Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.


Search the Community

Showing results for tags 'quasar'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Welcome
    • Welcome
  • Beginners
    • Getting Started General Help and Advice
    • Getting Started Equipment Help and Advice
    • Getting Started With Observing
    • Getting Started With Imaging
  • Community
    • Official SGL Announcements and Events
    • StarGaZine
    • SGL Challenges and Competitions
    • SGL Star Parties
    • Star Parties & Astro Events
    • Celestial Events Heads Up
    • The Astro Lounge
  • Retailers
    • Sponsor Announcements and Offers
    • FLO Clearance Offers
    • IKI Observatory
    • Supplier Reviews
  • Astro Classifieds
    • For Sale / Swap
    • Wanted
  • Equipment
  • Observing
  • EEVA (Electronically Enhanced Visual Astronomy)
  • Imaging
  • Science
  • WADAS's WADAS Discussion Forum
  • Beaufort Club's Topics
  • Swindon Stargazers Club's Topics
  • East Midlands Stargazers''s Topics
  • Central Scotland Astro's Topics
  • SGL Cumbrian Skies's Topics
  • Herts, Beds and Bucks Group's Topics
  • SGL East Anglian Group's Topics
  • South Leicester Observers's Topics
  • South Wales Group's Topics
  • SGL Surrey Observers's Topics
  • South Yorkshire Stargazers's Topics
  • Yorkshire Astronomers's Topics
  • Devon and Cornwall's Topics
  • West Midlands's Topics
  • Essex Cloud Dodgers's Topics
  • Essex Cloud Dodgers's New equipment
  • NLO and Planetarium's Topics
  • Astronomical Society of Edinburgh's Discussion
  • Dorset Stargazers's Topics
  • Hairy Stars Club (Comets)'s Tutorials and Guides
  • Hairy Stars Club (Comets)'s General Discussion
  • Hairy Stars Club (Comets)'s Observing Campaigns
  • Hairy Stars Club (Comets)'s Analysis results
  • Hairy Stars Club (Comets)'s Useful Links
  • Pixinsight Users Club's Pixinsight Discussion Forum


  • Astro TV
  • Celestial Events
  • SGL Calendar
  • Astro Society Events
  • Star Parties
  • WADAS's Events
  • Beaufort Club's Events
  • Astronomical Society of Edinburgh's Events
  • Dorset Stargazers's Events


There are no results to display.

There are no results to display.

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL







Found 6 results

  1. How do you top a night where you observed two quasars and one supernova? You go to a darker location and focus almost exclusively on quasars in the magnitude 13-14 range. On the night of June 14 I drove almost 80 minutes north of Las Vegas to the Paranaugat wildlife Refuge arriving after sunset but well before true darkness set in. A quiet location but for the highway I used to get there - I didn't realize how much traffic this highway received after dark - not a five minute period went by without cars/trucks speeding by washing over my viewing location with their headlights - I got really good at keep my eyes closed to protect my night vision. And it was dark - this was my first Bortle 1 location with the horizon being completely black except for due south where the light dome of Las Vegas glowed dimly on the horizon up to about 10 degrees. The Milky Way was brilliant. Air temperatures dropped from the mid-90s (F) to the mid-80s (F) and winds dropped to nearly nothing in the hour after sunset. Despite being such a dark location my views of galaxies were never 'crisp' - I've had far better galaxy views from other locations (that are less dark) so there must have been a good bit of moisture in the airmass up high. Stars were clear with beautiful spikes coming from the bright ones. Several 'visibility test targets' were jumped through as I was waiting for twighlight to fade. The Hercules Cluster (M15), Alberio, and M92 all old friends revisited. My normal test targets - M65, M66, NGC 3628 - were briefly observed a few times over the course of the night but never impressed (which was disappointing). First hunt of the night was MKN 501 - a mag 14.5 quasar an unknown distance away. I hopped down from Eta Her and found a "V" asterism of roughly mag 8 stars that pointed right to the target area. After camping on a mag 12.6 star I was able to see the faintest galactic haze around a 'star' at the right location - that's the target with the 'star' being the quasar shining bright in the galactic core. Quasar find #5! Staying in Hercules I went hunting for B3 1715+425 - a mag 13.3 quasar listed at 2.1 Gly distant. I found the start of this hunt a challenge as I started star hopping from Iota Her - which was a challenge to find as it's not an overly bright star and doesn't stand out in the finder scope. I could clearly see it naked eye but had difficulty translating that to the finder scope. I eventually did find Iota and star hopped up to the area via a line of mag 5 - 6 stars to M92. I hopped to the correct location, positively