Bungielad Posted March 20, 2014 Share Posted March 20, 2014 Hi all, Could someone please explain how you get spikes on stars when taking pictures? Cheers, Bungielad Link to comment Share on other sites More sharing options...
Scott Posted March 20, 2014 Share Posted March 20, 2014 the diffraction spikes are caused by the secondary spider on a newtonian such as your explorer 130p Link to comment Share on other sites More sharing options...
sandyshaw Posted March 20, 2014 Share Posted March 20, 2014 Stop down your camera aperture OR put some spider vains on your objective if there is none. Link to comment Share on other sites More sharing options...
DaveS Posted March 20, 2014 Share Posted March 20, 2014 Use any telescope with a secondary supported by vanes. Diffraction gives spikes.I understand that some people actually *add* them to otherwise spikeless images taken with refractors.For the life of my I don't know why. Link to comment Share on other sites More sharing options...
RikM Posted March 20, 2014 Share Posted March 20, 2014 They are a diffraction effect caused by the spider vanes holding your secondary mirror. They are more obvious and nicer if your star is bright and your collimation is good. Link to comment Share on other sites More sharing options...
Bungielad Posted March 20, 2014 Author Share Posted March 20, 2014 Cheers guys, No way did I think it was the vanes, ya live and learn eh!Personally I think they look dead good jotted around here and there.Bungielad. Link to comment Share on other sites More sharing options...
PeterCPC Posted March 20, 2014 Share Posted March 20, 2014 HiYou can add your own during processing if you get a piece of software called starspikes pro3. Then you can add as many as you want and stipulate length/intensity etc. It's a plug in for Photoshop/Paintshop etcPeter Link to comment Share on other sites More sharing options...
Bungielad Posted March 20, 2014 Author Share Posted March 20, 2014 Thanks for that peter.Bungielad Link to comment Share on other sites More sharing options...
DaveS Posted March 20, 2014 Share Posted March 20, 2014 * shakes head in bafflement *Still, as I said in another thread, De gustibus etc.. Link to comment Share on other sites More sharing options...
Bungielad Posted March 20, 2014 Author Share Posted March 20, 2014 As said DaveS......De gustibus etc....Bungielad. Link to comment Share on other sites More sharing options...
Astrosurf Posted March 21, 2014 Share Posted March 21, 2014 I, too, like the diffraction spikes!Alexxx Link to comment Share on other sites More sharing options...
knobby Posted March 21, 2014 Share Posted March 21, 2014 Diffraction spikes ...Astro photography marmite :-) Link to comment Share on other sites More sharing options...
RobH Posted March 21, 2014 Share Posted March 21, 2014 I like spikes, which is a good thing as my RC produces them. Astro 'fairy dust'Another way to get them if you want them and have a refractor is to tape some thin cotton or fishing line across your objective to simulate a 4 vaned spider. Link to comment Share on other sites More sharing options...
Zakalwe Posted March 21, 2014 Share Posted March 21, 2014 I like spikes, which is a good thing as my RC produces them. Astro 'fairy dust'Another way to get them if you want them and have a refractor is to tape some thin cotton or fishing line across your objective to simulate a 4 vaned spider.Hehe...so we spent £thousands trying to get equipment that delivers light in the most accurate fashion possible, and then go and introduce something that causes on optical aberration... Link to comment Share on other sites More sharing options...
RobH Posted March 21, 2014 Share Posted March 21, 2014 Indeed we do......if we were doing science, then that would be bad, but most of us are doing technical art :-) Link to comment Share on other sites More sharing options...
mrjolly Posted March 21, 2014 Share Posted March 21, 2014 As I found out to my expense a short while ago, a good way to get a star spike with a refractor is to forget to move the washing line out of the way when you're down the bottom of the garden... Link to comment Share on other sites More sharing options...
glowingturnip Posted March 21, 2014 Share Posted March 21, 2014 as a newt user, I too am duty bound to love spikes don't think I'd ever add them manually though Link to comment Share on other sites More sharing options...
DaveS Posted March 21, 2014 Share Posted March 21, 2014 Diffraction spikes ...Astro photography marmite :-)He he..I like marmite, but don't like (Artificial) diffraction spikesGo figure, as our American friends say. Link to comment Share on other sites More sharing options...
mitchelln Posted March 21, 2014 Share Posted March 21, 2014 The need for pretty spikes bred in from birth. Twinkle twinkle little star! Link to comment Share on other sites More sharing options...
Alien 13 Posted March 21, 2014 Share Posted March 21, 2014 As I found out to my expense a short while ago, a good way to get a star spike with a refractor is to forget to move the washing line out of the way when you're down the bottom of the garden... Same thing happened to me i spent ages trying to figure what had gone wrong then i noticed the washing line on the second session what a relief.Alan Link to comment Share on other sites More sharing options...
Mr TamiyaCowboy Posted March 21, 2014 Share Posted March 21, 2014 With your telescope and as others before me have mentioned, the spider vanes in telescope make them. BUT !!!! in photograpghy, we cheat. with a dslr and lens , we run a very long shutter speed and have a fairly high F number ( F11 and upwards ). this combination give car lighttrail photographs star spikes on the streetlamps and likes. photography stores sell filters , 4 star -6 star - 8 star , when fitted this double triple/trebble the spikes. next time its overcast, throw on a camera lens set the dslr up for long exposureand high F number pint at street lights and see the effect the settings have. Link to comment Share on other sites More sharing options...
Zakalwe Posted March 21, 2014 Share Posted March 21, 2014 The spikes seen with a DSLR and lens are caused by the blades of the iris. A high f-number means the lens is stopped down, so the blades intrude into the light-path. You can normally tell how many blades are in the lens by counting the spikes.A similar effect is seen when shooting with the lens wide open. The background is blurred into bokeh due to the shallow depth of filed. Cheaper 5-bladed lenses gives a pentagonal shape. More expensive lenses gives a smoother bokeh. Link to comment Share on other sites More sharing options...
Mr TamiyaCowboy Posted March 21, 2014 Share Posted March 21, 2014 Bokeh, yep i must say bokeh can give some nice effects , have to say i like my stars nice and sharp, minimal spiking,but camera and lens i like to introduce some spiking when possible. Link to comment Share on other sites More sharing options...
lensman57 Posted March 21, 2014 Share Posted March 21, 2014 Hi all,Could someone please explain how you get spikes on stars when taking pictures?Cheers,BungieladYou can get diffraction spikes even with a super expensive Apos depending on the brightness and type of the stars and close or at the point of correct focus, the design of the lens cell, the type of spacing between the elements can also have an effect.A.G Link to comment Share on other sites More sharing options...
RobH Posted March 21, 2014 Share Posted March 21, 2014 The need for pretty spikes bred in from birth. Twinkle twinkle little star! Very true. Joe Public thinks that stars look like that.A colleague of mine, who was around when I was processing an image, actually asked me why the stars didn't look like stars....the image was with a refractor and had no spikes. I added some and showed her, and she said that they looked much better! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.