Astronomy/photography

[UncleTim]

I disagree.


Those things are moving.
1. None of the background stars are showing any motion, except the close ones.
2. The trails suggest travel and a trail that is suggestive of similar speed. They seem similar in speed but that too could be an optical illusion.

3. I wonder if the time lapse (assumed 31 seconds) would cause the objects much closer to develop tails and the farther ones to seem stationary (which of course they are not). Notice there are several that exhibit this tail effect and they all seem to be set against far away stars as the background, for the most part. I think this is slight motion against a 31 second exposure.


Or a fleet of aliens passing by.

[Greg A]

SpaceX has now launched 242 starlink satellites through Jan 29th, so Jon’s assessment of the streaks is highly probable. Consumer service is expected to start up mid year.

[cpaharley2008]

I remember when the sky was clear of any satellites, back in the 1950's and then seeing our first one in 1962 or 63?

[MyronL]

So that's an airplane up there.

[cpaharley2008]

Originally Posted by MyronL

So that's an airplane up there.

No, that is Myron's television..........

[John in Santa Cruz]

airplanes usually blink, so their trails look dashed.

that could be a satellite or a meteorite. The ISS (Space Station) in particular can be very bright in the hour or so after full darkness sets in.


here's an airplane,

[rubicon327]

Admins - maybe posts 581-606 should be peeled off into a new thread titled astronomy/photography? Seems that several members on here might like that and would contribute some very good information.

[Mike Lewis]

Originally Posted by John in Santa Cruz

I have a few eyepiece FL's to choose from

What?! They aren't ALL two-inch eyepieces? How embarrassing!

Just kidding-- that's a great collection any amateur astronomer would envy. Good for you!

ML
currently in Olema, CA

[Mike Lewis]

It may not be so bad, at least regarding Musk's satellites. Ninety minutes or so after sunset and before sunrise, low earth orbit satellites like Musk's are in earth's shadow, and should be invisible from the ground in visible light. This is when professional astronomy takes place from the ground.

Except-- the Musk satellites will "glow" in infrared all the time, so ground-based infrared astronomy is screwed. Most IR astronomy takes place in space now, I think.

ML
in Olema, CA

[John in Santa Cruz]

its more like 2.5-3 hours after sunset. 90 minutes after sunset is about when it finally gets properly dark at our middle temperate latitudes. Low Earth orbit satellites are visible for about another hour after that, give or take. and the higher the orbit, the longer they are visible.

AFAIK, these satellites will only glow in longwave 'thermal' IR, which is not a usable band for terrestrial astronomy, thats what the James Webb Space Telescope was built for. Terrestrial astronomy only uses short wave near IR.

These satellites *will* be extremely noisy in the microwave range, since they are 2-way communications. This will make a mess of radio astronomy.

[Telescopist]

Originally Posted by Mike Lewis

It may not be so bad, at least regarding Musk's satellites. Ninety minutes or so after sunset and before sunrise, low earth orbit satellites like Musk's are in earth's shadow, and should be invisible from the ground in visible light. This is when professional astronomy takes place from the ground.

I have to say that you don't appear to understand the extent of the problem. The professional astronomy community is aghast at what is happening. One example has to do with the Large Synoptic Survey Telescope [LLST] which was recently renamed the Vera Rubin Observatory. Dr. Rubin was an unheralded woman physicist. She hypothesized that some type of mysterious substance now labeled "dark matter" is the reason why spiral galaxies do not, over time, wind up like spring in a watch. The LSST observatory located in the Atacama Desert will see 'first light' sometime in 2020.

This telescope -- an immense technological achievement will have an ambitious array of scientific objectives which include studying the physics of dark energy and dark matter, census taking re: small bodies in the solar system, examining the structure and contents of the Milky Way galaxy, and detecting gravity waves. Many of these studies will be performed in visible wavelengths between 380 and 740 nanometers.

The LLST will house the largest digital camera ever constructed -- a 3.2-gigapixel CCD imaging camera. To give you some sense of how sophisticated this camera is, it is about the size of a small SUV and weighs over 6,000 pounds. The concern is that this camera will be damaged and science compromised by a string of Starlink satellites.

