Basically, lensed quasars are a result of a background quasar that happens to be directly behind a massive galaxy with sufficient gravity to bend the quasar light around it and make it appear as multiple points. The most famous example is the Einstein’s Cross located in Pegasus. To introduce this class of objects as a potential observing list, the Double Quasar in Ursa Major is probably the easiest, so start with this one.
The double quasar is physically located just under 14 billion light years away, but the lensing galaxy, YGKOW G1, lies about 4 billion light years distant. This system was the first object of this class to be observed. Take a look at the Hubble photo below. DoubeQuasarHST.jpg
Since I’ve observed this object more than a dozen times, sometimes resolving and others not. It depends on aperture, seeing and sufficient magnification. I used at least 450x+ in all of my observations. Some of my more memorable observations are as follows:
With my 22” reflector (June 2003), several of us saw both as distinct blue points of light that pops in and out, about 75% in. Very well resolved. The same group of us saw it as two white steady points of light in Gregg’s 25” reflector. It was pointed out to me that the figure and smoothness of my mirror must be fantastic since we could perceive color. I’m not quite sure though. Any optics gurus out there could comment? Both the 22” and 25” are figured by John Hall (Pegasus Optics) during the height of his career about 15 years ago.
With Steve Kennedy’s personal 28” f/3.66 at Shingletown Star Party, I swung his scope down pretty low, about 20 degrees above the horizon. It was rock solid, two bright points of light at over 500x.
With Jimi’s 48” reflector, Faith, Jimi and I saw this object. It was BLAZING! Faith was the only one that night saw the lensing galaxy, YGKOW G1! I didn’t see it. Jimi saw it on an earlier night.
For those who wants a short, but very challenging list of lensed quasars, take a look at my Galaxy Trios guide on my website. I’ve included 8 of them at the end of the book. It’s free!
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