2 replies to this topic

[Phil49]

Hello everyone,

 

I processed my images taken from April 29 to 30 with my new ToupTek 585 camera, my 8 x 1.25" filter wheel.

 

I targeted LDN 1251, not necessarily an easy choice for starting out in LRGB, but I figured that with my 4 or 5 years' experience in OSC with Pixinsight it would be manageable...

 

So I took 250 images of 120 sec, unity gain 120 and default offset, at -10°C.

100 x R, G and B images.

 

I made darks, flats and dark flats with NINA's PLU assistant, and used WBPP v2.8.2 in Pixinsight v1.9.2.

 

Having no benchmark, for my first LRGB processing, I followed two approaches, Cuiv The Lazy Geek's in this video:

 

- https://www.youtube....h?v=XCotRiUIWtg   (starting at around 2h31mn for LRGB process) 

 

And another recent one by Peter Zelinka here:

 

- https://www.youtube....h?v=_MpfyJnGTPQ

 

Once I'd retrieved my images, I started by processing my LRGB masters as follows:

 

- GraXpert to remove gradient

- BlurXterminator

- NoiseXterminator (30%) to remove noise

- Spectrophotometriccolorcalibration

 

I then used ChannelCombination to combine the 3 colors and got this:

 

 

But as you can see, there's a sort of more or less rectangular purple shape, but not perfectly geometric, superimposed on the background image.

 

I looked at all my images with Blink, but I wasn't struck by any flaws, on the luminance master we can also notice a very slight veil with a shape that could look a little bit like the one on the RGB combined image but it's hard to tell...

 

The image below is the luminance master also processed with GraXpert BlurXterminator and NoiseXterminator :

 

 

With my final image, I managed to remove most of this purplish rectangular shape but we can guess it in some parts...

 

I tried to use SCNR as advised somehwere in this forum, inverting first the image, and without inverting, but to no avail...

 

I've uploaded samples as well as the final image (Tiff file) if someone could take the time to look at the images and give me their opinion...

 

- https://drive.google...VI9?usp=sharing

 

Again, this is my very first LRGB processing and therefore I haven't got much experience to know if this purple shape is to be expected under some circumstances, or if it could be the bug with the firmware of my filter wheel that I would need to apply in order to get rid of the banding due to the IR light of the filter wheel to move the plate!

 

Kind regards

 

Philippe

Edited by Phil49, 12 May 2025 - 06:42 AM.

[Phil49]

Hi all

 

I've been talking to toupTek support for over a week now, and they've asked me to flash the firmware on my filter wheel.

 

In fact, my symptoms closely resembled an already-identified problem linked to the filter wheel rotation control LED that doesn't go out.

 

So I flashed the firmware, asked them if I had to redo all my DOFs, and they told me that only the flats and dark flats had to be redone, not the darks.

 

So I redid my flats and dark flats, processed my images again with WBPP (Pixinsight v1.9.2) and alas, when I got to the channel combination, the same problem again!

 

I ran StarXterminator on the RGB combined image, and you can clearly see the banding and purple color...

 

 

So either the firmware flash had no effect, or there's another cause to the problem.

 

Or, maybe, not only flat frames, but also light frames and dark frames are affected and therefore, I'll check out this hypothesis with my current target, vdb 149 I've been shooting over three nights and will add another one if tonight is a clear night again!

 

In the meantime, I've extended my thinking to my flat creation process, in case that's a lead, a process I've been using for years with an Aptek A4 tablet, under which I put white A4 sheets and thin neutral gray binder dividers (about two of each) to achieve exposure times beyond 2 or 3 sec to smooth out any flickering from the led source, which visually seems uniform.

 

In OSC, I've never had any worries, but what intrigues me is that on a single flat frame, there are no round spots like with my OSC flats with an Optolong L-Pro or IDAS LPS filter, which I systematically use for my photos.

 

And then there's a texture that resembles paper veins!

 

I thought it was the sheet I use as a sandwich, but even when inverted with one of the spacers, it's the same thing...

 

The flats may have nothing to do with it, I'm just trying to look for potential leads...

 

I'm waiting ToupTek support reply, they're really nice and doing their best to help me, but I'm afraid that if it's no longer just a question of firmware, they'll gradually abandon research...

 

Thanks for any help,

 

Philippe

Edited by Phil49, 18 May 2025 - 07:34 AM.

[Phil49]

to be continued...

 

In spite of my issue, I managed to remove most of the problems with the different steps of the LRGB process, but I need to tweak a lot Curve transformation to remove the last purplish colors...

 

 

If you take a careful look at the image, you can still notice a light touch of this purple color, but banding as vanished.

 

However, I can't help thinking that without these shortcomings, my image would be even better, notwithstanding my mastery of Pixisinght, of which I only consider myself a novice after only two years of laborious use!

 

Philippe

Edited by Phil49, 18 May 2025 - 07:35 AM.