APOD: Satellites over Orion (2021 Jun 01)

[APOD Robot]

Satellites over Orion

Explanation: What are those streaks across Orion? Most are reflections of sunlight from numerous Earth-orbiting Starlink satellites. Appearing by eye as a series of successive points floating across a twilight sky, the increasing number of communications satellites, including SpaceX Starlink satellites, are causing concern among many astronomers. On the positive side, Starlink and similar constellations make the post-sunset sky more dynamic, satellite-based global communications faster, and help provide digital services to currently underserved rural areas. On the negative side, though, these low Earth-orbit satellites make some deep astronomical imaging programs more difficult, in particular observing programs that need images taken just after sunset and just before dawn. Planned future satellite arrays that function in higher orbits may impact investigations of the deep universe planned for large ground-based telescopes at any time during the night. The featured picture, taken in 2019 December, is a digital combination of over 65 3-minutes exposures, with some images taken to highlight the background Orion Nebula, while others to feature the passing satellites.

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[keesscherer]

Looks more like geosynchronous satellites. Because before Starlink sats where up i made this image in 2015:


M42 Orion Satellite Highway and an Asteroid. (Explore) by Kees Scherer, on Flickr

[biver]

Yes, these are geostationnary satellites, that appears at the declination of M42 from our mid-northern latitudes.
Satellites streaks are 45' long on this picture, this correspond to the motion of stars in 3min. (i.e. geostationnary satellite when tracking stars), starlink would move by 45' in 1second, but individual exposures are 3min. long...
In addition mid-december M42 is close to opposition in the sky where LEO satellite are unlikely illuminated after twilight.
Nevertheless around summer solstice it is hard to take long exposures without satellite streaks, many of them likely being Starlinks.
Nicolas

[Lorenzo Comolli]

These streaks are NOT starlink satellites but "normal" geosynchronous satellites.
Proof is the length of streaks that is about 0.75 degrees, corresponding to a streak of sidereal motion of declared 3 min exposures.

Website of author is reporting the same image and it is described correctly as "Satellites passing over M42", no reference to starlink.
http://amir.torgheh.ir/picture.php?/1469/category/14

Please correct title and description of APOD, so not to diffuse fake news!

Regards,
Lorenzo

PS: thanks to my friend Edoardo Radice for noting the error.

[Kevin E.]

Hi !

I already had this kind of image in 2011 : https://www.webastro.net/forums/topic/8 ... ers-orion/
(in the right of the picture, very difficult to remove)

At this time, it was Geosynchronous satellites ! Then, I am not sure that it is starlink's satellites in the picture.

Kevin

[RJN]

Looks more like geosynchronous satellites. Because before Starlink sats where up i made this image in 2015:

Yes, thank you. My bad. The text on the main NASA APOD has now been updated. We apologize for the oversight.
- RJN

[orin stepanek]

Getting crowded up there; surprising they don't bump into each other!

Even kitty has concerns!

[Guest]

The exploration of the deep Cosmos in ligth and radio waves will suffer a slowdown to the point of useless from ground in spite of the giant telescopes being constructed due to the interference in visible and radio waves caused by the satellite constellations, is incredible that at this point there are no protection laws for the sky, research will be highly impacted as well as a considerable number of other satellites, space probes an other launching because its impossible to predict the position of each satellite and all the debris it creates with enough precision, observations like star occultations will be useless due to incertainity, also consider the out of order satellites floating without control and the enhaced chance a meteor hit a satellite of these constellations causing uncontrolled debris, even more. No less is the RF contamination from the sky that might affect humans, wildlife and plants as well as molecules in the atmosphere. Humans are doing exactly the opposite of what they say, increasing space contamintion

[CharlyUY]

The exploration of the deep Cosmos in ligth and radio waves will suffer a slowdown to the point of useless from ground in spite of the giant telescopes being constructed due to the interference in visible and radio waves caused by the satellite constellations, is incredible that at this point there are no protection laws for the sky, research will be highly impacted as well as a considerable number of other satellites, space probes an other launching because its impossible to predict the position of each satellite and all the debris it creates with enough precision, observations like star occultations will be useless due to incertainity, also consider the out of order satellites floating without control and the enhaced chance a meteor hit a satellite of these constellations causing uncontrolled debris, even more. No less is the RF contamination from the sky that might affect humans, wildlife and plants as well as molecules in the atmosphere. Humans are doing exactly the opposite of what they say, increasing space contamination
Goodluck astronomers and astrophysics! Money is stronger than knowledge, rich businessmen are blowing that candle in the dark called science...

