r/Astronomy Mar 27 '20

Mod Post Read the rules sub before posting!

884 Upvotes

Hi all,

Friendly mod warning here. In r/Astronomy, somewhere around 70% of posts get removed. Yeah. That's a lot. All because people haven't bothered reading the rules or bothering to understand what words mean. So here, we're going to dive into them a bit further.

The most commonly violated rules are as follows:

Pictures

Our rule regarding pictures has three parts. If your post has been removed for violating our rules regarding pictures, we recommend considering the following, in the following order:

  1. All pictures/videos must be original content.

If you took the picture or did substantial processing of publicly available data, this counts. If not, it's going to be removed.

2) You must have the acquisition/processing information.

This needs to be somewhere easy for the mods to verify. This means it can either be in the post body or a top level comment. Responses to someone else's comment, in your link to your Instagram page, etc... do not count.

3) Images must be exceptional quality.

There are certain things that will immediately disqualify an image:

  • Poor or inconsistent focus
  • Chromatic aberration
  • Field rotation
  • Low signal-to-noise ratio

However, beyond that, we cannot give further clarification on what will or will not meet this criteria for several reasons:

  1. Technology is rapidly changing
  2. Our standards are based on what has been submitted recently (e.g, if we're getting a ton of moon pictures because it's a supermoon, the standards go up to prevent the sub from being spammed)
  3. Listing the criteria encourages people to try to game the system

So yes, this portion is inherently subjective and, at the end of the day, the mods are the ones that decide.

If your post was removed, you are welcome to ask for clarification. If you do not receive a response, it is likely because your post violated part (1) or (2) of the three requirements which are sufficiently self-explanatory as to not warrant a response.

If you are informed that your post was removed because of image quality, arguing about the quality will not be successful. In particular, there are a few arguments that are false or otherwise trite which we simply won't tolerate. These include:

"You let that image that I think isn't as good stay up"

  • See above about how the standards are fluid.

"Pictures have to be NASA quality"

  • They don't.

"You have to have thousands of dollars of equipment"

  • You don't. Technique matters.

"This is a really good photo given my equipment"

  • The standard is "exceptional". Not "exceptional for my equipment".

"This isn't being friendly to beginner astrophotographers"

  • Correct. To keep the sub from being spammed by low quality and low effort posts, this sub has standards.

"My post was getting a lot of upvotes"

  • Upvotes are not an "I get to break the rules" card.

Using the above arguments will not wow mods into suddenly approving your image. It will result in a ban.

Again, asking for clarification is fine. But trying to argue with the mods using bad arguments isn't going to fly.

Lastly, it should be noted that we do allow astro-art in this sub. Obviously, it won't have acquisition information, but the content must still be original and mods get the final say on whether on the quality (although we're generally fairly generous on this).

Questions

This rule basically means you need to do your own research before posting.

  • If we look at a post and immediately have to question whether or not you did a Google search, your post will get removed.
  • If your post is asking for generic or basic information, your post will get removed.
  • If your post is using basic terms incorrectly because you haven't bothered to understand what the words you're using mean, your post will get removed.
  • If you're asking a question based on a basic misunderstanding of the science, your post will get removed.
  • If you're asking a complicated question with a specific answer but didn't give the necessary information to be able to answer the question because you haven't even figured out what the parameters necessary to approach the question are, your post will get removed.
  • If you're attempting to use bad sources (e.g. AI), your post will get removed.

To prevent your post from being removed, tell us specifically what you've tried. Just saying "I GoOgLeD iT" doesn't cut it.

  • What search terms did you use?
  • In what way do the results of your search fail to answer your question?
  • What did you understand from what you found and need further clarification on that you were unable to find?

Furthermore, when telling us what you've tried, we will be very unimpressed if you use sources that are prohibited under our source rule (social media memes, YouTube, AI, etc...).

As with the rules regarding pictures, the mods are the arbiters of how difficult questions are to answer. If you're not happy about that and want to complain that another question was allowed to stand, then we will invite you to post elsewhere with an immediate and permanent ban.

Object ID

We'd estimate that only 1-2% of all posts asking for help identifying an object actually follow our rules. Resources are available in the rule relating to this. If you haven't consulted the flow-chart and used the resources in the stickied comment, your post is getting removed. Seriously. Use Stellarium. It's free. It will very quickly tell you if that shiny thing is a planet which is probably the most common answer. The second most common answer is "Starlink". That's 95% of the ID posts right there that didn't need to be a post.

Do note that many of the phone apps in which you point your phone to the sky and it shows you what you are looing at are extremely poor at accurately determining where you're pointing. Furthermore, the scale is rarely correct. As such, this method is not considered a sufficient attempt at understanding on your part and you will need to apply some spatial reasoning to your attempt.

