Astronomy and DSLR Astrophotography Blog

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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I haven’t been writing for a while now because I had so much stuff to do. This year I am finishing my secondary school and I am already preparing for the exams. Nevertheless, I haven’t been so passive at astrophotography. I have to admin that drive for my mount was damaged since summer and I hadn’t been capturing astrophotos for a half of the year. A friend of mine repaired it last month so I ordered some other cool stuff to upgrade it: I changed the holder of secondary mirror (spider) and mounted new rings for guidescope.

Yesterday I calibrated system again and did this shot of NGC2403 galaxy in Camelopardalis:

Galaxy NGC2403, taken with Orion Optics Europe f/4.5 on Vixen GP-DX SS2K @ Photo Credits: Primož Cigler

It’s composition of 26 exposures, each of 5min on ISO800 with Baader modified Canon 350D and IDAS LPS P2 filter. The mount was Vixen GP-DX with SkySensor 2000PC and the telescope Orion Optics Europe 8″ f/4.5. I processed image with Iris, Photoshop and Lightroom. It’s not my the best image of this object, but I am satisfied with a result because it’s a proof that everything is OK with the mount.

My Astrophotography tutorial will be continued as soon as I find more time.

Clear Skies!

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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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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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As I promised here, today I will present the alt-azimuth mount, why it’s good and why it isn’t for astrophotography.

The main difference between equatorial mounts and alt-azimuth mounts is the direction of moving of axis. While at equatorial mounts one (R. A.) axis is parallel to the Earth’s axis of rotation at alt-azimuth one axis is always horizontal and another is vertical. In the beginning it’s much more friendly for the user since it’s very easy to use but for astrophotography is practically useless. A lot of telescopes for visual astronomy comes with alt-az. type of mount. When we are watching an object and we don’t have a drive installed on our mount for automatic slewing we usually move the object in the center of the field, observe it for minute or so and then we move the telescope again. But that doesn’t work for astrophotography because the tracking has to be smooth and constant.

Another problem is that there alt-az. mounts are always less precise because the both axis has to be moved in the same time and that means that the controller has much more work to do and that every single moment the star has different direction and relative speed in the sky.

The last but not the least problem is field rotation wich occurs due to relative spped of the stars mentioned above. As we know the stars are virtually moving around the northern and southern celestial pole and when we have rotating the objects that are more distant from the centre of rotation are moving faster. And that occurs at alt-az. mounth that when we do some minutes long exposure – the stars in the centre of the field are sharp but on the eadges they looks loke they are rotating around the centre of the picture.

To conclude, if you like just to observe the sky the alt-azimuth mount is a good idea since it is easy to use and easy to build (it’s not expensive). But if you are planning to do the astrophotography then youhave to avoid alt-azimuth mounts.

Thanks for reading!

Image source: See Viewo

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The following, also very popular mount, is fork equatorial mount. As the name tells us it is one version of equatorial mounts which means that one of two axis is parallel to the Earth’s axis of rotation. In this way we avoid slewing at the both axis at the same time when capturing the astrophotos and simplicity almost always means less errors.

We find fork equatorial mounts mostly in observatories since they are more often made for bigger telescopes and not-portable. The exception here are two the biggest manufactures of astronomy equipment: Celestron and Meade. Meade’s the most popular telescope – LX200 – has this type of mount. Nevertheless, the most common use of fork equatorial mount is in smaller to mid-size observatories – mostly professional.

The fork equatorial mount exists in rough from two parts: the base and a fork. Fork is attached to the base and enables moving from East to West (R. A. axis) whereas telescope is attached in the middle of the fork and allows us to navigate from North to South (Declination axis). The main advantage of the fork equatorial mount is that it doesn’t require meridian flip – that problem occurs at german equatorial mount when is passes the meridian and has to go 360° around or it stops slewing.

To conclude, fork equatorial mounts are mostly used in the observatories, they costs much and are heavy, accurate and not-portable.

I have worked several times with fork eq. mount but I don’t like it at all! I have german equatorial at my home and it suits me the best! For everyone who needs portable and reliable mount I advise german equatorial.

Thanks for reading!

Image source: Wikipedia.org

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There are several different types of equatorial mounts but surely the German Equatorial mounts are the most popular among amateur astrophotographers and astronomers. Let’s see why?

At German’s type of the mount we have two axis: one is parallel to the Earth’s rotate axis and another is rectangular to it. This is because when the mount is tracking there is no need to move both axis as the same time but just one. This makes those mounts so popular and useful because in theory you need just one motor to track the moving of the night sky. You also don’t get any other errors like field rotation or similar.

The axis which moves from east towards west is R. A. (Right Ascension) axis and the another one that enables us to move telescope from South to North is named Declination axis.

At this version of mount we need counterweights to balance the whole system. This procedure is very important to do it as precisely as possible because the better balanced mount slews better!

When setting-up we have to do everything in the right order to assure that in the end our mount tracks as precisely as possible:

1. Put the tripod to the flat and solid ground.
2. If you are using tripod make sure that the leg labelled with “N” (North) is positioned right to the North. Help yourself with a compass.
3. Attach the equatorial head to the tripod or pier.
4. If your mount has a polar finder check the time and a date, rotate the two wheels on the R. A. axis to the right date and time and check the position of Polaris (Northern Hemisphere) or the Southern Cross (Southern Hemisphere) in the polar scope and align the stars with the marked positions.
5. If necessary do a drift-align (the guide how to do it follows in the next posts).
6. Put a telescope on a mount.
7. Balance the whole system with counterweights and moving of the telescope tube.
8. Enjoy the good tracking!

That’s short review of the German equatorial mount. More read:

• http://en.wikipedia.org/wiki/Equatorial_mount
• http://starizona.com/acb/basics/equip_mounts_gem.aspx
• http://science.howstuffworks.com/telescope5.htm

Image source: http://www.company7.com/vixen/mounts/counterweights.html

Thanks for reading!

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As we all know, the sky above us is apparently moving. The sun, the moon and stars are travelling every day from east to the west. This fact is not very practical in astrophotography especially because for deep-sky imaging the long exposures are obligatory. That means if we just put the camera to the usual tripod and make a one minute lasting exposition then we get just the star trails. The following video demonstrates the virtual rotation of the southern sky. The Megellan’s Clouds are visible also:

I believe that everybody understands what I mean.

However, this daily ritual of our home planet is not very appropriate for astrophotography. We need special mounts with tracking which tracks with just the same speed as the sky is moving. The Earth rotates quite slow so the stepper motors must track really slow and smooth to assure enough good tracking. All the bearings and gearwheels must be made very precisely to avoid any unpredictable jumps and so on. It is extremely important that we have a stable tripod or pier otherwise everything is worthless.

In general we three different types of mount: Alt-azimuth mount, German equatorial mount and Fork equatorial mount. All three has their advantages and disadvantages and every single of them I will describe in the following posts.

Stay tuned!

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