The astrophotography has been keeping me occupied lately. This is my first attempt at planetary imaging. Lots to learn, I know. Don't see much astrophotography here so thought I'd share.
Taken with a 8" f/10 scope with a 2.5x powermate (like a teleconvertor) giving it an equivalent focal length of around 5000mm. Camera was a DBK21 CCD camera.
The dark spot is the shadow of one of the moons, and you can just make out the Great Red Spot at the top.
All up I'm pretty happy with it. Suspect the scope needs some tweaking of the collimation which should give a sharper image. Will have to try that next time, haven't done it before.
>The astrophotography has been keeping me occupied lately. This >is my first attempt at planetary imaging. Lots to learn, I know. >Don't see much astrophotography here so thought I'd share.
>Taken with a 8" f/10 scope with a 2.5x powermate (like a >teleconvertor) giving it an equivalent focal length of around >5000mm. Camera was a DBK21 CCD camera.
>The dark spot is the shadow of one of the moons, and you can just >make out the Great Red Spot at the top.
>All up I'm pretty happy with it. Suspect the scope needs some >tweaking of the collimation which should give a sharper image. >Will have to try that next time, haven't done it before.
Much depends too on "seeing" conditions. The atmospheric stability. Most times you just have to wait and hope for the best days. The very same perfectly collimated optics can provide a draw-dropping 3D-looking view of Saturn one day, and an irregular mushy blob the next. Look into the sharpening techniques that web-cam astrophotographers use, by combining details from many many frames to virtually look through the turbulent atmosphere, capturing and combining those bits of each image that are stable and sharp.
You might also try stopping down the aperture of your telescope during bad seeing conditions. A larger aperture means that your telescope is trying to image through larger lower-frequency areas of atmospheric turbulence. If the turbulence that night is mostly of the lower-frequency variety it will help to filter it out. I keep a 6" mask handy for those times to put on my 16" scope. Apodizing masks also cure things on some days for planetary imaging.
>The astrophotography has been keeping me occupied lately. This >is my first attempt at planetary imaging. Lots to learn, I know. >Don't see much astrophotography here so thought I'd share.
>Taken with a 8" f/10 scope with a 2.5x powermate (like a >teleconvertor) giving it an equivalent focal length of around >5000mm. Camera was a DBK21 CCD camera.
>The dark spot is the shadow of one of the moons, and you can just >make out the Great Red Spot at the top.
>All up I'm pretty happy with it. Suspect the scope needs some >tweaking of the collimation which should give a sharper image. >Will have to try that next time, haven't done it before.
Much depends too on "seeing" conditions. The atmospheric stability. Most times you just have to wait and hope for the best days. The very same perfectly collimated optics can provide a jaw-dropping 3D-looking view of Saturn one day, and an irregular mushy blob the next. Look into the sharpening techniques that web-cam astrophotographers use, by combining details from many many frames to virtually look through the turbulent atmosphere, capturing and combining those bits of each image that are stable and sharp.
You might also try stopping down the aperture of your telescope during bad seeing conditions. A larger aperture means that your telescope is trying to image through larger lower-frequency areas of atmospheric turbulence. If the turbulence that night is mostly of the lower-frequency variety it will help to filter it out. I keep a 6" mask handy for those times to put on my 16" scope. Apodizing masks also cure things on some days for planetary imaging.
> The astrophotography has been keeping me occupied lately. This > is my first attempt at planetary imaging. Lots to learn, I know. > Don't see much astrophotography here so thought I'd share.
> Taken with a 8" f/10 scope with a 2.5x powermate (like a > teleconvertor) giving it an equivalent focal length of around > 5000mm. Camera was a DBK21 CCD camera.
> The dark spot is the shadow of one of the moons, and you can just > make out the Great Red Spot at the top.
> All up I'm pretty happy with it. Suspect the scope needs some > tweaking of the collimation which should give a sharper image. > Will have to try that next time, haven't done it before.
> -- > Troy Piggins
You need at least 25,000mm to really shoot Jupiter. Nice shot at 5000mm though.
In article <20091024013...@usenet.piggo.com>, usenet-0...@piggo.com wrote: >The astrophotography has been keeping me occupied lately. This >is my first attempt at planetary imaging. Lots to learn, I know. >Don't see much astrophotography here so thought I'd share.
>Taken with a 8" f/10 scope with a 2.5x powermate (like a >teleconvertor) giving it an equivalent focal length of around >5000mm. Camera was a DBK21 CCD camera.
>The dark spot is the shadow of one of the moons, and you can just >make out the Great Red Spot at the top.
