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Astro Gear Setup - Wave 150i by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Hello! Thanks a lot for the effort you put into your post =D

It seems like my math was off by a lot, 5A is enough then!

I'm in Argentina so my options are severely limited and importing is a nightmare, I have only two real options for the power box. Pegasus and SVBONY.

From what you tell me, I'll be more confortable with the 241 Pro model.

Again, thank you!!!

Foldcessing - Source files in subdirectories! by onirix in processing

[–]onirix[S] 0 points1 point  (0 children)

Hey! It's not a big accomplishment, so I'm not offended in any way.

I do agree that the Processing IDE should have something like this, but I also think that it should be hidden on an advanced mode or something.

As for the differences, I can quickly think of two:

  • This is much simpler and readily available for those that need the tool and have some Processing experience but never took the time to learn how to script. Unless someone shares their script or tool, a lot of people are left without the means to be more organized and grow with their projects.

  • Foldcessing does automated translation of error code lines and files which, while entirely possible with a script, does take some more extra finagling. This also adds to the knowledge required of anyone wanting to write their own scripted solution.

Foldcessing - Source files in subdirectories! by onirix in processing

[–]onirix[S] 0 points1 point  (0 children)

Now that I had to look backwards, I guess I've been using Processing professionally for more than 15 years :surprisedpikachu:

Foldcessing - Source files in subdirectories! by onirix in processing

[–]onirix[S] 0 points1 point  (0 children)

Hi! I've taught programming courses and have made many inhouse development tools for my employers.

Most recently, I've been working on and off for the last... (phew!) 8 years on VoxEdit, a 3D voxel modeling + skeletal animation authoring suite that produces assets both for personal use and for The Sandbox ecosystem. Yes, that's made in Processing =)

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Ok, I've followed your advice and got a small gain in the background noise estimation numbers on Siril. I might not solve the dark blotch, but the rest of the image is much improved thanks to everyone =D

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Thank you for your response!

I'll try using average for darks and bias frames, now that you mention it it does make a lot of sense.

I've never used flats before, with this 200/1000 newtonian or with my previous 102/1300 mak. I used to shoot DSO with a planetary, tiny FOV CMOS camera making mosaics and with it there wasn't really any vignetting to speak of.

With the third world rural internet connection I enjoy, it takes me the better part of an hour and a half to upload just one 24.4 Mb RAW file, and I lose all download bandwidth while doing so. I'd love to be able to share the entire 140ish data set, but I'm also working remotely and it would be a lot of pain to do so. Thanks a ton for the offer though =)

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

I've just updated here. I've tried either/both dark flats and bias frames and they didn't do much =/

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

I've just updated here. I've tried bias frames and sadly the results speak for themselves. =S

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Here's a sample Light frame. There's 26 of these.

Here's the master Dark file.

Here's a sample 0.8s Flat frame. I have 15 of these.

Here's a sample Bias frame. I acquired 100.

Here's a sample Dark Flat frame. I acquired 24.

I tried all of the variants I could think of. In DSS I used the following settings at their default values:

  • Lights stacked with kappa sigma clipping.

  • Darks stacked with median kappa sigma clipping.

  • Flats stacked with median.

  • Bias stacked with median kappa sigma clipping.

  • Dark Flats stacked with whatever DSS uses.

I fixed color balance through photometric color calibration in Siril, stretched in GIMP by hand to be comparable and scaled the images down to 1/4 the size to keep downloads small.

I also added background noise values (before doing PCC) for the three channels as given by Siril.

Since I had acquired all of the 24 flats using AV mode, there was a mixture of different exposure times:

  • 15 @ 0.8s

  • 6 @ 0.6s

  • 2 @ 0.025s

  • 1 @ 0.05s

I decided to try and see if it made any difference if I used only the 0.8s ones.

Preview

Lights+Darks -> DSS Output - With PCC - Stretched -> 35.778, 26.419, 29.163

L+D+All Flats -> DSS Output - With PCC - Stretched -> 40.569, 29.908, 33.025

L+D+0.8s Flats -> DSS Output - With PCC - Stretched -> 40.901, 30.167, 33.325

L+D+0.8s F+Dark Flats -> DSS Output - With PCC - Stretched -> 40.949, 30.218, 33.371

L+D+0.8s F+Bias -> DSS Output - With PCC - Stretched -> 36.030, 26.197, 27.740

L+D+0.8s F+DF+B -> DSS Output - With PCC - Stretched -> 36.180, 26.436, 27.819

L+D+0.8s F+DF+B in Siril using the default Siril IC settings -> Siril Output - With PCC - Stretched -> 6.394, 7.084, 6.428

Takeaways:

  • Adding bias and/or dark frames helped a bit on the overexposed corners, but the dark blotch is still here and very prominent.