CharlyUY

[Chris Peterson]

The exploration of the deep Cosmos in ligth and radio waves will suffer a slowdown to the point of useless from ground in spite of the giant telescopes being constructed due to the interference in visible and radio waves caused by the satellite constellations, is incredible that at this point there are no protection laws for the sky, research will be highly impacted as well as a considerable number of other satellites, space probes an other launching because its impossible to predict the position of each satellite and all the debris it creates with enough precision, observations like star occultations will be useless due to incertainity, also consider the out of order satellites floating without control and the enhaced chance a meteor hit a satellite of these constellations causing uncontrolled debris, even more. No less is the RF contamination from the sky that might affect humans, wildlife and plants as well as molecules in the atmosphere. Humans are doing exactly the opposite of what they say, increasing space contamination
Goodluck astronomers and astrophysics! Money is stronger than knowledge, rich businessmen are blowing that candle in the dark called science... :cry:

I predict very little impact on visual astronomy from satellite constellations. It's actually something of a challenge to produce an image like that in today's APOD. Normal image processing techniques make the satellite tracks go away automatically. It takes more work to produce a final image that retains them! The vast majority of astronomical imaging utilizes stacks of several images, which allows artifacts to be removed- not just satellites, but airplanes, asteroids, cosmic ray strikes. It is only a handful of special visual projects which involve very fast, large aperture survey telescopes that are going to have problems, because many satellites are bright enough with these scopes to cause blooming on their CCD detectors, which can ruin the entire frame. But I expect we'll see technical solutions to this problem (like selective shuttering).

The RF all these satellites utilize is harmless to biological systems and has no effect on the atmosphere. It's potentially a problem for radio telescopes, but in most cases the radios on the satellites have steerable beams or can be turned off completely, and they are already experimenting with doing so when in the path of critical equipment on the ground.

[johnnydeep]

Starlink over Orion

Explanation: What are those streaks across Orion? Most are reflections of sunlight from numerous Earth-orbiting Starlink satellites. Appearing by eye as a series of successive points floating across a twilight sky, the increasing number of SpaceX Starlink communication satellites are causing concern among many astronomers. On the positive side, Starlink and similar constellations make the post-sunset sky more dynamic, satellite-based global communications faster, and help provide digital services to currently underserved rural areas. On the negative side, though, these low Earth-orbit satellites make some deep astronomical imaging programs more difficult, in particular observing programs that need images taken just after sunset and just before dawn. Planned future satellite arrays that function in higher orbits may impact investigations of the deep universe planned for large ground-based telescopes at any time during the night. The featured picture, taken in 2019 December, is a digital combination of over 65 3-minutes exposures, with some images taken to highlight the background Orion Nebula, while others to feature the passing satellites.

Could someone explain why observing "just after sunset and just before dawn" would be more affected by satellites than at other times?

Also, why would higher orbiting satellites affect deep sky observing more than other types?

Is this all solely about the amount of time a satellite would spend in the field of view of a telescope, that time being shorter the faster the orbital speed and the smaller the FOV?

[Chris Peterson]

Could someone explain why observing "just after sunset and just before dawn" would be more affected by satellites than at other times?

Also, why would higher orbiting satellites affect deep sky observing more than other types?

Is this all solely about the amount of time a satellite would spend in the field of view of a telescope, that time being shorter the faster the orbital speed and the smaller the FOV?

In order for satellites to be seen or imaged, they have to be in the Sun. From an observation point on Earth, that typically means near sunrise or sunset, because points higher in the sky are shadowed by the Earth. But the higher the orbit of the satellite, the higher it can be in the sky and still be in sunlight. At the height of geosynchronous satellites (as in today's image) they will be in sunlight most of the time. (Some odd things happen at high latitudes, where the Sun may never get very far below the horizon, as well.)

The time that the satellite is in the field is usually not an issue, although high orbit satellites will linger longer on individual pixels, increasing the possibility of blooming with large apertures.

[Amir H. Abolfath]

Hello every one,
The title was a mistake that comes from my bad English when I sent image to APOD editors. Mr Nemiroff asked me to check texts but I did not told him to correct title and just said:
“All is Ok, but I am not sure all satellites are starlink, may some other passes. Not bad idea if write some lines are starlink.”
This comes from on that night in desert I captured M42 I saw passage of some sats and on my mount software saw Starlink with numbers, that was my first time I heard about them.
In my first email to APOD I meant that Sats now are problems for astrophotographers and this image is a simulation the problem but my som Starlink passes too. But cause of bad my English I could not tell correctly and don’t want to hide truth.

Apologize everyone
Amir

[johnnydeep]

Could someone explain why observing "just after sunset and just before dawn" would be more affected by satellites than at other times?

Also, why would higher orbiting satellites affect deep sky observing more than other types?

