oraclePosted By Yang Shuai |
How does the Televue Oracle3 compare to the televue Pronto. What would a good price be for a used Oracle.
Posts Made By: Yang Shuai
March 9, 2004 04:34 PM
Forum:
TeleVue
April 18, 2005 10:47 PM
Forum:
Refractors
Sky 90 or TMB 80Posted By Yang Shuai |
I am looking for a small portable apo refractor. I am wondering whether I should get the sky 90 with its 10mm advantage in aperture or TMB 80 with its perfect color correction. How do they compare under the stars?
June 27, 2005 02:25 AM
Forum:
Refractors
TMB 80 CollimationPosted By Yang Shuai |
Hi
Does anyone know whether the Tmb 80/480 can be user collimated.
Does anyone know whether the Tmb 80/480 can be user collimated.
November 25, 2005 06:17 PM
Forum:
Refractors
Effect of Dust on Optical PerfomancePosted By Yang Shuai |
Just wondering how much of an effect dust have optical performance. I often hear that a small amount has no effect. Is this true? How much dust is needed before having an impact on image quality. What about scratches or imperfection in the lens. I saw ads for refractors and for telephoto lens that states they have one or two small scratches on the lens but no effect in image quality. Could that be possible?
December 23, 2005 04:36 PM
Forum:
Digital SLR AstroPhotography
Red strips/bands in photoPosted By Yang Shuai |
I was out recently trying out my digital rebel xt for some simple night photography. Unfortunately some photos have some faint red strips through them. Not all the photos have some. Can anyone tell me what they are and what is causing it.
Exposure was 30" @ f/4 @ ISO1600. In camera dark frame subtraction was used.
Also there seem to be considerable noise in the photo. Is that normal for a exposure of only 30"? Does dark frame subtraction help reduce noise or does it just take care of hot pixels?
Would noise reduction programs like NeatImage and NoiseNinja work on astrophotos or would it take out faint stars.
Exposure was 30" @ f/4 @ ISO1600. In camera dark frame subtraction was used.
Also there seem to be considerable noise in the photo. Is that normal for a exposure of only 30"? Does dark frame subtraction help reduce noise or does it just take care of hot pixels?
Would noise reduction programs like NeatImage and NoiseNinja work on astrophotos or would it take out faint stars.
August 30, 2006 11:07 PM
Forum:
Refractors
Piggyback TMB 80Posted By Yang Shuai |
Can anyone suggest a way to piggyback a camera or attach a finder to a TMB 80/480. What accessory would I need.
September 1, 2006 07:04 AM
Forum:
Digital SLR AstroPhotography
Lens RecommendationPosted By Yang Shuai |
In your experience, which lens works best for astrophotography. I have found that some lens that are stellar for daytime photography don't do very well after dark. ie Zeiss 50mm f1.7, Nikon 17-35mm f2.8 and Canon 300mm f4L. What really bothers me are the chromatic abberrations I have seen from many lens, even those that are highly rated. In most cases, even fairly faint stars are surrounded by a blue halo and with some lens it is blue on one side and red on the other. The lens you recommend can be in any mount and I am interested in your opinion on everything from ultra wideangle to supertelephoto.
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