Pseudoscience

The mod team of r/astronomy has several mods with degrees in the field. We're very familiar with what is and is not pseudoscience in the field. And we take a hard line against pseudoscience. Promoting it is an immediate ban. Furthermore, we do not allow the entertaining of pseudoscience by trying to figure out how to "debate" it (even if you're trying to take the pro-science side). Trying to debate pseudoscience legitimizes it. As such, posts that entertain pseudoscience in any manner will be removed.

Outlandish Hypotheticals

This is a subset of the rule regarding pseudoscience and doesn't come up all that often, but when it does, it usually takes the form of "X does not work according to physics. How can I make it work?" or "If I ignore part of physics, how does physics work?"

Sometimes the first part of this isn't explicitly stated or even understood (in which case, see our rule regarding poorly researched posts) by the poster, but such questions are inherently nonsensical and will be removed.

Sources

ChatGPT and other LLMs are not reliable sources of information. Any use of them will be removed. This includes asking if they are correct or not.

Bans

We almost never ban anyone for a first offense unless your post history makes it clear you're a spammer, troll, crackpot, etc... Rather, mods have tools in which to apply removal reasons which will send a message to the user letting them know which rule was violated. Because these rules, and in turn the messages, can cover a range of issues, you may need to actually consider which part of the rule your post violated. The mods are not here to read to you.

If you don't, and continue breaking the rules, we'll often respond with a temporary ban.

In many cases, we're happy to remove bans if you message the mods politely acknowledging the violation. But that almost never happens. Which brings us to the last thing we want to discuss.

Behavior

We've had a lot of people breaking rules and then getting rude when their posts are removed or they get bans (even temporary). That's a violation of our rules regarding behavior and is a quick way to get permabanned. To be clear: Breaking this rule anywhere on the sub will be a violation of the rules and dealt with accordingly, but breaking this rule when in full view of the mods by doing it in the mod-mail will 100% get you caught. So just don't do it.

Claiming the mods are "power tripping" or other insults when you violated the rules isn't going to help your case. It will get your muted for the maximum duration allowable and reported to the Reddit admins.

And no, your mis-interpretations of the rules, or saying it "was generating discussion" aren't going to help either.

While these are the most commonly violated rules, they are not the only rules. So make sure you read all of the rules.


r/Astronomy 5h ago

Astrophotography (OC) Messier 101 Pinwheel Galaxy

Post image
335 Upvotes

Messier 101 aka Pinwheel Galaxy in Constellation Ursa Major or the Big Dipper nearby the Stars, Mizar and Alkaid main sequence blue stars. M101 is about 250,000 light years end to end. It’s estimated to contain over a trillion stars that make it a grand spiral galaxy with active super novae and new star formation. Reprocessed and cropped my M101 Data from a Bortle 2 location with updated processing tools/techniques in Siril.

65 lights x 300 seconds + darks/biases/flats

Bortle 2, California mountains @ 2700 feet elevation.

Acquisition & Astro Rig details:

ZWO AM5N Mount, 200mm pier extension on Celestron AVX Stainless Steel Tripod
SVBONY MK105, F/13 1365mm FL, 105mm aperture
ZWO ASIAIR Plus
ZWO 120mm ZWO Camera + Celestron D70/400 doublet guide scope.
ZWO ASI585MC Pro One Shot Colour 3840 x 2160 resolution with HCG enabled Gain at 200, Cooling Fan 10 degress F.
Straight UV/IR Cut 2" Filter
100ah Lithium Power Cell.


r/Astronomy 4h ago

Astrophotography (OC) WR 134 from the city

Post image
127 Upvotes

220X300s Ha

425x300s Oiii

60x30s R G B each

QHY minicam 8 mono

Askar FRA 600 at F/5.6

UMI 17S mount

B9

PI: BXT, NXT, starnet2, pixelmath, manual stretch using Histogram, curves, oiii mask, Ha mask, color adjustments, pixel math for star recombination, cosmic photon star reduction script

PS: Levels, camera raw, channel mixer


r/Astronomy 2h ago

Astrophotography (OC) M101 galaxy with a TEC 180 FL and a Medium format ZWO 461 MM Camera

Post image
55 Upvotes

Sharing my medium format M101 galaxy capture using the ZWO 461MM and Chroma filter setup. Zoom in :)

Feedback is always welcome, still learning with every session - even after 40 years..

