r/Astronomy • • Mar 27 '20

Mod Post Read the rules sub before posting!

904 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
  • Images that don't fill the frame because you were shooting through an eyepiece

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 and the mods are under no obligation to explain this decision to you.

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.

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 you asked Chat GPT or any other LLM, your post will be removed (see our rule regarding sources).
  • 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.

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.

Content

Due to the profusion of AI slop apps, we're no longer allowing apps at all. No, we don't care if you're wanting a "review". No we don't care if they're free. No we don't care if you put it in a website.

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 • • 14h ago

Astrophotography (OC) Saturn captured with my C11

Post image
882 Upvotes

r/Astronomy • • 3h ago

Astrophotography (OC) Heart Nebula | Bortle 8.4

Thumbnail
gallery
100 Upvotes

🔭 - Seestar S50
⏳ - 7053x20 (39.18h)
⚙️ - Siril & AdobePhotoshop

• This is a 2-panel Mosaic showing off the Heart and Fish Head Nebula under Atlanta, Ga skies. One of my favorites for sure. Hope you enjoy & clear skies to all 💫


r/Astronomy • • 10h ago

Astrophotography (OC) SH2-171, Teddy Bear Nebula

Post image
225 Upvotes

Taken from my bortle 9 balcony in Paris, this was didn't have such a strong gradient as I normally get here, so I enjoyed the processing a lot! I'd like to revisit this object with my wider FOV rig next year, I think it looks pretty cool

Equipment and acquisition:

- Askar 71F + 0.75X reducer

- Asi585MC Air

- Teseek 17

- SvBony + asi120mm guide camera

- ZWO EAF, ZWO EFW

- L-Ultimate filter: 216 x 180 sec

- Antlia ALP-T SII-OIII 3nm: 233 x 180 sec

(approx. 22.5 hours in total)

- 30 darks, 30 flats per filter, 30 bias

Processing (PI)

WBPP 2x drizzle, SetiAstro AutoDBE, SPCC, blurX correct only, starX

On starless images: DBXtract, linear fit to Ha, then channel combination. Extract L component. SetiAstro statistical stretch (soft), then manual curves transformations with different color and range masks, selective color correction script, noiseX. For luminance, stretch and masked curves to bring up details, noiseX. LRGB combination, dark structure enhance script.

For stars: setiastro NB to RGB star stretch, pixelmath to recombine with starless


r/Astronomy • • 6h ago

Astrophotography (OC) Orion Nebula & Running Man Nebula

Post image
39 Upvotes

The great Orion Nebula and Running Man Nebula! This majestic stellar nursery is about 1400 light-years away and is one of the brightest deep sky objects in the night sky!

A very nostalgic target for me. This was the first deep sky object I captured 10 months back when I was just getting started in this hobby. Visited this back again now that the orion constellation is back up again! 🙂

Telescope: Seestar S50
Data: 4.5 hours
Tools used: GraXpert, Siril, GIMP
Script mentions: DeepSNR, CosmicClarity Sharpen, VeraLux (Revela & Curves), HDR_multiscale
Bortle 8-9


r/Astronomy • • 8h ago

Astrophotography (OC) IC 1318 and the foreground star Sadr

Post image
44 Upvotes

I found this session while going through my stored astrophotography data. I captured it from my Round Rock backyard on October 31–November 1, 2025, but had never processed it. This is its first finished image.

The bright star near the center is Sadr, also known as Gamma Cygni—a supergiant marking the center of the Northern Cross in Cygnus. It appears surrounded by the clouds of IC 1318, but that’s a line-of-sight effect: Sadr is roughly 1,800 light-years away, while the nebula lies much farther behind it, around 4,900 light-years away.

The red nebulosity is glowing hydrogen gas. The dark lanes cutting through it are clouds of dust blocking light from behind. This field captures part of the extensive gas-and-dust complex around Sadr.

The finished image combines 40 five-minute exposures—3 hours and 20 minutes—with my ASI585MC Air. Processing brought out the faint nebulosity and dust structure while controlling the stars and the glow around Sadr. A session sitting on a drive finally became an image.

Acquisition: ASI585MC Air, 40 × 300 seconds retained from 47 frames; gain 107, offset 15, recorded sensor temperatures −19.1 to −16.3°C. The headers record an AM3 mount and approximately 384 mm focal length; the telescope model is unconfirmed. Filter information was not recorded, and I no longer remember which filter was used.

