Trying to see what I can manage with camera/lenses alone. Here's a first stab at the Orion nebula. I think I need to take some shorter exposures to recover the trapezium area and then blend them together...

[fractal]

Wow.. that looks great!

[joodiespost]

nice shot! what camera and how did you do it?

[pingflood]

I used my 50D and 400/5.6 lens. It's six 30 sec exposures at ISO 1600 stacked -- I really need to add a LOT more since there's a bunch of noise left. I'll try something like 20 60 sec exposures and then a handful of shorter ones to get the detail in the trapezium area, then stack the two sets separately and blend in photoshop...

This stuff is HARD!

[goddo31]

Quite an awesome job there mate - I bet it's hard, but I'm looking forward to seeing how you go.
Thanks for the exposure info that's pretty interesting.

cheers,

[Ben_Edict]

That's a good first image. Just noisy. For the Trapezium you need shorter exposures, so that should be easy. How did you track the camera? On a simple tracking mount or piggyback on a scope? At 400mm fl you already need considerable precision, to keep the pinpoint stars.

My own first attempt with a K20 is here. The exposure varies between 16s @ 800ISO to 30s @1600ISO. It is always hard to achieve a realy black background without loosing faint nebulosity... SO I decided against too vivid colours in favour of preserving fine tonality. The result is certainly a bit more dull, than yours: (I don't quite know why, but it looks especially wafull after uploading. The original file looks much better!)

[pingflood]

I have pretty dark skies so can get away with decently long exposures. As for tracking, I'm using an AstroTrac TT320X. It's given me 5 minute exposures with round stars at 300mm which is pretty impressive. I had to stick to shorter with the 400mm though since the weight of it was twisting the ball head mount plate slowly and if I let it go for 2 mins or more I got slightly oval stars. Going to have to look into a better suited head to hold the camera/lens I think... I gather ball heads often slip ever so slightly even if you get the mount plate solid.

[Ben_Edict]

I have pretty dark skies so can get away with decently long exposures. As for tracking, I'm using an AstroTrac TT320X. It's given me 5 minute exposures with round stars at 300mm which is pretty impressive. I had to stick to shorter with the 400mm though since the weight of it was twisting the ball head mount plate slowly and if I let it go for 2 mins or more I got slightly oval stars. Going to have to look into a better suited head to hold the camera/lens I think... I gather ball heads often slip ever so slightly even if you get the mount plate solid.

That's interesting. We have an Astrotrack in our Astronomical Association for travelling, but we never could use it for anything longer than 200mm (indeed I never used it personally, as I use an old Vixen SuperPolaris for travelling).

I build simple massive clamps when I used a C8 as a tracking plattform in the past (4 cameras at once). It was not really user friendly, because you had to tighten screws with spanners - but no slippage...

Ben

[pingflood]

I've seen Gain Lee use 800mm and up with his AstroTrac -- I think the key is the polar scope. I've heard stories about the collimation being off on a bunch of them, and then you are pretty much out of luck trying to track at longer focal lengths.

Once we've moved overseas I will probably setup with an HEQ5 or EQ6 mount and autoguiding, and then get a decent APO refractor to shoot through. But for now, the Astrotrac is awesome for learning AP (and processing) and getting my feet wet.

[Ben_Edict]

I've seen Gain Lee use 800mm and up with his AstroTrac -- I think the key is the polar scope. I've heard stories about the collimation being off on a bunch of them, and then you are pretty much out of luck trying to track at longer focal lengths.

Once we've moved overseas I will probably setup with an HEQ5 or EQ6 mount and autoguiding, and then get a decent APO refractor to shoot through. But for now, the Astrotrac is awesome for learning AP (and processing) and getting my feet wet.

Ah, thanks for that info. We'll have to have a look at the Polar scope then. Should be easy to correct. It sure looks like a very convenient tool for the occasional "snapshot".
Ben

[pingflood]

Yeah, I'm really enjoying mine so far. Check out Gain Lee's stuff with it and you can see that it can perform incredibly well if you get it setup right:

ASTROTRAC PHOTOGRAPHY C O S M I C B U G

[joodiespost]

so why is stacking necessary? what does that accomplish?

[Nitrok]

Interesting photo. I didn't know you can catch Nebula without telescope.

[Ben_Edict]

Interesting photo. I didn't know you can catch Nebula without telescope.

It depends on the size of the nebulae. If they are very small (a couple of arcsec across), you need a telescope to get a meaningsful image. But many nebulae, like the Orion nebula, are so big, that most telescopes focal length is too long (and the angle of view too small). Here photographic lenses from 200mm to 500mm are quite common. The problem is only, that on brighter stars you usually get the typical blue halos around the stars, if the lens is not fully apochromatic.

Ben