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alexbb

Bubble and lobster claw area

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Hello all,

I started a while ago shooting the bubble and the M52, first in Ha, then RGB and then O3 too. 25min on each RGB channel, 5-6 h on Ha and 1.5h on O3. Here is the result:

Then I asked myself if I should shoot L, more RGB, more narrowband or if I should go for another target. And I decided that I should try a mosaic in this area and catch the lobster claw too.

The decision being took, I went below, left and then above again for panels 2, 3 and 4. R first, some of the G after. The rest of G and the B the next night. Last night I also shot 45 minutes of O3 on each of the remaining panels - 2, 3 and 4 and planning to shoot another 45 minutes on each panel the following nights, if possible. I will then leave the country for 2 weeks and I'll be back with a full moon when I will try to shoot some Ha. There will be no much time left either for this target as it reaches the limits where I can point my telescope from my balcony.

I'm aiming for 1.5-2h of O3 on each panel and 2-3h of Ha this year.

Supposing the acquisition can be done, I still have to stitch/process/stitch/combine all the layers.

Now, this is something I've never done before and I don't know which is the best approach.

I tried yesterday the new APP, I threw at him all the R subs and asked it to combine them in a mosaic way or a normal way. In mosaic it was failing with a null pointer exception and in normal way it was failing with an index out of bounds exception. So I answered myself an older question if I should wait for the APP or buy Registar and I bought the second after the first one didn't work.

I registered and stacked with DSS all the R, G, B and O3 frames for each panel with the best R frames set as reference.

Then I processed with StarTools each panel as RGB with the same settings and combined the RGB panels with Registar. Now this gave me a result which is almost ok, but you can see a separation line or two between panels 1 and 2 (the one with the bubble and the one below).

I processed each O3 layer with StarTools applying the same settings and I combined these too with Registar. Then I split the RGB mosaic into channels and I added the O3 over the G and B channels as lighten only in GIMP and I combined back again the layers into an RGB image. I colour balanced and enhanced this result in StarTools. The result is attached.

What do you think about my workflow and what approach did you find the best and how do you do it? Also, how can I normalize the layers and still be sure that I stretched them the same? There are some variables that come into play, the worsts mostly because during multiple nights I have different transparency and seeing conditions.

Many thanks and clear skies,

Alex

PS. and an annotated version: http://nova.astrometry.net/user_images/1668494#annotated

BubbleArea-F585-2017-06-21-RGB-O3_p01.jpg

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Getting there. 6h of Ha added, shot through the Canon lens and aligned with Registar. I ~fixed the panels merging and now they look smoother for the RGB too.
I'll add more Ha until the moon goes away and I can shoot O3 too.

Annotated version: http://nova.astrometry.net/user_images/1696939#annotated

Clear skies!

BubbleArea-F300-F585-2017-07-10-RGB-HaO3_p01.jpg

Edited by moise212
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Thanks, Chris!

I just got today an 8 position EFW and an OAG and still clear skies :icon_scratch:

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2 minutes ago, moise212 said:

and still clear skies :icon_scratch:

I don't know why I just wrote this. I should have kept it to myself :angry1:

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Looks good. Don't forget that, although you will stretch you NB before adding it in blend mode lighten, you can also stretch it in situ while it is still a layer over a colour channel. It may be an advantage to pin the background first if you do decide on a further stretch while the NB is still a layer.

Olly

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1 hour ago, ollypenrice said:

Looks good. Don't forget that, although you will stretch you NB before adding it in blend mode lighten, you can also stretch it in situ while it is still a layer over a colour channel. It may be an advantage to pin the background first if you do decide on a further stretch while the NB is still a layer.

Olly

Thanks, Olly!

There are a couple of things that I don't understand or don't know how to do them with GIMP, those in bold.

I tried before to add the Ha to R and O3 to G and B layers, but this last one was a Ha-HOO combination which lighted my RGB image. I thought about this as I processed the Ha and O3 as Ha-HOO and it was then ~balanced and tweaked and it had a neutral background, keeping in mind that I had very limited O3. I reduced the stars in the HOO image and I hoped that they won't lighten my RGB ones and it was true for most of them.

I can try more methods, but I only have StarTools and GIMP. I don't have the courage yet to go PI.

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5 hours ago, moise212 said:

Thanks, Olly!

There are a couple of things that I don't understand or don't know how to do them with GIMP, those in bold.

I tried before to add the Ha to R and O3 to G and B layers, but this last one was a Ha-HOO combination which lighted my RGB image. I thought about this as I processed the Ha and O3 as Ha-HOO and it was then ~balanced and tweaked and it had a neutral background, keeping in mind that I had very limited O3. I reduced the stars in the HOO image and I hoped that they won't lighten my RGB ones and it was true for most of them.

I can try more methods, but I only have StarTools and GIMP. I don't have the courage yet to go PI.

I'm assuming that GIMP resembles Photoshop for all this:

By 'in situ' I just mean that you have the NB over the colour as a layer in 'lighten only' so you should be able to open Curves at this stage?

If so you put an anchor point on the curve at the level of the background sky. (In Ps put the cursor on the background and alt-click.) You can then lift the curve above the anchor point to increase the Ha contriution to the colour layer.

If you can't do it like this you can try giving the NB more of a stretch and applying it. The thing is that the NB noise will be in the dark parts which are normally darker than the same parts of the colour layer. In Lighten Only the noisy parts of the Ha will not be applied, in this case. In short you can over-stretch a NB layer when aiming to add it in Lighten Only. If you feel you want to, that is.

Olly

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16 hours ago, ollypenrice said:

I'm assuming that GIMP resembles Photoshop for all this:

By 'in situ' I just mean that you have the NB over the colour as a layer in 'lighten only' so you should be able to open Curves at this stage?

If so you put an anchor point on the curve at the level of the background sky. (In Ps put the cursor on the background and alt-click.) You can then lift the curve above the anchor point to increase the Ha contriution to the colour layer.

If you can't do it like this you can try giving the NB more of a stretch and applying it. The thing is that the NB noise will be in the dark parts which are normally darker than the same parts of the colour layer. In Lighten Only the noisy parts of the Ha will not be applied, in this case. In short you can over-stretch a NB layer when aiming to add it in Lighten Only. If you feel you want to, that is.

Olly

Thank you! It's more or less the same as I do it. I usually stretch it (develop) in StarTools, which keeps the background low and stretches what it's above. It's also predictable, opposed to manual stretch. If needed, I bring then back manually the background to a lower value, by using curves and pinning the foreground and lowering what's to the left. Sometimes I process an image in GIMP too as you described above and blend it with the StarTools result, but StarTools is better at removing the noise if you give it linear data to work with.

 

I should have progressed last night with the image, but after I switched the manual FW with the EFW, I have a huge amount of tilt somewhere and I can't yet figure it out. So I lost last clear night.

Clear skies!

Alex

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Some progress, now with 7.5h of Ha and 5h of O3. Maybe I can gather ~10h of O3 and I guess that's about all I can see this season on this target :sad:

Also here: http://nova.astrometry.net/user_images/1709043#annotated

Ha: http://nova.astrometry.net/user_images/1709055#original

Thoughts are welcomed.

Clear skies!

Alex

BubbleArea-F300-F585-2017-07-19-RGB-HaO3_p01.jpg

Edited by moise212
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23 hours ago, Astrosurf said:

Gorgeous images. The blue/green (O3?) on the Bubble is lovely.

Alexxx

Thank you! It's O3, indeed.

Alex

Edited by moise212
it's O3
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