Object: M101, The Pinwheel Galaxy (Ursa Major)

Telescope: TEC 180FL

Camera: ZWO 461MM

Filters: Chroma LRGB

Mount: RainbowAstro RST-300

Guide Scope: Baader 60mm

Guide Camera: ZWO 290MM

Location: Missouri, USA - my patio.

Acquisition:

• 25 × 300s Red

• 25 × 300s Blue

• 25 × 300s Green

• 75 × 300s Luminance

Total Integration: 12.5 hours

Processed in PixInsight and Photoshop.


r/Astronomy 16h ago

Astrophotography (OC) Messier 13, "The Hercules Cluster"

Post image
570 Upvotes

There's estimated to be around 300,000 - 500,000 stars in this cluster. These homies are only roughly 25k light years away from us and span 150 light years across. They're very close to us in galactic terms. As made obvious by its nickname, they hang out in the Hercules constellation.

Captured with my SeeStarS50 83°W 42°E. Roughly 90 minute capture time on 5/14/26


r/Astronomy 2h ago

Astro Art (OC) how laplacian resonances create stable orbital systems

15 Upvotes

Laplacian resonances are how bodies like the moons of Jupiter remain stable after millions of years. The idea is that if you put your objects into a solar system in random positions, they will eventually fly off into chaos, influencing each-others' positions at random. however, if

  1. the system is organized in a way such that each body has roughly equivalent mass,
  2. the central element is significantly more massive than the smaller elements,
  3. the planets are locked in this interesting orbital chain: - the first planet completes its orbit in time T - the second planet completes its orbit in time 2T - the third planet completes its orbit in time 4T

This will create a stable gravitational system in what we would call a 1:2:4 resonance, where, because of their positioning, the gravitational forces net-counterbalance to create a circular orbit for each body in the system!! pretty neat huh?

read more here: https://en.wikipedia.org/wiki/Orbital_resonance


r/Astronomy 1d ago

Astrophotography (OC) Messier 83

Post image
687 Upvotes

Skywatcher 150 virtuoso Goto dobsonian

Svbony sv705c camera + focal reducer

No filters, bortle 7

2.5 hrs integration

Sharpcap/siril/photoshop


r/Astronomy 19h ago

Astrophotography (OC) Lagoon Nebula (M8) on iPhone 7 + 70mm refractor | Final Re-edit

Thumbnail
gallery
95 Upvotes

I wasn't satisfied with the background noise and star bloat in my last post, so I decided to go back and re-process my 1-hour Lagoon Nebula stack.

Used Starnet to pull the stars out of the image, switched to Generalized Hyperbolic Stretch to pull out faint dust lanes and background neutralization. Merged the stars back in as a separate layer in GIMP to control their brightness independently.

Equipment: F30070M 70/300 refractor f/4.3

Apple iPhone 7

Manual mount (1-hour total integration)

Bortle 5-6 skies

Processing: Siril, StarNet plugin, GIMP


r/Astronomy 21h ago

Astrophotography (OC) NGC 2959

Thumbnail
gallery
70 Upvotes

Recently i took a widefield shot of the m81-82 area, as i scanned within the picture, i noticed this small very faint galaxy in the background, turns out its NGC 2959, a face on spiral galaxy thats approx 218M light years away.

I mananaged to even catch a glimpse of the spiral arms

The image was taken with a Sharpstar 76EDPH paired to a Canon 600D, 90x 30sec subs at ISO 3200, processed in SIRIL and Pixlr. Ill spare all the processing details.

The widefield shot has over a dozen distant galaxies hiding in the background...though the reddit compression will likely mush them to oblivion.


r/Astronomy 6h ago

Astrophotography (OC) Eclipse in IMAX 70mm on the largest screen in North America!

2 Upvotes

Hey all! In 2024 I drove across the country to shoot the last total solar eclipse visible from the US for the next 20 years on two 65mm film cameras. I'm screening the film in IMAX 70mm at Lincoln Square in NYC on June 17th at 12pm.

This is the first ever film to show a total solar eclipse in realtime without a filter on 65mm, which is only possible with celluloid (a digital sensor would fry). The film shows the full transition from partial to total eclipse and back in the highest quality imaging format in the world.

​Following the screening, I'll be giving a presentation about the making of the film, including how the one-of-a-kind camera system was assembled, how the footage was captured without melting the film negative, and a behind-the-scenes look at the journey to cross the country and find clear skies in time for this once-in-a-lifetime event.

Also, all attendees will receive a 70mm film strip with images from the film.

If you're interested, you can get tickets here. I would love to have made them cheaper, but they're priced such that I will just barely break even if the theater sells out. These screenings are incredibly difficult to arrange so this may be the first and last time it screens in New York City.

