Comet 81/P WIld
Comet 81/P Wild

Comet Wild 2 is a short periodic comet with an orbital period of 6 years. Before its close encounter with Jupiter during September 1974 his orbit was almost circular and had a 43 year period. But the gravitational pull of the giant gas planet made Wild 2 to a member of the inner solar system. In 2004 the comet was target of the NASA mission "Stardust", which took samples of the coma and returned them back to earth. Our image was obtained during a trip to southern france in February 2010 and shows a nice 1 degree long tail.

AstronomyCast

Astronomy Cast

Astronomy Cast takes a fact based journey through the cosmos as it offers listeners weekly discussions on astronomical topics ranging from planets to cosmology.

Welcome!

Since 2002 our little observatory is mainly dedicated to NEO follow-up work, chasing and confirming newly discovered minor planets crossing the earth' orbit. After years and nearly 2000 positions measured we finally made our first discoveries in 2008. Compared to the long lists of other amateurs our 4 MBA's (main belt asteroids) up to this date are nearly nothing. But the first two discoveries of 2008QX19 and 2008RZ77 came within a week and we were happy. But both objects faded away beyond the range of our telescope. In December 2009 they "brighten" to magnitude 20.2 and 20.9 and hopefully we'll be able to recover both of them.
If you are an astrometrist and and looking for targets please see our follow-up page.

Besides this exciting work we still find time to make some pretty pictures of the other inhabitants of the universe. Our efforts and hopefully also our progress can be followed in the gallery. Enjoy!

Astrometric Summary

The tables below show the time spent observing minor planets for each month of the year. A night is counted as used when at least one triplet of images was acquired. An exceptional good month was April 2007 when 15 clear nights were recorded.

Year Positions
sent to MPC
Nights
used 
Total number
images taken 
Total exp.
time (min.) 
Avg exp.
time (s) 
Resid. RA Resid. DEC
2011 499 32 14613 6791,2 27.9 +0.06 ±0.46 -0.16 ±0.47
2010 580 41 15383 7001,4 27,3 +0.00 ±0.46 -0.11 ±0.49
2009 835 71 16181 6805,9 25,2 +0.08 ±0.43 -0.13 ±0.46
2008 515 52 13923 5594,4 24,1 -0.03 ±0.43 -0.08 ±0.47
2007 664 71 12998 5042,8 23,3 -0.03 ±0.43 -0.09 ±0.40
2006 234 26 5619 2765,6 29,5 +0.13 ±0.50 -0.21 ±0.51
2005 206 26 3974 2710,8 40,9 +0.21 ±0.78 -0.11 ±0.51
2004 90 15 4203 2065,7 29,5 -0.11 ±0.52 -0.16 ±0.48
2003 67 10 -- -- -- -0.08 ±0.51 +0.08 ±0.61
Total 3191 342 ´82281 619,2 h

 

 

Nights used by month
Year Jan. Feb. March April May June July August Sept. Octob. Nov. Dec. Total
2011 2 0 12 6 10 2
2010 0 0 7 7 0 3 6 5 6 6 1 0 41
2009 7 3 8 8 3 2 4 13 9 8 3 3 71
2008 3 8 3 0 9 4 7 4 2 4 2 6 52
2007 0 1 5 15 7 6 6 7 6 7 6 5 71
2006 5 0 0 3 0 0 0 2 6 5 2 3 26
2005 3 0 0 4 5 4 2 0 0 5 2 1 26
2004 2 2 6 4 0 0 0 0 1 0 0 0 15
2003 0 0 0 0 0 0 0 0 4 1 0 5 10

 

Positons measured by month
Year Jan. Feb. March April May June July August Sept. Oct. Nov. Dec. Total
2011 28 0 203 130 138
2010 0 0 77 99 0 12 51 53 96 177 15 0 580
2009 80 82 106 83 15 19 19 141 146 105 30 9 835
2008 28 100 20 0 46 38 48 35 16 67 18 99 515
2007 0 6 25 186 59 44 62 48 61 81 61 31 664
2006 58 0 0 10 0 0 0 18 55 45 15 33 234
2005 14 0 0 27 1 14 8 0 0 87 19 16 206
2004 15 11 44 18 0 0 0 0 2 0 0 0 90
2003 0 0 0 0 0 0 0 0 29 6 0 32 67
Comet C/2007 Q3 (Siding Springs)

This comet is further fading in brightness. During mid March a break up was reported by british amateur Nick Howes using the Faulkes Telescope.

