Getting started with what I have...possible?

[Rykielz]

I've been reading this sub forum for the past few days and I never really knew it was possible to take pictures of stars and nebulae with a DSLR!

I like star gazing and space but I'm not sure if that type of photography is for me (still trying to figure out what I like). I was wondering what I could do to just start off and get my feet wet with what I have.
I have a T1i, kit lens (18-55mm), nifty-fifty and I have Sigma 70-300mm on the way. A good Tripod and cable release is next.

Considering what I have/will have in a few weeks what can do with it in terms of astrography?
I think I'll be able to take some decent pictures of the moon with the Sigma 70-300mm, but I am more interested in pictures of nebulae and the milky way galaxy. Is that possible with what I have or do I need a telescope + equatorial mount?

[ameerat42]

Hi Rykielz. Something to understand first off. The night sky is a mixture of "point sources" and "extended sources" of light. Stars that you can never magnify past "points" - you can only make them appear brighter - are examples of the former, while planets, moons, the sun, nebulae, and everyday objects are examples of the second.

Stars (point sources) respond only to the size of the objective (lens or mirror, and it's efficiency) used to image them, regardless of the actual f-ratio used.

Extended objects rely (more) on the actual f-stop, because the image they produce is magnifiable.

Now, with the equipment you've got, set the camera up with the widest angle lens that gives you the maximum diameter of glass for the light to pass through. (For example, a 50mm lens at f/2.8 gives an aperture of 17.8 mm.)

Pick a nice, moonless, dark area of interesting sky, set you camera at about 400ISO, and let it go for about 30 seconds. Look at the results and go from there.

Note that, the longer your exposure time the longer you star trails. As you progress, look into image stacking software (too much for this thread).

For the moon and your 300mm lens, you'll get an image of about 3mm width at the sensor.

Make sure your tripod is steady, and if you can, lock the mirror up to avoid vibrations.

There's a heap more, look for similar threads here. Good luck (and wish upon a star or two). Am.

[Rykielz]

I see... That helps alot! I have read up on image stacking and star trails software, can't wait to give it a shot!

I should be at ~480mm on my crop body with the 70-300mm lens, would that be enough for a decent sized moon?

set the camera up with the widest angle lens that gives you the maximum diameter of glass for the light to pass through.(For example, a 50mm lens at f/2.8 gives an aperture of 17.8 mm.)

If I use the 50mm, should I use it at 1.8 or stop down abit?not really sure how DoF works way up in the sky.

Silly question: I'll be focusing manually right?

[jmx]

For nebula photos, you'll really need an equatorial mount to get anything worthwhile. They start around $700, and a decent one can be had for $1500. The 300mm lens aimed at Orion (one of the bigger brighter nebulae) will get you something decent on an equatorial mount. For other nebula, its 400-500mm and up needed. This will take many many months of practice, and many hours of computer processing time after the fact.

For milky way, just use your 18-50mm lens and try 30sec exposures, maybe at f/4 ISO 800, using RAW. Yeah, you'll need to focus manually. Convert your raw to 16bit TIFF files and play with them in photoshop or gimp. This all could be done successfully on your first try if you have a dark sky. Same with star trails.

[ameerat42]

Look at this link for some useful info. (There are others.) http://home.hiwaay.net/~krcool/Astro/moon/howtophoto/
The first table is image sizes for focal length.

There's no DOF to worry about for sky photography. Try a shot with f/1.8 and then a few stopped down.

What jmx says is right for really getting into it. Am

[Rykielz]

Thanks JMX and Am! I don't mind spending money on equipment but I want to know if I will enjoy it first.

[A.S.I.G.N. Observatory]

Here's what can be done with a DSLR, wide lens and a simple image stacking program.

http://www.asignobservatory.com/index.php?option=com_content&view=article&id=84&Itemid=125

All on a cheap Aldi $19 tripod.

Baz.