PhotoGav Posted November 16, 2018 Share Posted November 16, 2018 I seem to be majoring on cluster images at the moment and here is my most recent target - the Perseus Cluster (Abell 426). It is not a star cluster, but a galaxy cluster, and a pretty darn big one too! It is located in Perseus, just east of Algol, where Medusa's slain head appears. The apparent diameter of the cluster is quoted as about 860' or just over 14º. The field of view of this image is a maximum of 1.8º, so only around 12% of the whole galaxy cluster! As I said, the Perseus Cluster is huuuuge. In fact, it is one of the most massive objects in the known universe. It is situated around 240 million light years away from Earth and contains thousands of galaxies. I used PI to annotate the image and it identified 287 PGC objects. Here is an interesting snippit from Wikipedia concerning the central bright galaxy in the image, Perseus A or NGC 1275: "In 2003 a team of astronomers led by Dr. Andrew Fabian at Cambridge University discovered one of the deepest notes ever detected, a B♭, after 53 hours of Chandra observations. No human will actually hear the note, because its time period between oscillations is 9.6 million years, which is 57 octaves below the keys in the middle of a piano. The sound waves appear to be generated by the inflation of bubbles of relativistic plasma by the central active galactic nucleus in NGC 1275." Wow! Technical Details: Skywatcher Esprit 100ED, QSI 683-WSG8, Baader 1.25" Filters, HEQ5 RGB = 18 x 600s each L = 16 x 1200s TOTAL = 14 hours 20 minutes I hope you like the image and as ever I look forward to hearing your opinions. Clear skies! Link to comment Share on other sites More sharing options...
tooth_dr Posted November 16, 2018 Share Posted November 16, 2018 12 minutes ago, PhotoGav said: In 2003 a team of astronomers led by Dr. Andrew Fabian at Cambridge University discovered one of the deepest notes ever detected, a B♭, after 53 hours of Chandra observations. No human will actually hear the note, because its time period between oscillations is 9.6 million years, which is 57 octaves below the keys in the middle of a piano. The sound waves appear to be generated by the inflation of bubbles of relativistic plasma by the central active galactic nucleus in NGC 1275. Best fact of all time Wonderful image. Do you reckon there would be any mileage in taking shorter Lum? 20 minutes lums is pretty long :0 Link to comment Share on other sites More sharing options...
PhotoGav Posted November 16, 2018 Author Share Posted November 16, 2018 21 minutes ago, tooth_dr said: Wonderful image. Do you reckon there would be any mileage in taking shorter Lum? 20 minutes lums is pretty long :0 Thank you. I opted for longer Lum subs in the hope of eeking out a bit more detail in the galaxies, which I think has worked. I have slightly sacrificed star colour intensity by using longer subs in RGB, but again, this was to concentrate on the galaxies as the image is primarily about them rather than the stars in there. What benefit would you imagine shorter Lum subs would bring? Link to comment Share on other sites More sharing options...
Davey-T Posted November 16, 2018 Share Posted November 16, 2018 Beautiful image Gav, let's hope there's an astro' imager "up there" taking pic's of our local group. Dave Link to comment Share on other sites More sharing options...
domstar Posted November 16, 2018 Share Posted November 16, 2018 Crikey, I think you've just blown my mind. I think I need a sit down. Link to comment Share on other sites More sharing options...
Stu Posted November 16, 2018 Share Posted November 16, 2018 Errrr, wow! What else to say. That's an amazing shot Gav, and great info too. Thanks Link to comment Share on other sites More sharing options...
CraigT82 Posted November 16, 2018 Share Posted November 16, 2018 Cracking image. But how exactly do 'sound waves' travel through space??! Link to comment Share on other sites More sharing options...
