NGC7380, The Wizard.

[MARS1960]

Well guys this is last nights attempt at the Wizard (NGC7380).

I'm not really loving it but i think it maybe a slight improvement over my heart nebula from the other night.

SW100ED native, Stock Canon 60D with CLS LP clip filter, Mgen guided, 18 subs @ 600s, dithered, stacked in DSS, processed in PS.

I was hoping for more from 3 hours intergration time but i think/hope it's my processing letting me down again. 

C&C very welcome.

[Astrosurf]

That's not bad at all considering it's an emission neb. When you finally get a camera that registers Ha you'll be amazed at the detail. You also won't need to push the stretching so far so the noise won't look so bad. But you really must do darks. I find they have a powerful effect on my images.

Can you give us an idea of your processing steps? 

Alexxx

[MARS1960]

1 minute ago, Astrosurf said:

That's not bad at all considering it's an emission neb. When you finally get a camera that registers Ha you'll be amazed at the detail. You also won't need to push the stretching so far so the noise won't look so bad. But you really must do darks. I find they have a powerful effect on my images.

Can you give us an idea of your processing steps? 

Alexxx

Thanks Alexxx. 

I must admit i do get confused, for everyone that says do darks there is another that says they are not needed with modern DSLR's.

Craig Stark professes that dark frames will only add more noise, it' s better to use dithering and sigma kappa stacking which i did.

My processing was PS, levels and curves x 4 iterations and Noel Carboni's astro tools actions for vertical and horizontal banding removal, local contrast enhancement, space noise reduction, enhance DSO/reduce stars, LP removal enhanced flatten and star colour enhancement.

[StargeezerTim]

Nice one Mark.

I did find that using a modded camera makes so much difference with targets like this. However that would mean another raid on your piggy bank that might be feeling the strain!

You have a green tinge that you can get rid of with colour balance, or better still, download the HLVG action (its free) and you can improve it with one click. Nice round stars, the MGEN looks like it is working well! 

After a quick go with HLVG and colour balance and some noise reduction...

[MARS1960]

1 minute ago, StargeezerTim said:

Nice one Mark.

I did find that using a modded camera makes so much difference with targets like this. However that would mean another raid on your piggy bank that might be feeling the strain!

You have a green tinge that you can get rid of with colour balance, or better still, download the HLVG action (its free) and you can improve it with one click. Nice round stars, the MGEN looks like it is working well! 

After a quick go with HLVG and colour balance and some noise reduction...

Whoa, thanks Tim, that looks so much better.

Downloading HLVG now.

Its a shame that the halo removal i used had no effect on those three fat stars.

 

[StargeezerTim]

17 minutes ago, MARS1960 said:

Thanks Alexxx. 

I must admit i do get confused, for everyone that says do darks there is another that says they are not needed with modern DSLR's.

Craig Stark professes that dark frames will only add more noise, it' s better to use dithering and sigma kappa stacking which i did.

My processing was PS, levels and curves x 4 iterations and Noel Carboni's astro tools actions for vertical and horizontal banding removal, local contrast enhancement, space noise reduction, enhance DSO/reduce stars, LP removal enhanced flatten and star colour enhancement.

Do you add bias frames? Your right, you don't really need darks when you dither, at least that is what I have found, but you do need bias frames, and flats help, though do don't seem to have much in the way of vignetting or gradients in your image. Processing is the hardest part... the good thing is that you have the data so as your skills develop you can return to the data with new found skills and really improve on it.

p.s. you can add bias frames now if you want. Just cap the camera, go to TV mode, fastest shutter speed (4000th sec on mine), take twenty or so and add them to the lights in DSS. 

[MARS1960]

Thanks Tim, i had some great advice on my other thread about taking calibration frames but had so much going on in my head when trying to get everything else right i completely forgot, will certainly be taking flats and bias next clear night.

[StargeezerTim]

3 minutes ago, MARS1960 said:

Thanks Tim, i had some great advice on my other thread about taking calibration frames but had so much going on in my head when trying to get everything else right i completely forgot, will certainly be taking flats and bias next clear night.

Easy to add bias now Mark (see my last post). Give it a go and experiment...

 

p.s. those stars are blown... hope you havn't destroyed any life forms on them...

[MARS1960]

Just now, StargeezerTim said:

Easy to add bias now Mark (see my last post). Give it a go and experiment...

Thanks Tim, i'll take some and have a play in a bit. I assume i can just keep them in a library for another time too?

