A selection of images taken from WHO showing the development of the comet over the past three months
Despite the brightening moon Hale-Bopp's tail still remains prominent .The ion tail now showing a more filiamentary structure:
The dust and ion tails now span a full twenty degrees. The dust shells appear to be getting more extensive enveloping more of the central condensation.
In this labelled image of the comet we identify the sizes and structures visible in the coma at present from information released courtesy of ESO: Hale-Bopp Update 27th Feb.
Wavefronts more prominent this morning with one very active jet lying to the south east. The pair of jets to the north have now subsided.
Clear skies this morning gave a great view of HB. Naked eye views showed an ion tail about as long as a clenched fist at arm's length (ten degrees). The view at 130x with 50cm gets more impressive each time I look at it. The bright fan of material to the south now appears to have a "sawtoothed" appearance on its west side. This was revealed by short CCD images to result from a contrast effect of the bright wavefronts in the coma. Visually I could see only two of these, but CCD image revealed about four or five, with three jets appearing on the opposite side of the fan.
The comet continues to brighten steadily - now about mag 2.4. The dust tail is broadening and is visible for at least 1.5 deg in 10x50B.Deep CCD images also reveal a faint but fairly broad ion tail pointing north east.
For original uncropped image taken 0609h U.T. 3rd Feb taken with a 135mm lens and SX CCD - Click here:
The presence of the bright moon interferred with comet observations tonight, but several images of the comet were obtained with short exposures using 135mm lens (2.5x 1.7 degree field) and 50 cm f/4 Newtonian. Visual observations 130x with 50 cm showed a very bright elongated nuclear region with a brilliant small fan radiating to the south.This view was very reminiscent of views of Comet Hyakutake at closest approach last March. CCD images became saturated at exposures longer than ten seconds due to presence of bright moon, however a broad dust tail about half a degree in length was recorded with 135mm lens. Prime focus unsharp masked images through 50 cm revealed a jet structure now more evident than when last imaged on 16th January. A broad jet fans to the south, while diametrically opposite is a narrow bright jet to the north east, with a further two jets either side. There was also a hint of two dark nuclear shadows bordering these features.The whole nuclear region although saturated in these images has a now much more elongated appearance.
The comet is now becoming better placed in the morning skies. It is presently at mag 3. The dust tail has now become broader, this image has recorded it about 0.5 deg in length.
The above image is a 2x10 sec exposure with 135mm f/2.8 lens and SX CCD. It equates to a view of the comet obtainable with binoculars.
Observed Hale-Bopp at 0545h UT here this morning 14th Jan under reasonably dark clear skies (mag 5.5 at zenith), although fog was just beginning to form. Best views were obtained with 20x80B which showed a much more pronounced tail about 1.5 deg in length fanning out to the north. Telescopic view (50cm f/4 130x) was "disappointing" compared to those we were getting last month. There seems to be less evidence of those spectacular jets now. CCD images revealed two main jets evident to the north east - now much subsided and also a broader fan to the south west. The nuclear detail looked entirely different to images we were getting in early December. I don't know whether this can be explain by the changing geometry of viewing or whether we are now getting obscuration of the jets by the developing coma?
Hale-Bopp is still visible in the evening sky for half an hour after sunset.Its high orbital inclination and elongation of 28 degrees combines to keep it visible despite its conjunction with the sun.
This false colour image produced from the imaging software Winmips shows at least eight jets in Hale-Bopp's coma.
The comet is now becoming a difficult target in the evening sky as it closes towards the sun. We shall attempt to continue imaging it over the next few weeks but suspect this will becoming increasingly difficult until mid January when it begins to elongate from the sun. We have constructed a mosaic of Hale-Bopp images marking the development of this remarkable object during the past 12 months of observations from Worth Hill Observatory:
Unsharpmasked images showed a magnificient array of eight jets around the comet nucleus. The north easterly jets still remain the brightest. The comet is now mag. 4.5.
The comet has now three bright jets lying in a north easterly direction. They appear to be lengthening and brightening on a daily basis, and are certainly more pronounced than a few weeks ago.
Having just passed the anniversary of Comet Hale-Bopp's discovery it is interesting to compare today's observations with those of a year ago. In August of last year 4x40 sec exposures with 50 cm f/4 revealed a coma diameter of 1.3 arcmin. The comet was then 930 million km. from the Earth. At this distance, on my images one arcmin measures 270,000 km, so the coma diameter equates to 350,000 km. At the same time ESO measured the coma to be 10 arcmin which equals 2.7 million km. One year later the comet is now just about 410 million km from the Earth, and on my images 4x40 sec exposures reveal a coma 5.25 arcmin in diameter. This equates to a coma of 624,000 km in diameter - nearly twice the size of last year. If you use the 2.7 million km estimate by ESO, then the apparent size of Hale-Bopp must be at least 22 arcmin and probably more i.e. getting on for the size of the moon. Not bad for an object half way between Mars and Jupiter!
The brightest part of the fan extends from P.A. 58-322 deg, and is at its most intense at 350 deg. From P.A. 322-270 deg there appears to be a "darker area" where the coma fades. At P.A. 270 deg (due west) - a second jet is appearing, which seems to be getting stronger each night I image it. The coma fades and narrows around the southern boundary, but at P.A. 138 deg as from last night I think I see the beginnings of a further jet. Observations with 50 cm f/4 and SX CCD (20 sec exposures).
