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G2 night sky tests

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Kevin Burfitt

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Last night I did some test shots to see the best settings to take photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back yard facing straight upwards, setting it to manual (15seconds, f2.0) and using the remote to take several shots which I then merged in Photoshop.

Conditions were not perfect - there is a fair bit of light pollution where I live and it was very windy (so the camera probably shook a little)

These were not guided photos so there is field rotation in the shot (I'll move up to guiding them with a telescope later, first I want to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine images better, or anything else that would improve them, I'd love to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
 
Really nice shots. Surprising, actually - I wouldn't have expected combining shots to produce a much different effect than, say, adjusting levels.

You mention you're thinking of using a telescope next time. Do you have one? I've got a Celestron 8" telescope with motor drives, and have thought about mounting my camera on that (not necessarily through the telescope, but on the mount, to take advantage of the drive). Up 'til now though, I didn't think it would make much of a difference, as 3×zoom at 15" exposure produces negligible rotation trails.

Scott.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
--

The only thing to do with good advice is pass it on; it is never of any use to oneself. - Oscar Wilde
http://www.ScottOwen.org
 
s©tt said:
Really nice shots. Surprising, actually - I wouldn't have expected
combining shots to produce a much different effect than, say,
adjusting levels.
Click to expand...
Combining is much better than adjusting levels because it is much closer to actually having a longer exposure on your shot (If you think about normal photos this makes sense, otherwise you could shoot everything at 1/1000th of a second and just adjust the levels)

I'd really like to combine the images as 16-bit TIFFs but Photoshop 6 doesnt seem to let me do that with 16bit, just 8bit.

For comparison I'll put a single frame up with adjusted levels too
s©tt said:
You mention you're thinking of using a telescope next time. Do you
have one? I've got a Celestron 8" telescope with motor drives, and
have thought about mounting my camera on that (not necessarily
through the telescope, but on the mount, to take advantage of the
drive). Up 'til now though, I didn't think it would make much of a
difference, as 3×zoom at 15" exposure produces negligible rotation
trails.
Click to expand...
I want to 'piggyback' mount the camera on the telescope - I have an ETX-90 with polar mounting (you need Polar to hide the rotation).

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
 
Kevin Burfitt said:
closer to actually having a longer exposure on your shot (If you
think about normal photos this makes sense, otherwise you could
shoot everything at 1/1000th of a second and just adjust the levels)
Click to expand...
Of course you're right, I'm just surprised it worked out so well. I'll try a few... just as soon as I get my camera back from repair :-/
Kevin Burfitt said:
I want to 'piggyback' mount the camera on the telescope - I have an
ETX-90 with polar mounting (you need Polar to hide the rotation).
Click to expand...
Yes, I too have a 'polar' (or equatorial) mount on my C8, with drives to compensate the Earth's rotation. Have your found a piggyback-mount for your camera yet?

Scott.

--

The only thing to do with good advice is pass it on; it is never of any use to oneself. - Oscar Wilde
http://www.ScottOwen.org
 
Hi Kevin,

I am really impressed about your ski pictures!

I am quite newbie in this. Last afternoon I read about "combining pictures with Photoshop".

How are you suppressing the noise?? As far as I can understand, if you just stack two pictures you are to have more noise.

You are also saying that combining is better than adjusting levels. Do you mean that levels will be higher?

Do you know some document I can read about this matter??

By the way, I found a site with a freeware software for stacking astro pictures:

http://www.astrostack.com/download.html

Nexus.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
 
Nexus said:
Hi Kevin,

I am really impressed about your ski pictures!

I am quite newbie in this. Last afternoon I read about "combining
pictures with Photoshop".

How are you suppressing the noise?? As far as I can understand, if
you just stack two pictures you are to have more noise.
Click to expand...
Yes, the noise increases through stacking if you don't do it right - and I'm not 100% certain I'm doing it right yet, I'll need to ask some photoshop experts!

I used the function I did because it looked good, today I'll find out what function I really should have been using to reduce noise.
Nexus said:
You are also saying that combining is better than adjusting levels.
Do you mean that levels will be higher?
Click to expand...
If you average all the images together, then the noise tends to cancel out but the actual starlight will tend to stay solid. This can then have its levels adjusted.

