this post was submitted on 09 Aug 2024

32 points (100.0% liked)

Astrophotography

1783 readers

1 users here now

Welcome to !astrophotography!

We are Lemmy's dedicated astrophotography community!

If you want to see or post pictures of space taken by amateurs using amateur level equipment, this is the place for you!

If you want to learn more about taking astro photos, check out our wiki or our discord!

Please read the rules before you post! It is your responsibility to be aware of current rules. Failure to be aware of current rules may result in your post being removed without warning at moderator discretion.

Rules

I | Real space images only.

Astrophotography refers to images of astronomical objects or phenomena exclusively.
~~Images that show objects or people below the Kármán Line (100km) will be removed.~~ We won't be enforcing this rule for now, but as the community grows eventually we will split and have a separate space for just landscape astro.
Images must be an accurate representation of a real astronomical object.
See this page for more details

II | Original and Amateur Content Only

Image posts can only be images that you have captured and processed yourself, or discussion about capturing and/or processing your own images.
Images acquired from public sources, professional observatories, or other professional services are not allowed.
If you have done a drastic alteration or reprocessing of a prior submission, you may repost your edit - but only after a minimum of one week has passed.

III | Post Types

Image posts are to link directly to the image, not to landing pages, personal galleries, blogs, or professional sites. Link to these in the comments. (AstroBin and Imgur, are allowed)
Questions are welcome here for the time being.
Links to blogs, articles or external websites should be interesting and promote discussion about amateur astrophotography.

IV | Titles

All image posts should just include include the name of the object being photographed. Extra info such as equipment, it being your first image, or other information should go in a comment along with your acquisition info. Please see this page for more details.

If your post is removed, try reposting with a different title. Don't hesitate to message the mods if you still have questions!

V | Acquisition and Processing Information

All submitted images must include acquisition and processing details as a top-level comment. All posts without this information may be given a warning, and if not updated will be removed.
This includes the telescope, mount, camera, accessories, and any other pieces of equipment you used to capture the image.
You must also include processing details, i.e. the programs you used and a general rundown of the workflow/processes you used within those programs. “Processed in Photoshop” is not enough.

founded 1 year ago

MODERATORS

bigborpa

lefty7283

M51 - The Whirlpool Galaxy in HaLRGB (live.staticflickr.com)

submitted 3 months ago by lefty7283 to c/astrophotography

1 comments fedilink hide all child comments

top 1 comments

sorted by: hot top controversial new old

[–] lefty7283 4 points 3 months ago

I originally planned on shooting this from a dark site on top of a mountain but my laptop had other plans. Ended up taking this from my driveway instead (at least when I still had a driveway), but I'm very pleased with the detail I got at just 610mm focal length. There are also a number of other galaxies in the uncropped pic including one over a billion light years away from us (calculated from redshift). This image was taken with a monochrome camera through filters for luminance (all visible light), red, green, blue, and Hydrogen-alpha (656nm), which were combined into a color image. The Hydrogen-alpha was combined with red (described below) to enhance the hydrogen nebulae in the galaxy (red splotches in the spiral arms). Captured on March 21, 22, 24, and 29th, 2021 from a Bortle 6 zone

Places where I host my other images:

Flickr | Instagram

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-120MC for guiding
Moonlite Autofocuser

Acquisition: 10 hours 2 minutes (Camera at Unity Gain, -15°C)

Lum - 106x120"
Ha - 30x300"
Red - 40x120"
Green - 40x120"
Blue - 50x120"
Darks- 30
Flats- 30 per filter

Capture Software:

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

PixInsight Processing:

BatchPreProcessing
StarAlignment
Blink
ImageIntegration
DrizzleIntegration (2x, Var β=1.5) (Lum only)
StarAlign Ha, R, G, B stacks to drizzled L
DynamicCrop
DynamicBackgroundExtraction

Luminance:

EZ Decon + Denoise
ArcsinhStretch + histogramtransformation to bring nonlinear

RGB:

ChannelCombinaiton to combine monochrome R, G, B stacks into color image
PhotometricColorCalibration
SCNR green

Adding Ha:

I followed this tutorial which I find produces much better results than my previous NBRGBCombination script technique:

http://www.arciereceleste.it/tutorial-pixinsight/cat-tutorial-eng/85-enhance-galaxy-ha-eng

PixelMath to make Clean Ha. This effectively isolates just the Ha from the red continuum spectrum

Ha-Q * (Red-med (Red))

Q=1.0416

PixelMath to combine Clean Ha
PixelMath to add Ha to RGB image ($T)

R= $T+B*(Ha_Clean - med(Ha_Clean))

G= $T

B= $T+B*0.2*(Ha_Clean - med(Ha_Clean))

B=3

HaRGB:

Slight SCNR
HSV Repair
ArcsinhStretch + histogramtransformation to bring nonlinear
ColorSaturation to slightly desaturate Ha regions
HistogramTransformation to further stretch to match lum brightness

Nonlinear:

LRGBCombination with stretched L as luminance
Several CurveTransformations to adjust lightness, contrast, colors, saturation, etc.
MoreSCNR
ACDNR
LocalHistogramEqualization
More Curves
ColorSaturation to slightly desaturate Ha regions
MMT noise reduction
EZ StarReduction
Final Curves
Resample to 60%
DynamicCrop to 3555x2000
Annotation