Forum Replies Created
-
Posts
-
Posted by Richard Miles at 18:12 on 2014 Jan 28
That’s a great shame – I hadn’t seen that painting before (maybe we never now will see it!). It is Donati’s Comet as you can see Arcturus near the head of the comet.There was a Donati’s Comet painting from the Paul Mellon collection by William Turner of Oxford on loan at the Royal Academy, next door to Burlington House a few years ago. It was an almost exact representation of the stars in Bootes and in that case Arcturus was comingled with the head of the comet. You could easily see the star on the original but it was a lot less obvious on any copy of the painting. (see Slide 17 at: http://britishart.yale.edu/collections/highlights/prints-drawings
Posted by Robin Leadbeater at 19:32 on 2014 Jan 27
Hi David,Type 1a are indeed the standard candle but you need to take into account the extinction due to everything between it and us. This is done in various ways eg by measuring the amount the spectrum is reddened (The spectrum should get brighter towards the blue but here has a downward slope towards the red) or by measuring the strength of the absorption lines from the interstellar material like the Na D lines here. There is an impressive (to me at least!) early analysis of these in http://www.astronomerstelegram.org/?read=5797 CheersRobin
Posted by David Strange at 18:47 on 2014 Jan 27
Why should that be Robin? I thought these things were meant to be standard candles!CheersDavid
Posted by Robin Leadbeater at 17:10 on 2014 Jan 27
And I see David’s is still on the front page of spaceweather.com currentlyMike I see your spectrum shows the interstellar NaD line which does not bode well for this object reaching the originally predicted brightness Robin
Posted by Mike Harlow at 14:50 on 2014 Jan 27
I made my first attempt at a supernova spectrum last night but using an objective prism. Reasonable result but it’s just about at the limit of what I can do with my current set up. The spectrum is on the Forum of the Orwell Astronomical Society at:http://forum.oasi.org.uk/viewforum.php?f=6.Sorry that I’ve got red to the left in my image against the usual convention. But then prisms do disperse in the opposite direction to gratings(!).Mike.
Posted by David Strange at 13:33 on 2014 Jan 27
And here’s my attempt with a Star Analyser and Celestron 9:http://spaceweathergallery.com/indiv_upload.php?upload_id=93325David
Posted by R A Marriott at 03:37 on 2014 Jan 26
I&I News, New Series No. 11 (9 May 2013) is a 33-page issue dedicated to Horace Dall. It includes Jim Hysoms obituary of Horace; Over unknown Iceland on a Raleigh roadster by Ben Searle, with a selection of Horaces photographs; Horaces papers on The camera obscura, A null test for paraboloids, FP3 Series II film, Atmospheric dispersion, Maksutov telescopes, Visual astronomy in the ultraviolet, Telescope eyepieces, Finding and guiding on dark skies, Photoelectric methods in amateur astronomy, Filter-type solar prominence telescope for amateurs, and A DollondWollaston telescope; Comments on the null test by F. J. Hargreaves; Memories of Horace Dall by Robin Scagell; The genius of Horace Dall by Martin Mobberley; Horace Dalls observatory by Mark Stuckey; and two short pieces by myself, on the protoype Dall-Kirkham and the Horace Dall Medal and Gift. It also includes links to Robin Scagells 52-minute video of Horace, filmed in 1982, and Gee Hurkmans 6-minute video of his cycle journey across Iceland in 2010. Like all issues of I&I News, this issue was sent to all Members with e-mail, and is available for download (when logged in) from the Members Only area of this website: Menus – Members/Downloads/Sections/Instruments and Imaging Section/navigation link 2. It is also available for download from the Instruments and Imaging Section website at http://www.britastro.org/iandi/iandinewsdall.htmBob Marriott: Director, Instruments and Imaging Section
Posted by Nick James at 17:15 on 2014 Jan 25
Hi Neil/Len,Yes, Horace Dall was an extraordinary character who was as well known for his travelogues as he was for his astronomy. He met his wife in Patagonia and the Journal contained frequent reports of his trips. The Iceland cycling expedition is mentioned in Jim Hysom’s very interesting summary of Horace’s life (JBAA 97,2,1987) which is worth a read. You can get it from ADS here.I’ve just had a look at the website and the photos and descriptions of that tour show very clearly what kind of man he was. Nick.