Ideally I'd like to do this on the RAW image from the G2, which has 10-bits per channel, so I could stack up to 64 images without losing a single bit of information.
Nexus said:
Do you know some document I can read about this matter??
Click to expand...
I don't know a specific one, but there are many on the net - even ones that talk about stacking negatives for conventional astrophotography (not digital) - so it seems to be a well-known method.
Nexus said:
By the way, I found a site with a freeware software for stacking
astro pictures:

http://www.astrostack.com/download.html
Click to expand...
Yes, I've used that for smaller images, but it cannot handle full-sized 2274x1702 images from the g2, and the new version which handles 1600x1200 does not yet work with color.

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
 
Nice job Kevin. I would try shooting at ISO 50 as you will get the least amount of CCD noise. Yes this will mean longer exposure (more images) but the results should be cleaner.

Morris
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
 
morris said:
Nice job Kevin. I would try shooting at ISO 50 as you will get the
least amount of CCD noise. Yes this will mean longer exposure
(more images) but the results should be cleaner.
Click to expand...
I'll try that tonight (if the sky is clear) - but I was wondering what the best ISO would be...

Obviously ISO 50 has less CCD noise, but it also picks up less light, so what I really want is the best signal-to-noise ratio (which may be ISO50, but could potentially be ISO100 or something else) - I wish I knew how to test signal-to-noise on an image :)

I think I'll try to drag the computer out into the garden and use some remote capturing software (Breezes G2Remote sounds cool, I might try that) - easier than pressing the remote button lots of times

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
 
Wow, what lens are you using? Seems like an extremely narrow field of view.
Kevin Burfitt said:
morris said:
Nice job Kevin. I would try shooting at ISO 50 as you will get the
least amount of CCD noise. Yes this will mean longer exposure
(more images) but the results should be cleaner.
Click to expand...
I'll try that tonight (if the sky is clear) - but I was wondering
what the best ISO would be...

Obviously ISO 50 has less CCD noise, but it also picks up less
light, so what I really want is the best signal-to-noise ratio
(which may be ISO50, but could potentially be ISO100 or something
else) - I wish I knew how to test signal-to-noise on an image :)

I think I'll try to drag the computer out into the garden and use
some remote capturing software (Breezes G2Remote sounds cool, I
might try that) - easier than pressing the remote button lots of
times

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
 
s©tt said:
Really nice shots. Surprising, actually - I wouldn't have expected
combining shots to produce a much different effect than, say,
adjusting levels.
Click to expand...
Noise is random whereas the image content is not. Therefore, if you add two pictures, you increase the noise energy by 2x, but the image energy by 4x. As a result, the signal-to-noise ratio is reduced by 2x. You can extend this to as many images as you wish. Said another way, you are averaging away the random noise while preserving the image. The only downside is that the image may change or move between shots, creating blurring, just as with a long exposure.

It is common in many types of measurements to take multiple measurements and average them to reduce noise.
 
A similar thread is here:
http://www.dpreview.com/forums/read.asp?forum=1010&message=3178928

I have some astrophotography at http://www.pbase.com/emagowan/astrophotography and some comet photos there as well. When I get home this evening I'll post some of the Lyra shots using the heat sinks. I usually piggyback the camera on a C8. I prefer ISO 50 or 100.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
 
Very nice pics! How do you piggyback your cam on your C8? (I have a C8 too.)

Which program/tools to you use to stack your images?

How did you get such enlargements of e.g. Jupiter? (i.e. which camera, lenses, mounting, postprocessing etc.?)

Scott.
Ed Magowan said:
I have some astrophotography at
http://www.pbase.com/emagowan/astrophotography and some comet
photos there as well. When I get home this evening I'll post some
of the Lyra shots using the heat sinks. I usually piggyback the
camera on a C8. I prefer ISO 50 or 100.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
Click to expand...
--

The only thing to do with good advice is pass it on; it is never of any use to oneself. - Oscar Wilde
http://www.ScottOwen.org
 
Hi,

I found this link to a combining software in one of the dpreview's forums. I have tried it and it works quite good for a newbie like I do...

http://www.stepok.com/dpp/dpp.htm

I have also tried to combine uncomposed RGB pictures (got them from AstroStack) and I have got good color pictures too.