identified the mag 8.4 star that was my 'base camp' for this hunt...then could clearly make out the mag 13 and 13.4 stars nearby but the quasar was nowhere to be seen...it was supposed to be sitting between the mag 8.4 and mag 13 stars...but nothing was there. Upped the magnification from 120x to 240x but it didn't help. No joy on this target. I'm thinking my star chart program must have been off in either magnitude of the target or location...because mag 13 targets were easily seen this night. Next I swung the scope over to Draco and PG 1634+706 (A Sky & Telescope target this month) - a mag 14.7 quasar listed 7.6 Gly away (but this month's Sky & Telescope said the distance is most likely incorrect due to time/space expansion). I star hopped over from Pherkhad in Ursa Minor to a grouping of mag 6-8 stars and then down to the target area. Positively IDing the quasar was not that difficult tonight as there isn't much else in the immediate vicinity...but a series of mag 12-14 stars ring the area and were all visible. The quasar stood out as a compact star-like body. Quasar #6! Next down to the tail of Draco for MKN 180 - a mag 14.5 target an unknown distance away. The star hop from the tip of the tail (Gianifar) wasn't too difficult...and I made a postive ID based off where the faint stars were in relation to one another...the quasar formed the corner of a parallelogram with 3 other stars - but it was faint. This was about the faintest target of the night and averted only. Quasar #7. Next moving up Draco's body to PG 1351+640 - a mag 14.3 quasar listed 1.1 Gly distant. A pretty easy star hop and a line of mag 10 stars pointed right to the averted-only quasar. It was faint but there were stars a little further away that were more faint. Quasar #8!! A little further up the body and star hopping over from Ursa Minor led to 3C 305.0 - a mag 13.7 quasar listed at 550 Mly distance. The star hop was the biggest challenge here as so many faint stars were visible it was tough for me to keep track of which star I was really looking at. After about 10 minutes of hunting/checking/moving/hunting/checking/verifying I finally made it to the correct target location and could see a faint star-like object in the faintest of haze - that's the target. Several mag 14.x stars were clearly visibile in the vicinity. Averted vision brought out the most of the haze...but the target was not difficult in these conditions. Mark that as #9!!! Final ultra deep target of the night was IRAS 17371+5615 - a mag 14.0 target listed at 960 Mly. Another challenging star hop trying to pin down faint stars in the head of Draco...eventually did it and camped out on a mag 10.3 star where the quasar was out on a ring of mag 14.x stars in the same EP view. I was able to pin down each of the mag 14 stars with the target quasar being #3 in the line. This was a faint target...but it was there. An even 10 quasars logged! Time to view a few more old friends - M101 with darkness showing between faint farms, M51 which was the only stunning galaxy of the night with the arms showing about as clearly as I've ever seen them, M63 with the bright core and expansive dim glow, and M94 was just a bright core. Then down to NGC 4618 and NGC 4625 - both of which were little more than faint smears. 4618 was clearly brighter and the core stood out well. I finished up my CVn tour with the Cocoon galaxy and companion NGC 4485 - the Cocoon had a bright core and appeared maybe "quarter-on" facing...4485 was non-discript. Their proximity lends itself to interaction but I couldn't see any through the EP. A great, dark night. Very pleased with the very faint targets I was able to pin down. 6 new quasars observed (+1 more missed) and 3 new galaxies. I'm all smiles (well I am now after a decent sleep). Happy hunting.
  2. So conditions around mid night last night were excellent (or rather as good as it gets here... NELM 4 -4.25 at zenith), low humidity. So decided to give my Quasar hunt one more try. Managed to get down to mag 21.7 using short exposures 10x25s (average stack) using the Ultrastar mono x2 binned. This was using the C8 at F5. No LP filter. The NGC4666 (Superwind field is littered with Quasars as per Martin's deep maps). I identified and marked 3 but there are more in the image if anyone wants to give it a go. The most distant one in the image that I marked is barely visible and required an aggressive stretch. It has a magnitude of 21.7 and a redshift of 2.25 which puts it at 11.6 Bly. Note the dark circle you see in the center is not technically vignetting that you see at high focal reduction. It is actually a reflection I am getting off the optical system. I suspect it is due to the clear filter I use to keep dust off the sensor. I will take flats next time which should fix this. Enjoy...
