Rosette with Astrodon, One night.

[ollypenrice]

An unlucky week, weather-wise, but the last night was a good one (clear all night and a reasonable 21.45 on the SQM.) Not having had the weather for a faint project we felt the Rosette was a good bet for plenty of signal in a short time. I've never shot this one in our 3nm Astrodon Ha but Sara's looks great so I gave it a go. Honestly, it's out of this world. Tiny stars and wispy outlying structure where the 7nm only picks up a diffuse glow. This is 24x15 minutes but 6 of those were on a poor night and the 18x15 shot on the last night gave an identical result.

This Ha is processed harder than I'd do it for a standalone image but, when combined with RGB, an Ha image becomes highly diluted so a pushy processing works better. 

Meanwhile the other half of the dual rig, carryng Tom's FSQ106 and Yves' SXVH36, was collecting colour in 10 minute subs. By the end of the night we had 9 per channel. There's no luminance here. I processed the RGB for small stars and high colour saturation and then came the fun bit, trying to persuade all the faint Ha detail to appear in the final image. Firstly it went into red in blend mode lighten and into blue likewise at 20% (as surrogate H Beta.) I added more to red in blend mode Screen and a little as Screen and as Luminance (15%) over the RGB until, bit by bit, most of the faint outer wisps were coming through. I think it's quite deep for one night (or two if you allow for the dual rig advantage...!) 

Bigger available on the last page of my SmugMug account.  https://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-Tzm8KZS

Olly

[cfpendock]

Those 3nm Astrodons certainly perform well, at least in the hands of someone who knows what they are doing..... Fantastic images (as usual), Olly. 

Chris

[steppenwolf]

I particularly like the mono version of this, Olly, although there is no doubt that true star colours add a lot to an image. The dual rig is earning its keep.

[MartinFransson]

That is outstanding! I am REALLY curious about your workflow with blending the HA into the red and blue channels since I´ve been experimenting with this myself. Do you edit the red channel separately as a B/W image or is it somehow done in the RGB image? Do you have any tips for tutorials on this?

[Pompey Monkey]

That's another corker Olly!

Getting the faint Ha to show in my Horsehead is something I'm struggling with - I'll give your workflow a try.

[ollypenrice]

6 minutes ago, MartinFransson said:

That is outstanding! I am REALLY curious about your workflow with blending the HA into the red and blue channels since I´ve been experimenting with this myself. Do you edit the red channel separately as a B/W image or is it somehow done in the RGB image? Do you have any tips for tutorials on this?

My basic method, once all images in the story are perfectly aligned and cropped to fit over each other, is this:

- LRGB or RGB prepared with strong colour and all star processing finished. (No more star colour enhancement or reduction will be done after adding Ha.)

- Split channels and paste Ha onto red.

- In Levels, change blend mode to lighten. Eyeball on and off to see what Ha is doing to red. If it's doing a lot (maybe even too much) drop it on as it is anyway. (Afterwards you just paste the HaLRGB onto the LRGB and adjust the opacity if the Ha has gone too far. This is easier than trying to guess how much Ha to put on.) If the Ha is not doing anything or not doing enough then adjust it in Curves while it is still a layer over red. You can take your Ha over its noise limit when it's applied over red in blend mode lighten and it won't show. I often have to super-stretch Ha for galaxies in this way. Flatten, combine channels and save as HaLRGB or HaRGB.

- I may then apply Ha as luminance but only at a low opacity, never exceeding 15%.

- This time I also dabbled with Ha over red and Ha over RGB in Screen mode but I won't advise on this till I know what I'm doing! This time I was just messing about in the dark.

- Since Ha traces the same gasses as H Beta, which is blue, youcan justify a little in the blue channel in blend mode lighten.

Olly

[ollypenrice]

2 minutes ago, Pompey Monkey said:

That's another corker Olly!

Getting the faint Ha to show in my Horsehead is something I'm struggling with - I'll give your workflow a try.

The key thing, Paul, is that you can stretch the Ha in situ over the red till it darned well sings! In blend mode Lighten it's the bright signal, not the faint, which is being applied and the noise, of course, is in the faint stuff so doesn't get into the red till you've gone crazy. If it does show then you can black clip the Ha in situ or drop the bottom end of the Curve and, again, this thuggery won't go into the final image...

Olly

[PhotoGav]

I am shocked to hear that Les Granges has been having weather issues. I was sure that you had done a deal with the Sky Gods involving many souls in recompense for never a cloud.

That is a splendid Rosette. I do love this target, so full of interesting details and some fascinating science going on in there too. By all accounts it might be a mirror of our own solar system formation with all that lovely shapely dusty stuff slowly compacting into little balls and starting to orbit one of the central stars. (I await a real scientist to correct and clarify this statement!).