To make matters exponentially worse both for the professional astronomy community but amateurs like myself is the fact the the FCC has enthusiastically endorsed Starlink's plans to launch upwards of 42,000 of these satellites in the next several years. Amazon is jumping on the bandwagon as well. They have announced plans to launch 3,000 satellites to offer broadband internet coverage.

Except-- the Musk satellites will "glow" in infrared all the time, so ground-based infrared astronomy is screwed. Most IR astronomy takes place in space now, I think.

Actually aside from the visible wavelengths it is in the area of radio-astronomy where the biggest concern lies. Radio telescopes are already saturated by the ubiquitous irradiation of satellites communication from space stations as well as from the ground.

[Mike Lewis]

I assume the FCC had a public comment period before approving Musk's satellites. If they are that big of a problem for professional astronomy, how did the satellites get approved? The FCC (and ITU) have reserved portions of the radio spectrum for astronomy in the past. Press reports made it sound like the astronomers were caught flat-footed by Musk's initial launch, which is unlikely.

[Telescopist]

Originally Posted by Mike Lewis

I assume the FCC had a public comment period before approving Musk's satellites. If they are that big of a problem for professional astronomy, how did the satellites get approved? The FCC (and ITU) have reserved portions of the radio spectrum for astronomy in the past. Press reports made it sound like the astronomers were caught flat-footed by Musk's initial launch, which is unlikely.

I hope this doesn't offend anyone's political sensibilities. Ajit Pai who Trump appointed as FCC chairman was responsible for repealing net neutrality rules, which had required internet service providers to offer equal access to all web content. Pai was general counsel for Verizon prior to assuming his current position. It might be fair to assume that his sympathies lie with the giant telecommunication companies and not with some yo-yo astronomers. He might have provided a gratuitous ear to the concerns of the professional astronomy community but obviously not much more than that.

[Greg A]

Tough issue as global Internet serving small rural and remote areas of the globe is needed and about the only approach to make this happen is satellites. Towers can never cover the remote and rural areas completely and there are quite a few issues with putting microwave towers all over the landscape that probably outweigh the satellite issues.
Probably went the way of greatest need in deciding as I doubt Ajit Pai is a Musk fan.

[Telescopist]

This is an image taken with Dark Energy Camera on the 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory last November. The observing session involved searching for dwarf galaxies in the outskirts of the Large Magellanic Cloud. Nineteen Starlink satellite trails crossed the image during the six-minute exposure. 40,000 more ought to be a real hoot.

[Telescopist]

The LSST/Vera C. Rubin 8.4 meter primary mirror successfully cast 2008. From planning stage to first light some of these giant telescopes take over 15 years to complete.

[John in Santa Cruz]

Originally Posted by Telescopist

The LSST/Vera C. Rubin 8.4 meter primary mirror successfully cast 2008. From planning stage to first light some of these giant telescopes take over 15 years to complete.

indeed, due to the political issues, the TMT is taking even longer.... Planning for the TMT started in 2000, its 2020 and they are still stalled by ongoing protests, it should have been fully operational by now.

[Telescopist]

Originally Posted by John in Santa Cruz

indeed, due to the political issues, the TMT is taking even longer.... Planning for the TMT started in 2000, its 2020 and they are still stalled by ongoing protests, it should have been fully operational by now.

Yes. As you know there are only 3 viable terrestrial sites to install this new generation of telescopes: Canary Islands, Atacama Desert, & Mauna Kea. TMT will probably be the last telescope installed on Mauna Kea due to the political situation.

[John in Santa Cruz]

If the 'natives' got their way according to their rants, white man would leave the island, remove Waikiki etc, and stop all air and sea travel except by dugout.

IMHO, that would be funny if it wasn't so sad.

[Viajante]

Originally Posted by John in Santa Cruz

If the 'natives' got their way according to their rants, white man would leave the island, remove Waikiki etc, and stop all air and sea travel except by dugout.

IMHO, that would be funny if it wasn't so sad.

So, so sad. So, so, so unfair. The saddest thing in 100 years. The most unfair thing in the history of the world.