Archive for August, 2009

Latest Spirit Update

August 30, 2009

Spirit and opportunity are two martian rovers which seem to be exploring Mars forever. Nothing can take them down — dust storms, harsh winter or soil traps. Spirit is in trouble though, since spring of this year she is stuck in the sand and can not move. And now she is getting even more troubles. Dust storm is blocking the sun and Spirit is not getting enough power. Will this be the end? Only time can tell, so enjoy it’s pictures while you can:

Full circle view from Spirit panoramic camera. This location is called Troy, Spirit is stuck there since spring 2009. Click for smal, 260 degree view. Image credit: NASA.

Part of a full circle view from Spirit panoramic camera. This location is called "Troy", Spirit is stuck there since spring 2009. Click for small, 360 degree view. Image credit: NASA.

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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.

Space Shuttle Gas Tank

August 26, 2009

Honestly I never thought about that big thing as a gas tank. For me it was another little discovery today after watching this video:

Not painting this thing saves about 600 lb (272 kg) in weight. Is this how much paint weights? It’s probably some super heavy duty pain, so should be pretty big amount saved in dollars too. When you watch Space Shuttle launches on TV news, you rarely think of such stuff.

Cariann says that color was changed from white to orange on STS-3 mission, I am not lazy, I checked it out, so you don’t have to ;-) This is true, on YouTube you can find STS-1 and STS-2 launches, both of them have white external tanks, while STS-3 is orange. The latest STS-127 is orange as well.