Trunk in Ha

[johnrt]

The postie has been very kind recently. Not only has he brought me a WO megrez 72 (from TJ) - but the other day he turned up with an Atik 314l+ & filter wheel too!

Switching from DSLR to CCD has been like starting from scratch all over again. Light leaks, spacers which needed filing down, aligning, focusing, empty power tanks, satellites and clouds have been just some of the problems!

In between all the head scratching I managed to squeeze in 6 10 minute subs of the Trunk Nebula IC 1396. I found processing the images after you capture is different to dslr images, more head scratching!

Anyway I finally ended up with this. Hope you like it.

Scope - WO Megrez 72 (Imaging) & ST 80 (Guide)

Camera - Atik 314l+ (Imaging) & QHY5 (Guide)

Flter - Astronomic 12nm Ha

6x 10 minute subs

[adamsp123]

Nice one John, and just like you I found a CCD is a world away from using and processing the DSLR data.

[MarkF]

John, thats great, I seemed to have skipped the DSLR imaging bit, as I don't have a DSLR but do have a camera good enough for taking piccies. So jumped straight into CCD and LRGB, I am so glad you are saying the processing is a bit head scratching, it definitely is for me.

Hmmm, the 314L was my target camera to buy, but a 16ic camera along at the right price, 314L next year if I keep up the interest

Can't offer any tips, as I am still trying to find some myself, other than I learnt in DSS to keep all the LRGB subs in the list and just check the ones you want to stack. BUT make one of the Lum subs as reference frame for all stacks, just uncheck it when doing the RGB stacks otherwise they don't line up when you merge channels in PS. Took me a day to get that working

[Tom How]

Good choice of camera - that icx285 chip if fantastic for Ha work - and it is much quicker to stack frames when they are only 1.5MP I know - I use one!

CCD imaging is a bit of a learning curve - several things seem to have gone wrong on that image including the clipping of the black and the artifact along the bottom. The stars also look over sharpened (but that might be a jpg thing) and their are strange low frequency artifacts in the background and general brightness levels.

I'd suggest going and taking 3 subs of a bit of empty starfield (in ha) and make sure you can calibrate the image correctly with flats and bias frames. The aim being to make sure you end up with a nice flat image without any tricky nebula confusing issues.

[Les Tilly]

Great Start John you have some good data there.

The black point is clipped a little. Did you take any darks or flats with the camera ?

Les

[johnrt]

Hi Les, Tom

Yes I took darks/bias and flats but I had a light leak in the filter wheel, it's down the right edge of the frame.

Not sure if that caused the artifact along the bottom edge too. There was a dark artifact along the top edge, almost the opposite of the bottom but I cropped this out. Any ideas on what may have caused this if it wasn't the light leak?

Thanks all for the positive feedback, it's certainly a different ball game with ccd to dslr.

[Les Tilly]

Make sure everything is light leak free I know with my Filters I had a relection on the edge of the filters causing a perfect straight edge about a 1/5 of the image I had to put tape around the edge of the Square filters or they say Paint the edge but that was my Problem it can take a little time to find the cause

Les

[johnrt]

I think I've fixed the light leak problem - here is a 5 minute dark sub at -5C, stretched in PI

[Les Tilly]

Looks good to me. What temp do you normally run the cooling?

Les

[johnrt]

I have been running it at -5C up to now.