Quasar 3C 273, 5 April 2010

[Rob_K]

This is the brightest quasar ("quasi-stellar object") in the sky, usually sitting at around mag 12.9 but sometimes brighter. At a red shift of 0.16 it is one of the closest quasars, at an inferred distance of a bit greater than 2 billion light years. Amazing to think of the 2 billion year+ journey the light made to be trapped on the sensor of my Canon 400D!

3C 273 is an important object because it was the first of the optically-bright radio sources to be identified as an extremely luminous object at a cosmological distance from Earth. Quasars appear to be very bright galactic nucleii. 3C 273 has an enormous jet extending out from it for a distance of 200,000 light years, visible as a 23 arcsecond long filament when viewed from Earth. Various of the big telescopes have imaged the jet in detail (eg insert at bottom-left corner).

3C 273 sits in Virgo, and Saturn is currently only about 6 degrees away. In this image (4 x 30sec @ 200mm), the quasar seems to be around mag 12.4. It is said to have brightened to as much as mag 11.7 in the past.

http://i727.photobucket.com/albums/w.../3C273text.jpg


Cheers -

[erick (Eric)]

Great Rob. That's now my finder chart. I've had this one on my list for a year now - I have to see it at least once! Mind boggling to think that the photons that will (hopefully) enter my eye have come such a tremendous distance. Furtherest object that can be seen with an amateur scope?

[Rob_K]

Originally Posted by erick

Great Rob. That's now my finder chart. I've had this one on my list for a year now - I have to see it at least once! Mind boggling to think that the photons that will (hopefully) enter my eye have come such a tremendous distance. Furtherest object that can be seen with an amateur scope?

Thanks Eric. There are a few other quasars you should be able to see through your scope, at even greater distances. PKS 2155-304 in Piscis Austrinus for example (early morning target ATM).
http://www.seds.org/~spider/spider/Misc/qso.html

Re using my image as a 'finder', that's OK but be aware that there is a faint star at mag 13.5 only 52" from 3C 273. The transparency wasn't great for the shot because of smoke in the air - the star does show very faintly, but is obscured a bit by the top line of the cross-hair in the enlarged, circular crop.

Cheers -

[Rob_K]

Oops, PKS 2155-304 at around 1.5 billion ly is closer than 3C 273!

The list shows z = 0.17, but it should be 0.116. But you might be able to get some others on the list that are further away.

If 3C 273 is around mag 12.4 ATM, maybe it might juuuuust be gettable in my scope (if the smoke disappears)!

Cheers -

[erick (Eric)]

Only 1.5 bly - sheesh! dump that one

Thanks for the advice on the nearby star. It'll be a challenge to be sure I am on the right faint spot of light. But, it just has to be done!

[Rob_K]

Originally Posted by erick

Thanks for the advice on the nearby star. It'll be a challenge to be sure I am on the right faint spot of light. But, it just has to be done!

It's not a crowded field, should be fairly easy Eric! Here's a tight-in DSS image, and an AAVSO 1-degree chart. Might need a bit of rotating to get our view.

Cheers -