Posted by Neil Morrison at 21:24 on 2014 Jan 24
I Have just viewed Horacec Dalls remarkable Journey and the picture. Please may the pictures and narative be considered for printing in a future edition of our journal. Having toured arround Iceland in the comfort of a tour bus routing along the Icelantic A1 road ( much of which is still unmetalled)a few years ago I can appreciate the rigours that Horace Dall endured. True grit.Neil
Posted by Gary Poyner at 10:15 on 2014 Jan 23
Gordon’s pre-discovery image of SN 2014J and a spectrum and image taken by David Boyd can be seen on the BAAVSS web page…http://www.britastro.org/vss/Gary
Posted by Gordon Mackie at 00:13 on 2014 Jan 23
Robin Leadbeater wrote:
Images here show the sn clearly visible from Jan 15th. http://www.k-itagaki.jp/psn-m82.jpgHow was this missed in such a popular object for 6 days ?! There must be quite a few people kicking themselvesRobinI suppose I should be, but I’m still delighted I managed to discover it independently, even if it was a day after the first people did (http://stargazerslounge.com/topic/206101-bright-supernova-in-m82/#entry2187099)Gordon
Posted by Robin Leadbeater at 21:58 on 2014 Jan 22
Images here show the sn clearly visible from Jan 15th. http://www.k-itagaki.jp/psn-m82.jpgHow was this missed in such a popular object for 6 days ?! There must be quite a few people kicking themselvesRobin
Posted by Robin Leadbeater at 21:48 on 2014 Jan 22
I am following up a report of it being visible in an image taken 19th Jan. http://stargazerslounge.com/topic/206101-bright-supernova-in-m82/It seems a bit unlikely given how many people must look at this object every night but if it does pan out what is the procedure for reporting it? Anyone here versed in issuing ATELS ?CheersRobin
Posted by Nick James at 19:14 on 2014 Jan 22
Bob,The time of the first report on TOCP is 2014 01 21.81 which corresponds exactly to the UCL time of observation (19:20) so is the TOCP report from the UCL group?Well done to them! Nice to get an SN discovery from Mill Hill. What was the last object discovered from there I wonder?Nick.
Posted by R S Winter at 17:41 on 2014 Jan 22
Dear AllThis Supernova was observed by chance at ULO Mill Hill Observatory last night. This was during a student training session. Steve Fossey has applied for this to be a discovery image. See:http://www.ucl.ac.uk/maps-faculty/maps-news-publication/maps1405RegardsBob Winter
Posted by Robin Leadbeater at 15:28 on 2014 Jan 22
A type 1a so I make that around Vmag 8.5 (plus any extinction) in a couple of weeks time. I sense the first high resolution amateur sn spectra beckoning 🙂 Robin
Posted by Tony Davies at 15:30 on 2014 Jan 16
Sad news indeed. John Dobson held some very interesting views on cosmology but his work on Dobsonian mount telescopes certainly brought better astronomical views within the budget of many more budding astronomers. A very interesting person.
Posted by Grant Privett at 21:19 on 2014 Jan 11
In the days Martin refers to, AstroArt was only just becoming available and the Starlight software didnt seem to autoscale. AstroArt improved things a lot. USB was also a great step forward. The TC255 based camera I used in 1994 was 340×240 pixels and took 7 seconds to download via parallel port. You wouldnt have it as a guider now. It was a different world.
Posted by Martin Mobberley at 20:01 on 2014 Jan 11
Paul,I used an MX916 CCD during the 1990s and up to 2002, mainly with a 49cm Newtonian and a 16cm f/3.6 reflector. It was reliable and images could be taken without any dark frames, which was just as well as there was nointernal shutter, so dark frames would have been a hassle. Since then I’ve mainly used an SBIG ST9XE. I switched to the SBIG camera for a number of reasons. The raw images were much noisier, but once a dark frame was subtracted they were noticeably deeper, and the SBIG has a built in shutter.But I think the main reason I switched was that at the time I far preferred the CCDSoft software which integrated with The Sky planetarium package. Initially there was no third party software for the MX916 and the supplied software was very clunky indeed. Of course the MX916 of the1990s had parallel port download too which was very slow. Nevertheless, I had very reliable service from the MX916 over many years and it was very reasonably priced, without the painful ‘one dollar equals one pound’ rip-off price that we have to put up with so frequently in the UK!!Martin
