2023-04-18, 09:09 AM
I used the “Database Power Search Tool” in SkyTools 4 Imaging to select and download a list of Quasars in Virgo with a Redshift (z) between 4 and 6.
On that list I found BTC40 J1429+011 listed at Magnitude: 19.40 I, so I thought I’d fit my IR Pass IR742 filter and see if I could record this Quasar. An on-line search indicated the following:
SIMBAD Basic data :
[VV2006] J142926.5+011954 -- Quasar
ICRS coord. (ep=J2000): 14 29 26.4254653128 +01 19 53.572666764 (Optical)
B 24.55
V 22.53
G 20.579714
u (AB) 23.63
g (AB) 24.04
r (AB) 21.121
i (AB) 19.731
z (AB) 19.578
Although I could not hope to record objects at mag 23 or 24, I figured I might be in with a chance at i=19.731 using my IR742 Filter.
SkyTools 4 showed this Quasar with a Redshift (z): 4.84 and Light Time: 13.0 Gyr.
IMAGING DATA
After Calibrating, Aligning and Stacking the frames, using averted vision and knowing the pre-conceived position of BTC40 J1429+011, I could just detect a faint smudge where the Quasar was meant to be, but I wouldn’t have bet the farm on it.
So, I had a fascinating journey into the universe of on-line Professional Resources and using SIMBAD and Aladin Lite, I managed to find a set of reference images which showed that my Quasar was indeed a “ghost”, an imaging artefact that had been amplified through image processing techniques such as mirco-contrast enhancement and deconvolution.
Oh well, for one brief moment I felt like I had nailed it, but it was not to be.
I have included the following images:
Astrometry.Net Results for the 1600x1600 inverted crop.
A composite image from Aladin Lite overlaid on my up-sample image showing the offset between the real Quasar and my candidate. Even though this offset is small, it is significant that all other objects faithfully line up with no offset.
Such is life.
Cheers
Dennis
On that list I found BTC40 J1429+011 listed at Magnitude: 19.40 I, so I thought I’d fit my IR Pass IR742 filter and see if I could record this Quasar. An on-line search indicated the following:
SIMBAD Basic data :
[VV2006] J142926.5+011954 -- Quasar
ICRS coord. (ep=J2000): 14 29 26.4254653128 +01 19 53.572666764 (Optical)
B 24.55
V 22.53
G 20.579714
u (AB) 23.63
g (AB) 24.04
r (AB) 21.121
i (AB) 19.731
z (AB) 19.578
Although I could not hope to record objects at mag 23 or 24, I figured I might be in with a chance at i=19.731 using my IR742 Filter.
SkyTools 4 showed this Quasar with a Redshift (z): 4.84 and Light Time: 13.0 Gyr.
IMAGING DATA
- I captured 60x60 sec exposures.
- Tak Mewlon 210 F11.5
- Tak x0.8 Reducer
- ZWO ASI294MM Pro Camera
- Bin 2x2 (3126x2088 Pixels)
- IR Pass Filter IR742.
- Suburban Bortle 6/7 skies.
After Calibrating, Aligning and Stacking the frames, using averted vision and knowing the pre-conceived position of BTC40 J1429+011, I could just detect a faint smudge where the Quasar was meant to be, but I wouldn’t have bet the farm on it.
So, I had a fascinating journey into the universe of on-line Professional Resources and using SIMBAD and Aladin Lite, I managed to find a set of reference images which showed that my Quasar was indeed a “ghost”, an imaging artefact that had been amplified through image processing techniques such as mirco-contrast enhancement and deconvolution.
Oh well, for one brief moment I felt like I had nailed it, but it was not to be.
I have included the following images:
- Full FOV showing a 1600x1600 crop overlay
- My inverted 1600x1600 crop showing the “ghost” position of the Quasar.
- An enlarged composite showing the offset between the actual position and my "ghost" object.
Astrometry.Net Results for the 1600x1600 inverted crop.
- Center (RA, Dec): (217.333, 1.368)
- Center (RA, hms): 14h 29m 20.033s
- Center (Dec, dms): +01° 22' 03.673"
- Size: 11.7 x 11.7 arcmin
- Radius: 0.138 deg
- Pixel scale: 0.439 arcsec/pixel
- Orientation: Up is 359.9 degrees E of N
A composite image from Aladin Lite overlaid on my up-sample image showing the offset between the real Quasar and my candidate. Even though this offset is small, it is significant that all other objects faithfully line up with no offset.
Such is life.
Cheers
Dennis