by Dick Flasck
| Date | 8/11/04 |
|---|---|
| Location | Lake Sonoma, CA |
| Darkness | 7.0 at zenith |
| Seeing | Very good |
| Weather | Wind at 0 MPH, 70 F An all around excellent night. |
| Equipment | 17.5" f/4.1 Homebrew Dob with Discovery mirrors and Homebrew eq platform |
| EPs | Orion 50 mm Plossl, Televue 32 mm Plossl, 11 mm Nagler, 4.8 mm Nagler. |
Targets:
First target: B1422+231 is listed as a Mag 16.5 Z=3.62 lensed quasar. There are 4 quasar components with mags of 16.5, 16.7, 17.3, and 20.4. Maximum component separation is 1.2 arcsec's. Luckily, the intervening lensing galaxy (Z=0.34) at mag 22 is much dimmer than the quasar. So if you see the light, it is in fact the quasar not the galaxy. Like Einstein's Cross without the pesky galaxy spewing light all over the field.
For more information see: http://www.jb.man.ac.uk/research/gravlens/lensarch/B1422+231/B1422+231.html
The field of the QSO is littered with many stars dimmer than mag 15. Extreme care was taken to identify the correct object. Detailed measurements using Megastar and the DSS image were used to assure location of the correct target.
The star hop started from Arcturus using the 50 mm Orion EP and proceeded north. When the field was identified, the 32mm, 11mm, and finally the 4.8 mm EPs were sequentially employed.
Mag 10 stars GSC 2008:1100 and GSC 2008:689 were used as the coarse pointers. Mag 13.3 stars GSC 2008:612 and GSC 2008:1074 (about 3 arcmin's from the QSO) were used as medium scale pointers. And the fine pointers were mag 14.1 GSC 2008:834 and two other mag 15+ stars picked up on the DSS photo. It is certain that the QSO is identified correctly in the DSS photo. There is a mag 17.5ish star about 25 arcsec's SE of the QSO, but the brighter object (not the mag 17.5 star) is precisely at the published location of B1422+231. This QSO has been extensively studied professionally, so the precise location is without question.
All of the stars referred to above were clearly visible, except the unnamed mag 17.5ish star. The QSO was visibly with averted vision over 50% of the time. David Silva confirmed the observation. I attribute the ease of this hunt to the excellent night, and the extra care taken with eye dark adaption.
No splitting, or elongation of the quasar image was observed. So we were seeing the four components as one stellar object. Considering the brightness of the components, and the fact that the lensing galaxy does not overwhelm the field (as with Einstein's Cross), This QSO may have potential for revealing its individual components with modest sized (<20") scopes.
Target B: Einstein's Cross The night was so good, that I decided to give EC a look. The starhop starting at Zeta Aqu was easy. The lensing galaxy, CGCG378-15 at mag 15.1 was easily detected with the proper elongation. 20 minutes of observing resulted in no confirmed observation of any of the quasar components. An occasional pinpoint flash could be seen close to the galaxy core, but I attribute that to "shot noise" in my retina. Maybe later in the year when EC is a bit higher.
Posted on sf-bay-tac Aug 12, 2004 19:57:28 PT
Converted by report.pm 1.2 Jan 07, 2005 20:47:04 PT