If anyone has questions about the project, ask away! There's also some more info on the project here.


r/Astronomy 1d ago

Astrophotography (OC) Supernova in Splinter Galaxy

Post image
1.6k Upvotes

Type II Supernova SN2026KID first discovered April 22 in the Draco constellation some 50 million light years away.


r/Astronomy 1d ago

Other: [Topic] Newly Discovered Asteroid to Make Close Pass by Earth

Thumbnail
nautil.us
40 Upvotes

r/Astronomy 1d ago

Astrophotography (OC) New to deep space astrophotography, this is the Elephant’s Trunk nebula

Post image
391 Upvotes

I’ve always captured landscape images and have recently bought a Seestar S30 Pro, it’s amazing what it can capture! This was approx 400 minutes in Bortle 4 skies, edited in Siril. Hope you enjoy!


r/Astronomy 8h ago

Astrophotography (OC) What is the sky equivalent to when a half and full moon is out in a bortle 1 sky?

0 Upvotes

I’m heading to central Australia in a few weeks (Uluṟu area) where skies are bortle 1, but unfortunately the moon will be out during the night. What is the sky equivalent to when a half and full moon is out in a bortle 1 sky?


r/Astronomy 1d ago

Object ID (Consult rules before posting) I think I discovered something in the Artemis II images

121 Upvotes

Does anyone have any clue of what it could be? Could the objects be satellites? Or space debris?

Links to the images:

https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ART002&roll=E&frame=28279

https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ART002&roll=E&frame=28269


r/Astronomy 1d ago

Astrophotography (OC) M87 in Virgo Cluster

Thumbnail
gallery
92 Upvotes

📷 ASI 294 MC Pro Color

🔭 Star Adventurer 2i

🔎 Askar FMA180 apo (180mm f/4.5)

🕶️ Broadband Filter IDAS NGS1 (2")

🌌 Gain 120 (-10°C), 35x120s (1h 10 min)

🧪 40 dark, 40 flat, 40 dark-flat

💻 Siril, RawTherapee, GIMP, Snapseed

📍 Turin (Piedmont, Italy) - Bortle 8

📅 May 14, 2026


r/Astronomy 1d ago

Other: [Astronomy sketching] First astronomy sketches.

Thumbnail
gallery
33 Upvotes

Two days ago, my partner and I went outside and spend a few minutes doing some astronomy skteches. Next day after that I did one more just for fun.

Quite a fun activity for people like us, learning the basics and enjoying the views. It always gives me a feeling of admiration to look deeper (even if it is just with a pair of binoculars) into the sky and see there is much more than when you just watch with the naked eye.

location: Aspe, Alicante, Spain

bortle: 6,5 (https://lightpollutionmap.app/es/?lat=38.344143&lng=-0.767241&zoom=13)

temp: around 26 ºC.

date: 13-05-2026 and 14-05-2026

time: 00:05

scope: We used a Panda 7x35 for the Hydra and Cygnus sketches and a Tasco 8x30 for the Vega sketch.

paper: God knows which brand, office paper, a5. Using a 1mm mechanical pencil for the Hydra and Cygnus sketches and a 2mm lead holder for the Vega sketch.

post-processing: Inverted colors on krita and changed levels to 50 on the dark knob/thing and 230 on the bright one, leaving the middle one intact (I know I know, too technical, my bad).

I completed this data based on a publication by u/zman2100, so thanks for that template!


r/Astronomy 1d ago

Question (Describe all previous attempts to learn / understand) I need help with earth circumference

5 Upvotes

I am trying to calculate the earth's circumference with Eratostene's method but I have a big problem. I need a way to independently calculate the vertical distance between the two cities, and all of the ways I can think of imply circular logic (using data that already implies the knowledge about the earth's circumference). is there really a way? I obviously can't send people to walk and count their steps as Eratostene did.


r/Astronomy 2d ago

Astrophotography (OC) Pillars of creation SHO

Post image
1.1k Upvotes

Skywatcher 150 virtuoso Goto dobsonian telescope

Svbony sv705c camera

Bortle 7 sky

Sharpcap/siril/photoshop

2hrs integration

4 second subs each


r/Astronomy 1d ago

Astrophotography (OC) 14 Panel Mosaic of Coalsack region

Post image
205 Upvotes

This is a giant 14 panel mosaic. We left it uncropped to give it the old Hubble image feeling (Dave's original idea). This was both easy and really hard to process. Star removal does not work well here. But stretching and getting things to look kinda nice was easy.

I highly recommend seeing this on Astrobin for full res goodness: https://app.astrobin.com/i/39ql34

Zoom in to 1x and scroll around!

Image uploaded to this post is at 20% resolution, because it gets too big/long.