Processing: bias and 100 same-night flats, conservative hot-pixel correction, registration and weighted integration in PixInsight. Compared 29-frame and 40-frame stacks and selected 40 for lower noise. Empirical field-star color balance, conservative BlurXTerminator, StarXTerminator separation, masked NoiseXTerminator, then scripted stretches, local contrast, selective color and localized halo control. Stars were blended back separately. No synthetic nebulosity was added.


r/Astronomy • • 20h ago

Astrophotography (OC) The Soul Nebula (IC 1848) in SHO

Post image
286 Upvotes

Target: IC 1848, the Soul Nebula

Location: Bortle 6, South Carolina

Gear:
Askar 103APO (700mm f/6.8)
ZWO ASI2600MM Pro
ZWO AM3N on iOptron LiteRoc tripod
ZWO ASIAir
Antlia 3nm Ha, OIII, SII and Antlia V-Pro RGB

Integration (about 22h 23m):
Ha: 44 × 500s (6h 07m)
OIII: 59 × 500s (8h 12m)
SII: 51 × 500s (7h 05m)
RGB (stars): 20 × 60s each
Calibration: darks, flats, bias


r/Astronomy • • 13h ago

Astrophotography (OC) M95 — Barred Spiral Galaxy in Leo

Post image
70 Upvotes

This is my first time processing this M95 data, captured from my backyard in Round Rock, Texas, on March 12–13, 2026.

M95 is a barred spiral galaxy about 33 million light-years away in Leo. Its central bar and tightly wound spiral arms give it that distinctive ringlike appearance.

The finished image combines 56 two-minute exposures—1 hour and 52 minutes—captured with my ASI2600MC Air and no added filter.

Processing included calibration and stacking in PixInsight, photometric color calibration, and separate treatment of the galaxy and stars. The final adjustments bring out the bar and surrounding ring while keeping the bright center controlled. A tighter crop gives M95 more presence in the frame.

Acquisition and processing details: ASI2600MC Air, 56 × 120 seconds, gain 200, offset 50, approximately −10°C, no added filter. Headers record an AM3 mount and 387 mm focal length; the telescope model is unconfirmed. Calibrated with a matching 28-frame 120-second dark master and a candidate flat; flat calibration is approximate because its bias pedestal was assumed. PixInsight VNG debayering, registration, PSF-weighted integration with Winsorized sigma rejection. Compared all 56 on-target frames with the sharpest 40 and retained 56. ABE background correction, plate solving and Gaia DR3 SPCC color calibration, mild BlurXTerminator, StarXTerminator, and masked NoiseXTerminator. Luminance-preserving stretch, separate star recombination, masked galaxy contrast and sharpening with core protection, and a native-resolution crop. No generative image processing.


r/Astronomy • • 2h ago

Astrophotography (OC) A picture of Luna shot with my Sony Cyber-Shot Dsc-Hx300

Thumbnail
gallery
11 Upvotes

I have finally managed to get better settings for moon photography and managed to capture these beautiful pictures of Luna!

I am using a Sony Cyber-Shot Dsc-Hx300 that my dad gifted me years ago :)

Any tips and comments regarding the pictures are welcome :)


r/Astronomy • • 8h ago

Astrophotography (OC) Saturn

Enable HLS to view with audio, or disable this notification

21 Upvotes

Believe it or not, the image in the eyepiece was even better than the video!

12" DOB + Astral Fields EQ Platform

SVBony 705C + ADC + Barlow 2x

Firecapture + PiPP+ Autostakkert + Registax + Fast Stone Image Viewer


r/Astronomy • • 16h ago

Astrophotography (OC) Moon halo tonight in TX

Thumbnail
gallery
80 Upvotes

Images taken with iPhone 17


r/Astronomy • • 11h ago

Astrophotography (OC) Update on my Astrophoto Journey

Thumbnail
gallery
25 Upvotes

I have recently purchased and received my Dwarf3. It has been raining for the past week and I took the chance on the clear skies to capture the moon as the first test and C 63 Helix Nebula. I am extremely happy how these both turned out after editing in Lightroom. I will be focusing more on deep space with the dwarf3 as my Mirrorless full frame camera and telescope can capture the moon and Milky Way at a better resolution.


r/Astronomy • • 20h ago

Astrophotography (OC) What do y’all think of my latest image?

Post image
120 Upvotes

This is IC 1795, or otherwise known as the Fish Head Nebula.

