All in all a good night for me

[Daniel]

Had a strantge night last night, the sky looked very clear but because of mist I could only actually see the summer triangle and Jupiter, so altogether a bad night for imaging.

That said, I sorted a lot of technical problems, after downloading a beta hand control driver my goto's were spot on and I my guiding was pretty damn good too on the CGE mount.

so overall I was really happy with last night despite the dodgy imaging weather.

Anyway, I took this M16 through the mist, I haven't had a chance to treat it in photoshop yet, and it's not that great because of the weather, but the stars seem to have stayed round, so im still happy.

this is 36x120s ISO800 flats and darks applied on a skywatcher 120ED using a modded Canon 40D guided with an 80ED and a DSI

[Fay]

Very good indeed Daniel. Everything looks nice & focused!

[Daniel]

Thanks, im looking forward to imaging this again once the weathers good, never thought I'd be able to get much on eagle. might try it with the SCT though, would be nice to get in closer.

Funny you should mention the focus, I have 2 sets of flats for this image I need to try, one set which i used had the focus messed up, I think the cable got wrapped round the mount while slewing. The other set I re-adjusted the focus on, not sure if it'll help since they won't have exaclty the same focus, but they should be closer than the ones I used.

[Fay]

Daniel, I am just sorting out some problems with the setup, at the moment. There is always something to sort out!!!! Daniel, I have suddenly got excited.................... your corners are not bunched up I all looks nice & flat!!!!!!!!!!!!!!!!

I am very interested as we are both using similar equipment.

Did you use the focal reducer or what?

[Daniel]

Hi Fay, the image has admitedly been cropped but i shall post the full image when i get home tonight, it too is nigh on coma-less. The reason being is a kit change, I went out and bought another scope, a skywatcher 120ED seems I get a lot less coma with it than before, that said, the meade .63 coma corrector was doing wonders on the 80ED, the only reason i was getting some stretching on those last images I posted was because they were unguided and my polar alignment was pretty off. looking forward to trying that again with the 80ED guided, still can't beat it for those really wide shots! Also, the vignetting Im getting on the flatenner is pretty controlable with the flats im taking now i've sorted my light box (well light tube really, it's a rolled up piece of cardboard with a night light stuck in the end of it)

[MarkS]

Daniel,

Lovely round stars there.  The image is nicely composed but clearly a bit noisy.  Your new setup is clearly working very well.

What is the focal length of the 120ED?

Mark

[Daniel]

Hi Mark, yes im hoping I can sort out the noise on a clearer day (yesterday would have been good had I not been working late)
The 120ED is 900mm (F7.5) gives me a nice in between FOV. I was thinking of going for the 100ED but that's got a much narrower FOV, that said probably would've been better for eagle as it's so small.

Went out last night anyway, was too late to set up the full scope but mounted the camera on the CG5, was hoping to take some wide fields of nebula etc. How the hell do you guy's resolve nebulosity when you do that? i took about 30 mins on north american nebula and couldn't see anything.

[MarkS]

Putting a modified camera with standard lens directly on the CG5 is an ideal way to take widefields with nebulosity - I don't know what could have done wrong.

1) You must still use your light pollution filter (unless you have a dark site)
2) You must use a sensible aperture e.g. somewhere in the range F2-F5.6

[Daniel]

Hi Mark, I used my light polution filter (clip in type) but im wondering if the lens I was using wasn't ideal, I used the 70-300mm lens I have which is pretty bog standard, i think i was on F5.6 which was as low as it would let me go.

Might have another go over the weekend if we get a break in the clouds, quite nice being able to set up in around 5 minutes.

[MarkS]

Daniel,

What you've described sounds fine with the clip-in filter.  Also,  F5.6 is plenty capable of picking up nebulosity.  Give it an exposure of 5-10 minutes and you should definitely get results ...

Mark

[Daniel]

ahh, yes I'll have to sort out the guidescope too, would be nice if I can mount both scopes AND the camera to the same side by side plate

[MarkS]

Your CG5 periodic error is 60arcsec peak to peak.

With a 70mm lens that is only about 3 pixels. Once you shrink the image you won't notice it at all.  The problem you might get is from drift if your polar axis is a long way off.

But it is certainly worth a trying without a guidescope ...

[Daniel]

Fantastic, I shall try that then at the first chance I get, though this weekend isn't looking great

[Daniel]

oh, one more thing, I've uploaded the full frame M16 to show the coma (or lack of) Im getting around the edges, this is processed a little more too with a bit of smoothing out, think i prefer the colours in the first more though



You will also notice the blurry dust bunnies which I think are because of my out of focus flats i accidentally took

[Fay]

The stars still look nice & flat around the edges Daniel. I think that the if the the star fields around the edges are not too dense then the edges are a lot better. Don't forget you did not do very long exposures for this & not many frames.