Wide Field Surprise

CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
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weixing
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Wide Field Surprise

Post by weixing »

Hi,
I was testing my Canon EF 50mm f/1.8 II prime lens for wide field astrophotography on last monday 3 Jul 2006 at the multi-storey carpark near my block. I hope I can find the best fastest f-stop for this camera len. I took a 60s (at ISO 800) shot at every f-stop from f/1.8 to f/6.3. A LPR filter was mount on the Lens to reduce the light pollution.

As I was examine the images, I find that I can see some part of milky way on the images. I decided to process and stack the images (12 images at different f-stop :P ) and see what can I get. I setup the camera and lens to take the flat field and dark frame... supposed to took during the imaging session, but I guess it better than none... :P :P

To my surprise, the image looks quite good... Hmm... I think we don't need very dark sky to take decent wide field astrophotograph after all and it is possible to do that in Singapore. :P :P :P

By the way, the fastest f-stop that will produce a decent star image for the Canon EF 50mm F1.8 II prime lens is at f/4... err... at least for my standard. :P

Have a nice day.
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Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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kingkong
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Post by kingkong »

hi weixing, may i know which LPR you used?
thanks.
kong
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ykchia
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Post by ykchia »

Hi WX:

Excellent result - Now how does a single shot ( best shot) look like?

rgds
yK
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mrngbss
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Post by mrngbss »

You mentioned you used a LPR. Is that for telesccoep use? If yes, then how do you fit a 1.25" or 2" LPR to the front of your EF lens?
Wee Nghee the Pooh
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weixing
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Post by weixing »

Hi,
hi weixing, may i know which LPR you used?
I used the celestron LPR filter... I think any broadband filter will do.
Excellent result - Now how does a single shot ( best shot) look like?
Thanks. I post some of the single shot image (all the images are at different f-stop) under another thread: http://www.singastro.org/viewtopic.php?p=26837#26837

You mentioned you used a LPR. Is that for telesccoep use? If yes, then how do you fit a 1.25" or 2" LPR to the front of your EF lens?
Yes. It's a normal Celestron 2" LPR filter for telescope used. Just get a step-down ring (to 48mm) for your camera lens.

Have a nice day.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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chrisyeo
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Post by chrisyeo »

Hi Weixing,

I must say I'm surprised myself! Well done! Is there somewhere we can get the full resolution image?

What seems odd is the bright orange halo in the middle, which I presume is the effect of the LPR. I wonder how to remove the gradients..

Can you post a picture of what the 2" LPR with the step-down ring on the lens looks like? I'm curious to see..

Thanks. Great shot! :)

Chris
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cataclysm
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Post by cataclysm »

That is quite a breakthrough Weixing!
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weixing
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Post by weixing »

Hi,
I must say I'm surprised myself! Well done! Is there somewhere we can get the full resolution image?
I attach a zip file which contain a full resolution medium quality jpeg file... for those who interested to take a look... it look quite ugly at full resolution... I didn't perform a lots of processing on it... too lazy... :P :P
Can you post a picture of what the 2" LPR with the step-down ring on the lens looks like? I'm curious to see..
Ok. No problem.

Have a nice day.
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Yang Weixing
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Tachyon
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Post by Tachyon »

Hmm.. any reason why you use the UV Skylight filter together with the LPR? Might that not cause additional reflections on bright objects?

Just wondering...
[80% Steve, 20% Alfred] ------- Probability of Clear Skies = (Age of newest equipment in days) / [(Number of observers) * (Total Aperture of all telescopes present in mm)]
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weixing
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Post by weixing »

Hi,
Hmm.. any reason why you use the UV Skylight filter together with the LPR? Might that not cause additional reflections on bright objects?
Just to protect my lens only... :P Anyway, I didn't notice any internal reflection at the moment.

Have a nice day.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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