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Posted by Gary Poyner at 16:30 on 2011 Nov 17
Hold the mirror up to a light source and look through the bottom. You will soon see if it needs re-coating or not, as you will see light shining through the worn area’s. Washing a 12 inch is fairly straightforward, but try not to use any liquid which contains lanolin, as this ‘may’ leave small white marks on the mirror surface. Always use distilled water too.My 51cm mirror is from OO and has Hi-Lux coatings. It’s great! I’ve also compared a 25cm with and without Hi-Lux, and the Hi-Lux wins every time. If you do get the primary done, have the secondary done as well, whether you think it needs doing or not. Good luck,Gary
Posted by Callum Potter at 14:40 on 2011 Nov 17
I don’t know if this is what you are looking for Martin, but the Sky and Telescope magazine website has a useful calculator, and a table through to March 2012.http://www.skyandtelescope.com/observing/objects/javascript/3304091.htmlI have not checked how accurate the GRS transit times are, though.Regards, Callum
Posted by Callum Potter at 14:34 on 2011 Nov 17
Hi Mark,I had a diagonal re-aluminised by Vacuum Coatings in the summer, and they did a good job. Helpful in advance, and returned in expected timescale, and coating looks fine.I have been thinking about getting my main mirror re-aluminised too, but I have been thinking about OO for that, mainly because Crewe and Saturday morning opening makes it a bit easier for me to take the mirror to them and collect. As its 52cm I’m not so keen on shipping it.But I think i will try giving it a clean first, as i’m not sure it really needs re-aluminising yet. I cleaned a small centre area to respot it over the summer, and it looks fine there. So, you might find that the coating is still good but dusty.Regards, Callum
Posted by M C Butcher at 11:20 on 2011 Nov 17
Gordon, Sorry I haven’t responded earlier but I have only just read your question on this Forum page. I live in the Inner Hebrides and use an unmodified Canon 40D as I refused to purchase more than one camera for all my domestic and astronomical needs. Prior to that I used an Olympus OM-4Ti film camera, I have no experience of any other cameras. I too have been intimidated by both the cost and the complexity of modifying a DSLR. I use my camera with a tripod (for Aurora, Noctilucent Clouds, startrails and general domestic photography) and inconjunction with my Meade LX-90 8". It has worked very well for all subjects except the fainter Emission Nebulae (where it works but the IR filter requires the exposure times to be either too long or for there to be an excessive number of sub-exposures), and detailed Solar System work, where the seeing (as I am almost at sea level) can be a severe trial. To control the camera I use the Canon TC-80NC remote controller. As I do not have an auto-guiding capability for my telescope the length of the sub-exposures can be a real problem when imaging deep-sky objects. As all my astronomy is conducted from home I usually use mains power to run my camera (and the LX-90 and the Dew controlling system).A disadvantage of the 40D is that it does not have a video mode, this would help a lot with getting over the problem of poor seeing with Solar System objects. One advantage of the 40D is that you can customise certain settings within the camera which then remain set (until you decide to change them), this means that you do not have to set all of the specific astronomical seetings into the camera each time you go out, all that is required is that you dial up whichever customised setting you want (the 40D has 3 and I have them configured for Deep-Sky, Solar System and Photometry work). For image processing I use a general photographic package (Photoshop CS5), an astronomical software (Images Plus) and a noise reduction software (Noise Ninja). For film astrophotography I used Michael Covington’s book on astrophotography (very good) and Jerry Lodriguss’ CD book on using Photoshop for astrophotography (also good). On moving to a digital camera I purchased Michael Covington’s book on DSLR Astrophotography and Jerry Lodriguss’ CD book on DSLR Astrophotography. In hindsight the latter which is pretty much my ‘bible’ was all I needed. Obviously we all work to budget of both money (to spend) and time (to devote) to our hobby and you must make your own choices. I am well aware of the limitations which my circumstances place on the astronomy that I do(most importantly the implications that the weather here has on what I can and can’t achieve), and I am content to operate within those limitations.Please ask if you have any further questions, I would be delighted to help in any way that I can.RegardsMartin Butcher
Posted by Tom Moran at 21:06 on 2011 Nov 14
Tremendous image Pete. The sun gave us a good show here in the NE on Sunday but sadly clouded out Mon/Tues.Tom Moran
Posted by Marlyn Smith at 14:49 on 2011 Nov 14
This amazing image was taken Pete Lawrence on 20111112 at 12.23UT showing an enormous filament around the NE limb and quadrant extending for over 1 million kms. Also a large diffuse prominence on the SE limb plus a wealth of active regions. Quite some image Pete!Posted by Nick James at 11:54 on 2011 Nov 05
I’ve gone back to the original raw video from the camera at BH and have re-edited the Awards part so that Hazel is now visible (just) in the bottom right hand of the frame.Callum is right that it would be nice to have a couple of cameras, one on the screen and one on the speaker, but then the editing process required before we could upload the video would be more of a problem and probably, if it depended on me, wouldn’t get done…Nick.For those technically interested the camera at BH is an HD widescreen one locked off on a bracket at the back of the room. It feeds to an SD DVD recorder which records the widescreen picture in a 4:3 letterbox format but with a bizarre aspect ratio. The audio is now recorded on a separate voice recorder with a tie mic. I have a script that rips the DVD, sorts out the aspect ratio and then crops the video. I then align the audio with the video, combine them and generate the MP4s that get uploaded to the BAA website. To get Hazel in the FoV I manually ran this process with different crop settings.
