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Astronomy Picture of the Day

Nah...looks like in a volcano.

Nah...looks like in a volcano.

@Eyvazova_2009 said in #1:

It's magnificent, isn't it?

It's breathtaking! M74 is often regarded as a picture-perfect example of a spiral galaxy. A gaseous gyre, a cosmic sunflower.

What's particularly amazing about this image is the stark difference in resolution compared with the previous best infrared view of this spiral galaxy astronomers had. The Spitzer Space Telescope (with a primary mirror diameter of 0.85 m [2.8 ft]) imaged M74 in the infrared in 2006:
https://www.spitzer.caltech.edu/image/sig06-018c-nasas-spitzer-space-telescope-view-of-m74

It's really unfair to compare this image to the James Webb Space Telescope's (with a primary mirror diameter of 6.5 m [21 ft]) picture that is featured as the APOD today:
https://apod.nasa.gov/apod/ap220722.html

It's unfair precisely because the angular resolution of a (reflecting) telescope depends on the diameter of its primary mirror. The larger the mirror, the better the resolution:
https://en.wikipedia.org/wiki/Angular_resolution#The_Rayleigh_criterion

And the JWST's (https://en.wikipedia.org/wiki/James_Webb_Space_Telescope) primary mirror is about 7.65 times wider than the Spitzer Space Telescope's (https://en.wikipedia.org/wiki/Spitzer_Space_Telescope) mirror. Spitzer already was great and very impressive. JWST is going to be amazing and ridiculously impressive!

@Eyvazova_2009 said in #1: > It's magnificent, isn't it? It's breathtaking! M74 is often regarded as a picture-perfect example of a spiral galaxy. A gaseous gyre, a cosmic sunflower. What's particularly amazing about this image is the stark difference in resolution compared with the previous best infrared view of this spiral galaxy astronomers had. The Spitzer Space Telescope (with a primary mirror diameter of 0.85 m [2.8 ft]) imaged M74 in the infrared in 2006: https://www.spitzer.caltech.edu/image/sig06-018c-nasas-spitzer-space-telescope-view-of-m74 It's really unfair to compare this image to the James Webb Space Telescope's (with a primary mirror diameter of 6.5 m [21 ft]) picture that is featured as the APOD today: https://apod.nasa.gov/apod/ap220722.html It's unfair precisely because the angular resolution of a (reflecting) telescope depends on the diameter of its primary mirror. The larger the mirror, the better the resolution: https://en.wikipedia.org/wiki/Angular_resolution#The_Rayleigh_criterion And the JWST's (https://en.wikipedia.org/wiki/James_Webb_Space_Telescope) primary mirror is about 7.65 times wider than the Spitzer Space Telescope's (https://en.wikipedia.org/wiki/Spitzer_Space_Telescope) mirror. Spitzer already was great and very impressive. JWST is going to be amazing and ridiculously impressive!

The image is far too epic to be real ... they're probly using the new t'scope to spy on the Rooskies, Chinese, Martians, etc, etc ...

Consider the Webb Project's timing ...

I'd also like to add this particular design can indeed function as an exquisite antenna for reception/transmission of terrestrial signals ...

In fact, for all we know it's real purpose is as an offensive directed energy weapon ... I put nothing beyond these madmen ...

And the best part, the icing on the cake ? We payed for it all ...

The image is far too epic to be real ... they're probly using the new t'scope to spy on the Rooskies, Chinese, Martians, etc, etc ... Consider the Webb Project's timing ... I'd also like to add this particular design can indeed function as an exquisite antenna for reception/transmission of terrestrial signals ... In fact, for all we know it's real purpose is as an offensive directed energy weapon ... I put nothing beyond these madmen ... And the best part, the icing on the cake ? We payed for it all ...

@boilingFrog said in #5:

The image is far too epic to be real ...

And you ascertain this by what means? The universe is epic. Pictures of the universe therefore are bound to be "too epic to be real" as you say.

You can see M74 (in optical light and worse angular resolution) through a hobby astronomer's telescope (commonly available for a few hundreds to a few thousands of dollars) under a good night sky (little to no light pollution). The very fact that it's called M74 tells you that it's one of the Messier objects, catalogued by Charles Messier (26 June 1730 – 12 April 1817). It was discovered by Pierre Méchain in 1780:
https://en.wikipedia.org/wiki/Messier_74

... they're probly using the new t'scope to spy on the Rooskies, Chinese, Martians, etc, etc ...

