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

astrophotography astrophotography, camera, canon, constellation, dark nebula, deep-sky, galaxy, milky way, nebula, stars

Yesterday I have received e-mail from Mathew, asking me about usefulness of SCT telescopes for deep-sky astrophotography. He agreed to reply to his question in this post, since this is pretty general question and others may find it useful too. Here’s his message:

“Hi,

My name is Mathew Oehler, and over the past several months I have become more interested in astrophotography, after having general photography as a hobby for about 6 years.

Last year a family friend was gracious enough to give me a 100mm Orion refractor telescope, and I have gotten excellent use out of it in viewing Saturn, Jupiter, and the Orion nebula among other things.  More recently I purchased a T-ring that enabled me to connect my Canon Rebel to the telescope, and was disappointed in its capability.  I would ideally like something designed to reach deeper, so I can get some clearer shots of nebulas and galaxies. I have heard that Schmidt-Cassegrain telescopes are designed for this purpose, but I’m having trouble finding good information amongst the sea of astrophotography information on the internet.  Are SC telescopes good for this, and will a standard one have an equatorial mount that I can put a motor onto?

Thank you in advance for any help you can provide me!”

The answer is not very simple (as always). The main reason why SCTs are so popular telescopes is their portability and compact size. They have a short optical tube because the light goes three times through it before it reaches the focus. The consequence is that they have long focal length comparing to diameter of the primary mirror which means slow optics (high f-ratio) – typically between f/8 and f/12. And here’s the catch! F-ratio is a king at photography because it tells you how many light the optics gathers per pixel. The lower f-ratio means more light, which means lower ISO setting (less noise) and shorter exposition to go deeper. This is the main reason why SCTs are not so good and popular among astrophotographers. In spite the fact they are compact, they have long focal length, small field of view (a lot of nebulas on the sky are larger than the diameter of the Moon) and require long exposition. Usually they come with mounts which are not capable to guide accurate enough to achieve pin-point stars at longer expositions (5min and more). All their characteristics suits for planetary and moon imaging, where longer focal lengths are needed and guiding is not so critical. On good mounts and with company of high detective CCD cameras they are good optical instruments for small planetary nebulas and galaxies, but I would highly dissuade this type of imaging the deep sky from beginners.

Mathew, I suppose that you have an achromatic telescope, because I have heard just good things about 100mm APO Orion refractor and it is good imaging instrument. I suggest you to start imaging at wide angle, since this is the easiest and the cheapest option. DSLR in combination with kit lens is good start point and your first object are star trails (if you don’t have a mount with tracking) or Milky Way (if you have the mount). It’s good to have in mind that you need to “build” your equipment from the ground, that means that first you need a good tripod, then mount and at the end the optics and camera. Note that good mount is astrophotographer’s best friend and it’s worth to buy a good one in the beginning, because you can put on whatever you want (just camera with kit lens or 16 inch RC). Later on you can buy a telephoto lens or APO middle-sized refractor which has many many objects in range (practically all the M catalogue and long list of NGC objects). If you are interested in little smaller objects you may find 8-10 inch f/4-f/6 high-quality Newton good instrument as well. At the end there are more exotic telescopes like SCTs, RCs which cost a fortune and need very expensive and good mounts (in range of 6000+ USD).

I hope I have answered to your question. You are welcome to leave a comment if I haven’t.

And if anyone have a question related to astrophotography just contact me. I’ll try my best to solve your problem …

equipment astrophotography, deep-sky, equipment, guide, milky way, sct, telescope

I think it’s not right always showing just the best works you produce. Sometimes it’s also good to represent worse pictures to show the world you also have troubles with everything and to encourage those who are not so good at astrophotography yet. I had a disaster last Thursday, capturing the Rho Ophiuchi region.

Last week we had some clear skies out here and on Thursday I decided to go to the near hill named Bohor to caputre the Rho Ophiuchi region, which is a large cloud of colorful nebulas, a part of Milky Way. June is the only month when this region is accessible to photograph from our latitude because it comes the highest on the night sky – about 20 degrees. Se we had clear skies, warm weather, no moon – perfect astrophotography conditions. I packed my mount Vixen GP-DX with SkySensor 2000 PC to the case with all the accessories and went to the Bohor to take some shots. I arrived there 2 hours before the astronomic night, prepared everything, aligned the mount, focused my modified Canon 350D with Canon 70-200 f/4.0 IS L lens and waited for the night. I started shooting at 23.45 LT. After first two shots I saw that everything works OK and went into the car, watching a movie for two hours. When  the film finished I was planning to take some darks and then to go home but when I checked the destination folder for images on my laptop I immediately noticed that something had gone wrong – THERE WERE JUST 6 PICTURES!!! OMG, I was awake till 4 a. m., getting just 6 frames. There was noting else to do, I had about half and hour till the dawn so I packed up the mount and everything and went home.

