric telescopes are the most appropriate for these objects.

So, now you know which objects are in the range of your equipment. I hope that you enjoyed reading.

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So let’s continue with the tutorial. The last time we have chosen the object. Today we will take a look at some common camera settings for astrophotography. In this tutorial I will be using modified Canon Rebel XT (350D). Modified means that I have replaced original filter in front of CMOS sensor with replacement filter of Baader. I have listed some good guides how to do it here.

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.

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The very first thing we have to do when we start an astophotography is to choose the object. We have to know what are benefits of our equipment, what we are planning to capture, what is FOV (field of view) of our telescope and camera, how “deep” our system goes and so on. Let’s take a look at some of this questions.

When we are deciding which object we will be capturing we can help ourselves with different astronomy software. They display imaginary sky and we can take a walk into nigh sky, choosing the objects, checking the rising, setting, magnitude, distance, … All this parameters are important when we are selecting the target for astrophotography.

There is a lot of different programs available on the web for astronomy. Some are free and others are paid. There are some of them:

• Starry Night
• Hallo Northern Sky
• Cartes du Ciel
• SkyMap
• Stellarium

In this tutorial I will be using Starry Night. It is paid but it offers endless of useful options like FOV and has  really a huge database of objects.

First of all we have to know what type of object is appropriate for our astrophotography setup. The predispositions for deep-sky astrophotography are:

• Telescope of telephoto lens
• Mount for tracking that tracks very accurate (under 2″ of error) or has option of auto-guiding
• DSLR or CCS camera with remote control of exposition

In Starry Night we put the parameters in the the section Equipment:

Then we select FOV of our telescope and camera. The program displays us the rectangle that out astrophotography setup “sees”.

So, what’s next? We have to choose the target that we are going to capture. Here are some basic directives:

• Make sure that object is in the field of view at least 3 hours in the total darkness. It has to be at least 15-20° above the horizon all the time of the capturing. Make sure that you have specified your date/time and location accurately!
• Make sure that object roughly fits to the field of your telescope’s view. The rectangle that we have specified before helps us at this step. Make sure that it is not too small – it doesn’t make any sense if you are photographing a very small planetary nebula at 600mm of focal length.
• Make sure that it is not too dim. Almost all the objects from Messier catalogue are OK, and all the bright objects from NGC makes good target as well. If the object is dimmer than 10th magnitude then bigger telescope then 8″ is recommended.
• If you don’t have GoTo or it’s unreliable then make sure that you are able to find the object in the night sky. Help yourself with bright stars, print the carts out.
• If you are using german equatorial mount then make sure that object doesn’t pass the meridian during the planned time of capturing.

Some good objects to start with: M45 (Pleiades), M42 (Orion Nebula), M44 (Beehive Cluster), M27 (Dumbbell Nebula), NGC7000 (North American Nebula), M31 (Andromeda). They are all bright and easy to find even with binoculars.

And here we are. We have the object.

Next time we will take a look at the conditions in the athmosphere that affects to the astrophotography – the weather, seeing, transparency and more.

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I am quite sure that you have already heard about stock photography. If you didn’t let’s Google it or read this article on Wikipedia. In short: the main idea is to sell the images that has commercial value for low price. The Stock sites has a lot of photographers who upload their photos and the buyers (designer, web-designers, magazines, design studios etc.) who buy these images and pay a little amount of money comparing to hiring the professional photographer.

More than one year ago I have registered at one of the leading Stock engine – Shutterstock. I haven’t known this type of photography and I haven’t expecting very much. I just wanted to try the feeling of selling the photos on-line. And that’s where it started.

At the very beginning you have to upload 10 pictures and at least 7 needs to be approved to became a member. I have uploaded some my the best astrophotos and next day in the morning there was a success: 3.25$. I forgot to mention that they pays you 0.25$ per download, no matter how large the image is. There are also another Enchanced licenses and you are paid much more for them – up to 30$ per download, but they are rare.

Later on I have uploaded also a lot of other images, non-astro. But very soon I have figured out that they are not selling as good as the astrophotography pictures do. I think that the reason is that there is not a lot of astrophotographers who sells their pictures on stock sites and consequently there is a lack of these images on stock sites.

Would you like to join? Here are two mayor stock photography sites where I am registered. I would be delighted if you register trough my referral:

• Shutterstock
• iStockphoto

And here is the image which sells the best. 345 so far and counting …

Pleiades @ Primoz Cigler

Thank you for reading! I hope that this was interesting reading …

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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

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Canon’s low-priced range of Digital Single Lens Reflexive (DSLR) cameras are extremely popular between amateur astrophotographers. In this group we can find the following cameras as they appeared on the market:

• 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!

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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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