A telescope at Lagrange point L2 (https://en.wikipedia.org/wiki/Lagrange_point#L2_point), about 1.5 million km (≈930,000 miles) away from mother earth, is ill-suited as a spy satellite. Espionage is done from low earth orbit (altitudes of 250 to 1000 km or 155 to 620 miles), for example:
https://en.wikipedia.org/wiki/KH-11_KENNEN

This makes sense, because in espionage, small surface features really matter. So you want to be as close as possible (for your limited angular resolution to translate into optimal ground sample distance) without deorbiting due to atmospheric drag. Travelling 1% of the Earth-Sun distance away from the earth (that's about 6,000 times farther away than typical spy satellites) makes absolutely no sense whatsoever for this purpose.

Furthermore, the JWST is the finest infrared space telescope in the world, designed specifically to observe very faint galaxies in the early universe (they glow in the infrared due to redshift arising from the metric expansion of space). Naturally myriads of astronomers have applied for observation time. So many in fact that in the language of hoteliers one would have to say that JWST's observation schedule will be pretty be much booked out for the next couple of years. Every minute of JWST observation time is exceedingly precious and little to none can be wasted (it could potentially break at any point in time and if it does it's probably beyond repair because it's so far away from earth). That's why research applications are checked for scientific importance by a specialised committee. Only scientifically promising applications can get observation time. So the JWST simply doesn't have time to do anything other than the only thing it has been designed for: nonstop astronomical observations (of the early universe for the most part).

Consider the Webb Project's timing ...

What about it? This space telescope has been under construction since 2007. Has been proposed in 1996. It has been delayed due to technical reasons (they had to make sure everything would work perfectly) a gazillion times. It's a joint project of NASA, ESA and CSA. What's you point?

I'd also like to add this particular design can indeed function as an exquisite antenna for reception/transmission of terrestrial signals ...

Naturally, it's a scientific instrument, so it has to have a means of transmitting the collected data back to earth. It wouldn't be much use to us, if we had to send a manned mission to Lagrange point L2 (which would be extremely challenging) in order to retrieve the hard-drives manually. We're in the information age, radio waves have been discovered around 1890 by Heinrich Hertz. Their use has been standard practice in data transmission from space probes back to earth since the 1960s at least.

In fact, for all we know it's real purpose is as an offensive directed energy weapon ... I put nothing beyond these madmen ...

I know you're probably joking and not being serious, but that's absurd. What exactly is a 6.5 m (21 ft) mirror at a distance of 1,500,000 km (≈930,000 miles) from earth going to do? Laser tattoo removal?

And the best part, the icing on the cake ? We payed for it all ...

Yeah. You. Me. Every US citizen (all 331,893,745 of them). Each and every Canadian (38,654,738). All citizens of countries belonging to the EU (447,007,596). A total population of 817,556,079 (in 2022).

The total cost of the JWST is US$9.7 billion (including future operative costs) for the US (NASA developed the telescope and operates it), US$850 million for the EU (ESA provided instruments for the telescope and the launch) and US$165 million for Canada (CSA provided fine-guidance sensors).
That's a total cost of US$10.715 billion. Development began in 2003, launch happened in 2022 and mission duration will be 10 years minimum and probably around 20 years. So the JWST will probably still be around in 2037 (conservatively assuming 15 years of mission time).

That's US$10.715 billion for the JWST in 34 years. US$315 million per year. Even ignoring the minor EU and Canadian contributions, that would be less than US$1 per US citizen per year. 95 ct per capita per year to be exact. In reality it's even less.

By comparison, the US spends US$782 billion each year for its military budget (that's more than what China, India, Russia, Saudi Arabia, France, Germany, United Kingdom, Japan, South Korea, and Brazil spend on defence combined).
That's US$2,356 per US citizen per year.

At current average gas prices (≈US$5/gal) and average gas mileage of ≈6 gallons/100 mi (Ford F-150), that "95 ct per capita per year" figure means you could drive a whopping additional 5 km (3.2 miles) once per year, if your country hadn't built the JWST! Amazing.

In my opinion that's a reasonable price to pay for literally the best space telescope ever. The JWST is the envy of the entire world. But feel free to disagree.