Equipment:

Sky-Watcher Quattro 200p

Explore Scientific Exos2 GT (Average guiding RMS 0.5 arc seconds

Canon T2i (I full spectrum modified)

GSO 2 Inch Coma Corrector

ASIAIR Mini

Asi120mm Mini

8x50 Guidescope

Svbony Sv240

__________________________________________________

8 Hours 30 Minutes total exposure time, 40 minutes in broadband for stars, and 7 hours 50 minutes in narrowband. Taken over 2 nights with a near full moon. Five minute exposures for narrowband, and thirty second exposures for the stars.


r/Astronomy • • 2h ago

Other: [Topic] [Crosspost] AMA: We’re members of UC Berkeley Space Sciences Lab — the team managing NASA’s ESCAPADE mission to Mars. Ask us anything this Wed., Oct. 28 at 11:30am PT / 2:30pm ET on u/UCBerkeley.

Thumbnail reddit.com
5 Upvotes

You can submit your questions now: https://www.reddit.com/u/UCBerkeley/s/we4fFYuTje


r/Astronomy • • 1d ago

Astro Art (OC) So apparently Neptune isn't actually that blue.

Thumbnail
gallery
192 Upvotes

The deep cobalt in most popular images comes from contrast-stretching and color balancing meant to bring out cloud features. When researchers reprocessed the Voyager 2 data in 2024, they found Neptune is closer to a muted greenish-blue, much like Uranus, and only slightly bluer.

This is my attempt at what you’d actually see. It's a view from the upper atmosphere of neptune above its cloud tops, as if you teleported there and taken a photo with a phone. Sunlight there is about 1/900th as strong as on Earth, so the scene is dim, like dusk or heavy overcast day on Earth. Theres also a couple stars and Triton just above the horizon.

How I made it: The base was rendered in SpaceEngine. AI was used for the cloud texture, haze, realism, the moon, etc. I did the color grading and final adjustments in Photopea.

Analysis:

This image is consistent with what Neptune probably looks like, though nobody has seen it from this vantage, so it’s a plausible reconstruction and not a verified one. The clouds are long, thin horizontal streaks, as expected for a planet whose winds reach about 2000 km/h and stretch features along lines of latitude. The thick raised ribbons are meant to be high methane-ice cirrus. Voyager 2 showed long light-colored cirrus-type clouds floating high in the atmosphere, and NASA puts their heights at of the order of 50 kilometers above a deeper cloud deck, with streak widths of 50 to 200 kilometers. The lit left sides, the soft bluish shadows falling to the right, and the haze softening everything toward the horizon follow NASA’s description, in which the deck is deep enough that scattering by the overlying molecules diffuses light into the shadows, which look blue. The smooth haze-to-black gradient at the limb matches how any thin atmosphere looks edge-on, and the haze reaching above the cloud tops fits models in which a thin aerosol haze reaches high into the stratosphere. The color is a muted azure-blue rather than a deep ultramarine, which is deliberate, because Neptune’s true color is a greenish blue, and the saturated deep blue of the Voyager pictures came from enhancement. The lighting is dim because as I said, sunlight at Neptune is only about 1/900 as strong as at Earth. It also comes from one consistent direction which is shown by Triton’s lit left side, the faint cool brightening along the left horizon, and the cloud highlights and shadows. Triton is the brightest object in the frame, with a pale cream-pink tint and a smooth surface. That fits a moon with a surface reflectance of roughly 0.7 to 1, slightly pink nitrogen frost, and very few impact craters. At about 0.45° across, which is my estimate from its orbit, it’s roughly the Moon’s apparent size from Earth. The two stars are compact and dimmer than Triton, as they should be for an exposure set for a lit haze band.

Image 1 is meant to replicate a phone photo as if you teleported there and took a picture. It uses convincing lifted blue-tinted blacks, smooth blotchy noise left by noise reduction in the dark sky instead of film grain, restrained sharpening with slight local-contrast halos, held highlights, small glowing star points, a slight handheld tilt, and JPEG compression. It has no vignette or color fringing, because phone processing corrects both.


r/Astronomy • • 1d ago

Astrophotography (OC) Elephant’s Trunk Nebula

Post image
933 Upvotes

I have been doing a bit of work imaging IC 1396 recently. It has been difficult due to the weather but this is from the past month, over multiple nights.

Equipment:
Astromodified Canon 700d
Skywatcher 72 ED DS Pro
Skywatcher AZ GTI in EQ Mode
Optolong L-Enhance Filter
ASI Air Mini
ZWO 120mm Guide Cam with 30mm Guide Scope

175 x 180 sec exposures taken over multiple nights with 20 darks taken each night to match.

20 Flats
20 Bias

Each night stacked separately then combined using APP.

I started with a pretty heavy crop to isolate the trunk section.

BGE, deconvolution and de-noise in Graxpert.

Siril for SPCC.

Star removal using StarNet through Siril.

