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Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

dunlap.utoronto.ca

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Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#31

Post by dylan604 »

lvspiff wrote: post #27
shiftpgdn wrote: post #16

Can someone smarter than me explain why astronmers can't stick something like this on the back of an existing geostationary platform (like what is used for the XM radio sattelites) and get amazing data out of them? Surely sticking something like this array 100km into space will yield better results without the overhead of a 20 year mission plan like James Webb or Hubble.

I've always wondered that myself - If the Russians could build and launch sputnik in 1957 and get it around the earth a few times why aren't we seeing a huge number of backyard dad+son duos building rockets to launch their own telescope array. Its amazing that its a 60 year old feat that is still only in the hands of governments and massive corps

Rocket science ain't easy. Just because you can build a great telescope does not mean you can build a rocket. Also, I could only imagine the NIMBY revolt when you file your permit plans to build launchpad-38A in your backyard. I hope you don't spend too much time wondering before coming to obvious answers

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#32

Post by dylan604 »

sandworm101 wrote: post #26

Forget this telescope. I'm more intrigued by the location: New Mexico Skies, a campground for telescopes. I'd rather visit such a place than most any museum. https://nmskies.com/

This is "when I grow up" type of wish to have my gear at this type of location for my remote sessions. Otherwise, I'd just really like for my retirement plot to be remote like this.

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#33

Post by dylan604 »

buescher wrote: post #10
1024core wrote: post #5

RAIT (Redundant Array of Inexpensive Telephoto lenses)?

Not that inexpensive - that's a $12000 lens with a nearly 6" aperture. The telescope itself is a fairly specialized instrument. It's more like a redundant array of very fast (for a telescope) lenses. From the paper: "Our primary goal is to test predictions that at very low surface brightness levels galaxies display a wealth of structures that are not seen at higher surface brightness levels." (But yes, the lenses are…

There are plenty of much cheaper telescopes in that 6" aperture range. My 152mm was only $1k. My polar mount was $1500. Even adding in a tracking scope/camera to attach is still a fraction of the price of single lens. Tack on a similar SBIG dedicated astro camera and cheap laptop to run the guiding and imaging would still come in under that price tag.

So, is there an advantage of having all of the lenses on the same tracking platform to justify the expense of the single mount? If you place individual 6" scopes in an area where humans could comfortably move between them all pointed at the same object or even slightly different areas to get the wider image, would that not be the same/similar result? Essentially, building the VLA but with commodity off-the-shelf visible scopes.

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#34

Post by itishappy »

dekhn wrote: post #28
buescher wrote: post #10

Earlier quoted context omitted.

Not that inexpensive - that's a $12000 lens with a nearly 6" aperture. The telescope itself is a fairly specialized instrument. It's more like a redundant array of very fast (for a telescope) lenses. From the paper: "Our primary goal is to test predictions that at very low surface brightness levels galaxies display a wealth of structures that are not seen at higher surface brightness levels." (But yes, the lenses are…

The thing to appreciate is that in academic science, $12000 lens is inexpensive; the scale is different from consumer and prosumer pricing. A typical project like this would get at least a million dollaras in funding (see https://www.artsci.utoronto.ca/news/astronomer-roberto-abrah... which shows they got $2M to buy lenses; 120 lenses * 12K = $1.5M. I work with microscopes that cost $1M and just sit in a lab. That's…

> I work with microscopes that cost $1M and just sit in a lab. That's not atypical for an academic or industrial microscope.

Ooo, what for!? I always love hearing what people do with optical equipment I can't afford. :)

I'm sure I'd be interested in your pet project as well!

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#35

Post by dekhn »

itishappy wrote: post #34
dekhn wrote: post #28

Earlier quoted context omitted.

The thing to appreciate is that in academic science, $12000 lens is inexpensive; the scale is different from consumer and prosumer pricing. A typical project like this would get at least a million dollaras in funding (see https://www.artsci.utoronto.ca/news/astronomer-roberto-abrah... which shows they got $2M to buy lenses; 120 lenses * 12K = $1.5M. I work with microscopes that cost $1M and just sit in a lab. That's…

> I work with microscopes that cost $1M and just sit in a lab. That's not atypical for an academic or industrial microscope. Ooo, what for!? I always love hearing what people do with optical equipment I can't afford. :) I'm sure I'd be interested in your pet project as well!