@boilingFrog said in #5: > The image is far too epic to be real ... And you ascertain this by what means? The universe is epic. Pictures of the universe therefore are bound to be "too epic to be real" as you say. You can see M74 (in optical light and worse angular resolution) through a hobby astronomer's telescope (commonly available for a few hundreds to a few thousands of dollars) under a good night sky (little to no light pollution). The very fact that it's called M74 tells you that it's one of the Messier objects, catalogued by Charles Messier (26 June 1730 – 12 April 1817). It was discovered by Pierre Méchain in 1780: https://en.wikipedia.org/wiki/Messier_74 > ... they're probly using the new t'scope to spy on the Rooskies, Chinese, Martians, etc, etc ... A telescope at Lagrange point L2 (https://en.wikipedia.org/wiki/Lagrange_point#L2_point), about 1.5 million km (≈930,000 miles) away from mother earth, is ill-suited as a spy satellite. Espionage is done from low earth orbit (altitudes of 250 to 1000 km or 155 to 620 miles), for example: https://en.wikipedia.org/wiki/KH-11_KENNEN This makes sense, because in espionage, small surface features really matter. So you want to be as close as possible (for your limited angular resolution to translate into optimal ground sample distance) without deorbiting due to atmospheric drag. Travelling 1% of the Earth-Sun distance away from the earth (that's about 6,000 times farther away than typical spy satellites) makes absolutely no sense whatsoever for this purpose. Furthermore, the JWST is the finest infrared space telescope in the world, designed specifically to observe very faint galaxies in the early universe (they glow in the infrared due to redshift arising from the metric expansion of space). Naturally myriads of astronomers have applied for observation time. So many in fact that in the language of hoteliers one would have to say that JWST's observation schedule will be pretty be much booked out for the next couple of years. Every minute of JWST observation time is exceedingly precious and little to none can be wasted (it could potentially break at any point in time and if it does it's probably beyond repair because it's so far away from earth). That's why research applications are checked for scientific importance by a specialised committee. Only scientifically promising applications can get observation time. So the JWST simply doesn't have time to do anything other than the only thing it has been designed for: nonstop astronomical observations (of the early universe for the most part). > Consider the Webb Project's timing ... What about it? This space telescope has been under construction since 2007. Has been proposed in 1996. It has been delayed due to technical reasons (they had to make sure everything would work perfectly) a gazillion times. It's a joint project of NASA, ESA and CSA. What's you point? > I'd also like to add this particular design can indeed function as an exquisite antenna for reception/transmission of terrestrial signals ... Naturally, it's a scientific instrument, so it has to have a means of transmitting the collected data back to earth. It wouldn't be much use to us, if we had to send a manned mission to Lagrange point L2 (which would be extremely challenging) in order to retrieve the hard-drives manually. We're in the information age, radio waves have been discovered around 1890 by Heinrich Hertz. Their use has been standard practice in data transmission from space probes back to earth since the 1960s at least. > In fact, for all we know it's real purpose is as an offensive directed energy weapon ... I put nothing beyond these madmen ... I know you're probably joking and not being serious, but that's absurd. What exactly is a 6.5 m (21 ft) mirror at a distance of 1,500,000 km (≈930,000 miles) from earth going to do? Laser tattoo removal? > And the best part, the icing on the cake ? We payed for it all ... Yeah. You. Me. Every US citizen (all 331,893,745 of them). Each and every Canadian (38,654,738). All citizens of countries belonging to the EU (447,007,596). A total population of 817,556,079 (in 2022). The total cost of the JWST is US$9.7 billion (including future operative costs) for the US (NASA developed the telescope and operates it), US$850 million for the EU (ESA provided instruments for the telescope and the launch) and US$165 million for Canada (CSA provided fine-guidance sensors). That's a total cost of US$10.715 billion. Development began in 2003, launch happened in 2022 and mission duration will be 10 years minimum and probably around 20 years. So the JWST will probably still be around in 2037 (conservatively assuming 15 years of mission time). That's US$10.715 billion for the JWST in 34 years. US$315 million per year. Even ignoring the minor EU and Canadian contributions, that would be less than US$1 per US citizen per year. 95 ct per capita per year to be exact. In reality it's even less. By comparison, the US spends US$782 billion each year for its military budget (that's more than what China, India, Russia, Saudi Arabia, France, Germany, United Kingdom, Japan, South Korea, and Brazil spend on defence combined). That's US$2,356 per US citizen per year. At current average gas prices (≈US$5/gal) and average gas mileage of ≈6 gallons/100 mi (Ford F-150), that "95 ct per capita per year" figure means you could drive a whopping additional 5 km (3.2 miles) once per year, if your country hadn't built the JWST! Amazing. In my opinion that's a reasonable price to pay for literally the best space telescope ever. The JWST is the envy of the entire world. But feel free to disagree.
<Comment deleted by user>

Makes me wonder if anyone here has ever ground their own telescope mirror? I want to try it someday. I even have a record of H.G. Wells War of the Worlds broadcast to use as bearings. Can't find glass thick enough to do it, and am too cheap to buy it. Would be an interesting project.

Makes me wonder if anyone here has ever ground their own telescope mirror? I want to try it someday. I even have a record of H.G. Wells War of the Worlds broadcast to use as bearings. Can't find glass thick enough to do it, and am too cheap to buy it. Would be an interesting project.

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