Milliways Posted October 12, 2009 Share Posted October 12, 2009 I Have collimated my scope and now i have difraction spikes on bright stars? I have checked the spider vanes and all are equal.. Any ideas?Dave. Link to comment Share on other sites More sharing options...
Merlin66 Posted October 12, 2009 Share Posted October 12, 2009 I would have thought diffraction spikes on a Newtonian were a common occurance... I know they were there all the time in my 13" and 18".Why do you think there's a problem???? Link to comment Share on other sites More sharing options...
Astro_Baby Posted October 12, 2009 Share Posted October 12, 2009 Diffraction spikes are normal for a Newt - why do you think theres a problem ? Link to comment Share on other sites More sharing options...
calibos Posted October 12, 2009 Share Posted October 12, 2009 Because his collimation was probably so far out that his diffraction spikes were diffuse and all but invisible. Now the scope is properly collimated he's brought the spikes into sharp focus like they should be. Dude, its a good sign!! Sharp diffraction spikes means you're closer to good collimation than you were Don't know why they annoy some people. I remember scratching my head about why I prefered the view of M45 through my dob even though the FOV was too small to take it all in whereas I was less impressed by a good finderscope view which was able to show the entire cluster in all its glory. There was just something missing. Eventually had my homer simpson DOH! moment. No diffraction spikes in the refractor finder but lovely diamond spikes in the Newt/Dob. Thtas why I preferred the view in the main scope.Diffraction spikes are attractive to me. Its only when observing close doubles that they are an annoyance where I spike from the main star might be obscuring the fainter companion. Link to comment Share on other sites More sharing options...
adamsp123 Posted October 12, 2009 Share Posted October 12, 2009 Some imagers that use non spike making Refractors will "add" diffraction spikes to their pics using a software program, I must admit I do like the spikes on my pics using my Newt. So bottom line, congrats on your spikes they are right! Link to comment Share on other sites More sharing options...
Doc Posted October 12, 2009 Share Posted October 12, 2009 I have these spikes in my dob and I think they add to my view. I like them lots.... Link to comment Share on other sites More sharing options...
Astro_Baby Posted October 12, 2009 Share Posted October 12, 2009 You may be right calibos - maybe thats whats happening here.I have never looked down a refelector thats that far out of collimation that you cant see at least some diffraction spikes even if they are out of whack.Maybe the scope was so whacked out everything was diffuse. Link to comment Share on other sites More sharing options...
Milliways Posted October 13, 2009 Author Share Posted October 13, 2009 Hmm i have collimated the scope before and have never seen difraction spikes thats why there is a concern, jupiter has massive difraction spikes but all is well with the detail. Link to comment Share on other sites More sharing options...
Psychobilly Posted October 13, 2009 Share Posted October 13, 2009 hmmm spikes...For your newt I would tend to agree better colliamtion and focus they shoulkd be there... but for a Frac then theres something up...An as for imagers adding false spikes... I am shocked... Peter... Link to comment Share on other sites More sharing options...
dark knight Posted October 13, 2009 Share Posted October 13, 2009 Dave maybe your collimating laser is way out of whack, pop round any time an you can borrow my Hotech so a comparison can be made...Carl Link to comment Share on other sites More sharing options...
Milliways Posted October 14, 2009 Author Share Posted October 14, 2009 Dave maybe your collimating laser is way out of whack, pop round any time an you can borrow my Hotech so a comparison can be made...CarlThanks buddy that would be great are you coming to the spog meeting? and would it be poss to pop round tomorrow night?thanks again mate! Link to comment Share on other sites More sharing options...
NickH Posted October 14, 2009 Share Posted October 14, 2009 The hotech is a superb bit of kit..I have one on loan for review at the mo.. shame the sky is playing silly bummers, but you'll get on well with that Dave Link to comment Share on other sites More sharing options...
dark knight Posted October 14, 2009 Share Posted October 14, 2009 No problem Dave,,just pop over when your ready mate,,Steph's got 40 pints of real ale ready for drinking , I'm in all evening.. Link to comment Share on other sites More sharing options...
Milliways Posted October 15, 2009 Author Share Posted October 15, 2009 No problem Dave,,just pop over when your ready mate,,Steph's got 40 pints of real ale ready for drinking , I'm in all evening..Lovely mate thanks! you are a bad influence but i might try a pint or 2 if i am allowed for scientific reasons of course:evil6:be round about 8-8:30 if thats ok? Link to comment Share on other sites More sharing options...
dark knight Posted October 15, 2009 Share Posted October 15, 2009 i might try a pint or 2 if i am allowed for scientific reasons of course:evil6:But of course,,,the other chief tester (Steph) has now informed me there are only 30 pints left!!!!! and she still hasn't made her mind up!!! so a second opinion is urgently required in order to preserve (or not;)) the remaining stock, Link to comment Share on other sites More sharing options...
Wobbly Bob Posted October 15, 2009 Share Posted October 15, 2009 No wonder you are seeing diffration spikes :) Link to comment Share on other sites More sharing options...
Trull Posted October 15, 2009 Share Posted October 15, 2009 Using curved secondary mirror vanes can help, if you really don't like the diffraction spikes. I made mine from sawblades. Link to comment Share on other sites More sharing options...
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