Forum Replies Created
-
Posts
-
Posted by Nick James at 23:19 on 2013 Nov 27
James,Indeed, as Denis says, this comet’s performance has certainly been on a rollercoaster recently.The latest LASCO C3 image shows a significant blooming spike which implies that the comet is probably negative mag now. It will be interesting to see how it evolves through perihelion and we can watch how events unfold almost in real time using the SOHO cameras.Nick.
Posted by James Fraser at 16:13 on 2013 Nov 27
Now as bright as Antares according to a CIOC_ISON group on Facebook.
Posted by R J Andersson at 14:25 on 2013 Nov 27
.A lovely surprise when I opened my mail today to find this image on the front cover of the December Journal. :)Bob.
Posted by Callum Potter at 09:19 on 2013 Nov 27
Well seems to be visible on todays SOHO LASCO C3 images. Not sure how to infer how bright though…http://sohowww.nascom.nasa.gov/data/realtime/c3/512/Callum
Posted by Denis Buczynski at 22:18 on 2013 Nov 26
This comet can best be described as a roller coaster comet, it has been on the up and now (maybe )on the down. However it has continued to confound many predictions and it may yet do so again. There seems to be conflicting evidence abou the current situation. Both NASA and CIOC are still optomistic about the comet surviving perihelion passage. The first images from the SOHO spacecraft will tell us more. If there is a total disintegration of the comet,then we may have a superb post perihelion dust tail display like one seen with C/2011 W3 Lovejoy and we could see an headless wonder type comeet. With two days to got to perihelion all scenarios are still possible. The game may be getting towards the final whistle but sometimes the extra time can be the most exciting part of the event. This is why comets are a fascinating objects to follow, one never knows how matters can turn out. As usual the best advice is to watch that space, in what ever way you can.Denis Buczynski
Posted by Nick James at 22:41 on 2013 Nov 18
Revised e-Bulletin just issued with the following details:Saturday 23rd November in the new lecture room, Burlington House.Doors open at 14:00 and the meeting will start at 14.30 and is due tofinish by 17:30. Tea will be served in the library from 15:4014:30 – Welcome by the BAA President Mrs Hazel McGee, notices and OrdinaryMeeting14:45 – Peter Grindrod Exploring Mars: 50 Years of Discovery15:40 – Tea16:10 – Susanne Schwenzer "Curiosity in Gale Crater, from Bradbury landingto Glenelg and beyond"17:00 – Sky Notes – Callum Potter17:30 – Close
Posted by Americo Watkins at 18:48 on 2013 Nov 17
Yes I shall try that, it seems to be the general recommendation. The ND filters are actually sheets that are placed immediatly in front of the light panel in the same way that the paper and card as you have suggested.Cheers Eric
Posted by Eliot Hall at 08:58 on 2013 Nov 17
It might be worth experimenting with putting some paper/card in front of the EL panel to dim it as well.Inserting extra elements to the light path might add defects (e.g. vignetting, dust on filters, etc.) that weren’t there in the original image.
Posted by Americo Watkins at 02:06 on 2013 Nov 17
Hi Elliot,I have ordered additional neutral density filters to cope with the brightness hopefully which will allow me to use longer flatfield exposures to get past the problems of a mechanical shutter such as I have. Hopefully then any strobing effect shouldn’t present a problem- One hopes.Cheers Eric
Posted by Eliot Hall at 21:50 on 2013 Nov 16
Hi Americo,Don’t know if this helps…I’m building my own light box for to be used for photometry. I’m finding it difficult remove all gradient. I’m taking so much care as I think the precision for photometry is much higher than for imaging.I know someone who uses EL panel his only criticism is that you must reduce the luminance by diffusing to extend the expose time. Otherwise the a strobing effect appears in the flats in very short exposures.Cheers,Eliot
Posted by John Thorpe at 22:34 on 2013 Nov 15
I loved the Gravity movie too. The first film I have seen since 2001 a Space Odyssey which captured the look and feel of actually being in space. If you wish you can certainly find inaccuracies such as the space stations being in the wrong orbits, but the whole film got it just right.