C/2007 Q3 (Siding Spring)In our image from April 6 the fragment is not visible. The 14 inch telescope in Weinheim/Germany was used to capture this view. Strong winds and a particularly bad seeing of over 4 arcsec FWHM compromised the image. Q3 is moving slowly through the constellation Draco at a magnitude of around 11. The comet is now heading away from the sun to escape the solar system and never come back. Its visit in the inner solar system sent it on an hyperbolic orbit into interstellar space.
During our last "expedition" in February we imaged the comet with an 6 inch f/2.8 flatfield camera when C/2007 Q3 showed a nearly 2° long tail.  

The observatory

Guidestar-Observatory is located close to the Rhine-Valley on the edge of the town of Weinheim. In 200 meters above sea level there is a fairly good and dark eastern and southeastern sky, to the west is quite a lot of light pollution because of the densely populated Rhine Valley.

Windeck WeinheimThe station with its roll-off-roof is operational since 2003.

For power supply two solar panels are feeding three solar batteries with a capacity of 105 Ah each. The power consumption for a typical night goes up to 60 Ah (for mount, ccd-camera, dew-prevention, focuser and laptop). For almost 3 years now the station is relying solely on solar power

Close to the observatory the old castle Windeck sits on a hilltop overlooking the city. It was built around 1100 and is today a popular destination for tourists and locals alike, with a beautiful view over the Rhine Valley. On days with good weather conditions one is able to see the "Pfälzer Wald" (30 miles) and sometimes even the distant french Vosges mountain range.

The telescope

In late summer 2004 our 8" Vixen VC200-Cassegrain was replaced by a Celestron C14 that is mostly in f/5 config with a 0.5x focal reducer from Optec compressing the focal length to 2100 mm.
Attached to the C14 is a TCF-S motorized focuser also from Optec. The @focus-feature in CCDSoft makes it easy to achieve a precise focus. Together with the CCDSoft-plugin CFWHM it makes life a lot easier.

Roll-off-roofC14 backendCity of WeinheimJupiter risingsolar panelsCastle Windeck

In nights with good seeing we are able to achive FWHM of 1.9". Focus drift due to temperature differences can be compensated by monitoring the optical tube temperature with a probe.
The primary mirror of the C14 is locked with two threaded bolts to minimize the mirror shifting, that is so typical for SC-type telescopes.

The C14 is supported by an Astro-Physics AP1200GTO. This piece is a dream come true. Without to much tweaking of the PEC-curve the periodic error is less than 3 arcseconds. Active guiding with the build-in guidechip of the SBIG ST-8 camera is working very reliable.

PEC of AP1200The graphic shows the raw PE without correction in red (peak to peak 4.6 arc-sec). In blue with enabled PEC. The correction curve was generated with PemPro out of over 500 data points and 5 worm cycles. (Click on graphic to enlarge)

The pointing so far isn't perfect, mostly we achieve an accuracy of about 7' after a 50 degree slew and 15' after a meridian flip - probably still a mirror shift issue. Thats good enough for most of our work. We tried to improve the pointing with Software Bisques TPoint. But there seems to be some unpredictable movement that can not be compensated by software – maybe the dovetail is another weak part in the system and we have to replace it with tube rings.

at home ...

the astrometric program started in 2003 right after the completion of the astro-shed with the 8" Vixen VISAC VC200. Soon I was infected by the "blinking virus" and most of the "shutter-open-time" was devoted to measuring minor planets. Even though the golden age of the 90s was over, when a lot of minor planets where discovered by amateurs, it was and is fun taking part in the follow-up work and supporting the big surveys. The main reason for replacing the 8 inch in 2005 with a 14 inch Schmidt-Cassegrain was pushing the limiting magnitude to 20.7 mag. The only way to stay in the game. And after a long wait we were awarded by our first discoveries in September 2008 (2008 QX19 und 2008 RZ77).

... and abroad

For almost two decades our favorite place for doing astrophotography abroad is the mediterranean region of the Provence in southern France. In the late 1980s we made our first trips to the (in Europe) well know Observatory of Puimichel. With its 1 meter Newton it was then the largest telescope built and operated by an amateur.

In the 90s we discovered a nice little place 90 km west of Puimichel on the Plateau d'Albion. It is located north of the Luberon mountains and a sparsly populated region with an average altitude of 900 m. Lots of images in the gallery were made at this place. Usually good weather is accompanied by strong winds (Mistral). So you can have clear nights with a high degree of transparency and a real dark sky, but struggeling with bad seeing. For those trips the equipment is always with shorter focal length (less than 500 mm) and a good wind shelter is mandatory.