  3. Chris’s Backyard Astronomy. January 2017. A view beyond Earth’s lifetime Happy New Year to everyone. This month I am going to concentrate upon one topic only; something that came to my attention at New Year. The item in question is described as a QUASAR and makes a year in my life appear extremely insignificant. Eyewitness report: “Almost Older Than Time. Would we be able to see it? On Monday the 2nd of January we gathered in Chris's back garden observatory to spot a tiny pinprick of light that had been travelling 8 billion years, yes that's right 8 BILLION YEARS to reach us! Chris had done his homework, mapped out its position and identified a few pointer stars to help us in our search. The bright moon and lovely Venus stayed handily behind the house so a reasonably dark, clear sky helped us in our search. Our luck was in, the pointer stars in the shape of a triangle were in the (telescope) field of view and using averted vision I spotted our faint target, impossible to grasp the enormous distance through space and time the photons from this QUASAR had travelled. Once spotted it was easier to see it again as we all took turns to look at this black hole in action; a successful night, thanks Chris.” Susan Feist Quasi Stellar Radio Sources (QUASAR) The name was adopted originally because such objects were first observed by ‘seeing’ their radio waves and so they were assumed to be stars. Remember, telescopes are not just available to see things with your own eyes but some are capable of detecting lots of other forms of energy. The Jodrell Bank telescope near Manchester for example was once the greatest radio telescopes in the world. Jodrell Bank Radio Telescope: Image credit mattbuck Up until the 1960s a multitude of radio wave sources out in the sky were listed and catalogued. Critical to identifying these objects were to accurately log their precise position and then try and get identification too with a powerful visual telescope. This proved possible in some cases and as a bonus it was possible to catch the light and determine the spectrum of the object (see my previous column). Once you have the spectrum you can find out a lot of important information. However, visual recognition and thus scientific interpretation of some of these QUASARs eluded astronomers. 3C 48 I quote a lot of numbers and acronyms but really it’s not that complicated. QUASAR 3C 48 was the 48th entry in the 3rd Cambridge catalogue of radio sources. In 1960, using a huge 200 inch telescope, astronomers Sandage, Matthews and Bolton finally pinned this particular radio source to a 16th Magnitude star. Mount Palomar 200-inch telescope. Image credit: Coneslayer at English Wikipedia A refresher on magnitude Remember, the magnitude scale works counter-intuitively in reverse. Each step is a change of about 2.5 times in brightness. For example, to us the full Moon looks about 60,000 times brighter than the bright star Vega. On the other extreme QUASAR 3C 48 is about 10,000 times DIMMER than the dimmest star we can see with the naked eye! Object Magnitude Brightness we see on Earth The Sun - 26 Midday Sun Full Moon - 12 Moonlit sky Venus (now) - 4 Bright evening ‘star’ (now) Jupiter - 2 Yellowish star like Vega (bright star) 0 5th brightest star in the sky Yildun + 4.5 Star just visible with your eye Neptune + 8 Farthest planet appearing reasonably bright in a 10 inch ‘scope 3C 48 QUASAR + 16 At the limit of a very large amateur ‘scope Capturing the light from the QUASAR to enable a spectrum to be examined was some feat in those days but they did so. Sandage though was quoted describing the spectrum as “exceedingly weird”. What followed was a 3-year period of doubt and false reasoning because the spectrum just could not be interpreted within the range of known objects. In 1963 two other scientists, Schmidt and Greenstein, re-examined the spectrum of 3C 48 from 1960. Schmidt had previously examined a spectrum of a similar object (3C 273) and was thus experienced in these matters. What he immediately concluded was not weird but that object 3C 48 showed a “redshift of 0.37”. So, now we need a recap on redshift. Hearing an ambulance Recall the last time you stood by as the ambulance sped towards you and then away from you. We are all familiar with characteristic change in pitch of the siren. As it approaches you the pitch gets higher then as it leaves you the pitch gets lower. The lowering of the pitch as the sound source moves away from us is due to a ‘stretching’ of the wavelength caused by the speed of the ambulance relative to us. This is the Doppler effect and applies to all types of radiation including light. Normal spectrum above and red-shifted spectrum below. The tell tale absorption lines are moved to the right. Credit: Georg Wiora (Dr. Schorsch) via Wikimedia Commons So Schmidt was saying that the spectrum of QUASAR 3C 48 told us that it was (and still is) moving away at truly phenomenal speed! As we have discussed before, the painstaking work of Edwin Hubble in the 1920s enabled a connection to be made between the speed that an object is