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  • lefty7283OPMtoAstrophotographyM8 - The Lagoon Nebula in LRGB
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    2 months ago

    Another pic from my recent dark site trip! Decided to shoot something bright and in true color LRGB. If I had stayed another night and gotten more data I probably would’ve pushed the image more to get more background details, but overall I like this darker look on the image. Last time I shot this nebula was in 2022 using the false color OSH palette). Captured on July 26th, 2025 from a bortle 3 zone (deerlick astronomy village).

    Places where I host my other images:

    Flickr | Pixelfed

    Equipment:

    • TPO 6" F/4 Imaging Newtonian

    • Orion Sirius EQ-G

    • ZWO ASI1600MM-Pro

    • Skywatcher Quattro Coma Corrector

    • ZWO EFW 8x1.25"/31mm

    • Astronomik LRGB+CLS Filters- 31mm

    • Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm

    • Agena 50mm Deluxe Straight-Through Guide Scope

    • ZWO ASI-290mc for guiding

    • Moonlite Autofocuser

    Acquisition: 4 hours 2 minutes (Camera at -15°C), half unity gain

    • L - 49x120"

    • R - 267x120"

    • G - 23x120"

    • B - 23x120"

    • Darks- 30

    • Flats- 30 per filter

    Capture Software:

    • Captured using N.I.N.A. and PHD2 for guiding and dithering.

    PixInsight Preprocessing:

    • BatchPreProcessing

    • StarAlignment

    • Blink

    • ImageIntegration per channel

    • DrizzleIntegration (2x, Var β=1.5)

    • Dynamic Crop

    • DynamicBackgroundExtraction

      duplicated each image and removed stars via StarXterminator. Ran DBE with a shitload of points to generate background model. model subtracted from original pic using the following PixelMath (math courtesy of /u/jimmythechicken1)

      $T * med(model) / model

    Luminance Linear:

    • Blur and noisexterminator

    • Stars removed with starx

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    RGB Linear:

    • ChannelCombination to combine monochrome R G and B images in to single color image

    • SpectrophotometricColorCalibration

    • BlurXterminator (correct stars only)

    • HSV Repair

    • Extracted stars with starXterminator, to be used later for independent starless processing

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    • Slight saturation curve boost

    ** Stars only processing:**

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    • Slight SCNR to remove greens

    • Curves to boost saturation

    Nonlinear Processing:

    • LRGBCombination to combine stretched RGB and L images

    • NoiseX again (more for chrominance noise)

    • Several rounds of curve adjustments for lightness, contrast, saturation, color balance, with various masks

    • LocalHistogramEqualization (one at 16 scale for fine details, and another round at ~300 scale for larger structures)

    • More curves

    • Color Saturation

    • Even more curves

    • Slight SCNR on the background

    • Pixelmath to add in the stretched RGB stars only image from earlier

      This basically re-linearizes the two images, adds them together, and then stretches them back to before. More info on it here)

      mtf(.005,

      mtf(.995,Stars)+

      mtf(.995,Starless))

    • Resample to 80%

    • Tighter crop in on just the nebula

    • Annotation



  • lefty7283OPMtoAstrophotographyM27 - The Dumbbell Nebula
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    2 months ago

    After months of clouds and rain, I had a clear night and went out to a dark site! I shot this a few years back in narrowband which helped show the faint outer shell, but this time I decided to photograph it in true color LRGB. Captured on July 26th, 2025 from a bortle 3 zone (deerlick astronomy village).

    Places where I host my other images:

    Flickr | Pixelfed

    Equipment:

    • TPO 6" F/4 Imaging Newtonian

    • Orion Sirius EQ-G

    • ZWO ASI1600MM-Pro

    • Skywatcher Quattro Coma Corrector

    • ZWO EFW 8x1.25"/31mm

    • Astronomik LRGB+CLS Filters- 31mm

    • Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm

    • Agena 50mm Deluxe Straight-Through Guide Scope

    • ZWO ASI-290mc for guiding

    • Moonlite Autofocuser

    Acquisition: 2 hours 50 minutes (Camera at -15°C), halfunity gain

    • L - 31x120"

    • R - 19x120"

    • G - 18x120"

    • B - 17x120"

    • Darks- 30

    • Flats- 30 per filter

    Capture Software:

    • Captured using N.I.N.A. and PHD2 for guiding and dithering.

    PixInsight Preprocessing:

    • BatchPreProcessing

    • StarAlignment

    • Blink

    • ImageIntegration per channel

    • DrizzleIntegration (2x, Var β=1.5)

    • Dynamic Crop

    • DynamicBackgroundExtraction

      duplicated each image and removed stars via StarXterminator. Ran DBE with a shitload of points to generate background model. model subtracted from original pic using the following PixelMath (math courtesy of /u/jimmythechicken1)

      $T * med(model) / model

    Luminance Linear:

    • Blur and noisexterminator

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    RGB Linear:

    • ChannelCombination to combine monochrome R G and B images in to single color image

    • SpectrophotometricColorCalibration

    • BlurXterminator (correct stars only)

    • HSV Repair

    • ArcsinhStretch + HistogramTransformation to stretch nonlinear

    • Slight saturation curve boost

    Nonlinear Processing:

    • LRGBCombination to combine stretched RGB and L images

    • NoiseX again (more for chrominance noise)

    • LocalHistogramEqualization

    • Several rounds of curve adjustments for lightness, contrast, saturation, color balance, with various masks

    • Resample to 80%

    • Tighter crop in on just the nebula

    • Annotation














  • It varies a LOT from camera to camera, but a lot of them have a sweet spot around 800-1600 for astro. For astro/low light photography, a higher ISO actually decreases the noise in the image, as the signal gets amplified before it’s read. You can test it for yourself by taking several pics of something dark, and changing only the ISO between shots. Matching the brightness in post-processing helps show the noise in low ISO images.

    Also IIRC a lot of Sony cameras are noise-invariant when changing ISO






  • I know a few attendings that use it for dictation. It’ll record the entire convo with the patient, plus whatever the doc dictates to it, and by the time they’re out of the room a note is typed up in the right format they wouldn’t have to stare at the computer the whole visit. According to them it’s a lot more time efficient to have it dictate the notes and double check them at the end of the day, versus typing something up after every patient. It is approved by the hospital and integrated directly into the EMR, so I guess it’s HIPAA compliant