The scopes I work near are typically for applying cutting edge imaging techniques to cellular or organoid growth. Like this: https://www.zeiss.com/microscopy/en/resources/insights-hub/l...

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#36

Post by FredPret »

lvspiff wrote: post #27
shiftpgdn wrote: post #16

Can someone smarter than me explain why astronmers can't stick something like this on the back of an existing geostationary platform (like what is used for the XM radio sattelites) and get amazing data out of them? Surely sticking something like this array 100km into space will yield better results without the overhead of a 20 year mission plan like James Webb or Hubble.

I've always wondered that myself - If the Russians could build and launch sputnik in 1957 and get it around the earth a few times why aren't we seeing a huge number of backyard dad+son duos building rockets to launch their own telescope array. Its amazing that its a 60 year old feat that is still only in the hands of governments and massive corps

1) You need more than just getting to space, you need to go really fast when you get there. So, lots of propellant and a big rocket is needed. So, it's really expensive.

2) Because you're setting fire to a big tube of propellant that then goes crazy fast, you need all sorts of permits and safety reviews to do it

3) Space is hard, so your rocket will almost certainly blow up / fail a couple of times.

All of this means: big budgets and state-level patience and persistence is needed

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#38

Post by Iulioh »

perihelions wrote: post #3

Unfortunately their website is not built from a large, redundant array of off-the-shelf server parts. Here's a mirror, https://web.archive.org/web/20240507234024/https://www.dunla...

>Here's a mirror,

Ah!

So there's a large mirror involved?

(sorry)

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#39

Post by buescher »

dekhn wrote: post #28
buescher wrote: post #10

Earlier quoted context omitted.

Not that inexpensive - that's a $12000 lens with a nearly 6" aperture. The telescope itself is a fairly specialized instrument. It's more like a redundant array of very fast (for a telescope) lenses. From the paper: "Our primary goal is to test predictions that at very low surface brightness levels galaxies display a wealth of structures that are not seen at higher surface brightness levels." (But yes, the lenses are…

The thing to appreciate is that in academic science, $12000 lens is inexpensive; the scale is different from consumer and prosumer pricing. A typical project like this would get at least a million dollaras in funding (see https://www.artsci.utoronto.ca/news/astronomer-roberto-abrah... which shows they got $2M to buy lenses; 120 lenses * 12K = $1.5M. I work with microscopes that cost $1M and just sit in a lab. That's…

The point is it's not that inexpensive for the optics. I've worked in an interferometry lab where we used high-volume photographic lenses where we could, and yeah, they were probably an order of magnitude less expensive than something made for the purpose, and real exotic optics were more than two orders of magnitude more expensive.

But talking apples to apples, a $12000 professional camera lens is closer to something like a $12000 research microscope than you think in terms of the build-or-buy decision. There's also a whole industry of telescopes for amateurs that are made in low volumes to much higher optical standards than photographic lenses that are mostly not that expensive. A top tier 6" refractor might be $15K and blow the camera lens away as a general purpose astronomical instrument, but it would not be nearly as fast, which is important for this application, and if you placed an order for 120 of them, you might get them in five years. Maybe. I'd guess that made-for-the-purpose tubes would come in within a factor of two or three of the off-the-shelf lens if you could find a supplier. They might even be cheaper. The project risk would be larger, and that might be determining also.

Re: Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens

#40

Post by eichin »

lvspiff wrote: post #27
shiftpgdn wrote: post #16

Can someone smarter than me explain why astronmers can't stick something like this on the back of an existing geostationary platform (like what is used for the XM radio sattelites) and get amazing data out of them? Surely sticking something like this array 100km into space will yield better results without the overhead of a 20 year mission plan like James Webb or Hubble.

I've always wondered that myself - If the Russians could build and launch sputnik in 1957 and get it around the earth a few times why aren't we seeing a huge number of backyard dad+son duos building rockets to launch their own telescope array. Its amazing that its a 60 year old feat that is still only in the hands of governments and massive corps

The problem is the lack of a "backyard" ICBM program to piggyback off of... the R-7 that the sputnik launcher was based on "was designed with excess thrust since they were unsure how heavy the hydrogen bomb payload would be" (wikipedia.)
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