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Deep Sky Star "spikes"

Tracy

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William Optics 103mm
Celestron NexStar 8SE


I frequently see images with some stars with spikes (usually at least 4, sometimes more) around them. I know that a Bhatinov mask uses spikes for focusing, but these are not the type I refer to. Usually they primary spikes are at the 4 compass points, and then others are usually distributed equally in fours.

Is this something that is endemic to a particular scope style, like a reflector? I do not notice in in my refractor that I have, nor have I noticed in the few images I've captured with the NexStar 8SE (a Schmitt-Cassegrain design)?
 
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I use two different scopes for imaging a lil 61mm SharpStar EDPH II refractor is I am looking for a widefield view. The SharpStar is a APO triplet refractor. My other imaging Scope is a SkyWatcher 8" Astrograph or better known as a Imaging Newtonian Reflecting telescope. This is the one I get the diffraction spikes with. The spikes are caused by the vanes that hold the secondary mirror in place,

You can add diffraction spikes to a refracting scope one of two ways, First is to add them with a program in post-processing (sorry I'm not familiar with this program) the other way is to tape two thick threads to the dew shield perpendicular to each other.

Some people like the spikes, some don't. I can limit the spikes on the newt by...

OhNo

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I use two different scopes for imaging a lil 61mm SharpStar EDPH II refractor is I am looking for a widefield view. The SharpStar is a APO triplet refractor. My other imaging Scope is a SkyWatcher 8" Astrograph or better known as a Imaging Newtonian Reflecting telescope. This is the one I get the diffraction spikes with. The spikes are caused by the vanes that hold the secondary mirror in place,

You can add diffraction spikes to a refracting scope one of two ways, First is to add them with a program in post-processing (sorry I'm not familiar with this program) the other way is to tape two thick threads to the dew shield perpendicular to each other.

Some people like the spikes, some don't. I can limit the spikes on the newt by lowering my exposure time and increasing the number of images taken, keeping my SNR up......
 
Solution

Tracy

Dark Sky Lover
Founder
Messages
415
Reaction score
62
Location
Texas
Telescopes

William Optics 103mm
Celestron NexStar 8SE


Some people like the spikes, some don't. I can limit the spikes on the newt by lowering my exposure time and increasing the number of images taken, keeping my SNR up......
I'm not a fan of them personally... but was wondering if my William Optics refractor and flattener was screwing something up. :unsure:

My other imaging Scope is a SkyWatcher 8" Astrograph or better known as a Imaging Newtonian Reflecting telescope.

I'm honestly looking at a GSO 8" f/4 reflecting right now. It looks like it might be a decent introduction to a faster reflector scope. I have the 8" NexStar (great for planetary but haven't done much with DSO) and the William Optics ZenitStar 103mm that I really like for most (not all) DSO shots. I'm debating on a reflector or another refractor in the 70-80mm range.

Was REALLY curious why some shots showed them and others didn't, and hadn't thought about the vanes since the last reflector we had was about 25 years ago when my son was 10 years old and wanted a scope (I blame my addiction on him now). :D
 

OhNo

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Yeah, my wife is the reason I have too many scopes! As far as future scope purchases have a goal in mind, but never compromise on the best quality you can afford. The scope you mention will likely work for AP, the imaging Newts are usually a faster scope than their cousins the f/5 newts. The longer focal lengths newts usually have an issue with not being able to focus, and the focuser won't go into the tube far enough.

Another thing to keep in mind is most newtonian imaging reflectors will need a comma corrector (CC). In the other thread you started you mentioned buying a newt. I assume you meant for imaging. My SW Quattro was $800 Canadian, BUT the CC was almost $400. And you will need a colminator to align the mirrors.
 
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