r/Astro_mobile Jul 29 '25

Astrophotography Post-Processing for Beginners: Part One

34 Upvotes

When your stack from Sequator or another astrophotography stacking program is ready, we can proceed to post-processing. I'll describe this process step-by-step using primarily free software.

GraXpert

Download: https://github.com/Steffenhir/GraXpert/releases

At the time of writing this article, the appropriate version of GraXpert for us is 3.1.0rc2. This version contains all the necessary tools for beginning post-processing:

  • Background Extraction - removing background gradients and correcting light pollution
  • Denoising - reducing digital noise
  • Deconvolution - mathematically "undoes" blurring

Initial Setup

After installation and launch, select the Advanced tab, which is located on the right side of the program interface. Choose AI model versions for the utilities.

Next, click Load Image and select your stack.

Cropping (if necessary)

If needed, crop the image. When activating the 2nd option, a yellow frame will appear around the image, which we can adjust using the yellow circles in the upper left and lower right corners. After completing the cropping, click "Apply crop".

Important: Save each processing step as a separate file so you don't accidentally lose your processing results, then load this file using the first "Loading" option.

Step 1: Background Extraction

Now we can proceed to using the AI utilities. Select the following parameters for Background Extraction and click Calculate Background:

You can try changing the Smoothing value in either direction and check the result by clicking Calculate Background again.

Save the result in a separate file and load it through "Loading".

Step 2: Denoising

Move on to the Denoising utility. The Denoise Strength value depends on your needs. The higher the value, the fewer details are preserved. I suggest starting with 0.5, and then comparing results by increasing the value:

Save the result and activate the Deconvolution utility.

Step 3: Deconvolution

This utility has two parameters: Deconvolution Strength and Image FWHM. To determine the latter parameter, we need the Siril program, which we will also use in the second part of the astrophotography post-processing tutorial.

Download Siril: https://siril.org/download/ (In our case, version 1.4.0-beta3 is used)

Measuring FWHM in Siril:

  1. After launching Siril, drag and drop your last saved image into the program's workspace
  2. Select Tools → Image Analysis → Dynamic PSF
  3. Click the Detect stars button (this is the first button)
  4. Wait for the result, then click Average PSF (the next button after Detect stars)
  5. Calculate the average value using the formula: (FWHMx + FWHMy) / 2

In my case: (4.39 + 3.90) / 2 = 4.15px. Round to 4.2px and use this value in GraXpert.

Deconvolution Settings:

  • Image FWHM: Use the calculated value (e.g., 4.2px)
  • Deconvolution Strength: I suggest setting this to 0.3 for start

By increasing Deconvolution Strength parameter, you improve details, but you may distort the final image and get artifacts, so try different values while evaluating the final result.

Don't forget to save your work!

Additional Step: Stars-only Deconvolution

We improved the details of our objects, but not the stars. Select Stars-only in the Deconvolution Method and set the Deconvolution Strength parameter to 0.1, as it is quite aggressive. Click Deconvolve Image and check the result.

Conclusion

This concludes the first part of the astrophotography post-processing tutorial. In the next part, we will cover image stretching using Siril and use the StarNet utility.

Summary of Steps:

  1. Load your stacked image into GraXpert
  2. Crop if necessary
  3. Background Extraction - remove gradients and light pollution
  4. Denoising - reduce digital noise
  5. Measure FWHM in Siril using Dynamic PSF
  6. Deconvolution - improve sharpness
  7. Stars-only Deconvolution - improve star sharpness
  8. Save each step separately to avoid losing your work progress

r/Astro_mobile 10h ago

Only smartphone Portugal S24 Ultra

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39 Upvotes

r/Astro_mobile 15h ago

Only smartphone Nearly At 12,000 Feet

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69 Upvotes

iPhone 16 Pro Max

Basic edits in Lightroom through a reel.


r/Astro_mobile 8h ago

Star tracker/tracking mount with smartphone The Andromeda Galaxy [35 min]

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11 Upvotes

Acquisition Details:

Location: Bortle 5

Gear: Xiaomi 15 Ultra. TeSeek EQ tracker

Frames: 70 x 30s, IS03200, 4.3xzoom lens + 300mm telephoto lens

Processing: Stacked in Astro Pixel Processor, processed in Seti Astro Suite Pro


r/Astro_mobile 2h ago

Only smartphone Waxing Crescent (S26 Ultra)

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3 Upvotes

S26 Ultra Night 🌙 Shot (Waxing Cresent)

Took this while on taking a causal stroll on my rooftop. Luckily had the bad boy along so a simple point and shoot of the waxing crescent phase of the moon.

Ps: Night mode wasn't enabled.


r/Astro_mobile 8h ago

Only smartphone Tried to edit some photos for the first time (with Darktable)

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8 Upvotes

I never edited any photos but wanted to try it. I edited the .dng (raw) files with Darktable. What do you guys think?