Try it out and tell what you think. I am rather interested in learning more about this exciting matter!

Cheers,
Nexus.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
 
I heard there will be meteor showers tonite from 6-9pm eastern (aug 12)

wonder if i will be able to capture it from my digicam.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
--
--------------------------------------------------------------------
Canon s330, Canon s110, Olympus 340R owner
http://kaizenbiz.com/jush/pub/s330tests
 
You should be able to, if you have a clear sky, free of light-polution due to street lights, greenhouses etc.

On average, there will be one meteorite per minute, so get your camera on a tripod, M-mode, wide aparerature, 2-second delay timer, 15"-exposure, and just continue taking pictures.

The best direction in which to point the camera is probably in the direction of the Earth's orbit about the Sun, but straight up shoud also be fine.

Good luck, and please post any results!

Regards,
Scott.
graph110 said:
wonder if i will be able to capture it from my digicam.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
--
--------------------------------------------------------------------
Canon s330, Canon s110, Olympus 340R owner
http://kaizenbiz.com/jush/pub/s330tests
--------------------------------------------------------------------
Click to expand...
--

The only thing to do with good advice is pass it on; it is never of any use to oneself. - Oscar Wilde
http://www.ScottOwen.org
 
The best time should be from 10pm eastern on (as in until morning twilight). And yes, if the shutter is open when a meteor passes by, you'll certainly catch it. Good luck and clear skies!
graph110 said:
wonder if i will be able to capture it from my digicam.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
--
--------------------------------------------------------------------
Canon s330, Canon s110, Olympus 340R owner
http://kaizenbiz.com/jush/pub/s330tests
--------------------------------------------------------------------
Click to expand...
 
I use a piggy back mount I picked up from Rex's Astrostuff at the Mid-South Stargaze in French Camp, MS. You should be able to order a similar one from any Celestron or Meade dealer. I'd recommend one with a ball/swivel mount so the camera can be aimed wherever you want.

The stacked images (Jupiter, Moon, Saturn) in my pbase gallery are stacked video frames, not shots from the G2. Taken with a surveillance-type camera purchased from Supercircuits.com. Last week I received a 25mm Plossl and Digi-T adapter from Scopetronix and will be using that with a Canon ZR20DV camera and donate the surveillance camera to my astronomy club. I used Astrostack for the video frames but it is unable to handle the file sizes produced by the G2. You can stack with Photoshop but I'm a newbie with Photoshop and am not very proficient yet. Many other image editing programs will enable stacking also - the big advantage to Astrostack is that it does a good job of automatically aligning the images.
s©tt said:
Which program/tools to you use to stack your images?

How did you get such enlargements of e.g. Jupiter? (i.e. which
camera, lenses, mounting, postprocessing etc.?)

Scott.
Ed Magowan said:
I have some astrophotography at
http://www.pbase.com/emagowan/astrophotography and some comet
photos there as well. When I get home this evening I'll post some
of the Lyra shots using the heat sinks. I usually piggyback the
camera on a C8. I prefer ISO 50 or 100.
Kevin Burfitt said:
Last night I did some test shots to see the best settings to take
photos of the Milky Way.

These were simply done by placing the G2 on a chair in the back
yard facing straight upwards, setting it to manual (15seconds,
f2.0) and using the remote to take several shots which I then
merged in Photoshop.

Conditions were not perfect - there is a fair bit of light
pollution where I live and it was very windy (so the camera
probably shook a little)

These were not guided photos so there is field rotation in the shot
(I'll move up to guiding them with a telescope later, first I want
to figure out how to combine them properly).

If anyone has any comments on what ASA to use, or how to combine
images better, or anything else that would improve them, I'd love
to hear.

http://www.pbase.com/zaphus/sky_photography

--
Homepage: http://www.torps.com
Gallery: http://www.pbase.com/zaphus
Click to expand...
Click to expand...
--
The only thing to do with good advice is pass it on; it is never of
any use to oneself. - Oscar Wilde
http://www.ScottOwen.org
Click to expand...
 
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