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Double Stars

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#1 mic1970

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Posted 23 September 2019 - 08:58 AM

Can beginners be successful at shooting double stars?  If yes:

 

1.  What is the best general setup?

2.  What is the best ISO and capture time?  

3.  Can one do it in heavy moon light?  

 



#2 james7ca

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Posted 23 September 2019 - 09:51 AM

Yes, you can probably be successful in imaging double stars.

 

The "best general setup" is simply the one that you have. You really don't need much in terms of equipment since the requirements scale with the particular double (brightness and separation). In terms of moonlight, darker skies are better, but I suspect that you can work under almost any levels of light pollution or moon light (again, the requirements vary depending upon the double star you want to image).

 

I've imaged a number of double stars under my red/orange zone light pollution. A few have been done with DSLRs, but several years ago I switched to dedicated astro cameras and as with just about any imaging you can generally get better results using a recent generation astro camera (one of the inexpensive, one-shot-color CMOS cameras would be a good place to start).

 

Here is a link to an image that was done with a Sony NEX-5R camera and an 80mm refractor (Albireo, one of the finest double in the sky):

 

  https://www.cloudyni...dpost&p=8121875

 

And here is that same double taken under a full moon using a 5-inch refractor and a ZWO ASI174MM camera (an RGB image using filters):

 

  https://www.cloudyni...dpost&p=6857407

 

And here is something that was done with that same 5-inch refractor and a ZWO ASI178MM camera (a sub-arc-second double star):

 

  https://www.cloudyni...s/#entry8041810



#3 Alex McConahay

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Posted 23 September 2019 - 10:12 AM

What are you trying to capture in imaging double stars? 

 

Alex



#4 mic1970

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Posted 23 September 2019 - 10:45 AM

Not being a smartarss, as I'm not sure what you mean, but the stars with separation and colors.  Basically, want to save what I can see... hopefully with better detail.

 

 

 

What are you trying to capture in imaging double stars? 

 

Alex



#5 mic1970

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Posted 23 September 2019 - 10:48 AM

I noticed you are only doing 5 or 10 second subs... I have an 8" SCT, should I try that to get closer pics?  Are you using barlows at all?

 

PS.... those pics are exactly what I want to get.

 

 

Yes, you can probably be successful in imaging double stars.

 

The "best general setup" is simply the one that you have. You really don't need much in terms of equipment since the requirements scale with the particular double (brightness and separation). In terms of moonlight, darker skies are better, but I suspect that you can work under almost any levels of light pollution or moon light (again, the requirements vary depending upon the double star you want to image).

 

I've imaged a number of double stars under my red/orange zone light pollution. A few have been done with DSLRs, but several years ago I switched to dedicated astro cameras and as with just about any imaging you can generally get better results using a recent generation astro camera (one of the inexpensive, one-shot-color CMOS cameras would be a good place to start).

 

Here is a link to an image that was done with a Sony NEX-5R camera and an 80mm refractor (Albireo, one of the finest double in the sky):

 

  https://www.cloudyni...dpost&p=8121875

 

And here is that same double taken under a full moon using a 5-inch refractor and a ZWO ASI174MM camera (an RGB image using filters):

 

  https://www.cloudyni...dpost&p=6857407

 

And here is something that was done with that same 5-inch refractor and a ZWO ASI178MM camera (a sub-arc-second double star):

 

  https://www.cloudyni...s/#entry8041810


Edited by mic1970, 23 September 2019 - 10:48 AM.


#6 Alex McConahay

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Posted 23 September 2019 - 11:06 AM

>>>>>>> What are you trying to capture in imaging double stars?

 

What I mean is-----what is it special that you want to see in double stars? 

 

Are you trying to measure position angle? Are you measuring separation? Color variation? Orbital periods? 

 

Or are they just part of a larger "pretty picture" type of imaging? 

 

Will they be the center of the frame, and the double stars themselves fill most of the frame? 

 

Or will they just be incidental to a larger frame with lots of other stars and maybe nebula. 

 

Many, if not most, stars out there are double stars. So, we are imaging them in almost any picture we take of the heavens. But we rarely emphasize them in such pictures. And often, they do not show as doubles. 