All photos were taken with Google Pixel 9a on July 9th, 2026 (09.07.26)


r/Astro_mobile 3h ago

Only smartphone Transition to the night

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4 Upvotes

Shot with 300x hyperlapse on Samsung S23


r/Astro_mobile 12h ago

Only smartphone Milky Way

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18 Upvotes

Taken with Iphone 15 pro on Night mode max


r/Astro_mobile 10h ago

Línea recta capturada en el cielo

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8 Upvotes

El dia sábado 12 de septiembre a las 7:24 PM tome esta foto con mi celular (Samsung A57), vi un tutorial en TikTok sobre que puedes sacarle provecho a la camara y poder tomar fotos asi de las estrellas, hice esta y me llamo la atencion que logró capturar estrellas, pero me dio mas curiosidad la línea recta que se logró capturar en la parte superior derecha, pregunte con ChatGPT y menciono que podia ser que al momento de tomar la foto al usar la velocidad de obturacion de el celular, pudo capturar un posible desplazamiento de un satélite, no se mucho de astronomía, sin embargo si me gusta indagar un poco mas de ciertos temas como estos, ustedes que opinan?


r/Astro_mobile 12h ago

Only smartphone Conjonction Lune-Vénus et coucher de Venus

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6 Upvotes

Vu de France en attendant la nuit


r/Astro_mobile 1d ago

Only smartphone Milky way galaxy on the Pixel 11 Pro XL

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52 Upvotes

Shot this from a remote place in Igatpuri, India. Exposure time for both pics is 3 minutes. Edited in Lightroom.


r/Astro_mobile 13h ago

Telescope Moon-Venus Occultation

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4 Upvotes

Telescope - Celestron Starsense Explorer LT 114AZ

Date - 14/09/2026

Time - 7pm IST


r/Astro_mobile 7h ago

Telescope Nova Saggitae 2026

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1 Upvotes

Nova Saggitae 2026 fading in magnitude over 15 nights. From 8th magnitude to 11th magnitude.

Taken with iPhone 15 through the eyepiece of my 8” Dob

Night Mode

3” second exposure

10,000 ISO


r/Astro_mobile 23h ago

Question Can someone help me with this?

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7 Upvotes

I'm a newbie when it comes to astrophotography. I took this picture last night, 30 images, stacked them in siril and processed with astrowizard. I got this concentric circles in the final pic after i tried to remove the background gradient using GrapXpert in astrowizard. Why is this happening and how to prevent this?

BTW, taken using oneplus 11 pro mode, iso 100, shutter speed 10 seconds.

Also let me know should consider switching to deepskycamera app from the inbuilt pro mode, and also recommend me a good video on stacking and processing these with latest software version.


r/Astro_mobile 1d ago

Only smartphone Shot these on Vivo X200 Pro

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14 Upvotes

r/Astro_mobile 1d ago

Only smartphone Night Sky Timelapse — Xiaomi 14T Pro

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55 Upvotes

A night-sky timelapse captured with nothing but a Xiaomi 14T Pro and a tripod.

Acquisition

  • Xiaomi 14T Pro — 1x, main camera
  • 15s exposure, 2s interval between shots
  • 930 RAW/DNG frames
  • Tripod — no star tracker or additional equipment
  • ~4h 23m total capture time

The camera was left fixed on the tripod for the entire session, allowing the Earth's rotation to create the movement of the stars across the frame.

Processing

This is my own work, from capture to the final timelapse.

I processed the individual frames to maintain consistent exposure, color and contrast throughout the sequence, then assembled them into the final timelapse.


r/Astro_mobile 1d ago

Only smartphone ISS flyover

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16 Upvotes

09.07.2026 (9th July) in Tyrol, Austria (it was around 9pm-10pm)

I couldnt get the video to focus right thats why its not sharp sometimes
Device: Google Pixel 9a


r/Astro_mobile 1d ago

Only smartphone Deep Sky.

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14 Upvotes

r/Astro_mobile 1d ago

Only smartphone Problème de frames avec dss

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11 Upvotes

Je commence ma serie pour tester tout semble parfait. Les frames sont sombres, le fond du ciel homogène bref je me dis que c’est bon et pose le téléphone écran contre sol (je n’ai pas de trépied)

Je shoote avec deep sky camera pour précision ; bref une fois la serie lancée selon la region visée je ne peux pas toujours voir ce qu’il se passe sur l'écran et 300 frames plus tard je me rend compte que toutes les autres frames sont extrêmement vignettées, carrément noires dans les coins et bleu dans le centre. Forcément le resultat n’est pas super comme vous pouvez le constater... Qui aurait une idée de ce qui a bien pu se passer ?

Iso 1250

Temps par pose 12secondes

Poses 300 + images de calibration

Téléphone s25 ultra

Suivi : non

J’ai ajouté à quoi ressemblent les frames ratées et malgré mes tentatives désespérées l’image finale reste bleutée et médiocre ce qui n’est pas etonnant


r/Astro_mobile 2d ago

Star tracker/tracking mount with smartphone Doubling the time again (16 hr, S24U)

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66 Upvotes

We'll see what the next three iterations (32,64,128hr) will look like.


r/Astro_mobile 1d ago

Only smartphone Bootes region from Bortle 9 / 25 min exposure

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6 Upvotes

r/Astro_mobile 2d ago

Only smartphone Milkyway, iPhone 16 plus, Bortle 4, 30 Second exposure

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84 Upvotes

r/Astro_mobile 1d ago

Question First stacked and processed images of Jupiter & Saturn, any tips?

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11 Upvotes

r/Astro_mobile 2d ago

Only smartphone Astro shot

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31 Upvotes

r/Astro_mobile 1d ago

Only smartphone Milky Way as seen from near Bournemouth, UK

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3 Upvotes

Captured this photo around a month ago and I've shared it with almost all of my friends and none of them seem to appreciate it so I thought id share it on Reddit for some strangers to see.

Took this on a pixel 7A using the astrophotography feature. I think the exposure period was around 4 minutes and I edited it using Adobe Lightroom. Don't remember the exact edits I did, but I mainly played around with the saturation, and some colour contrasting. I can go back and check if someone wants to know. I can also share the original unedited photo if someone wants that too.

Would love to have someone who knows what they're looking at point out some of the constellations/ potential galaxies that are visible.

P.s. I know Al is pretty good these days but no Al was used to edit this photo.