Astro Modified 1100D... Tripod... Lenses... 1st time out help please!

[Fishpaste]

Hi -

Due to catastrophic car failure last week (cam belt broke taking the engine with it!), I am unable to order my nice new Skywatcher ED80 and HEQ5 for a few weeks...

However - I've just received my new Astro Modified Canon EOS 1100D (yay) - and want to put it to the test.

My question is this - using only this new astro camera with a standard (none tracking tripod) and a couple of lenses (18/55 & 70/300) - where would be a good place to point the camera first time out.. and using what settings?

I'm in England... in a moderately light polluted area (though I can get out into darker areas once I have a car sorted)...

Would it be possible with this simple setup to capture any nebula (I'm trying to test the astro modded camera, to see what it can do)... If I was to point it in approximately the direction of a nebula using the 70/300 zoom lense.. how far could I zoom in and what would be the maximum single exposure time (eg is it 5-10 seconds or 30 seconds)? ..or is this magnification too high without tracking.. sjould I stick to the smaller lense (18/55) - and if so what could I hope to capture with the astro camera?

thanks

[Astrosurf]

Blasted cars! Now, I'm no expert at this, but I'd point a fairly wide-angle lens at the Orion constellation as, not only are there nice blue and red stars, but there's the amazing Orion Nebula in Orion's belt. It's an emission neb so your modded camera will pick up the IR. Try a minute at ISO 800 and see if you get trailing. If so, reduce the exposure until the stars are round. It very much depends on your magnification: higher mag=more trailing. You can always try ISO 1600, if it's not noisy, to get more data. That depends on the camera. My Canon 1000D was very noisy but my 600D is very forgiving. 

Good luck!

Alexxx

[Fishpaste]

The person who modified the camera said the camera should produce it's best astro images at ISO 1600 - so I'll start with that... Assuming I can manage 3030-60 seconds without trailing, how many shots would you recommend for stacking (5..15..30+)? 

[Astrosurf]

The constellation's going to move and rotate (field rotation) over time as your tripod is static. I've not stacked images from a tripod set-up but take a few and see if they'll stack in Deep Sky Stacker. You can always reduce the amount of images to stack afterwards. I've not done this myself but ask on here about the DSS settings. I think there's a setting to cover field rotation but I'm not sure.

[Knight of Clear Skies]

I believe DSS will handle field rotation OK. I gave a quick try, but tripod shake and wispy cloud resulted in a poor final image.

For comparison, here's a 30 second shot of orion taken with a modded 100D in hazy conditions (18mm, f3.5, ISO 1600, 30 seconds):

And a close crop of the same image:

With the zoom lens you'll be looking at very short exposures. There was a recent thread where a poster took an image of the Orion nebula with a 75mm lens, I believe they were using 2 second exposures but I can't find it now.

Good luck with the modded 1100D.

[Knight of Clear Skies]

Found the thread, here it is. Please bear in mind they used a much faster lens than the 70/300.

[JKB]

The startrailing errors are also dependent on where in the sky the object is located. I know it sounds daft but true.Objects higher will rotate more but trail more so you can get longer exposures.  Also the focal length of lens used will add. A nice 35mm lens stopped down a bit will show less trailing than a 300mm due to the apparent field of view.

I would start somewhere high around polaris say, ISO to 800 and test the time before trails appear. Start say 15sec and check. Then take loads of them and stack in DSS.

Cheers

Jamie