Double Cluster in Perseus - CCD Lum with DSLR Colour test run

[Xiga]

During a seemingly never-ending run of bad weather that stretched from early October to late November, i managed to squeeze in a very quick test run on one night (Nov 7) when there was a brief patch of clear sky. I've been so busy lately with work, that i'm only just getting around to posting it now. I processed it a couple of days after capture, which is a few weeks ago now. I probably should revisit it and have another go, just not yet! 

I really just wanted to test how well it would work if i used the Atik383 for Lum, with my Nikon D5300 being used for colour. I'm used to processing OSC and NB data, not really LRGB, so this was a first. 

I took the D5300 data first, when conditions were decent. Then i switched over to the Atik, but conditions had already started to deteriorate. A mist had descended, and the moon was now up, so i had to cut it short. In the end, it was a struggle to find enough subs to even stack! 

So this is just 96 mins of D5300 data (32 x 180s at ISO 200) and 60 mins of Atik383 data (12 x 300s), both shot using an IDAS-D1 filter. The Atik stack was affected by mist and thin clouds, so i just had to rely on gradient reduction to remove the majority of it. In any case, this was only a test run, just to see how well it would work combining the two data sets. Scope used was a SW 80ed riding on a HEQ5-Pro. 

APP used for calibration, integration, and gradient reduction. Siril used for Photometric Colour Calibration. Photoshop used for everything else. Processing was actually quite tricky, if i recall! Here, the stars are both the main attraction, and the main source of frustration! You want the cluster to have a sort of natural glow, but at the same time all the other stars need to be controlled too. Not easy, and i probably didn't nail it tbh. During processing, I created a sort of Super Lum, by layering the D5300 stack (converted to mono, and in blend mode Lighten) on top of the Atik Lum. The stars were unaffected, but it did help to reduce some of the darker noisy pixels in the sky background, so it was well worth it. Even though it's only a starfield, I have to say though, the D5300 data held up well compared to the Atik data. I do really love the mini starburst diffraction spike-effect that the 8300 sensor produces on brighter stars, so even though it's a bit of a hard sell to give up the (considerable) extra fov that the D5300 provides, i aim to continue with this approach for future LRGB projects. The D5300 is actually quite good for colour, as even at ISO 200 it has low read noise (~2.7 e) and a decent FWC of ~16k. 

I've now sent the mount off to Dave at Dark Frame Optics for a much needed tune-up, so no chance of any imaging for the next few weeks. So no doubt the clouds will now suddenly decide to clear! 😋

CS.

Edited December 1, 2020 by Xiga

[Phillyo]

I'm not normally a fan of clusters but this is beautiful. Well done.

[michael.h.f.wilkinson]

Very nice indeed.

[tooth_dr]

Very nice Ciaran, that is a good combo

Have you considered a second ED80? 

[Sp@ce_d]

I like this.. you've done a nice job, very natural.

[Xiga]

7 hours ago, Phillyo said:

I'm not normally a fan of clusters but this is beautiful. Well done.

Thanks Phil (I hope that's your name!). I don't normally shoot clusters myself, but this made for a nice test target given the conditions and short timeframe.

6 hours ago, michael.h.f.wilkinson said:

Very nice indeed.

Thanks Michael.

2 hours ago, Sp@ce_d said:

I like this.. you've done a nice job, very natural.

Cheers Space_d 👍

[Xiga]

5 hours ago, tooth_dr said:

Very nice Ciaran, that is a good combo

Have you considered a second ED80? 

Thanks Adam. Tbh, no I hadn't. Even the thought of running a dual rig without a permanent setup is making me shudder, lol. Each time I decide to image, I have to carry everything down from the attic (2 flights of stairs) and setup completely from scratch. Then break it all down and carry it back up again once done. From the moment I decide to start fetching the gear, it usually takes me anywhere from 60-90 mins until the first sub is on it's way, so I am always looking for ways to simplify and speed things up. While the benefits of a dual rig would be nice (I never have enough data!) I simply can't see me carting a dual rig up and down each time. And then there's the added complexity of making it all work together, dithering, etc, etc.

[Allinthehead]

Lovely double cluster, you can just see the background dust starting to creep in. Great stars too.

[MartinB]

Great job on the process.  You've managed to create a sense of vibrancy whilst keeping everything looking natural.  Not easy.

[Xiga]

2 hours ago, Allinthehead said:

Lovely double cluster, you can just see the background dust starting to creep in. Great stars too.

Thanks Richard. In fact, i actually went out of my way to suppress some of the background dust you mention, mainly because i wasn't sure if it was truly background dust, or just residual mist/clouds! 🤷‍♂️ The conditions really were pretty poor. 

[Xiga]

1 hour ago, MartinB said:

Great job on the process.  You've managed to create a sense of vibrancy whilst keeping everything looking natural.  Not easy.

Thanks Martin, that's great feedback. Vibrancy is something i usually add as one of my final steps in processing, but on this occasion i applied very little, as i didn't find the image to respond particularly well to it, so i thought it best to hold back. 

[Miguel1983]

Lovely image ! 

[Mr Spock]

Lovely image. I really like the colour - it looks very natural.

[Ouroboros]

I think your technique has produced a lovely image. Very natural looking colour.  
 

Can someone explain this to me. Something I have noticed in images like this is that the bright stars often range in colour from blue/white to yellow/orange. But the fainter stars appear more yellow/orange than white.  Is that an artefact of the processing or is it because there are simply more faint red stars? 

[cfinn]

Dwarf stars far outnumber any other kind of star in the Milky Way, but by virtue of their small size and luminosity there are few that are visible to the naked eye. However, I suspect they start to dominate in long exposure images, even with amateur equipment, hence why the majority of the fainter stars have a yellow/orange cast to them. Hotter, more luminous stars (white/blue in colour) are relatively rare by comparison, but they dominate the naked eye view alongside red giants.

Edited December 3, 2020 by cfinn

[Ouroboros]

18 hours ago, cfinn said:

Dwarf stars far outnumber any other kind of star in the Milky Way, but by virtue of their small size and luminosity there are few that are visible to the naked eye. However, I suspect they start to dominate in long exposure images, even with amateur equipment, hence why the majority of the fainter stars have a yellow/orange cast to them. Hotter, more luminous stars (white/blue in colour) are relatively rare by comparison, but they dominate the naked eye view alongside red giants.

That makes sense. 

[Xiga]

On ‎03‎/‎12‎/‎2020 at 05:20, Miguel1983 said:

Lovely image ! 

Thanks Miguel!

On ‎03‎/‎12‎/‎2020 at 07:33, Mr Spock said:

Lovely image. I really like the colour - it looks very natural.

Thanks Spock. Logic dictates, therefore, that I got the colour balance right on this one 😉

On ‎03‎/‎12‎/‎2020 at 12:00, Ouroboros said:

I think your technique has produced a lovely image. Very natural looking colour.  
 

Can someone explain this to me. Something I have noticed in images like this is that the bright stars often range in colour from blue/white to yellow/orange. But the fainter stars appear more yellow/orange than white.  Is that an artefact of the processing or is it because there are simply more faint red stars? 

Cheers!