KINDA OLD BUT I STILL LIKE ITPosted By Roland Christen |
I love it!
Rolando
Rolando
Posts Made By: Roland Christen
June 3, 2005 11:41 PM
Forum:
Bad to the Bone Autos
June 7, 2005 05:51 PM
Forum:
CCD Imaging and Processing/Deep Sky
Another M13!Posted By Roland Christen |
>Even at f4.5 I get lots of distortion in the corners>>
Just a word about optical terms. Distortion is a simple displacement of a star image from its ideal position. It is the aberration common in inexpensive binocular eyepieces which show up as a bending of straight lines at the edge of the field of view (telephone poles bend away from the center as you sweep the bino across the field).
Distortion does NOT cause elongation of star images at the field edges (this is astigmatism). Distortion does NOT cause stars to have seagull or comet shapes (this is coma). Distortion is not the same as a lack of a flat field (this is field curvature, which also does not cause mishapened stars, rather it causes stars to be slightly out of focus at the field edges).
End of optics lesson
Roland Christen
Just a word about optical terms. Distortion is a simple displacement of a star image from its ideal position. It is the aberration common in inexpensive binocular eyepieces which show up as a bending of straight lines at the edge of the field of view (telephone poles bend away from the center as you sweep the bino across the field).
Distortion does NOT cause elongation of star images at the field edges (this is astigmatism). Distortion does NOT cause stars to have seagull or comet shapes (this is coma). Distortion is not the same as a lack of a flat field (this is field curvature, which also does not cause mishapened stars, rather it causes stars to be slightly out of focus at the field edges).
End of optics lesson
Roland Christen
June 8, 2005 05:10 PM
Forum:
CCD Imaging and Processing/Deep Sky
M13 processing help wantedPosted By Roland Christen |
M13 is one of the most difficult objects to get right. The sharper your optics are, the duller it will look because the stars just get so small that they occupy a small fraction of the space and leave more and more dark sky behind. What gets most people to say WOW is to burn the core out and show the outer fainter stars. But this eliminates the interesting core detail.
One way to bring out the outer stars without burning out the core is to use DDP in MaximDL. This processing step basically supresses the brightest stars and enhances the faint outer ones. The main advantage is that it prevents to a great degree the bloating of the brighter stars. Note "Mickey Mouse" in the two examples in the attached images.
Both images were taken with the 160F7.5 AP refractor and ST10XE camera. This first one is with normal processing. Note tyhe bloated looking stars.
Roland Christen
One way to bring out the outer stars without burning out the core is to use DDP in MaximDL. This processing step basically supresses the brightest stars and enhances the faint outer ones. The main advantage is that it prevents to a great degree the bloating of the brighter stars. Note "Mickey Mouse" in the two examples in the attached images.
Both images were taken with the 160F7.5 AP refractor and ST10XE camera. This first one is with normal processing. Note tyhe bloated looking stars.
Roland Christen
June 14, 2005 11:11 PM
Forum:
Equipment Talk
One For Roland ChristenPosted By Roland Christen |
The best method to know the exact wavefront error of your scope is to use the Roddier method. It requires that you take two images of an out-of-focus star (inside and outside focus). The images must be defocused to approximately 150 pixels. The camera must record them in 16 bit Fits format. Once you have these images, you can post them in the full 16 bit Fits format (only 150x150 pixels, please), and I can run a Roddier analysis. I would need to know the focal length and aperture of the telescope, and the size of the pixels used (the Fits header will provide that).
Roland Christen
Roland Christen
June 16, 2005 02:17 AM
Forum:
Equipment Talk
A Lesson in Low PowersPosted By Roland Christen |
Hi Alan,
We just had a similar discussion in the Binocular group. I tired to explain that a 15x50 bino would seem sharp on stars simply because the exit pupil would be small compared with normal binoculars. I don't think anyone really believed me .
Roland Christen
We just had a similar discussion in the Binocular group. I tired to explain that a 15x50 bino would seem sharp on stars simply because the exit pupil would be small compared with normal binoculars. I don't think anyone really believed me
.Roland Christen
June 16, 2005 02:31 PM
Forum:
Astro-Physics
Herschel wedgePosted By Roland Christen |
No problem.
Roland Christen
Roland Christen
June 17, 2005 04:29 PM
Forum:
Astro-Physics
AP160...delayed...*%#!Posted By Roland Christen |
There are no other projects delaying this refractor. I am putting all my efforts into making these lenses. I am here from 7 am until 9 pm every day. The spindles are running all that time. I have cancelled all my vacation plans for this summer to finish this project. The delay has been more due to the lens being totally new and some issues had to be worked out for more efficient production. Tooling, assembly processes, etc. I will do as much as humanly possible to get these all out well before Jan 2006. That was just an estimate by our office based on the progress so far, but I assure you that production is going much smoother as I climb down the learning curve.
I would not blame you if you wanted to cancel and buy something else, and we would certainly accomodate your request.
Roland Christen
I would not blame you if you wanted to cancel and buy something else, and we would certainly accomodate your request.
Roland Christen
June 20, 2005 03:18 PM
Forum:
CCD Imaging and Processing/Deep Sky
Strange dark frame pattern.Posted By Roland Christen |
Take several dark frames. Sometimes there is a left-over image from a previous exposure that appears in the first dark frame.
Roland Christen
Roland Christen
June 21, 2005 01:33 PM
Forum:
Astro-Physics
Whatcha think Roland ??Posted By Roland Christen |
I'm seriously looking for opticians, but they need to know what they are doing and need to have experience with production of precision optics.
Roland Christen
Roland Christen
June 24, 2005 01:03 PM
Forum:
CCD Imaging and Processing/Solar System
A final JupiterPosted By Roland Christen |
Looks super to me!
Roland Christen
Roland Christen
Funding Member