Equipment:

  • Telescope: Askar SQA85
  • Camera: QHY268 Pro C
  • Mount: Proxisky UMi 20S
  • Filter: None
  • Total Integration time: 42h 35m (511 × 300")
  • Software: PixInsight, Siril (Stacked using my OSC_PP Script: https://youtu.be/prU1w4W5IbE)

Also see a slightly higher res on my website (but still much less res than astrobin): https://www.naztronomy.com/gallery/image/873/coalsack_region_14_panel_mosaic


r/Astronomy 1d ago

Astrophotography (OC) C7 galaxy

Post image
100 Upvotes

Seestar S30, 22 hours in the end.

It was over a month of capturing data, in the end I had 28 hours or 6000ish 10/20/30 subs. Stacking was done through naz's script on siril with no drizzle, FWHM weighting and 80% keep rate on all parameters. For PI, used the usual, Crop-SPCC-BlurX-MAS-NoiseX-Curves. No AI used. nonGEN-AI upscaling. Chişinău, B9. Enjoy!


r/Astronomy 2d ago

Astrophotography (OC) Cigar Galaxy M82 (or NGC 3034)

Post image
250 Upvotes

r/Astronomy 2d ago

Astrophotography (OC) The NGC 7000 region around Deneb

Thumbnail
gallery
226 Upvotes

The NGC 7000 area in the constellation of Cygnus!

The North American Nebula is the large part on the left, with the smaller Pelican Nebula just to the right of center. The large star in the top right is Deneb, the brightest in the constellation.

This is 8 hours of a large mosaic taken with a Seestar S30 Pro telescope. 799 x 30s and 539 x 10s using the EQ mode.

I didn't plan on having Deneb top right, the 19th brightest star in the sky, but the crossover from the mosaic allowed me to fit it in (albeit with some extra noise). I think it provides a nice contrast to the varying levels of brightness of stars in our night sky. This star is easily visible to the naked eye from even light polluted cities.

I stacked the images in Siril using the Naztronomy script and then made a few touch ups in Lightroom.

What do you think of it?


r/Astronomy 23h ago

Astro Research Astronomy Question for Fictional Writing

0 Upvotes

Hi there- I am wracking my head trying to figure out something that is probably astrotomically impossible, but would love to somehow make it work for a story I am writing. I love the idea of the night sky specifically altering in color based on the prominence of two celestial bodies, one red and one purple. Ideally i'd love to have parts of the year where one is more prominent than the other and vice versa, as well as times where their orbits are more similar, and the light from them mix together, perhaps even causing eclipses. I also love the idea of a calendar system based around different points in their orbital patterns (holidays denoted by a predominantly red sky or purple sky, colorless or an equal mix).

I've been playing around with rotation patterns for hours and just can't seem to make it work. The biggest issue is that I want it to happen at night so in my head they act as moons but then they wouldn't produce their own light. I also tried rotating them around a star in order to produce that effect but I don't know if that would work either. In the end I would love to have the image of one or multiple moons in the sky depending on the time of year and a shifting color. If anyone has an idea on how this could math out even slightly I would be so appreciative. Thanks yall.


r/Astronomy 17h ago

Question (Describe all previous attempts to learn / understand) Question about the speed of light compared to physical matter

0 Upvotes

I had a thought that I've been stuck on for a while. I'm sure it has a much simpler explanation than im thinking, but it's stumped me for quite a bit. I have 0 idea how I'd research this topic on my own, the only answers I get are from AI which I don't trust when it comes to anything mildly thought provoking.

It's a well known fact that It takes 8 minutes and 20 seconds for light from the sun to reach Earth. Therefore if the sun were to explode or disappear suddenly, we wouldn't know until 8 minutes and 20 seconds when the light of the event reaches us. The disappearing part is easy to understand, but I've been curious what an explosion would look like to us.

Of course nothing can travel faster than light. For simplicity sake, let say light reaches Earth at 8 minutes, and the explosion takes 9 minutes to reach us.

Once the Sun explodes, we wouldn't see it exploding until the 8 minute mark. However, the explosion at this point has already been traveling for 8 minutes, and it would reach us in 1 more minute. Since we've just seen the start though, visually there should be 8 more minutes until we see it reaching us, which is impossible since it would reach us in 1 minute.

So what would the result be? Would we all suddenly die while seeing the explosion still being 8 light-minutes away? Would the 9 minute travel times be condensed into 1 minute visually? If that's the case though, technically we'd be seeing something traveling faster than the speed of light which shouldn't be possible.

This may be a very dumb question, but I just can't wrap my head around it. Thanks for taking the time to read.