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Posted by Paul A Brierley at 17:42 on 2010 Apr 07
Thank you Callum,Yes the Moon and planets will be my main interest, but I will also be using this for casual tours of the sky, taking in bright DSO’s.I want something that is portable, which I will use mostly during the week during Spring and Summer when I don’t have the time for Astro-Imaging because of work the following day. The OD250L looks to be the ideal solution to my problem. Tonight is another case. It’s lovely and clear here in Cheshire, and looks like staying like this for tonight. Because of the day length, I don’t have the time for any imaging. And that is where I’d use my 10"I think I’ll go and order one in time for the Summer.
Posted by Callum Potter at 09:36 on 2010 Apr 07
Hi Duncan,Asteroids covers the minor and remote planets too, i think, and Pluto.Fair point about the other planets – not sure why i missed venus out…Saturn section covers uranus and neptune, but I will probably add forums for them.The intention was to make the forums topic rather than section based.Cheers, Callum
Posted by Callum Potter at 09:29 on 2010 Apr 07
If lunar and planetary are to be the main interest, I would suggest going for the longer focal length. You can then get the same magnification with more comfortable longer focal length eyepieces.Callum
Posted by Len Entwisle at 09:52 on 2010 Apr 06
Hi Duncan , Looking at the category list I would think that ‘Uranus,Neptune or Minor Planets’ would be met by the current Asteroid (and subtitle) category . Probably Venus would be ‘at home ‘ with the ‘suitably re-titled’ Mercury category title ? That would become ‘Venus and Mercury’. There is little post volume to need more than this , I would think. Just my thoughts!Best wishes , Len E
Posted by Andrea Tasselli at 10:41 on 2010 Mar 27
Hi David,I don’t know about other imagers but I have imaged Saturn since 2001 and it never occurred to me that it changed colours at (around) oppositions. As for the current one (I missed the past apparition’s) I’m pretty sure it didn’t change colours, by and large. Fact is that *measuring* photometric changes in saturn’s globe is devilishly difficult and full of traps and catches. I tried to keep track of relative response of rings and globe in various colour bands (I think from 2004) but it is difficult to come down to hard facts. Certainly if such a thing does really happen any factual assessment can’t be based on the fancies of this or that imager. Besides, I can’t think of any reasonable physical explanation for the purported colour changes.Andrea T.
Posted by David Arditti at 14:15 on 2010 Mar 26
Interesting, I’ve never seen one of those before.Another good place to flag this up would be on UK Astronomy Buy & Sell.http://www.astrobuysell.com/uk/
Posted by David Arditti at 14:07 on 2010 Mar 26
That may be part of it Andrea, but I’m not convinced it is the complete explanation, because the colours of the globe, in most imagers’ images, around opposition, are really quite different to the colours away from opposition, as seen here. The effect is more than just an intensity change.I have done various observations to test the Opposition Effect of Saturn over the last 3 apparitions. In 2008 I concluded that the brightness of the rings increases most in the UV and IR, somewhat in the blue, and hardly at all in the red and green (I published a note on this, with images, in the Journal, April 2008). Now, assuming that the CCD filters that observers use are effectively blocked against UV and IR, this means that, in images, the rings should become blue-er near opposition. But I think actually imagers generally balance the colours so that the rings look white. This process would be expected to relatively suppress the blue in the globe, and make it redder or yellower. But what we are seeing is not quite this either. In fact I have found that no balance of the channels can make the globe colours look normal at opposition. So I am not decided whether this effect is something to do with the characteristics of filters, if if something more "real" is going on here.
Posted by Andrea Tasselli at 07:51 on 2010 Mar 26
Well, actually the explanation might be quite simple: The imager adjust his/her gain level so as not to over-expose any area of the planet. As Saturn closes in toward opposition (at very small phase angles) the rings brighten up considerably but not the globe. Keeping the same gain as not to overexpose the rings yields a lowered signal for the globe and hence more muted colours. By the way during this opposition I haven’t noticed any undue dulliness, since the rings brightness increase is very small (small rings angle).Andrea T.