Posted by Callum Potter at 14:52 on 2011 Nov 03
Would be good if there was a second camera on the speaker for the intro and starts, and for when there are presentations and the like.If the BAA invested in one, could be used to record meetings away from BH too…Just a thought…Callum
Posted by Nick James at 07:43 on 2011 Nov 03
Gary,Yes, we’ve noted that! The camera is locked off on a bracket at the back of the room and so we have a fixed field of view throughout the meeting. This is a compromise since, while it is nice to have some context, we need to zoom in on the screen to make the text legible.I’ll let you into a secret though. The automated video generation pipeline that I use for the BAA vids processes, crops and scales the raw video to generate the MP4. After several comments I had a look at the raw feed and Hazel is just on the far right of the screen. When I have some time I’ll re-run the awards bit with a different crop setting so she should magically re-appear. The only problem then is that the mic was still on David’s tie…Nick.
Posted by Gary Poyner at 16:14 on 2011 Nov 02
I enjoyed the meeting on Video too Nick, and the sound was a massive improvement. Well done. However it was somewhat spoiled with the video notshowing Hazel receiving her medal. Too late to do anything about it now of course, but perhaps something to remember for future meetings where medal presentations are made.Gary
Posted by Nick James at 06:53 on 2011 Nov 02
Roy,Thanks for the feedback. I use VLC and it is a remarkable little program that can play far more video formats than Windows Media Player can.Re the video, next meeting I’ll try to get the camera zoomed in more on the screen so that it should be a bit easier to read the slide text.Nick.
Posted by Jeremy at 19:15 on 2011 Nov 01
Thanks for uploading the videos, Nick.Always good to be able to catch up with mtgs I have not been able to attend.Sound quality is a vast improvement. Hopefully we can continue this with future mtgs.Go well!Jeremy
Posted by Gordon MacLeod at 17:39 on 2011 Oct 31
Thanks Tony.Grateful for the response.Best Wishes,Gordon
Posted by Roy Hughes at 10:54 on 2011 Oct 31
I downloaded the Sky Notes video as I never managed to make it to the meeting.The focus seems a little off, at least at the start of the presentation, and the text was just about illegible.As Windows Media Player 11 refused to play it I downloaded VLC media player and used that instead.VLC has a "sharpen" tool and a little bit of that made a great difference, some of the text was almost readable (though what it did to Damien’s Jupiter video has to be seen to be believed!)ThanksRoy
Posted by Tony Morris at 20:42 on 2011 Oct 30
PaulSorry I have not used a Nikon for AstrophotographyTony
Posted by Paul A Brierley at 20:36 on 2011 Oct 30
Thank you Tony,Do have any experience using Nikon cameras, and particularly the D40?Looking forward to your talk in two week’s at Astromeet.
Posted by Tony Morris at 20:25 on 2011 Oct 30
GentsThere will be a paper published in the near future in the BAA journal showing how to remove the IR blocking filter from a Canon EOS1000.Although many of the current crop of DSLR’s can produce excellent deep sky images there are more after market add ons for Canon EOS DSLRs than any other make. For instance at this moment the capability to use light pollution filters between the lens and the sensor is only available for Canon EOS camerasHave a look here:-http://www.astronomik.com/en/This allows wide field imaging with standard lenses.Also camera control:-http://www.backyardeos.com/RegardsTony
Posted by Roger Pickard at 16:55 on 2011 Oct 21
Yes, you do need to make sure you’re getting a photometric V filter. Norman Walker is the man to contact – enw07@btinternet.comCheers,Roger
