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Some needle galaxy LRGB data if anyone is interested


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I've attached my data from Sat night, on NGC 4565.  If anyone wants to have a go I would be most grateful.

The fits files have been calibrated and registered.  The red focus isnt the best, but I think it's usable.

There is about 10 hours in total, taken with mono CCDs, on ED80s in 300s exposures.

 

 

TIA

Adam.

 

 

St-avg-5400.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RL-MBB5-Green-ATIK_1stLNC_it3.fits St-avg-6300.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RL-MBB5-Blue-ATIK_1stLNC_it3.fits St-avg-7200.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RL-MBB5-Red-ATIK_1stLNC_it3.fits St-avg-18000.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RL-MBB5-Luminance-QHY_1stLNC_it3.fits

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Go on then, haven't captured this one myself, totally distracted me from what I was going to do :)

Good to test my skills, have ended up with a bit of colour mottle going on in the background. Not too happy with the stars either, managed to introduce some dark ringing.

Image11_ABE_registered.jpg

Edited by SamAndrew
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Hi Adam

I had a very quick look at the data in APP. The main problem is just as you say, the focus on the Red data is a good way off from the other 2 channels. This isn't easy to remedy in processing. You can still produce a good image though, as Sam has proven above. 

But seeing as you already have so much data in the other channels already, if it were me i would just wait and re-shoot the Red data. The end result will be so much better than anything you can do in processing. 

It's a shame it happened to the Red channel too. If it had been the Green, you could always have synthesized it in processing. Do you do your filters in a certain order? i.e try and shoot the Blue when the object is at it's highest point in the sky, and leave the Green to last?

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Something I've just realised Adam. I see that you are using the QHY for Lum and the Atik for Colour.

The QHY has much bigger pixels than the Atik (7.8um vs 5.4um), which means the pixel scales are 3.08" and 2.13". This is a quirk that most mono guys don't have to deal with, as most just use the same camera for all their filters.

All the detail is in the Lum, so you would be better swapping them around and using the Atik for the Lum. Especially for targets like this, where FOV is not that important and the main object doesn't take up that much room.

I'm just thinking, is there any benefit at all really to having the larger FOV for the Lum? Because you'll always have to crop out the outer edges anyway, as the Atik won't cover those bits (unless of course you bin the Atik 2x2).

And for extended objects, where you might need every last mm of the FOV for a particular target, then you could still use the QHY for Lum, but try drizzling the stack to recoup some of the resolution maybe?

Maybe another mono CCD user could confirm any of this makes actual sense or not! ?

Edited by Xiga
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9 hours ago, Xiga said:

Something I've just realised Adam. I see that you are using the QHY for Lum and the Atik for Colour.

The QHY has much bigger pixels than the Atik (7.8um vs 5.4um), which means the pixel scales are 3.08" and 2.13". This is a quirk that most mono guys don't have to deal with, as most just use the same camera for all their filters.

All the detail is in the Lum, so you would be better swapping them around and using the Atik for the Lum. Especially for targets like this, where FOV is not that important and the main object doesn't take up that much room.

I'm just thinking, is there any benefit at all really to having the larger FOV for the Lum? Because you'll always have to crop out the outer edges anyway, as the Atik won't cover those bits (unless of course you bin the Atik 2x2).

And for extended objects, where you might need every last mm of the FOV for a particular target, then you could still use the QHY for Lum, but try drizzling the stack to recoup some of the resolution maybe?

Maybe another mono CCD user could confirm any of this makes actual sense or not! ?

 

Cheers Ciaran. The QHY9 and the Atik 383L+ are actually based on the same Kodak KAF-8300 sensor so are pretty much identical in terms of specification and performance. This was my intention when I went down this route!

Re shooting colour - I left green to last knowing / thinking that you can synthesis it should clouds come in. Other than that I had no logic. I should have realised object would matter since I have done RGB image of low planets but I never thought ? Thanks for the tip  I will bear this in mind next time  

 

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4 minutes ago, tooth_dr said:

 

Cheers Ciaran. The QHY9 and the Atik 383L+ are actually based on the same Kodak KAF-8300 sensor so are pretty much identical in terms of specification and performance. This was my intention when I went down this route!