Posted by Gary Poyner at 17:47 on 2010 Mar 22
Hi Callum,It’s usually open all the time, although Thursdays is the ‘official’day, where you will generally find Arne Henden around to chat with.Occasionally they have invited guests at pre-determined times to answerquestions about a certain subject they specialise in. Open to non memberstoo (I think!). You certainly don’t have to sign in to Blue/Gold to enter the chat room (Blue/Gold is your membership status).Cheers,Gary
Posted by Callum Potter at 16:38 on 2010 Mar 19
Hi Gary,I tried out a little gadget to do that sort of thing a while back, but it did not work too well.But certainly worth revisiting.How does the AAVSO one work – is it live all the time ? or scheduled periods ? Is there always a resident ‘guru’ on hand ?Cheers, Callum
Posted by Gary Poyner at 16:15 on 2010 Mar 19
Excellent idea Callum. I hope we get lots of Variable Startraffic!I quite like the ‘live chat room’ run by the AAVSO, withoccasional guests answering queries and general questions,as well as people dropping in with comments and suggestions.Have you any idea’s yourself along these lines? Cheers,Gary
Posted by Sheridan Williams at 09:25 on 2010 Mar 10
Thank you for all the responses, I have now found a website coordinator and we will be launching the site in early April.In the meantime I need someone who has time to maintain the book list pages. I have compiled a list already but it is far from complete. If anyone has the time to do regular updates to the page this would be marvellous.Please contact me on: baa[at]clock-tower[dot]domand I’ll run through what I need and give you the link to the development site.Sheridan
Posted by John Cave at 18:55 on 2010 Mar 07
As a user of the Faulkes Telescopes this does seem a bit strange. I have an hour scheduled for this Thursday and the following Thursday both between 11.00a.m. and 12.00. Should anyone require any images or data that could be obtained during these sessions I would be only too happy to help. The both sessions are for the FTS (Australia). I have attached an image of the Crab taken with this telescope (unaltered).John.
Posted by John Cave at 18:49 on 2010 Mar 07
Great new forum Callum,The new site and forum are slick and up to date. I am sure it will be a big success.John Cave
Posted by Andrea Tasselli at 15:30 on 2010 Mar 05
You’re correct. While very down south it will be still visible in the UK even at its southmost declination (~-22deg S).Andrea T.
Posted by Richard Miles at 11:43 on 2010 Mar 05
David – Good point – thanks for flagging this oversight. This part of the site was set up after we had had our first successful BAA observing session at our Out-of-London meeting in Liverpool.There have been a few attempts in the last couple of years which have been clouded out but, after a long break, we were successful at the Christmas meeting last December 12 when we observed asteroid (1645) Waterfield at opposition as well as taking images of (7102) Neilbone and a few stars for calibrations.We took a total of 19 images on the day having started imaging before the formal meeting began and having had two consecutive 30-minute slots booked on the Faulkes Telescope South. I have just zipped the images and they occupy about 17 Mb. I’ll check with Callum to see about getting them to him and putting them in the archive.Richard
Posted by Roy Hughes at 17:32 on 2010 Mar 04
Not sure, I think it was the Astrofest following the announcement of Pauls death. The picture was in a pile of prints and maps being "remaindered" by the London Planetarium and I remember thinking at the time that they did not have a clue what they were selling me for a pound.
Posted by Phil Bourke at 07:43 on 2010 Mar 03
You’re quite right, Terry, the biggest difference between these ‘scopes was their overall finish. The amount of bright metal visable in a Fullerscopes tube was quite remarkable and the mount, although sturdy, needed some work to bring it up to standard. This was, of course, reflected in the price. Bottom line was that to buy Fullerscopes and then invest an amount of elbow grease would give you a good ‘scope at a very reasonable price.
