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Dragonfly: An optical telescope built from an array of off-the-shelf Canon lens
- tocs3 2y agoHere are some pictures. https://www.dragonflytelescope.org/gallery.html https://www.dragonflytelescope.org/gallery.html It uses a raspberry pi for each lens(https://www.raspberrypi.com/news/dragonfly-spectral-line-mapper/ https://www.raspberrypi.com/news/dragonfly-spectral-line-map...) Early paper about the telescope. https://ui.adsabs.harvard.edu/abs/2014PASP..126...55A/abstract https://ui.adsabs.harvard.edu/abs/2014PASP..126...55A/abstra...
- perihelions 2y agoUnfortunately 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.dunlap.utoronto.ca/instrumentation/dragonfly/ https://web.archive.org/web/20240507234024/https://www.dunla...
- araes 2y agoThis article talks about the upgrades they recently (2022) made to the telescope array and has a few example images. https://www.dunlap.utoronto.ca/new-dragonfly/ https://www.dunlap.utoronto.ca/new-dragonfly/ The publication resulting from the work, "Giant Shell of Ionized Gas Discovered near M82", can be found: https://iopscience.iop.org/article/10.3847/1538-4357/ac50b6/pdf https://iopscience.iop.org/article/10.3847/1538-4357/ac50b6/... The companion publication from Yale, "Nascent Tidal Dwarf Galaxy Forming", can be found: https://iopscience.iop.org/article/10.3847/2041-8213/ac3ca6/pdf https://iopscience.iop.org/article/10.3847/2041-8213/ac3ca6/... Edit: And, actually from the post below, full publications related at: https://www.dragonflytelescope.org/publications.html https://www.dragonflytelescope.org/publications.html
- Iulioh 2y ago>Here's a mirror, Ah! So there's a large mirror involved? (sorry)
- 1024core 2y agoRAIT (Redundant Array of Inexpensive Telephoto lenses)?
- buescher 2y agoNot 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 going to be cheaper from Canon than the tubes would be from a specialized telescope maker).
- dekhn 2y agoThe 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-abraham-transform-dragonfly-telescope-thanks-cfi-innovation-fund 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 not atypical for an academic or industrial microscope. One of the biggest issues in modern science is that to make many discoveries you need to pay very high prices to get the latest and greatest hardware. I've been exploring how to make lower cost telescopes and microscopes (and definitely love this project), that are "good enough" to open up new areas of research/discovery for people with budgets in the $1K-10K range. But it's hard! So far I have mostly been relearning what people already knew in the 1800s and early 1900s, that is easily obtained off-the-shelf tech today.
- itishappy 2y ago> 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!
- buildbot 2y agoAnyone know what sensor they are using behind all that nice Canon glass?
- perihelions 2y ago- "Each of the eight lenses in the array is connected to a Santa Barbara Imaging Group (SBIG) STF-8300M CCD camera. These cameras have Kodak KAF-8300 CCD detectors, which have a 3326 × 2504 pixel format." https://arxiv.org/abs/1401.5473 https://arxiv.org/abs/1401.5473 ("Ultra Low Surface Brightness Imaging with the Dragonfly Telephoto Array")
- buildbot 2y agoThank you!
- 0cf8612b2e1e 2y agoThat write up could have used significantly more details. Is this competitive with a traditional telescope? 1/1000 the cost? Just the benefit of not having to share instrument time? Being able to incrementally expand the array? Some kind of technical measurement for me to better appreciate the work.
- tupilaq 2y agoCool.. a more up-to-dateish version of Wide Angle Search for Planets (WASP[1] and SuperWASP[2]) [1]https://warwick.ac.uk/fac/sci/physics/research/astro/research/wasp/ https://warwick.ac.uk/fac/sci/physics/research/astro/researc... [2]https://www.superwasp.org/about/ https://www.superwasp.org/about/
- gammarator 2y agoDifferent science goals, though.
- antognini 2y agoThis kind of a setup of a large number of small, cheap detectors works well for observing diffuse objects with low surface brightness. Generally speaking telescopes improve with size because larger telescopes can resolve smaller objects, so you can concentrate the light from your source into a smaller patch and increase the signal-to-noise with respect to the background. But once you have resolved the object (which doesn't require a very large diameter for a diffuse object) you no longer get any benefit from a larger telescope except for the greater light collecting power. So there's no benefit to having a single large mirror vs a large number of smaller detectors. Since it's a lot easier and cheaper to just buy a bunch of off the shelf components rather than build a large mirror from scratch that is what they did here. A friend of mine in grad school worked on a project that is similar in spirit called ASAS-SN. It also used off the shelf cameras but distributed them around the world so that they could detect supernovae and other transients. Because everything was off the shelf they could build out their network on a shoestring budget. I think they're the first to discover the vast majority of all bright supernovae these days.
- perihelions 2y ago- "diffuse objects with low surface brightness" Are things amateur photographers with small telescopes (and lots of patience) sometimes discover, https://old.reddit.com/r/space/comments/13uco46/i_discovered_this_planetary_nebula_using_a_500/?sort=top https://old.reddit.com/r/space/comments/13uco46/i_discovered... ("I discovered this planetary nebula using a $500 camera lens, now it carries my name") https://www.astrobin.com/i9yy6f/ https://www.astrobin.com/i9yy6f/ (18 hours!)
- gnatman 2y agoI was struggling to see the planetary nebula inside that blue circle before I realized that is the planetary nebula. cool!
- perihelions 2y agoSomewhere there's a large, bright nebula in the shape of a red arrow no astronomer's ever noticed.