Re shooting colour - I left green to last knowing / thinking that you can synthesis it should clouds come in. Other than that I had no logic. I should have realised object would matter since I have done RGB image of low planets but I never thought ? Thanks for the tip  I will bear this in mind next time  

 

Ah, silly me. I thought it was a QHY8 you had, and not a 9. Doh! ? That makes much more sense, lol. 

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On 02/04/2019 at 22:51, SamAndrew said:

Go on then, haven't captured this one myself, totally distracted me from what I was going to do :)

Good to test my skills, have ended up with a bit of colour mottle going on in the background. Not too happy with the stars either, managed to introduce some dark ringing.

Image11_ABE_registered.jpg

Thanks again Sam.  I had a look at this tonight there at home, and you really have brought out a lot of the dust lanes.  I've tried again with my version and have ended up with a softer version, with not just as much detail.

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4 hours ago, wimvb said:

My version. Maybe ovderdid the blue a notch or two.

Tooth_dr_Needle_LRGB.thumb.jpg.d13cd7d42c9e07ab4a059c26d0704eae.jpg

Nice version Wim. I like the colours but there are some wide dark rings around the stars - probably something one of those advanced PI algoritms have created. Saw this post too late to get time to have a go today.

Edited by gorann
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Better @gorann?  Dunno what came over me to post that previous image. When I processed this image earlier today, there was a glare on my laptop screen, and I completely missed those horrible dark rings.

Tooth_dr_Needle_RGB2.thumb.jpg.6c91e566ef9a114af9a7ced2e98748a4.jpg

 

Edited by wimvb
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9 hours ago, wimvb said:

Better @gorann?  Dunno what came over me to post that previous image. When I processed this image earlier today, there was a glare on my laptop screen, and I completely missed those horrible dark rings.

Tooth_dr_Needle_RGB2.thumb.jpg.6c91e566ef9a114af9a7ced2e98748a4.jpg

 

Yes, that is more like it Wim! I have to use roller blinds in my home office to have it relatively dark when I process.

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On 01/04/2019 at 20:51, tooth_dr said:

Hi Adam

As you know, the only thing holding back this image is the Red data. It just needs re-shot due to the focus being off. 

But on the subject of getting more colour into images, i had a 10 minute go at the data just to show that the blues in the galaxy are all in there. Here is what i got, with no additional processing (NR, sharpening, etc), just stretching and colour balancing:

combine-RGB-image--180degCW-1.0x-LZ3-NS-mod-lpc-cbg-csc-NoSt.thumb.jpg.2e72289ac99ab3e08ee120ef9094e4d4.jpg

Just focusing on the galaxy itself, you can see that the blues and magentas are definitely there. And that's before doing any more work to help tease them out further. 

Here are the steps i took:

1. Star Colour Calibration in APP (you may have to watch the video tutorial on the forum to know what to do though). Don't worry if you don't want to do this step though, the WhiteCal plugin alone may be enough later on.

2. Save a non-stretched image from APP.

3. In PS, 1 Arcsinh-10 stretch (just to 'get the image going'), then a Levels adjustment to bring the Black Point back in. 

4. In PS, 1 Arcsinh-300 colour-preserved stretch. Flatten, then bring the black pont in. Then do again, but this time with a much smaller stretch, 30 instead of 300. Then bring the black point in and flatten again. 

5. Run HLVG on a Color Layer, then re-balance the colour channels to give a neutral grey background. 

6. Optional - If you've already ran Star Color Calibration in APP, then see if you like the colours you are getting. If not, then experiment further by running WhiteCal. Duplicate the layer, set blend mode to color, select the galaxy (tip - use the Quick selection tool) then run WhiteCal. Re-balance channels again and Flatten.

7. Run the Jay Gabany method of saturation (create 3 new layers above the background layer, set the top one to Luminosity, the middle one to Soft Light, and leave the 3rd one as Normal, then merge the 3 layers together). 

8. Run it again. 

8. Re-do HLVG on a Color Layer. 

 

If you save the Arcsinh stretching and Jay Gabany saturation routines as actions then they become almost a one-click routine, which speeds things up immensely. So the above literally only took me 10 mins to do. 

HTH, and i look forward to seeing your next version once you get the new Red data. And after seeing your version of the Leo Triplet, i know it will be awesome ?

Edited by Xiga
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