Kirjoittaja Aihe: Looking for help to photograph the diffraction limit of telescope  (Luettu 722 kertaa)

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Poissa sheungyiuphoto

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Hi everyone, I am an international art student here in Helsinki and wanted to asking for help with astro-photography. My Finnish is really basic so please excuse me for using English to write this post. I am a newbie in astro photography so I would appreciate if you can give me some guidance on how to achieve three specific images I want.

I recently read about Rayleigh's criterion (angular resolution) and am inspired by how the resolution of telescopes and other optics instrument is limited by the diffraction of light.


For that reason, I want to photograph three images of Gamma Virginis using a diffraction limited telescope. I want to take photos of (1) an indisguishable blob of the two stars (2) a clear distinct two stars and (3) Gamma Virginis with diffraction rings around them. I read in this article (http://www.skyandtelescope.com/observing/pushing-limits-a-spring-sky-double-star-romp/)  that Gamma (γ) Virginis is one of the finest double stars in the sky is a nice test for a 3-inch telescope. I am interested in seeing the images and also photographing the telescope myself. 

I wonder if anyone is interested in showing me online/ in person on how to achieve the effect, as well as, where to rent a 3-inch telescope in Helsinki. I would also really like to join seminar and events here conducted in English too. You can contact me at sheung.yiu.photo (at) gmail.com if you are interested in getting involved or if you have any questions. Thanks.

Poissa AstroIle

  • Periodinen komeetta
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Hello,

I think that you use public trlescopes like kaivopuiston tähtitorni. Check Ursa in this site. And ask advice.
Astrophotography is not easy. Double star photography method may be same as planetary photography by staking several hundreds of pictures (check planetary cameras). You should be patient because difraction limit weather is not every day matter.

Br.Astroile

Poissa Lithos

  • Galaksijoukko
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You should also use as small diameter telescope as possible, as you will not really be able to photograph diffraction limit of a scope, if you never get to image in seeing that makes it achievable. 50 - 100 mm objective diameter would make the task of reaching the diffraction limit of the optics far easier. Usually you can reach diffraction limit of only very low resolution (small objective diameter) telescope in usual quality skies.

Small, high quality apochromatic refractor, or perhaps achromat with say, green filter and mono planetary camera might be good choices to tackle your task. Choosing a star that is as high in the sky as possible will also help you some, as you will have least amount of atmosphere between you and the target.
Laitteet:
Sky-Watcher Explorer 200P / EQ5 (DK3 moottorit)
Celestron Nexstar 102 SLT
Sky-Watcher Skymax 127
Sky-Watcher Explorer 130 PM / EQ2

Poissa sheungyiuphoto

  • Meteoroidi
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  • Viestejä: 3
Hello,

I think that you use public trlescopes like kaivopuiston tähtitorni. Check Ursa in this site. And ask advice.
Astrophotography is not easy. Double star photography method may be same as planetary photography by staking several hundreds of pictures (check planetary cameras). You should be patient because difraction limit weather is not every day matter.

Br.Astroile

Thank you for your advice. I will definitely go have a look at the public telescopes. I emailed Ursa and they actually referred  me here. Let me go browse other forums on this site. Cheers.


Poissa sheungyiuphoto

  • Meteoroidi
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  • Viestejä: 3
You should also use as small diameter telescope as possible, as you will not really be able to photograph diffraction limit of a scope, if you never get to image in seeing that makes it achievable. 50 - 100 mm objective diameter would make the task of reaching the diffraction limit of the optics far easier. Usually you can reach diffraction limit of only very low resolution (small objective diameter) telescope in usual quality skies.

Small, high quality apochromatic refractor, or perhaps achromat with say, green filter and mono planetary camera might be good choices to tackle your task. Choosing a star that is as high in the sky as possible will also help you some, as you will have least amount of atmosphere between you and the target.

Thank you! so to re-iterate what you said, the best (better) telescopr combination for my purpose is:
a 3-inch telescope with a 50-100mm objective + apochromatic refractor pointing to the high sky.
Although I just check on a star map that Gamma Virginis appears to be pretty low in the sky right now, maybe this month is not the best time for it I guess.