Is this all solely about the amount of time a satellite would spend in the field of view of a telescope, that time being shorter the faster the orbital speed and the smaller the FOV?

In order for satellites to be seen or imaged, they have to be in the Sun. From an observation point on Earth, that typically means near sunrise or sunset, because points higher in the sky are shadowed by the Earth. But the higher the orbit of the satellite, the higher it can be in the sky and still be in sunlight. At the height of geosynchronous satellites (as in today's image) they will be in sunlight most of the time. (Some odd things happen at high latitudes, where the Sun may never get very far below the horizon, as well.)

The time that the satellite is in the field is usually not an issue, although high orbit satellites will linger longer on individual pixels, increasing the possibility of blooming with large apertures.

Thanks! The bit about satellites needing to be in the sun to be seen is the point I was missing. I guess that a satellite passing briefly in front of an astronomical object being observed could cause a "blink" in the photon stream, but I imagine the chance of that is so small, and the effect so negligible, as to be irrelevant. There is probably more risk from passing birds and bugs and whatever else might be floating around in the air!

[nebosite]

There is a silver lining here: I know these streaks are not starlink sats, but Spacex is poised to drop launch costs by 2-3 orders of magnitude with Starship. They are also leading the way in mass-manufacturing space hardware. The upshot is that for the cost of a hubble or JWST ($10 Billion), we will be able to launch dozens, if not hundreds of Hubble-class space observatories. Keep in mind that current space telescopes are so expensive because there is just one, it must be as light as possible, and cannot fail. With cheap launches, we can build them heavier (cheaper) and can afford to lose a few as we iterate better versions. Ground based astronomy will be pointless in a few years.

[Chris Peterson]

There is a silver lining here: I know these streaks are not starlink sats, but Spacex is poised to drop launch costs by 2-3 orders of magnitude with Starship. They are also leading the way in mass-manufacturing space hardware. The upshot is that for the cost of a hubble or JWST ($10 Billion), we will be able to launch dozens, if not hundreds of Hubble-class space observatories. Keep in mind that current space telescopes are so expensive because there is just one, it must be as light as possible, and cannot fail. With cheap launches, we can build them heavier (cheaper) and can afford to lose a few as we iterate better versions. Ground based astronomy will be pointless in a few years.

I doubt that ground-based astronomy will be pointless. It will be a long time yet before we can place telescopes in space that provide either the resolution or light gathering power of the largest ground-based ones. But broadly, I agree with your point. Just as an assortment of Earth observation and communication satellites are now appearing at commodity prices, so too will a lot of space-based research satellites.

[BillBixby]

Hello every one,
The title was a mistake that comes from my bad English when I sent image to APOD editors. Mr Nemiroff asked me to check texts but I did not told him to correct title and just said:
“All is Ok, but I am not sure all satellites are starlink, may some other passes. Not bad idea if write some lines are starlink.”
This comes from on that night in desert I captured M42 I saw passage of some sats and on my mount software saw Starlink with numbers, that was my first time I heard about them.
In my first email to APOD I meant that Sats now are problems for astrophotographers and this image is a simulation the problem but my som Starlink passes too. But cause of bad my English I could not tell correctly and don’t want to hide truth.

Apologize everyone
Amir

Thank you for the post and picture. The picture shows problems that are becoming worse. The posts show the problem is being addressed. The person with the backyard telescope, and camera, will have more problems to work around. But the problem is being addressed for the institutionalized T-scopes and antennas. I was not aware of the severity of the problem. Again, thank you for the picture and thank you to all posting replies that the problem is being addressed from many fronts.

Bix

[Chris Peterson]

Hello every one,
The title was a mistake that comes from my bad English when I sent image to APOD editors. Mr Nemiroff asked me to check texts but I did not told him to correct title and just said:
“All is Ok, but I am not sure all satellites are starlink, may some other passes. Not bad idea if write some lines are starlink.”
This comes from on that night in desert I captured M42 I saw passage of some sats and on my mount software saw Starlink with numbers, that was my first time I heard about them.
In my first email to APOD I meant that Sats now are problems for astrophotographers and this image is a simulation the problem but my som Starlink passes too. But cause of bad my English I could not tell correctly and don’t want to hide truth.

Apologize everyone
Amir

Thank you for the post and picture. The picture shows problems that are becoming worse. The posts show the problem is being addressed. The person with the backyard telescope, and camera, will have more problems to work around. But the problem is being addressed for the institutionalized T-scopes and antennas. I was not aware of the severity of the problem. Again, thank you for the picture and thank you to all posting replies that the problem is being addressed from many fronts.

Bix

Actually, amateur imagers are almost entirely unaffected. It's a bigger issue for some professional setups, but as noted, they have more resources to find workarounds and solutions.