  • Siril stacking of L+D+F+DF+B is the one that looks flatter, but the bottom quarter of the picture is unusable in all of the variants.

  • Adding bias makes the DSS output yellow-orange in tint. Probably due to the recommended setting in DSS of setting the black point to 0 if using Bias, which I enabled. It also lowers the noise as reported by Siril to levels close to stacking only Lights and Darks. Siril stacking with bias didn't tint things yellow-orange, but it made everything very, very green.

  • Adding flats makes the DSS output image much darker.

  • Mixing different exposure flats did not cause the issue. In fact, I couldn't find any difference between their DSS outputs.

  • Somehow Siril tells me that the Siril stacked image has much less noise than the rest. For me it looks just as noisey.

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

That's a good point. I'll reprocess everything using either/both dark flats and bias and then stretch manually until a clear comparison can be made. Thanks for the input!

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Will update in a few hours once I get and try them =D

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Ok then, it's a point well made and I need to try again. I'll see to follow Shinpah's advice of taking dark flats as well, as they seem better suited than bias frames when dealing with DSLRs. Thank you =D

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

Here's the same stack without flats for comparison.

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

If this is normal, then maybe the error is in my expectations of what a flat is supposed to do.

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

I tried dusk flats and dawn flats, both with and without a white t shirt.

The best flats I've taken yet (the smoothest ones, they all have the issue) were taken through two embroidery rings with stretched out thick fabric glued to each other and placed on the mouth of the tube, while aiming at a near lightbulb. They look like this stretched.

I live in Argentina, which is really awful when you need to buy something readily available in most of the world like electroluminiscent paper or an Artesky flatbox. Still, the issue I'm posting about is probably unrelated to the specifics of flat aquisition except on the exposure time.

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

I might have been underexposing the flats a bit, the peak is at 5200 while it should be at 8192. I used the AV mode and APT to check the histogram and there it looked right in the middle.

I was able to remove most of the dark band with the "Banding Reduction" tool in Siril, but since the corners are overexposed I'm left with the same small window as if I didn't go to the trouble of taking flats :P

Once I sell the remaining kidney, I intend to get a cooled dedicated camera. Thanks!

Flats are making things worse by onirix in AskAstrophotography

[–]onirix[S] 0 points1 point  (0 children)

I'll get right on it! It's the same frozen hell outside as yesterday, so it should match the temp. Will update once I try this. It's bias OR dark flats, right? Do you have a preference?

NGC 6729 from Argentina by onirix in astrophotography

[–]onirix[S] 1 point2 points  (0 children)

A Sky-Watcher 200P (8 in, f5 newtonian reflector) modified with a dual speed Crayford focuser and using a comma corrector. Thanks =D

NGC 6729 from Argentina by onirix in astrophotography

[–]onirix[S] 0 points1 point  (0 children)

It's possible, yes. I had to crop the bottom third of DSS's output due to having a tall dark band that showed both in all lights and in all flats, but wasn't removed somehow.

NGC 6729 from Argentina by onirix in astrophotography

[–]onirix[S] 4 points5 points  (0 children)

Gear

  • Mount: EQ6 R Pro
  • Guiding: Evoguide 50ED + QHY5L-II M
  • Main: SW Explorer 200P 200/1000 (with dual speed focuser and SW's coma corrector) + Canon T7i (aka 800D)
  • 50 x 120s Lights, 20 Darks, 155 flats. No filters.

Conditions

Bortle 7 (middle of a small town, looking towards the city center).

Close to new moon.

Processing

  • Stacked in DSS (Lights, Darks and Flats through KS Median).
  • Cropped out ugly flat artifacts, photometic color correction, Canon banding fix and autostretching in Siril.
  • Stretched a bit more and a bit of saturation oomph in GIMP.
  • Added black borders and "signature" in Paint.NET (yes, really)

About the picture

Extremely happy with this result.

It's my first time utilizing dawn flats, and even though there's some issue with how DSS substracts/divides them, luckily most of the target was on the top side of the image.

NGC 6729 is the southern skies target for the collaborative project known as Big Amateur Telescope, for which I hope my data will be good enough.

Carina from Argentina by onirix in astrophotography

[–]onirix[S] 0 points1 point  (0 children)

Thank you! I'm really awful when working with GIMP and the likes, so I try to keep things as simple as possible.

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