Nikon Full-Frame Astro DSLR

http://petapixel.com/2015/02/10/niko...full-frame-dsl
r-astrophotography/

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

On Tuesday, 10 February 2015 21:43:47 UTC-5, Davoud wrote:
http://petapixel.com/2015/02/10/niko...full-frame-dsl
r-astrophotography/

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

"modified" IR filter? Why not just remove it an replace it with a clear glass plate, like lifepixel.com does?

On Tuesday, February 10, 2015 at 8:43:47 PM UTC-6, Davoud wrote:
http://petapixel.com/2015/02/10/niko...full-frame-dsl
r-astrophotography/

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

The problem with these multi-megapixel chips is the very limited well depth and high noise levels. This limits their use in Astro-photography to the limited number of bright objects. The small pixel size and large pixel count does not add up to high resolution when it comes to astronomical images.

To give an example, a very faint object may register a count of only 300 out of 64,000 bits in a 16 bit image using one of these small pixel 35mm chips. The object will be squeezed into a very narrow range between the noise floor, say at 150 and the maximum exposure level of 300. That 150 count range then needs to be stretched into a 16 bit image in order to be processed further.

Contrast that with a similar sized chip consisting of 9 microns or even 12 microns where the well depth is some 5 times larger and the noise level is several times smaller. That same object will now register at a level of 1500, while the noise might be down to a level of 50. The range for this object is then 1450 which is stretched to a 16 bit image with almost 10 times the signal/noise ratio.

Uncapixel

On Wednesday, February 11, 2015 at 2:59:46 PM UTC-5, Uncarollo2 wrote:
On Tuesday, February 10, 2015 at 8:43:47 PM UTC-6, Davoud wrote:
http://petapixel.com/2015/02/10/niko...full-frame-dsl
r-astrophotography/

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

The problem with these multi-megapixel chips is the very limited well depth and high noise levels. This limits their use in Astro-photography to the limited number of bright objects. The small pixel size and large pixel count does not add up to high resolution when it comes to astronomical images.

To give an example, a very faint object may register a count of only 300 out of 64,000 bits in a 16 bit image using one of these small pixel 35mm chips. The object will be squeezed into a very narrow range between the noise floor, say at 150 and the maximum exposure level of 300. That 150 count range then needs to be stretched into a 16 bit image in order to be processed further.

Contrast that with a similar sized chip consisting of 9 microns or even 12 microns where the well depth is some 5 times larger and the noise level is several times smaller. That same object will now register at a level of 1500, while the noise might be down to a level of 50. The range for this object is then 1450 which is stretched to a 16 bit image with almost 10 times the signal/noise ratio.



Has anyone ever directly compared a DSLR to a comparably-priced astronomical CCD camera? Same scope, same night, etc?

Davoud:
http://petapixel.com/2015/02/10/niko...full-frame-dsl
r-astrophotography/

Uncarollo2:
The problem with these multi-megapixel chips is the very limited well depth
and high noise levels. This limits their use in Astro-photography to the
limited number of bright objects. The small pixel size and large pixel count
does not add up to high resolution when it comes to astronomical images.

To give an example, a very faint object may register a count of only 300 out
of 64,000 bits in a 16 bit image using one of these small pixel 35mm chips.
The object will be squeezed into a very narrow range between the noise floor,
say at 150 and the maximum exposure level of 300. That 150 count range then
needs to be stretched into a 16 bit image in order to be processed further.

Contrast that with a similar sized chip consisting of 9 microns or even 12
microns where the well depth is some 5 times larger and the noise level is
several times smaller. That same object will now register at a level of 1500,
while the noise might be down to a level of 50. The range for this object is
then 1450 which is stretched to a 16 bit image with almost 10 times the signal/noise ratio.

True enough, I'm sure. Nonetheless, there are plenty of bright
objects--M42, M45, M1, M31, the Milky Way, Comets, the Moon, and so on,
to satisfy an entry-level astrophotographer using a DSLR. S/he knows
nothing of noise floors, full wells, and the like, but still manages to
produce satisfying astrophotos with a camera that has custom white
balance controls and can thus be used for a variety of other purposes
as well. Tools like Pixinsight and Photoshop help too, of course.

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

On Wednesday, February 11, 2015 at 10:48:17 PM UTC-5, RichA wrote:
On Wednesday, February 11, 2015 at 2:59:46 PM UTC-5, Uncarollo2 wrote:

pedantic rant deleted

Has anyone ever directly compared a DSLR to a comparably-priced astronomical CCD camera? Same scope, same night, etc?

The comparisons between some DSLR and mid-range CCD seem close enough, at least with well-known objects.

Here is one, somewhat dated perhaps:

http://www.astroacres.com/dslr_vs_ccd.htm

Years ago in one of the mags, there happened to be film images of the M8+M20 region taken through a $$$$ Mak and through a small achro refractor piggybacked on a $$ MCT. The $$$$ Mak photo was certainly better, but the image from the small scope wasn't bad at all.

For many newbies, a $$$$ CCD will remain a dream, whereas a $ DSLR might not.

On Thursday, 12 February 2015 11:01:35 UTC+1, wrote:
(That concept eludes ugggaroller.)

According to Snell's law you are dense. And [therefore] slower than those of us who see the light unbesmirched by your bending [the truth] through your own [fractious] medium.

QED.

On Thursday, February 12, 2015 at 5:34:45 AM UTC-5, Chris.B wrote:
On Thursday, 12 February 2015 11:01:35 UTC+1, wsne... wrote:
(That concept eludes ugggaroller.)

According to Snell's law you are dense. And [therefore] slower than those of us who see the light unbesmirched by your bending [the truth] through your own [fractious] medium.

How much light have you seen through that unfinished 10-inch scope that you have been putzing around with for the last few years?

On Thursday, 12 February 2015 12:20:07 UTC+1, wrote:

How much light have you seen through that unfinished 10-inch scope that you have been putzing around with for the last few years?

Our ATM hero [Moi] has enjoyed a number of observing sessions under the night sky. Much as I hate to criticise, your sense of passing time is limited to your expenditure on thrift shop watches with automatic calendars. I have owned the 10" optics for less than two years. But, please, don't let the truth get in the way of your bitching.

Better a potty ATM than the Tea Party's bitch!

On Thursday, February 12, 2015 at 11:23:54 AM UTC-6, Chris.B wrote:
On Thursday, 12 February 2015 12:20:07 UTC+1, wrote:

How much light have you seen through that unfinished 10-inch scope that you have been putzing around with for the last few years?

Our ATM hero [Moi] has enjoyed a number of observing sessions under the night sky. Much as I hate to criticise, your sense of passing time is limited to your expenditure on thrift shop watches with automatic calendars. I have owned the 10" optics for less than two years. But, please, don't let the truth get in the way of your bitching.

Better a potty ATM than the Tea Party's bitch!

Don't take it personal Chris. Snellieboy is on a raving windmill tilting journey. He has us all in his sights (you, me, Peterson, Palsing, the video astronomer, and who knows who else). So no matter what you say, regardless of the subject, he's there to set you straight, the little demigod. Now isn't that just so cute?