 

On the other hand, if we plan to measure them scientifically, we may need equipment and techniques that magnify them greatly, preserve their true colors, orient the frame (to assure precise position angle measurements) and such. 

 

That is why we need to know what you are trying to do with the images.

 

Alex


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#7 RedLionNJ

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Posted 23 September 2019 - 11:47 AM

When the seeing is unusually good and there are no interesting planets in the sky, I sometimes image close doubles (and triples, and ....) with my planetary setup.

 

You can get some very pleasing results (colors, separations, diffraction rings) with very little effort.

 

I particularly like color contrasts as well as the challenge of really, really close separations. I've been able to get down to just under a half arcsec of clear separation using normal techniques (video, AS!3, Registax) and definite elongation when the target is around a quarter arcsec (with the 12-inch SCT).

 

It's a fun pasttime when the seeing cooperates.

 

Grant


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#8 The Ardent

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Posted 23 September 2019 - 12:11 PM

Like this?
https://www.cloudyni...a/?fromsearch=1

#9 mic1970

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Posted 23 September 2019 - 12:40 PM

....just want a picture for my future enjoyment, visual only.  

 

 

>>>>>>> What are you trying to capture in imaging double stars?

 

What I mean is-----what is it special that you want to see in double stars? 

 

Are you trying to measure position angle? Are you measuring separation? Color variation? Orbital periods? 

 

Or are they just part of a larger "pretty picture" type of imaging? 

 

Will they be the center of the frame, and the double stars themselves fill most of the frame? 

 

Or will they just be incidental to a larger frame with lots of other stars and maybe nebula. 

 

Many, if not most, stars out there are double stars. So, we are imaging them in almost any picture we take of the heavens. But we rarely emphasize them in such pictures. And often, they do not show as doubles. 

 

On the other hand, if we plan to measure them scientifically, we may need equipment and techniques that magnify them greatly, preserve their true colors, orient the frame (to assure precise position angle measurements) and such. 

 

That is why we need to know what you are trying to do with the images.

 

Alex



#10 mic1970

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Posted 23 September 2019 - 12:44 PM

Have you tried with a DSLR on SCT?  I have a nex-image 5 I can try, but I haven't had much luck other then planets.  

 

 

When the seeing is unusually good and there are no interesting planets in the sky, I sometimes image close doubles (and triples, and ....) with my planetary setup.

 

You can get some very pleasing results (colors, separations, diffraction rings) with very little effort.

 

I particularly like color contrasts as well as the challenge of really, really close separations. I've been able to get down to just under a half arcsec of clear separation using normal techniques (video, AS!3, Registax) and definite elongation when the target is around a quarter arcsec (with the 12-inch SCT).

 

It's a fun pasttime when the seeing cooperates.

 

Grant



#11 Alex McConahay

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Posted 23 September 2019 - 12:52 PM

Then, just take a picture.. If you want it larger, crop it and enlarge it, or get more focal length. If you want it more colorful, just increase the saturation. etc...….

 

As has been pointed out, almost any celestial picture is capturing double stars, although they may not be distinguishable, depending on the relative brightness and separation of the stars. But, if you want to focus on just the double stars, with them filling the frame, you may want to think in terms of planetary imaging techniques, which use much longer focal lengths and perhaps stacked video framing. 

 

Alex



#12 dmdouglass

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Posted 23 September 2019 - 01:13 PM

Mic1970

 

Visit this website:     https://doublestar.home.blog

 

He is a CN contributor, and posts regularly to the Double Star Forum, usually with his images.

Which... by the way...  are OUTSTANDING !!

And he does it from his backyard in Colorado.



#13 Dwight J

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Posted 23 September 2019 - 03:09 PM

To get a pleasing image, one where your target double stands out and you get enough separation between the stars, a large image scale is needed.  A long focal length scope, a barlow lens, and/or a small sensor imager would work.  I haven’t done this for years but I used a Philips ToU cam, a C8 with a 2X barlow to get enough scale for most doubles.  Wide ones like Albireo won’t need anything beyond prime focus.  A colour planetary imager would work well.




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