pjphilli
02-12-2010, 02:55 PM
Hi
I recently bought a GSO 8in Ritchey Chretien scope and although the weather in Sydney has not permitted any serious imaging with it I have run it through its paces for focusing and images tests. Please see the attached 20 second image of Rigel taken with a modified Canon 400D camera with lpf on the 8in RC at f8. I know Rigel is a very bright star but with only a 20 second image I was surprised to see an apparent "ghost" reflection of the RCs secondary mirror behind the image of Rigel. Longer test images of this star worsened this effect. Is this test too tough?
I see that there has been a previous thread regarding flaring on images by nearby OFF screen bright stars but I was told that this problem with the inner scope tube had been rectified. Any comments?
Cheers Peter
I recently bought a GSO 8in Ritchey Chretien scope and although the weather in Sydney has not permitted any serious imaging with it I have run it through its paces for focusing and images tests. Please see the attached 20 second image of Rigel taken with a modified Canon 400D camera with lpf on the 8in RC at f8. I know Rigel is a very bright star but with only a 20 second image I was surprised to see an apparent "ghost" reflection of the RCs secondary mirror behind the image of Rigel. Longer test images of this star worsened this effect. Is this test too tough?
I see that there has been a previous thread regarding flaring on images by nearby OFF screen bright stars but I was told that this problem with the inner scope tube had been rectified. Any comments?
Cheers Peter