receding and its distance. On doing the maths 3C 48 was located at 4 BILLION LIGHT YEARS distant. Ancient photons hit Bishop Monkton This dramatic distance estimation created disbelief in the astronomical community. Knowing how bright the object looks to us (Magnitude +16) and also knowing its distance, enables us to quite easily determine its true brightness close up and thus its power. The calculation for most QUASARs shows they have the luminosity of 10 Trillion (10,000,000,000,000) Suns, easily one of the most energetic objects in the Universe! As you may imagine this stimulated a decade long argument as to whether the observations were true or were these QUASARS just objects in our own galaxy that demonstrated weird physics? In more recent times, advancements in technology have enabled astronomers to study ‘normal’ galaxies in the region of these QUASARS and confirm that indeed they are very distant objects. On the 2nd January 2017 a group of villagers and friends congregated in my humble shed known as the Observatory and eventually, one by one caught a glimpse of light that has taken 8 BILLION years to get here. I stumbled across a reference to QUASAR 4C 11.69 also known as CTA 102. It is in the constellation of Pegasus looking west from the village at the moment. The old 9 inch SCT telescope used to spot the QUASAR This particular QUASAR was originally falsely classed as a magnitude +17 variable star. Variable stars are quite common but are usually quite regular in their variability. Not this one! Recently its magnitude has changed from +17 to nearly +11, which is an increase in brightness of 250 times. Think about this for a moment. This is an object that is TWICE the age of the Earth, more than half the age of the entire Universe as we know it and visible in my 9 inch telescope. Surely this is the most powerful and most distant visible object any of us will witness. Its brightness currently varies quite substantially on a daily basis so what is it? CTA 102 was discovered in the early 1960s from its varying radio source but was laughingly thought to be signals from an extra terrestrial intelligence and American folk rock band The Byrds wrote a song about it in 1967 called ‘Younger Than Yesterday’. It is in fact a giant black hole at the centre of a distant elliptical galaxy and its brightness is determined by what it is currently consuming. So the recent huge increase in brightness is a burp of cosmic proportions quite possibly as it gulps in stars or even other galaxies. I write this in the present tense but it is highly likely this object ‘died’ eons ago and no longer exists. A QUASAR; a disk of stellar material feeding a huge black hole and artist’s depiction of data via NASA’s Spitzer and Chandra telescopes. Credit: Nasa JPL The village group found it a challenge to observe but with careful attention to excluding all other light sources and using averted vision I believe all present witnessed the 8 BILLION year old photons. Retiring to the kitchen to consume a well earned cuppa, some of us had another peek about an hour later and it had significantly increased in brightness in that time so obviously it had done similar to us. What next? A few days later, from the observatory I captured a star field image to show the QUASAR CTA 102 here in the centre of frame against known reference stars. This is a stack of 20 x 30 second exposures. QUASAR CTA 102 approximately Magnitude 12. 8th January 2017; Chris Higgins CTA 102 is now going out of reach. If it is still belching at the same rate in the Autumn we should check back then to see if it has satisfied its hunger. Feel free to join me. Follow my Twitter feed for regular updates on this and new topics from the backyard observatory. Twitter: @owmuchonomy Astrophotos: https://www.flickr.com/photos/blue5hift/sets
  4. I've been watching Jim Al-Khalili's 'Beginning and End of the Universe', where in the second show he talks about gravitational lensing with reference to the twin quasar Q0957+561. Basically what's happening here is we see a double image of the quasar caused by the gravitational field of another galaxy that just happens to lie in our line of sight. So I had to have a crack at this myself with my C9.25 with reducer - so 1750mm thereabouts, LRGB 12 x 120s each. The quasar is faint at Mag 16.7, and the separation is only 6" of arc, which is about 10 of my pixels at 1x1 bin on my Atik460. A few of the individual luminance subs were really sharp (although this LRGB isn't exactly mush either). The large galaxy in the corner is NGC 3079: Mag.11.5 and a paltry 50 million light years away. Of course the really fun bit about making this sort of image is contemplating the quasar's distance at 8.8 billion light years ! (I just noticed Martin Meredith also imaged this quasar in January, with more interesting discussion) :