My only criticism, if I dare, is to suggest that the framing is not up to your usual standard of perfection. It irks me that the you have cut short the dusty bit at the top when there is plenty of 'empty' space below...!

Yet again, one of your images makes me really want another piece of equipment, in this case Astrodon 3nm filters.

[tomato]

These are just breathtaking images, I agree with Steve my favourite is the mono. Wishing now I had waited until a mono ccd had come onto the secondhand market, but I have plenty to learn with my OSC 314.

Steve

 

[ollypenrice]

45 minutes ago, PhotoGav said:

I am shocked to hear that Les Granges has been having weather issues. I was sure that you had done a deal with the Sky Gods involving many souls in recompense for never a cloud.

That is a splendid Rosette. I do love this target, so full of interesting details and some fascinating science going on in there too. By all accounts it might be a mirror of our own solar system formation with all that lovely shapely dusty stuff slowly compacting into little balls and starting to orbit one of the central stars. (I await a real scientist to correct and clarify this statement!).

My only criticism, if I dare, is to suggest that the framing is not up to your usual standard of perfection. It irks me that the you have cut short the dusty bit at the top when there is plenty of 'empty' space below...!

Yet again, one of your images makes me really want another piece of equipment, in this case Astrodon 3nm filters.

Of course, you're right on the framing!! To be honest the fine stuff at the top and, above all, on the left, did not present itself till highly stretched and, being anxious to get going following my fall from grace with the weather Gods, I was a bit trigger happy on behalf of our data-starved guests. I would, another time, move the Rosette itself a little down and a long way to the right as you suggest. 

Olly

[swag72]

I really do like the mono Olly and think that it's come out a treat. Interesting that you've gone the 15 minute route too ...... Do you really think the advantage of the fainter stuff in the 30m subs is outweighed by the number of 15m subs to combat the noise? Also, I'm not detecting that you are missing any of the faint stuff.

I've tried two faint targets now in Ha with just 15 minute subs and I'm not convinced that I would have got any more detail from them.

[PhotoGav]

36 minutes ago, ollypenrice said:

Of course, you're right on the framing!! To be honest the fine stuff at the top and, above all, on the left, did not present itself till highly stretched and, being anxious to get going following my fall from grace with the weather Gods, I was a bit trigger happy on behalf of our data-starved guests. I would, another time, move the Rosette itself a little down and a long way to the right as you suggest. 

Olly

A pleasant surprise to find the faint stuff! It's an interesting discussion regarding sub length vs faint detail vs noise. I have worked so far on the assumption that longer is better when the target can take it, so good to see that challenged. I await further evidence to be posted.

[ollypenrice]

11 minutes ago, PhotoGav said:

A pleasant surprise to find the faint stuff! It's an interesting discussion regarding sub length vs faint detail vs noise. I have worked so far on the assumption that longer is better when the target can take it, so good to see that challenged. I await further evidence to be posted.

The 15 minute subs in Ha were, in fact, part of an experiment. I hope to get some more in my habitual 30 min subs. On our cameras with lowish sensitivity and great well depth I'm still betting on longer subs.

Olly

Edit: I hadn't seen Sara's post but we've been talking about this. I really don't know the answer. I did have to work hard to get that faint stuff but, yes, it was in there. The advantage might be less if you can dither but we can't on the tandem.

[swag72]

I wasn't sure how best to conduct the this experiment Olly - I do have the same total length of subs (one set 30m and one set 15m) on NGC1499 - Of course this resulted in half the number of 30m ones......... Is it best to compare the same total exposure time do you think?

[ollypenrice]

6 minutes ago, swag72 said:

I wasn't sure how best to conduct the this experiment Olly - I do have the same total length of subs (one set 30m and one set 15m) on NGC1499 - Of course this resulted in half the number of 30m ones......... Is it best to compare the same total exposure time do you think?

Yes, I think you have to do it that way. The trouble is, the night also plays a part. My 'long sub' clincher was M31 when half as much L in 30 min subs caught the shape of the outer glow when twice as much in 15 min subs didn't. But who knows what effect the particular night had? 

Olly

[MartinFransson]

4 hours ago, ollypenrice said:

My basic method, once all images in the story are perfectly aligned and cropped to fit over each other, is this:

- LRGB or RGB prepared with strong colour and all star processing finished. (No more star colour enhancement or reduction will be done after adding Ha.)

- Split channels and paste Ha onto red.

