Starting out imaging

[dave1978]

After seeing the results recently people on the forum have had with their DSLR's im very temepted to give it a go either using a telescope or just the camera alone on a tripod. I have an 18-55 and a 75-300 lens for the camera.

I have a skywatcher 130 and a Celestron 102slt refractor both utilising the Celestron go-to mount. My camera is a Sony Alpha 200, i have been through the setting and can set the exposure time and ISO etc.

So my questions are, using Orion nebula as example?

1 - which of my 2 telescopes would be best suited?

2 - once nebula is centred and focused in an eyepiece i remove the eyepiece and attatch the camera, will there be a difference in focus?

3 - is it worth using a tripos and the 75-300 lens with long exposure?

thanks

[Shibby]

1 - I'd have to say the refractor; you probably won't even be able to achieve focus with a 130P & DSLR

2 - Yeah, you need to focus with the camera in place. I would recommend a bahtinov mask (mine is home made) and taking 10s exposures to check focus. The focus is very important.

3 - Definitely; depending on what mount you have, the tracking will enable you to take much longer exposures without star training.

PS: I would start with the lenses alone; the wider FOV will be much more forgiving while you learn

[jgs001]

Ok...

1) The 102, the same reason as Lewis, although you will almost certainly need an extension tube to reach focus with the 102. I'd also suggest some form of chromatic aberation filter to help suppress the blue halos... The baader SemiAPO works well.

2) Focus with the camera. Pick a nearby bright star and use that to focus, before moving to your target.

3) The 102 will give good image scale, but the 70-300 might be better for the quality of the lens.

You will need to track ideally, and the SLT mount will let you get around 40 - 45 seconds on M42 (focal length isn't an issue for this, but longer focal length is harder on the mount drive accuracy), but the lower in the East/West you can go, the longer you can go. You also need to balance the scope/camera combo out, you want it about balanced, but slightly tail (camera end) heavy, this keeps the gears engaged and helps a lot.

(I started imaging with an ST80 on an SLT mount with a 450d)