5 replies to this topic

[jgibson1@emich]

Let me start by stating, this write up was done on my phone from my dark sky site in the cold...... please forgive typos!

Wow! What a night of observing last night. I've spent the past six nights taking advantage of the clear dark skies of southern Arizona at the TAAA dark sky site near the Chiricahua mountains. I've observed many a new object including mostly very challenging planetary nebulae. NGC 351, Minkowski 1-7, & Jones-Emberson 1 were just a few of the objects hunted down and observed visually. I've been utilizing an 18" classic Obsession for my observations. It's not my scope but I'm fortunate to have access to this fantastic instrument. I do use my own oculars though.

In any case the highlight happened last night or actually early this morning. Some time ago I accidentally learned about an interesting quasar. I believe I saw it mentioned her on the forums. APM 08279+5255 ("5255") is a quasar in the constellation Lynx. This quasar is rather special in that it was recently ('90s) discovered during a survey of carbon stars. To much surprise the feeble red glow of this "star" was indeed the extremely red shifted light of an ancient super luminous galaxy from the very early days of the universe. At a redshift of about 3.911 this object is indeed very distant. In fact it's so far away and old that it's light left a smidge over 12 billion years ago.

I've spent some time in the past hunting down and observing 3C273 & the recent outburst blazaar with great success. After some research I decided to give this recently discovered quasar a solid attempt at visual observing. However, I did make one mistake...... It's reported magnitude of 15.2 is in fact it's red magnitude. Our eyes, or at least mine, aren't so keen on detecting red light.

Last night the skies were very transparent and steady. Both transparency and seeing were above average and ideal for hunting down 5255. At about 2 am I hunted down my guide stars and star hopped to a small triangle of stars and what resembled a hook. From there I used about 220x with a 10mm Radian to familiarize myself with the stars in the eyepiece to those on the charts I found on the web. I quickly discovered that despite 5255 being 15.2 magnitude it was not going to be as easy as a 15.2 mag white-blue object.

I upped the power to about 440x with my 4mm Plossl and was able to carefully star hop to the exact location of where 5255 should be and was saddened to not see what I thought would be a 15th mag star. However, I was dead set on seeing this elusively seductive galaxy.

I kept going through the motions of star hopping to its location. After 20 mins of doing this over and over I actually caught a glimpse of a couple stars where 5255 should be. They were fleeting appearances but as the seeing stabilized they would appear. Using my handy dandy chart from the all knowing web I was about 90% confident I had glimpsed 5255.

After this I decided to back down the power to 220x with the 10mm Radian. I was pleasantly surprised that the guide stars I was using to hop to 5255's location were more clearly visible now. I was excited and carefully studied the field and moved from star to star until I found it....

5255, albeit coming and going with seeing, was just visible. I had to cover my head a bit to help aid in the image contrast (remember that I'm at our dark sky site!). I consider myself a seasoned deep sky observer and was surprised at how absolutely difficult this object was to spot in an 18" scope. I cannot find definitive data but I read that the blue magnitude may be closer to 17+!!! This would explain the challenge of observing this quasar.

Overall I'm very happy with the observation and am glad I got this object checked off my bucket list before my move back to Michigan in less than a month.

I fully encourage anyone with dark skies and a large scope to give 5255 a shot. It's very cool to look back in time over 12 billion years!!

I'd love to know if anyone else found this quasar as challenging as I did.......

Clear Skies,
Jason

[sgottlieb]

Congratulations on tracking down this ultra-distant and luminous quasar!  APM 08279+5255 has been discussed a number of times on CN -- you might want search on its name.  I've observed it 3 times in my 18-inch and my experience was pretty similar to yours.  I should mention there are two mag 15-16 stars within 1', so one really needs a photographic finder chart to make sure you're seeing the quasar, and not one of these stars.

 

As far as the magnitude, as you mentioned, 15.2 is a R-band (red) magnitude and I doubt the V magnitude is brighter than 16.0.  In fact, a more recent paper (2009), gives a V magnitude of 16.448 with a stated accuracy of 5%.

 

Here are my last couple of observations, from a blue/green site --

 

18" (2/23/06): I carefully starhopped over to the position of this extremely distant quasar and then used a photographic finder chart to pin down the location with respect to nearby faint stars.  With averted vision an extremely faint "star" was visible roughly 25% of the time.  I couldn't hold the object steadily for more a few seconds at a time, but the detection was not difficult to repeat.  The QSO forms the northern vertex of a small triangle with two mag 15-16 stars less than 1' SW and 1' SE.

 

18" (2/3/05): Used a DSS finder chart to positively identify APM 08279+5255, which appeared as an extremely faint 16th magnitude star at 225x.  Located ~50" NE of a slightly brighter mag 15 star.

[jgibson1@emich]

 Hello sgottlieb,

 

Thank you for the detailed feedback.  I should have specified in my original posting that I did use a photographic chart to confirm the exact speck.  The relentless back and forth between the quasar and my guide stars also helped to ensure I was seeing the correct speck of light.

 

I'd agree that the quasar was only visible for 20'ish % of the time.  I'm glad to hear that others had similar experiences with this target.  And thank you for shedding some light on the V-magnitude.  Never dreamed I'd be observing 16.4 magnitude objects.

 

Clear Skies,

Jason

[quazy4quasars]

The Quasar APM08279+5255  has a V mag of about 16.5 and was barely visible as a point source in 25" at 450x  from an excellently dark location in the

Northern Sierra Nevada.

 

The object is strongly magnified and appears as two distorted images separated by .3 arcsec.

         

 

The Quasar APM08279+5255 was touted as the brightest known object in the universe BEFORE it was seen to be gravitaionally magnified.

 

 There are far easier objects at up to z+3.6 which are still well over 11 billion ly "deep" - I listed some of them in the topic  "bright Quazars"  

for anyone who is interested.

[jgibson1@emich]

The Quasar APM08279+5255 was touted as the brightest known object in the universe BEFORE it was seen to be gravitaionally magnified.

 

 

Wow!  I did not realize it was a gravitationally lensed object.  Very neat.

 

Now that I am living back in MI I doubt I will get chance to observe this again until I return to the desert on vacation.

 

Jason

[quazy4quasars]

  Do you guys get clean high pressure in late summer and fall?  If you are out where you can see well enough to star hop,

 

  You can still bag these babies.  As point sources, they do not fade to invisibility like exstended sources do,  You need to be

 

   certain where to look-  find the field, crank up the magnification,  note the glimmer.  Which babies am I referring to?  Well,

 

   Check out the HLQSOs that I listed  under "The Billion Light year Club"  and  in "Bright Quazars"  (sic)  You WILL Bag Them.

 

   Remember -  COMPLETE familiarity with their fields.  Check out SKYMAP.org.  You can print color inverted, any scale, and 

 

   even rotate images.  NO more poring over the Bonner Durchmasterrung up at the university science library. All you have to

 

   do is save the image to your computer and then click "Print"!

Edited by quazy4quasars, 09 April 2015 - 10:34 PM.