Frankfurt Quasar Monitoring

The Frankfurt Quasar Monitoring Project

The Frankfurt Quasar Monitoring Project is a privately run observing programme by Stefan Karge (Frankfurt, Germany), focusing on photometric measurements of Quasars, BL Lac objects (Blazars) and selected AGN. Since the beginning in 1998, more than 13 000 observations have been recorded for about 400 quasi stellar objects (as of 1-2023). A selection of particularly bright and interesting objects is presented here.
Most of these elusive objects are faint stellar objects in a foreground star field of our own galactic home. To identify the extragalactic stellar object in question, observers are provided with finding charts. Most quasi stellar objects are optically variable to a certain extent, so comparison stars are also presented to determine the actual optical brightness. Brightness estimations can be done by visual observations or by
photometric reduction of digital images. In addition, the user of this website may also like to know some more detailed information about the desired quasi stellar object.
On top of each object page a
table provides data, like the redshift of the object, its position, the light travel time and the total optical range of variability, et cetera. Of course, some additional background informations are also given concerning the discovery circumstances, emission properties, observing advices and interesting nearby objects, and so on.
For each object you will find:
  • a table containing object data
  • a finding chart with the object position (marked with dashes) and comparison stars
  • a table containing the comparison stars magnitudes
  • an optical light curve, based on observations by the Frankfurt Quasar Monitoring Project
  • a text block titled "Notes" containing additional informations
  • a list of related literature
  • some links related to the object.
This website shall serve as an observer´s manual and additional database for observers around the world who like to observe something very special: Quasi Stellar Objects. The website was created from the perspective of an active observer, not from a scientists point of view. The whole website was designed in English. As a native german speaking person, the author tried his best to find the correct english words. For questions and remarks, feel free to contact the author by e-mail (s.karge [at] gmx [dot] net).

Good luck with your observations !

How it all begun, or: Why that ?

The author has been a longtime deep sky observer. Apart from the deep sky showpieces it became more and more interesting to search for new challenges off the beaten path: for example, observing M31-globulars with an 11-inch SCT (resulting in a total of 15 globulars!), faint planetaries from the Abell- and PK-catalog, galaxy clusters, and so on.
To enlarge the group of observing targets in terms of even larger cosmological distance a new challenge occupied the author´s night time activities: Quasars and AGN. The first quasar
the author observed successfully was of course 3C 273, the brightest object of its class. It was in late March 1995, using a 14-inch SCT, when, for the first time, some 2 giga light-years old photons touched the retina of the author´s eyes. A great experience, so this class of objects has been dominating the author´s observational activities ever since. In early 1998, a systematic observing programme started, accompanied by the production of finding charts and data research.

At that time, only very few publications about quasar observing existed, for example E.R. Craine´s "Handbook of Quasistellar and BL Lacertae Objects" (1977), T. Hansen´s article in
the Deep Sky Magazine "The “Deepest” Deep Sky Objects" (1991) and W. Steinicke´s "Katalog heller Quasare und BL Lacertae Objekte" (1998).

So there was a lot to do, and answers had to be found on new questions:
  • How do these objects appear in the eyepiece ?
  • Does their appearance change with aperture ?
  • How bright do they appear ?
  • What minimum aperture needs to be used to spot these objects in the eyepiece ?
  • Are there other bright/new objects within the reach of medium aperture telescopes ?
  • Are there additional photometric sequences for brightness estimations ?
  • Do the resulting magnitudes correspond to other published data ?
As there were only a few informations readily available at that time, most of this research was like making the first steps on an uncharted territory. Looking back, this was a very interesting, exciting and inspiring time.

Things changed in 2006, when the digital era started at
Taunus Observatory, where a great deal of observations was carried out. With the introduction of a large format CCD-camera more precise measurements became available and the number of photometric results increased. In addition, the opportunity of using distant observatories by remote control had great impact on the extent and quality of this observing project. The photometric results have been published mainly by the VSNET, the AAVSO, and of course on this website.

Observatories and telescopes involved 

Visual observations:

8-inch f/5 Newton on alt-azimuth mount (Dobson)
11-inch f/10 Schmidt-Cassegrain on german equatorial mount (C11 on G11)
12.5-inch f/8 CDK on german equatorial mount (Planewave on Paramount ME, Taunus Obs.)
14-inch f/11 Schmidt-Cassegrain on german equatorial mount (C14 on AD-7, Taunus Obs.)
18-inch f/4.5 Newton on alt-azimuth mount (Dobson)
24-inch f/10 Cassegrain on german equatorial mount (Taunus Observatory)
In addition, the 24-inch reflector was equipped with aperture stops to simulate telescopes
of 8-inch, 10-inch and 13-inch of aperture.

CCD observations:

Taunus Observatory
(Germany, IAU Code B01):
24-inch Reflector @ f/3.3 & f/10, with STL11000M
CDK @ f/5 & f/8 Astrograph (Planewave), with STL11000M and QSI583
The Taunus Observatory is operated by the Physikalischer Verein in Frankfurt, Germany.

OpenScience Observatories (Tenerife, Spain):
COAST-Telescope: 14-inch f/11 Schmidt-Cassegrain, with FLI PL KAF-09000 / SBIG STL-1001E
PIRATE-Telescope: 17-inch f/6.8 Corrected Dall-Kirkham, with FLI PL16803
The OpenScience Observatories are operated by the Open University (United Kingdom)
on the island of Tenerife, Canary Islands.

Bradford Robotic Telescope
(Tenerife, Spain):
14-inch f/11 Schmidt-Cassegrain (@f/5.3), with FLI ML4710
The Bradford Robotic Telescope is operated by the University of Bradford (United Kingdom)
on the island of Tenerife, Canary Islands.

Tzec Maun Observatory (New Mexico, USA, IAU Code H10):
180mm f/7.32 Refractor, with ST-10XME
206mm f/7.87 Refractor, with STL-6303 / STL-11000M
-inch f/3.8 Maksutov-Newton, with ST-10XME / STL-6303
-inch f/9 Ritchey-Chrétien, with STL-6303
The Tzec Maun Observatory is operated by the Tzec Maun Foundation (USA).

Tzec Maun Observatory (Australia):
- Pingelly, Western Australia (IAU Code D25),
  150mm f/7.3 Refractor, with STL-11000M
- Moorook, South Australia (IAU Code D96),
  150mm f/7.3 Refractor, with STL-11000M
The Tzec Maun Observatory is operated by the Tzec Maun Foundation (USA).

Additional observations have been carried out by commercial remote-observatories from around the globe with different telescopes regarding type and aperture.


My special thanks to the Physikalischer Verein (Germany), the Tzec Maun Foundation (USA), the University of Bradford (United Kingdom) and the Open University (United Kingdom) for giving the author the opportunity of free access to their telescope facilities. The author is grateful for their commitment and support.
I also like to thank the following persons for their help and support: Rainer Kling, Dr. Sighard Schräbler, Lyra Turnball, Uwe Pilz, Gary Poyner, Dr. Kari Nilsson and Gregory Hirsch.

Clear skies to you all !

Stefan Karge / Frankfurt Quasar Monitoring

© 2011-2023 by Stefan Karge

   ¦   Frankfurt Quasar Monitoring