Archive for the ‘Stargazing’ Category

My First Astrophotography Pictures

August 29, 2009

Astrophotography is a complex and expensive hobby. But nothing can stop you from getting some decent results from your backyard. Of course it’s nothing like Hubble beauty you see in Internet, but because you got those pictures yourself they have a special meaning to you.

Let’s say you got your first astrophotography telescope, how to get your first pictures? The simplest and fastest way is this one:

1. Use Stellarium to find the object you want to take picture of. At the time of observation it should be high in the sky (the higher the better, if it’s above 45 degrees it’s considered good already :-) Object should be bright, magnitude ~7 or less is fine, and large enough 10 arcminutes or larger. Messier objects usually fit well for this description.

2. Setup your telescope, hook up camera to telescope and do a 3 star alignment. Don’t bother with drift alignment for now. You probably can not shoot pictures with longer than 30 seconds exposure anyways.

3. Pick a bright star near the object and focus your telescope with bahtinov mask.

4. Go to object and center it, you can shoot picture with maximum ISO setting on your camera, usually you will be able to see the object from one photo in this case.

5. Don’t forget to set your camera to RAW format, you can use any ISO setting, ISO 800 or 1600 isually most common used, but it does not really matter, ISO 100 works just as good, because ISO setting does not change actual sensitivity of the sensor. If you caught photon from distant star you caught it no matter what your ISO setting is.

6. Shoot as many object pictures as you can, without connecting your camera to computer you probably will be limited to 30 second exposure time. These pictures are called lights.

7. After an hour or so — check your focus on a bright star again.

8. After you have a desired amount of lights (the more — the better), put a lens cup on your telescope and shoot some dark pictures (10-20 is enough).

9. Use Deep Sky Stacker software to stack your lights and darks. This is the simplest free one I found, you just open your files and click “stack”. There are a lot of parameters, don’t bother too much with them, go with recommended ones.

10. After you got your stacked picture (a huge TIFF file), open it in Photoshop (my wife is a designer, I am lucky she has one) or in GIMP (this program is free) and process it. Processing stacked image is a science itself, I am just starting, so I am not very good at it. The main things you should do is to adjust levels and curves. Once I learn more about it, I will do a separate post. Keep in mind — this step is very important, your stacked result image will look nothing like the one you can get after post processing.

Here is what I got with my 70mm refractor from front yard. Unfortunately I don’t have a dark place near my house, there is so much light from everywhere , so I can read while I take pictures :-)

M27 Nebula pictured from my front yard with 70 mm refractor.

M27 Nebula pictured from my front yard with 70 mm refractor.

M13 globular cluster

M13 globular cluster. Here you can see I screwed the very middle of it while casting Photoshop spells.

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Meteor Shower On Wednesday

August 8, 2009

Perseids meteor shower is coming! Wednesday August 12 will be the best time to watch Perseids. We can expect 1-2 meteors a minute at that night. Don’t worry if you don’t have telescope or binoculars, you don’t need any equipment to watch the meteor shower. Here is a short video explaining what are meteors, where do they come from and how to observe them:

Astronomy magazine also posted a tutorial video, it is not so beautiful as the above, but has more information :-), you can watch it here. Let’s hope we’ll have a clear sky that day.

Best Astrophotography Telescope

July 12, 2009

I finally compiled all the stuff I learnt while looking for my first telescope into one nice simple guide. On this page I will post everything I learn about digital astrophotogrpahy. Currently I don’t know very much, that’s why there is only one article there :-)

The first and so far only article is about how to choose the best telescope for astrophotography. It contains minimum knowledge you should have when choosing your first telescope and as usual it has a lot of nice pictures.