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Sunday, 22 December 2013

20131221 - ISON Not Found + the start of a theory

Over the past few days two famous telescopes have been looking for C/2012 S1 ISON.

The Arecibo (the world's largest Radio Telescope in Puerto Rico) reported yesterday that they had found nothing. 

The Hubble Telescope reported late yesterday that they had found no trace of it. Here is a link to their results.

There may be a few bits around, but they would be less than 150 meters in size.

So there is no need to throw any life rafts, Just wreaths :( 

Why and when ISON started to break up is now the question that is being asked and various theories, which need to be tested, are being put forward. My personal theory - unproven - is that sometime in the lead up to the 13th November (perhaps a day or two before) the nucleus of the comet started to become unstable, whether a chunk broke away or it started to crack I do not know. The visible effect is shown in this image that SON@OSC took on the morning of the 13th November. If you look a third of the way along the lower tail you can see a discontinuation. +Padma Yanamandra-Fisher  picked up on this event as soon as she saw the image.



Over the next few days the comet physically changes as can be seen in the following image from the morning of the 15th .

The following day, the 16th, it seems calm down a bit (through cloud).



Morning of the 19th through thin cloud again!



The next event was noticed on the morning of the 22nd. +Charles Bell  pointed this out to me. towards the end of the displayed lower tail there is a branch off - looks like half a feather on an arrow. I think that a day or two before there was another major fracture to the nucleus.




This was the last time I saw ISON . I think by this time the nucleus was fatally flawed and came apart during its near encounter with our Sun.


It is important to recognise that the images of ISON represent only part of the history of the comet. They are, of course, an important resource, especially if and when other images can be added to the time line. I still have a number of images to process and perhaps some of those will add to the story.

Other data now needs to be brought together and analysed. A lot, but not all, of this data has either been captured by amateurs or is in the public domain. A number of amateurs have already started modelling this data, some of which at first glance supports my idea. Until I fully understand this data (and other data), myself I will not present it and only then with permission.

I will be looking to see what the professionals come up with. One thing about of astronomy is that there is always something new to learn.

Finally

After a cloudy night, this morning I managed to finds some holes in the clouds and brought the cameras into focus and at dawn take some flats.

Late afternoon we struggled up the observatory hill with the framework for the new roll off observatory to house the new telescope.

This evening is cloudy again :( which was disappointing as Search Light Observatory Network had received a request to record a stellar occultation which would been taking place now. Alas the observatory hill is covered with a damp cloud.

Friday, 20 December 2013

20131220 - All change in the Observatory

As I mentioned in the previous Blog it is time for exoplanets again.

What is an exoplanet (or extrasolar planet)? It is a planet that is in an orbit around a star other than our own Sun :)

I received a few days ago, along with the other Searchlight Observatory Network Observatories, the agreed list of targets and time table from Professor +Svetlana Berdyugina at Kiepenheuer-Institut für Sonnenphysik .

Svetlana has been observing exoplanets for a number of years. It was Svetlana and her team that discovered, a number of years ago, that a planet (HD 189733b) in orbit around HD 189733 is blue. This was later confirmed this year by Hubble observations.

There are a number of different ways to discover and monitor exoplanets. The current project involves known exoplanets using a technique called Exoplanet Transits. This only works with systems that are near to edge on to us. The observation process involves measuring the change in brightness of the host star when an explanet passes in front of it. The techniques involved are similar to those used for variable star observing. I will write, in the near future, a number of Blogs covering the various methods of discovering and monitoring exoplanets :).

Ideally I should have changed the telescope configuration and started some test runs a few days ago, but after a few months of overall good observing nights the weather changed. We have had clouds, we have icy rain and lots of interuptions with the power.

Yesterday's driving rain stopped me from opening the observatory so with the alarm set early I went up to the observatory to check it out. Apart from a few small wet spots and the need to reset the power everything was OK. It was still fairly cloudy but with holes so I managed to see some stars for the first time in days. It was not suitable for imaging properly but decided to take some images of Comet Lovejoy before changing the configuration.




After these were taken it was time to start to change the configuration.

For the past couple of months the ST8 CCD Camera along with its filter wheel has been on the 4" F4 Pentax refractor and the ST7 CCD Camera was on the C14 F11 SCT.

I now needed to swap the cameras over and also reduce the focal length of the C14 by putting in a focal reducer and once done rebalance the telescope and check that the cable will not get tangled up, (four power cables and four data cables!).

That is the easy bit done! The sky or should I say the clouds stopped most other things being done until this evening and daybreak - providing that it is clear.  So hopefully I will be able to refocus the two telescopes and take new sets of dark, flat and bias frames.

N.B. For none astronomers I promise to do a Blog posting in the next few days explaining the reasons why I needed to change the configuration and what are the effects.

There are a number of jobs I can do during the day, some of which are already under way, including producing an observing timetable.

It is now starting to get dark. There are thick clouds on the horizon and thin cloud overhead. Providing the cloud overhead does not get much thicker I will be able to finalise the configuration, otherwise it will be the case of getting up at four in the morning to check if the cloud has gone and if it has to do the finalisation then.

As there will not be much to show image wise with exoplanets, I will be showing images of various objects that I have yet to process, or will be able to take when exoplanet observing is not taking place.

Other work in progress

I am in the middle of getting another observatory up and running. I have building a roll off structure for it and late afternoon we got it up to the observing area ready for cladding. Pictures tomorrow.

The other day

I mentioned in the previous Blog that a drop in power stopped the telescope mount from working for an hour or so. What I did not mention was that the computer and cameras did not stop.

The following image was taken at ten o'clock at night with just moonlight. It will give you an idea of the power of the telescope (4" refractor) and a time controlled CCD camera :) The distance to the buildings is about three miles.