Nevertheless, on Sunday I decided give it a try and I processed the image. Honestly, I suspected to be worse, but it’s far from that I was planning to do. So here you have, Rho Ophiuchi nebula, not so perfect:

Rho Ophiuchi region @ 6 x 5min, ISO 800, RAW. Author: Primož Cigler

I hope that next time I will show something more attractive. And which are yours most common troubles you are dealing with?

Thanks for reading!

astrophotography, personal astrophotography, canon, deep-sky, images, milky way, nebula, stars

I have decided to publish step-by-step how-to tutorial for astrophotography beginners. It’s International Year of Astronomy and I am pretty sure that there is a lot of people who are interested in astronomy and astrophotography, but they don’t know where to start.

Weekly I will publish articles guiding you trough the process of astrophotography – from equipment to the imaging tips and processing of images on the computer. Each article will cover specific part and every single of them is important for good results.

There are several different types of objects up there and they require different type of equipment, capturing, processing. In this tutorial I will focus on deep-sky astrophotography with DSLR camera and with amateur equipment in range up to 5.000$. If you are beginner – don’t be afraid! There is a possibility to start astrophotography with much lower budget and get stunning results. You just need to be patient and don’t give up.

Contents:

• Part I: Choosing an Object
• Part II: Camera Settings
• Part III: The Telescope

Don’t forget that we all learn from mistakes. With patience and enthusiasm everything is possible. Enjoy the Universe and Clear Skies!

NGC6888 - The Crescent Nebula @ Primož Cigler

astrophotography astronomy, astrophotography, deep-sky, equipment, guide, images, milky way, nebula, stars, tutorial

Yesterday I haven’t written a post because I was travelling. I am on holidays now, so I’ll publish just one deep-sky astrophotography:

M42 (Orion nebula) @ Primož Cigler

Orion nebula is reflection nebula in constellation Orion (the hunter). It is located approximately 1300 ly from us. It’s just the brightest part of very large nebula complex which stretches between almost all the brightest Orion’s stars and consists of Barnard’s Loop, Horse-head nebula, Flaming-tree nebula and M42, M43 and NGC1977:

Orion Complex (M42, M43, NGC1977, Horse-head, Flaming-tree nebulas @ Primož Cigler

The first picture was taken with a telescope Orion Optics Europa 8″ @ f/4.5 with Vixen GP-DX mount and auto-guided. The conditions were bad (light pollution on the South, half of moon, bad transparency and seeing). The camera was unmodified Canon 350D. The picture was taken on 18th of December 2007 and it’s the combination of 39 times 3 min exposures and 10 times 20 s exposures (for core details).

The second picture was taken with a lens Canon EF 70-200L IS USM f/4.0 at 200mm and f/4.5 with modified Canon 350D piggy-backed on Vixen GP-DX without auto-guiding. The exposition was 25 times 3 min. The picture was taken on 8th of January 2008.

That’s all for today, thank you for reading and watching!

astrophotography astrophotography, constellation, deep-sky, images, milky way, nebula, Orion, stars

In this post we will take a look at one of the most important equipment for astrophotography – that’s camera.

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

astrophotography, equipment 300D, astronomy, astrophotography, canon, equipment, images, milky way, rebel, veil

From time to time I’ll publish some my astrophotos here. And today, for Christmas eve I’d like to present you one of my images.

Pleiades @ Primoz Cigler

Pleiades are stargroup in our local Galaxy, Milky Way. They are approximately 440 ly (light years) distant from us which is “pretty near”. They’re also known as M45 (Messier’s catalogue), Seven Sisters, Seven Stars. In the sky we can find them in the constellation of Taurus. They can be seen by naked eye as a group of seven stars but with indirectly observation we can notice that there is some blue glow around and between them. This blue glow are gasses in the universe which are illuminated by stars in the group.

Pleiades are very frequently target of astrophotographers because they are very beautiful, they cover a huge area in the sky and they are resonably bright comparing to other deep-sky objects.

I took this photo 19th January 2007 with camera Canon 350D and telescope Orion Optics 8″ @ f/4.5. The exposure was 9 times 5 minutes, which were combined and processed with Iris and Photoshop. All the setup was autoguided with SkyWathcer 80/400 and Meade LPI.

I hope that you like the image. You can leave the comment if you do.

astrophotography astrophotography, deep-sky, images, M45, messier, milky way, pleiades