- In Levels, change blend mode to lighten. Eyeball on and off to see what Ha is doing to red. If it's doing a lot (maybe even too much) drop it on as it is anyway. (Afterwards you just paste the HaLRGB onto the LRGB and adjust the opacity if the Ha has gone too far. This is easier than trying to guess how much Ha to put on.) If the Ha is not doing anything or not doing enough then adjust it in Curves while it is still a layer over red. You can take your Ha over its noise limit when it's applied over red in blend mode lighten and it won't show. I often have to super-stretch Ha for galaxies in this way. Flatten, combine channels and save as HaLRGB or HaRGB.

- I may then apply Ha as luminance but only at a low opacity, never exceeding 15%.

- This time I also dabbled with Ha over red and Ha over RGB in Screen mode but I won't advise on this till I know what I'm doing! This time I was just messing about in the dark.

- Since Ha traces the same gasses as H Beta, which is blue, youcan justify a little in the blue channel in blend mode lighten.

Olly

Oh wow... that´s gonna take me some time to figure out

When you mention splitting the channels, do you mean extracting them to new, separate images?

[ollypenrice]

18 minutes ago, MartinFransson said:

Oh wow... that´s gonna take me some time to figure out

When you mention splitting the channels, do you mean extracting them to new, separate images?

In a sense yes, but it's no big deal. In Photoshop you just go to Channels - and use the drop down arrow to - Split Channels. The three channels all opaen separately. Paste your Ha onto red and then go to Layers where you change the blend mode from Normal to Lighten. When happy you flatten and then go back to Channels where the drop down arrow takes you to the option Merge Channels. Choose RGB mode and then just put red in red, green in green and blue in blue and say OK. The recombined image will need a new name because it has entirely replaced the pre-split one which will be left unchanged.

Trust me, you're talking to world's biggest comuter numpty here. (Actually, no, Monique is worse but we're both bad!!)

Olly

[MartinFransson]

That´s brilliant!! What a great feature!

 

[gorann]

Yes, fantastic images!

Such a pity that a single Astrodon filter costs as much as a good small telescope, but maybe one filter is enough? = The Ha Astrodon. Just have to refocus when using cheaper OIII and SII ones. Or as Olly, just use it with RGB,  or just use it alone - the mono image is fantastic in its detail.

[DaveS]

This is seriously making me look for a shorter FL 'scope to get more on my 694 sensor, with the realisation that I'll never get anything like as good from here.

BTW, with 3 nm filters you're only getting the Ha, with 7 nm you're getting a lot of [NII] as well. Mind you, a set of four Astrodons is an invitation to bankruptcy . I could only afford them in 1.25" form.

[gnomus]

3 hours ago, ollypenrice said:

Of course, you're right on the framing!! To be honest the fine stuff at the top and, above all, on the left, did not present itself till highly stretched and, being anxious to get going following my fall from grace with the weather Gods, I was a bit trigger happy on behalf of our data-starved guests. I would, another time, move the Rosette itself a little down and a long way to the right as you suggest. 

Olly

Perhaps another opportunity will present itself soon..........

[opticalpath]

4 hours ago, ollypenrice said:

In a sense yes, but it's no big deal. In Photoshop you just go to Channels - and use the drop down arrow to - Split Channels. The three channels all opaen separately. Paste your Ha onto red and then go to Layers where you change the blend mode from Normal to Lighten. When happy you flatten and then go back to Channels where the drop down arrow takes you to the option Merge Channels. Choose RGB mode and then just put red in red, green in green and blue in blue and say OK. The recombined image will need a new name because it has entirely replaced the pre-split one which will be left unchanged.

Trust me, you're talking to world's biggest comuter numpty here. (Actually, no, Monique is worse but we're both bad!!)

Olly

I find it easier to do all the Ha blending in RGB without splitting the channels, by using Image/ Apply Image.  It lets you do it all pretty much in one step and see the results immediately without the need to split and remerge channels.. 

Put the Ha in as a (hidden) layer above the RGB, then highlight the RGB layer; in the Channels window highlight the desired target channel in RGB (say red) and use Image/ Apply Image, selecting the hidden Ha layer as 'source' and set the desired blend mode and opacity before hitting 'OK'.  As long as you have kept the RGB composite view visible in the Channels window, you instantly see the effect on the RGB and can try different blend modes and opacities till you find what works best. Or if you prefer, keep only the Red channel visible to see exactly what is happening to red only as you blend in the Ha.   Then flip over to blue as target channel and Apply the Ha again in the same way, at say 15%.  Image/ Apply Image ... even lets you specify a mask in the same step to control the regions where the blend is to occur. 

Adrian

[ollypenrice]

A version with a tad more oomph to the processing...

Olly

[cfpendock]

Nice.  Stars look a bit tighter, (if that's possible), and a bit more contrast in the nebula? Difficult to say more on my monitor, but in a way I prefer the original.  None the less very nice....

Chris

[Barry-Wilson]

Love the second version Olly - this target holds up well to some bold colour.