GHS using human weighted luminance.

Curves adjustment using VeraLux Curves.

HDR Multiscale.

SCNR in Siril

Recombination of stars.

Slight saturation increase.

Thanks for looking!


r/Astronomy • • 23h ago

Astrophotography (OC) NGC 2174 — Monkey Head Nebula, reprocessed

Post image
62 Upvotes

Another look at the Monkey Head Nebula, NGC 2174. I’ve posted this target before, but this version revisits the original exposures with updated processing to bring out the dark lanes and give the nebula more separation from the surrounding stars.

I captured this from my backyard in Round Rock on November 8, 2025, using my ZWO ASI585MC Air. The finished image combines 45 five-minute exposures—3 hours and 45 minutes of total integration.

For this reprocessing, I compared several stacks and kept all 45 exposures. I worked on the nebula and stars separately, refined the background, and applied restrained sharpening to make the smaller structures easier to see. A slightly wider crop gives the faint outer cloud more room.

Acquisition and processing details: ASI585MC Air, gain 107, offset 15, 45 × 300 seconds. The headers identify a ZWO AM3 mount and 383 mm focal length; I have not confirmed the telescope model. The filter was not recorded and I do not remember which was fitted. Recorded sensor temperature was approximately −15.2 to −16.5°C.

Bias calibration and 99 same-night flats, targeted bad-pixel correction, PixInsight VNG debayering and registration, PSF-weighted integration with Winsorized sigma rejection. Compared 36-, 42-, and 45-frame stacks and retained all 45. Background modeling and empirical field-star color balance, mild BlurXTerminator, StarXTerminator, NoiseXTerminator, followed by masked luminance contrast/sharpening, a small ridge lift, and reduced star brightness. Final RGB presentation; no generative image processing.


r/Astronomy • • 1d ago

Astrophotography (OC) The Rosette Nebula-NGC2244

Post image
315 Upvotes

Not every plan goes to plan. Sometimes technology goes haywire and I wake up to find my telescope pointing at the ground with wires snagged. Sometimes the meridian flip doesn’t work and I gather no data. Focuser doesn’t work, guiding flies off the handle. So many variables. In this instance it didn’t centre on the target. This was my second imaging session of the night. Still gathered something worth processing. 2.5hrs on the Rosette Nebula from my rooftop in Toronto under bortle 8 skies. Next time will hopefully be better. Still happy with the results though. Clear skies everyone.

30x300s lights
Calibration frames
Gain 100
Cooled to -5

Gear: Svbony 122mm apo, zwo 2600mc pro, ragdoll 17 pro, Optolong L-Ultimate, zwo guide cam & scope, zwo Asiair, zwo eaf.

Stacked in Astro Pixel Processor. Processed in Pixinsight. DBE, D Crop, blur x, noise x, stat stretch, star x, narrowband norm, range mask, curves transformation. Further editing in photoshop.


r/Astronomy • • 1d ago

Astrophotography (OC) My best Andromeda galaxy image

Post image
276 Upvotes

Yesterday was clear night but with full moon out, so I decided to try image nebulae in Andromeda, and then add it to my 6 hours of data captured in July. Dwarf 3 tracked perfectly for the entire night, until it had less than 20% battery left. But still it captured over 8 hours of data. If you zoom in there will be visible small red nebulae in the galaxy. So far it's over 14 hours of exposure, a record for me.

Telescope: Dwarf 3;

Exposure: 14 hours;

Subs: 60s 50gain, 120s 70gain;

Bortle: 5;

Processed in Siril.


r/Astronomy • • 19h ago

Question (Describe all previous attempts to learn / understand) Where are the best deserts in NA to stargaze/camp

18 Upvotes

I'm asking because I eventually want to take a camper out to watch the night sky somewhere with little to no light pollution. I'm assuming it's somewhere in Arizona/Nevada but I want to know if anyone in the sub has a place in particular that stood out to them


r/Astronomy • • 1d ago

Astrophotography (OC) Solar Activity 25.10.2026

Post image
119 Upvotes

Telescope: Acuter 40 

Camera: touptek 678 mono 

EAF: ZWO EAFN 

Mount: Skywatcher Solar Quest 

Best 1200 of 12000 frames processed 

Stacked in PIPP and Astrosurface

Impgg: convolution sharpening and inversion

PI: blurX and solar tools - contrast and color

PS: color balance, curves, saturation and channel mixer

Cropped in PSX


r/Astronomy • • 1d ago

Astrophotography (OC) My sharpest Moon image so far

Post image
76 Upvotes

Telescope: Dwarf 3. Conversion done in PIPP, stack of 90% out of 999 frames in Autostackert and deconvolution, sharpening, saturating done in Astrosurface. Compressed for reddit, original image has over 18 megapixels


r/Astronomy • • 1d ago

Astrophotography (OC) Image I got of M45 - Pleiades

Post image
348 Upvotes

Was fortunate enough to get out to some dark skies last weekend, and got around 10 hours of exposure with just my DSLR, Kit lens, and star tracker. Hope you guys enjoy!