  5. Is it possible in near real-time observing to capture photons that set out in the first billion years of the life of the universe? Under current estimates of the age of the universe and its expansion, any such object will have a redshift of at least 5.7. While preparing the indices that will accompany the forthcoming deep maps release, I spotted a possibility listed in the Veron catalogue [1], which goes under the unromantic name of SPIT J17210+6017 after the Spitzer First Look Survey. This quasar has an estimated redshift of just a fraction under 5.8, corresponding to light seen from a universe just 0.97 billion years old. A listed V magnitude of 20.6 makes it a very challenging target for my alt-az mounted 8" scope.This object lies in the rich galaxy fields in the centre of Draco, more or less equidistant between NGC 6361 (Arp 124) and VV 1840, the former being my starting off point last night before hopping down to identify the correct field for the quasar. With a sky of SQM 20.3 I went for 30 second subs.With some wishful thinking, the quasar started to appear after live stacking of 6 or 7 subs, but by 10 it was reasonably certain:I continued stacking just to be sure. Here are closeups at 10, 16 and 28 subs, compared to the DSS image.There are even more distant quasars listed (this doesn't quite make the top 20 in the Veron catalogue) but most are significantly fainter (but still worth hunting down!).Thanks for looking, and a big thanks to Paul for the robust live stacking in LodestarLive that makes this kind of thing so much fun.Martin[1] Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010), accessed as Table VII_258_vv10 on VizieR.
  6. After several weeks of not pulling out the scope I was pleased to finally have a chance to hit a clear, dark sky location. Red Rock State Park in California was the location du jour - a Bortle 2 location I hit when ever in this part of the country on business. Conditions were great with temperatures in the low 80s (F) and negligible winds. A light haze lingered on the horizon due to stronger winds earlier in the day. After judging conditions were OK when M65, M66, and NGC 3628 were all visible a great night began. I had wanted to do some deep deep observing so I searched SkyTools3 for quasars within the ability of my scope - the listed came up with a couple that I hadn't heard of before so i got excited. First up was HE 1106-2321 in Crater - listed as a mag 13.7 quasar. Despite not having star hopped in several weeks I found it easiest to hop down from Beta Crt to a mag 8.9 star that served as a base. From there a line of three stars led away to a strong L asterism. The quasar was between the first two in the line...but was FAINT. I had to move magnification up to 240x to pull out the faint photons in averted vision. I was able to get a clear view twice while the scope was slowly moving but upon only viewed faintly a few other times. A mag 13.2 star was more easily visible in the proximity. Next up was moving up to Virgo for SN2012cg. Hopping through several galaxies I was able to find the supernova glowing brightly (may have been a touch brighter than the listed mag 12.0). It overpowered it's host galaxy NGC 4424...with the galaxy's glow only possible with averted vision away from the supernova. The nova is very close to the galactic core. Also in the area NGC 4417 and NGC 4445 were faintly observed - just faint fuzzies. I swung the scope over to UMa and star hopped over to MKN 421 which was supposed to be rather difficult to find because not much is in the local area. But I found a double kite (or diamond) asterism that made locating the quasar pretty easy. The mag 6 stars nearby nearly overpowered the quasar but it was visible with averted vision - not that it was too faint...but the other stars just overpowered it. Taking a break from the ultra deep observing I moved over to Antares and observed M 4 and NGC 6144. M 4 was stunning at 120x looking like the many legs of a spider streaming away from the center point. NGC 6144 is a faint GC that wasn't much more than a grainy cotton ball - I imagine upping the magnification may have given a better view...but I was off again. Next up was the naked eye Lagoon Nebula which glowed very nicely at 120x and 240x. I went with and without UHC filter and was pleased with both views. The dark vein running through the nebula stood out best at 240x but was still visible at 120x. In the vicinity observations included the Omega Nebula (very nice with and without UHC filter), a few open clusters, and even the Ring Nebula which I like best without the filter as I get more color). I split the Double Double while around Vega. The final joy of the night was observing both the east and west parts of the Veil Nebula - just a whisper was visible with an unfiltered view but the UHC filter made it stand out very nicely. I had no idea that this nebula was soo big. Had to go with 46x to see it on any scale. A pretty good night - 2 new quasars, 1 new supernova, and a handful of nebula and faint galaxies. Today I'm off to Las Vegas and if i don't melt in the 100+ (F) heat I hope to put in some Bortle 1 viewing in the desert on Thursday and Friday. My scope has been begging for an even darker location. Could be fun! Happy hunting!
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.