[StargeezerTim]

10 minutes ago, MARS1960 said:

Thanks Tim, i'll take some and have a play in a bit. I assume i can just keep them in a library for another time too?

Yes you can... DSS will create a master Bias frame, you can delete the individual frames once that is created.use the same iso as the light frames... I take it you are using RAW format for your subs?

[MARS1960]

20 minutes ago, StargeezerTim said:

Easy to add bias now Mark (see my last post). Give it a go and experiment...

Thanks Tim, i'll take some and have a play in a bit. I assume i can just keep them in a library for another time too?

Yes always raw.

I have HLVG 88F on my desktop but cant seem to add it too carboni's actions, am i doing it wrong?

[Herzy]

1 hour ago, MARS1960 said:

Well guys this is last nights attempt at the Wizard (NGC7380).

I'm not really loving it but i think it maybe a slight improvement over my heart nebula from the other night.

SW100ED native, Stock Canon 60D with CLS LP clip filter, Mgen guided, 18 subs @ 600s, dithered, stacked in DSS, processed in PS.

I was hoping for more from 3 hours intergration time but i think/hope it's my processing letting me down again. 

C&C very welcome.

Wow. Very nice. was this taken when the moon was out? It's supposed to be clear tonight and tomorow and if I'm lucky I could possibly get 6 hours on this. It seems it's a far easier target then the bubble nebula.

I am worried, however, that my short subs (60s) aren't long enough to capture detail like you managed.

 

[MARS1960]

49 minutes ago, StargeezerTim said:

 

[MARS1960]

Thanks Herzy.

I started my session at 9.30 and the moon was up but was almost set, but i have a walnut tree in the garden and it was behind that anyway.

I don't know if your short subs will be long enough but i'm sure if you can get 4-6 hrs of them i would be very surprised if you didn't get a good image.

[Herzy]

Would you mind posting a single sub? I want to compare it to one of mine to see how the detail visible would compare. Thanks in advance.

[MARS1960]

Sure, here is a RAW sub straight from camera.

IMG_8961.CR2

[Astrosurf]

I get confused about darks! My darks always make my images so much smoother, but that's just my experience. I've seen on here that you don't need bias if you do darks, but I find the jury's always out!

I'll try binning when I can and see what happens.

Just have a go with darks and see what you get.

[MARS1960]

12 minutes ago, Astrosurf said:

I get confused about darks! My darks always make my images so much smoother, but that's just my experience. I've seen on here that you don't need bias if you do darks, but I find the jury's always out!

I'll try binning when I can and see what happens.

Just have a go with darks and see what you get.

Exactly alexxx, just try it, i was thinking exactly the same when binning appeared on my Mgen screen, it's like hey , i guess i'll just push it and see what happens 

[wimvb]

If you take too few dark subframes, then the master dark will be noisy, just as any stacked image from few frames. Noise can never be subtracted, due to its random nature; it only adds. An ideal master dark will consist of as many subs as possible. What is left in the master dark are hot and cold pixels, as well as any amp glow. Where these match the light frames, faulty pixels and amp glow will be subtracted. But faulty pixels (hot and cold) are very much temperature and exposure time dependent. If temperature and exposure time are different from your light frames, darks will not cancel out faulty pixels and amp glow. In a temperature controlled camera, the master dark usually fits the light frames, but in a camera that is not temperature controlled (DSLR), it is much more difficult to get a match.

An alternative way to get rid of faulty pixels is to remove them as outliers. If you dither during image capture, the faulty pixels will seem to move between sub frames after star alignment. They can then be identified as outliers and removed by the stacking software. This is done by kappa sigma clipping in DSS.

To improve this process, you can use something called "cosmetic correction", which removes too bright and too dark pixels before stacking. It's an option in DSS:

If your images suffer from hot pixels, and darks don't improve this enough, you can apply aggressive clipping by using a strong cosmetic correction and setting the Kappa parameter to a low value.

BTW, this video clip shows the effect of dithering. If you look closely, you'll see pixels moving around with a steady star background. In fact, it was the stars that were moving around in each subframe. After star alignment, the whole subframe, and with it the hot pixels, moves and the stars seem to be standing still.

http://wimvberlo.blogspot.se/2016/07/the-effect-of-dithering_21.html

[MARS1960]

Thanks for that wim, i have been doing that but i had sigma kappa clipping checked, so its best to use median sigma kappa clipping?

I have also downloaded pixinsight so lots of learning to do.

[wimvb]

Experiment to find out which stacking method works best for you.

I find the stacking procedure in PixInsight more flexible than the one in deepskystacker.