r/Astronomy • • 1d ago

Other: [Topic] Astronomy outreach event at the Boston common for ~1000 people

Thumbnail
gallery
27 Upvotes

Did an outreach event yesterday at the Boston Common that lasted almost 8 hours and had almost 1000 visitors!

I didn't have a lot of time for photos but helped a run of people take their first photo of the moon thru a telescope.

I had a Dwarf Mini, Sv503 102ed, and a Lunt 40 on the field. Also an S30 pro that I didn't have the capacity to run. The sv503 had a sun funnel during the solar event and an eyepiece during night event.

Organizations involved were PopScope, the Amateur Telephone Makers of Boston, Dark Sky Mass, and the Space Consortium. I (Naztronomy) are involved with all of these organizations and took part of every event. My legs are feeling it today. Huge volunteer turnout as well!


r/Astronomy • • 1d ago

Other: Positional Astronomy Jupiter and Venus "analemmas"

20 Upvotes

A recent post in r/AskPhysics by u/AccomplishedArea9551 pointed out that there is not much discussion around analemmas for celestial bodies other than the moon and sun.

The analemma can be thought of as the curve that plots the deviation of a given celestial body compared to an idealized uniformly moving version of itself in the Earth's equatorial plane. Accordingly, an analemma can be defined for a planet, and I laid out a 'theory of operation' on how one could potentially visualize that in my response. This was followed by some proof of concepts here and here.

However, going beyond this, I wanted to create a visual for the full 'closed' analemma curve for some celestial bodies, like Jupiter and Venus. With the help of Stellarium and python (cv2, numpy) I was able to do just that. It's my pleasure to share this with the rest of the community.

Caveats: The accompanying videos were created from an independent set of screenshots taken a few days earlier and so their field of view and orientation is not the same as those used for the curve tracing. But for our current purposes it matters very little. Please manually choose the 1080p HD quality if YouTube serves up a lower quality version.

Jupiter

Related video: https://youtu.be/GPb5ldNgWDQ

Jovian "analemma" over 12 years

Venus

Venus' analemma is a beautiful Lissajous curve.

Related video: https://youtu.be/JImVE25pHr4

Venusian "analemma" over 8 years

Saturn

(This section was added on 26-Oct-2026.)

Related video: https://youtu.be/mLt6EWf6q7E

Saturnian "analemma" over 59 years

Methodology

Planets execute complicated motions in the sky and any planetary analemma takes multiple years to make a closed curve. The time needed is generally the least common multiple of the orbital periods of the planet and the Earth. Even then the analemma curve may not close due to variations in the orbital parameters during that period. Thus, we need to be willing to accept approximately closed curves.

For instance, Jupiter's orbital period is 11.86 years which is (fortunately) close to 12 years. So we can take 12 years (~1 Jupiter orbit) as the approximate analemma duration for Jupiter. OTOH, Venus' orbital period of 224.701 days means that we need 8 years (~13 Venus orbits) for an approximate analemma.

Procedure

  1. Calculate the mean meridian transit period for the object in question; call this T hr
    • For Jupiter, T comes out to 23h 56m 23.928s
    • For Saturn, T comes out to 23h 56m 12.080s
    • For the inner planets, T averages to exactly 1 mean solar day (24h 00m 00.000s)
  2. Take screenshots in Stellarium every T hr making sure that the celestial body is always present/visible in the selected orientation and field of view
    • Since planets don't move that fast relative to their idealized mean, screenshots can be taken at an integer multiples of T instead
    • Preferably, automate the act of taking screenshots using a Stellarium script
  3. Take screenshots to span the duration that yields an approximately closed analemma curve
  4. Log the (x,y) pixel coordinate of the celestial body in each screenshot
    • This is easy to do if the screenshots are already scripted in Stellarium
  5. When all screenshots are captured, use the (x,y) coordinate data to create a trace and overlay the trace on the first screenshot
  6. Optionally, create a movie from the captured screenshots

For Jupiter, I took screenshots every 7T (6.98249414211851 days). For Saturn, I took screenshots every 15T (14.9604305353661 days). For Venus, I took screenshots every 6T (6 days).