- diracs_stache 2y agoNot too much to add from what others have mentioned but this looks like a good (low cost wide fov) photon bucket with low complexity (important for reducing stray/scattered light).
- shiftpgdn 2y agoCan 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.
- VohuMana 2y agoNot a professional so take this with a grain of salt but my guess would be weight first and foremost. From what I understand geostationary orbit isn’t cheap to get to and each added kilogram increases cost significantly. These lenses while not incredibly heavy are heavy enough to add a fair amount of cost.
- consp 2y agoI also doubt these lenses will hold up in a very cold or very hot near-vacuum.
- sgt101 2y agoI am no expert, but the things I would worry about: - cost to get into geostationary orbit might dominate the value/saving of the cheap instrument, so it might be smart to spend more on that - managing and controlling it might be very challenging - need to get the data down from it - might create difficulties and costs that kill the value - heating and cooling in space might kill it - radiation in space might kill the hardware - acceleration during launch might kill the hardware - the payload needs to be stable during launch or there will be an accident - scientific value might be lower than other missions for similar spend
- dekhn 2y agoProjects like this have been done; see for example https://www.jpl.nasa.gov/missions/arcsecond-space-telescope-enabling-research-in-astrophysics-asteria https://www.jpl.nasa.gov/missions/arcsecond-space-telescope-...
- gridspy 2y ago
- somethingsome 2y agoIs it possible to download somewhere in full quality a raw image captured with it?
- deleted 2y ago[deleted]
- sandworm101 2y agoForget 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/ https://nmskies.com/
- dylan604 2y agoThis 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.
- rhelz 2y agoQuestion: why is, saying having 100 different lenses simultaneously take images, rather than just a single one taking 100 sequential images, and then using something like registax to combine them?
- foota 2y agoI think you always want to take many pictures (significantly more than 100, it mentions a 10h integration time, which I think means taking photos for 10 hours in a row?), so if you take them 100x slower it will both take much longer, and there will be more drift in that time to account for.
- MeteorMarc 2y agoHow can multi-element lenses have less scattering than a large mirror telescope? Do they mean smaller diffraction patterns instead?
- gammarator 2y agoSee the third page of https://arxiv.org/abs/1401.5473 https://arxiv.org/abs/1401.5473
- formerly_proven 2y agoThough the characterisation of nano-structured coatings isn't quite right > However, the latest generation of Canon lenses features the first commercialized availability of nano-fabricated coatings with sub-wavelength structure on optical glasses. Nikon was actually first to market with this, as far as I can tell in the AF-S 300mm f2.8 VR in 2004.
- smaddox 2y ago> with unprecedented nano-fabricated coatings with sub-wavelength structure on optical glasses. Also known as an anti-reflection coating. Definitely not unprecedented. Cool project, though.
- gelstudios 2y agoFrom the various links in the comments, the telescope uses special filters in front of the lenses to capture the faint glow in specific wavelengths emitted by the circumgalactic medium (a new word for me!) aka "gas" around galaxies.
- gammarator 2y agoThat’s exactly why they are using commercial lenses! Canon’s modern AR coatings are so good that the performance for low-surface brightness imaging beats larger-aperture telescopes which can gather more light but scatter it around the image. See the third page of https://arxiv.org/abs/1401.5473 https://arxiv.org/abs/1401.5473
- DarkSucker 2y agoCan someone provide/link-to a principle of operation? I looked at references (https://www.dragonflytelescope.org/publications.html https://www.dragonflytelescope.org/publications.html) but they point to publications that look to be behind pay walls. In particular, I don't see how N co-aligned cameras is any different than N images taken in sequence with one camera (averaging over noise), other than a reduction in time required to take N images with one camera.
- gammarator 2y ago> they point to publications that look to be behind pay walls. If you click the “ADS” link you will find most will have links to a free preprint on arXiv. > other than a reduction in time required to take N images with one camera. Life is short!
- tocs3 2y agoHow does this relate to interferometry? I do not think they are keeping waveforms or timing or anything (except taking the pictures at about the sames time. Are they just stacking images?
- skykooler 2y agoEssentially. It's better than conventional stacking because they are taken through different lenses, so any lens flares/distortions/reflections etc in each camera should get averaged away by the others.
- ggm 2y agoLovely project. When comparing images from this and other scopes, remember that almost all Astrophotography nowadays has moved on from exposure from a single light pipe into a negative, and development onto a photo: They are constructs from grids of sensors, with differing receptance across the RF spectrum (visible and non-visible) subject to intense signal processing, and false colour projections. About the only point you can discuss as a comparator is the angular resolution and even that means asking how much has been interpolated. I love modern astro images but I am unsure we even should call them "photography" because they're "painted", by the astronomer or their appointed colour artist. "this one has more IR boost, but I added a hint of green for dramatic effect" Also to the angular resolution thing, we're often also looking at what is projected into our mind as a 2D structure. The horse head nebula is a 3D state of matter. It wouldn't look like JFK's head from our angle, but might well from another point of view, or a melon, or like.. nothing at all. Most "constellations" are not physically interconnected in any sense, and are not a group the way a galaxy or star+planets are, and need not lie the same distance away from us. They're the view of these objects on an imaginary surface painted by the astrologers. https://en.wikipedia.org/wiki/Flammarion_engraving https://en.wikipedia.org/wiki/Flammarion_engraving
- zyphr 2y agoFor drones something similar is done: "The 1.8 gigapixel sensor is made up of a matrix of 368 Aptina MT9P031 5-megapixel smartphone CCDs." https://newatlas.com/argus-is-darpa-gigapixel-camers/26078/ https://newatlas.com/argus-is-darpa-gigapixel-camers/26078/