Posted by Comet Section at 18:18 on 2013 Nov 15
This comet is now confirmed to have undergone an outburst, probably on Nov 14.0 Overseas observers are reporting the comet as bright as magnitude 5 this morning. A sequence of images taken by Tony Angel and Caisey Harlington over the past week show the quite dramatic changes that have taken place in the comet’s btightness and morphology. This sequence can be seen on the BAA Comet Gallery at the following link:http://britastro.org/baa/index.php?view=detail&id=1944&option=com_joomgallery&Itemid=200 It will be interesting to see if this increase in brightness and tail development continues through perihelion. There does not appear to be any observations indicating that the comet is disintegrating. Comet expert Z.Sekanina gives the following quote this morninghttp://arxiv.org/pdf/1310.1980v7.pdf"Alert: Starting at ?5h UT on November 14, comet C/2012 S1 has beenreported to be in major outburst. From early data, a preliminaryestimate for its onset is November 14.0 ± 0.2 UT, with an amplitude ofat least 2 mag. Intrinsically the comet is now almost as bright asC/1962 C1 at the same heliocentric distance. It is unclear whetherthis events nature is benign or cataclysmic".So the comet is now near perihelion and active, this is all the encouragement that will be need for observers to try and observe this comet in the difficult period around dawn especially with the moonlight interfering. I hope that many BAA members will have a go and try and observe this fascinating comet. Denis BuczynskiSecretary Comet Section
Posted by TonyAngel at 10:22 on 2013 Nov 15
C/2013 S1 ISON Is starting to show her pettycoats, (not meant as a sexist comment). I have sent a positive and negative of one of my images to Denis. The first impression I had this morning when the firt image downloaded was that I was looking at an old woodcut or engraving of a comet and I could understand why they called them Broom Stars!This is a link to the negativehttp://www.pinterest.com/pin/232287293254489065/
Posted by Americo Watkins at 17:14 on 2013 Nov 14
Unlikely to use that range often, it it does present a problem then I would have to consider an alternative method, but it would be only for that one colour at least.. Cheers Eric
Posted by Robin Leadbeater at 16:31 on 2013 Nov 14
Hi Eric,This link seems to confirm that I band flats are a problem using an EL panel, though this is a different supplierhttp://www.lightbuckets.com/forums/showthread.php?p=3118CheersRobin
Posted by Americo Watkins at 15:57 on 2013 Nov 14
Thanks Robin,that’s useful to know.I will also use some neutral density filters to reduce the brightness as I understand this could be a problem for unfiltered flat exposures.Cheers Eric
Posted by Robin Leadbeater at 11:46 on 2013 Nov 14
Hi Eric,I have investigated them for spectroscopy (I know Lothar Schanne who is mentioned on the Gerd Neumann site) but this is a rather different application where spectral content rather than field uniformity is more critical. Talking to Lothar, from the spectral content point of view I would say that they would be ok for BVR (even too bright for normal imaging flats perhaps) but the output is much lower in the I band.CheersRobin
Posted by TonyAngel at 21:48 on 2013 Nov 07
Dennis,Thank you for your detailed response. I will start this weekend.Best Wishes,Tony.
Posted by Comet Section at 18:44 on 2013 Nov 06
Hello Tony, It is good to hear that you will post your comet images to me for archiving in the COMET SECTION. All you need to do is to email me the images as jpeg attachments to the email and I will load them onto the Comet Gallery. You can email them directly to me atbuczynski8166@btinternet.com or email them to cometobs@britastro.org Send as many images as you want in one email as separate files. It is important to save the image using our archiving file naming convention such as 2013r1_20131106_0330_dgbthis runs like this object designation underscore date underscore time underscore observer name Also it is good practise to annotate the observational data onto the image itself as this ensures that the detail will always remain with the image. Any other information that is addional to the raw observational details can be written as a note in the email. I will then add this to the archive file on the BAA COMET GALLERY. Have a look at my latest image of 2013r1 taken this morning to at the link below.Denis Buczynskihttp://britastro.org/baa/index.php?view=detail&id=1839&option=com_joomgallery&Itemid=200
Posted by TonyAngel at 06:10 on 2013 Nov 06
Hi Dennis,Thank you for your kind comments.There is quite a simple answer to why I have not submitted them. 🙂 I have looked in the past at the Gallery and I have never been able to work out how to do upload. From what you have said above, all I need to do is email you with the relevant information along with the images with the file name in the correct format. Is that correct? Do you prefer one image per email and what email address should I use?Tony.