PhotoGav Posted November 16, 2018 Author Share Posted November 16, 2018 Thank you all for your comments. 1 hour ago, Davey-T said: let's hope there's an astro' imager "up there" taking pic's of our local group. Surely there has to be?! 7 minutes ago, CraigT82 said: But how exactly do 'sound waves' travel through space??! Good question - we all know that 'nobody can you hear you scream in space...'! I found another interesting article about the Perseus Cluster: https://www.nasa.gov/feature/goddard/2017/scientists-find-giant-wave-rolling-through-the-perseus-galaxy-cluster Perhaps that has something to do with it? Perhaps the waves aren't sound waves at all, but can be interpreted as a sound wave by us wee humans? Not that we can hear what we interpret...! Link to comment Share on other sites More sharing options...
tomato Posted November 16, 2018 Share Posted November 16, 2018 Another mighty fine image of my favourite kind of cosmological objects. I also thought sound waves needed some form of physical medium to be transmitted, but hey, with a period measured in millions of years you would have to listen out for them for quite a while.... Link to comment Share on other sites More sharing options...
tooth_dr Posted November 17, 2018 Share Posted November 17, 2018 18 hours ago, PhotoGav said: Thank you. I opted for longer Lum subs in the hope of eeking out a bit more detail in the galaxies, which I think has worked. I have slightly sacrificed star colour intensity by using longer subs in RGB, but again, this was to concentrate on the galaxies as the image is primarily about them rather than the stars in there. What benefit would you imagine shorter Lum subs would bring? Not a benefit, just wondering would it work too. I’m not sure I could get away with 20 minute luminance subs. I tried a 10min lum sub before and the ADU average was over 2000 Link to comment Share on other sites More sharing options...
PhotoGav Posted November 17, 2018 Author Share Posted November 17, 2018 10 hours ago, tomato said: Another mighty fine image of my favourite kind of cosmological objects. I also thought sound waves needed some form of physical medium to be transmitted, but hey, with a period measured in millions of years you would have to listen out for them for quite a while.... Thanks @tomato , having spoken with a friend of mine who understands physics (I tinker with it at best!), he reasoned that the sound was not ‘heard’ here on Earth, but was seen as a wave in the dusty environs of the Perseus Cluster, the dust giving the medium through which the sound can travel. So, the sound is ‘local’ to the Perseus Cluster and doesn’t need to travel to Earth (which it can’t as sound doesn’t travel through the almost nothingness of inter galactic space). It made some sense to me when he explained, I hope my ‘Chinese whisper’ of the explanation makes sense!! 1 hour ago, tooth_dr said: Not a benefit, just wondering would it work too. I’m not sure I could get away with 20 minute luminance subs. I tried a 10min lum sub before and the ADU average was over 2000 Ah, I see. Yes, I’m sure that 10 min luminance subs would show up the cluster. Give it a go! Link to comment Share on other sites More sharing options...
Barry-Wilson Posted November 17, 2018 Share Posted November 17, 2018 A fascinating, deep and thought provoking image Gav, an image to immerse oneself and contemplate the immensity. Perfectly processed and executed: congratulations. Link to comment Share on other sites More sharing options...
tomato Posted November 17, 2018 Share Posted November 17, 2018 Inspired by this image I turned the Esprit 150 on this target tonight, very optimistic given the 70% moon, and then the clouds came along... The neighbours probably heard my cursing sound waves, even if they didn’t get to Perseus A. Link to comment Share on other sites More sharing options...
PhotoGav Posted November 17, 2018 Author Share Posted November 17, 2018 6 hours ago, Barry-Wilson said: A fascinating, deep and thought provoking image Gav, an image to immerse oneself and contemplate the immensity. Perfectly processed and executed: congratulations. Thank you Barry. 1 hour ago, tomato said: Inspired by this image I turned the Esprit 150 on this target tonight, very optimistic given the 70% moon, and then the clouds came along... The neighbours probably heard my cursing sound waves, even if they didn’t get to Perseus A. yup, that sounds like astrophotography! Link to comment Share on other sites More sharing options...
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