>All up I'm pretty happy with it. Suspect the scope needs some >tweaking of the collimation which should give a sharper image. >Will have to try that next time, haven't done it before.
>> All up I'm pretty happy with it. Suspect the scope needs some >> tweaking of the collimation which should give a sharper image. >> Will have to try that next time, haven't done it before.
> Much depends too on "seeing" conditions. The atmospheric stability. Most > times you just have to wait and hope for the best days. The very same > perfectly collimated optics can provide a draw-dropping 3D-looking view of > Saturn one day, and an irregular mushy blob the next. Look into the > sharpening techniques that web-cam astrophotographers use, by combining > details from many many frames to virtually look through the turbulent > atmosphere, capturing and combining those bits of each image that are > stable and sharp.
Yes, this image was stacked from around 2500 frames of an avi file using Registax. Suspect that's the technique you're referring to.
> You might also try stopping down the aperture of your telescope during bad > seeing conditions. A larger aperture means that your telescope is trying to > image through larger lower-frequency areas of atmospheric turbulence. If > the turbulence that night is mostly of the lower-frequency variety it will > help to filter it out. I keep a 6" mask handy for those times to put on my > 16" scope. Apodizing masks also cure things on some days for planetary > imaging.
How does one stop down the aperture of a fixed aperture scope? The bare scope is f/10. With the 2.5x powermate it becomes an equivalent f/25. I haven't heard of people using those masks you're referring to. I'll look into it. Thanks.
> On Oct 23, 11:43 am, Troy Piggins <usenet-0...@piggo.com> wrote: > [---=| Quote block shrinked by t-prot: 14 lines snipped |=---] >> tweaking of the collimation which should give a sharper image. >> Will have to try that next time, haven't done it before.
> You need at least 25,000mm to really shoot Jupiter. Nice shot at > 5000mm though.
Anthony Wesley, the guy who discovered the that most recent impact scar on Jupiter, takes these sort of shots with an effective focal length of around 9000mm.
I'd be extremely happy if I can get anywhere near as good as that. Have you ever tried to image with something of the sort of focal lengths you're suggesting with back-yard amatuer gear? I'd love to see examples.
Troy Piggins wrote: > The astrophotography has been keeping me occupied lately. This > is my first attempt at planetary imaging. Lots to learn, I know. > Don't see much astrophotography here so thought I'd share.
> Taken with a 8" f/10 scope with a 2.5x powermate (like a > teleconvertor) giving it an equivalent focal length of around > 5000mm. Camera was a DBK21 CCD camera.
> The dark spot is the shadow of one of the moons, and you can just > make out the Great Red Spot at the top.
> All up I'm pretty happy with it. Suspect the scope needs some > tweaking of the collimation which should give a sharper image. > Will have to try that next time, haven't done it before.Nice one, Troy.
>> All up I'm pretty happy with it. Suspect the scope needs some >> tweaking of the collimation which should give a sharper image. >> Will have to try that next time, haven't done it before.Nice one, Troy.
> Since yours is 2500 stacked images, how come the moon is a dot, not a line? >:-)
They were taken over 90 seconds ;) Not sure, but suspect even that may have been too long. Maybe should have kept it down to 60 secs or so. Jupiter spins so fast you have to get in and get out real quick, so you're using as fast a fps as you can get. Some guys are shooting 45-60fps. The avi file size I took for this was 1.5GB! Just to get a measly little 15kB image!
>>> All up I'm pretty happy with it. Suspect the scope needs some >>> tweaking of the collimation which should give a sharper image. >>> Will have to try that next time, haven't done it before.Nice one, >>> Troy.
>> Since yours is 2500 stacked images, how come the moon is a dot, not >> a line? :-)
> They were taken over 90 seconds ;) Not sure, but suspect even > that may have been too long. Maybe should have kept it down to > 60 secs or so. Jupiter spins so fast you have to get in and get > out real quick, so you're using as fast a fps as you can get. > Some guys are shooting 45-60fps. The avi file size I took for > this was 1.5GB! Just to get a measly little 15kB image!
Cooled camera? Hand or auto-guided? Suburban location? Country?
> Troy Piggins wrote: > [---=| Quote block shrinked by t-prot: 19 lines snipped |=---] >> that may have been too long. Maybe should have kept it down to >> 60 secs or so. Jupiter spins so fast you have to get in and get >> out real quick, so you're using as fast a fps as you can get. >> Some guys are shooting 45-60fps. The avi file size I took for >> this was 1.5GB! Just to get a measly little 15kB image!
I'm considering (don't tell my wife) a cooled CCD for longer exposure, deep sky stuff. They're the duck's nuts. But won't be getting the top of the line ones. They go for $10k or multiples thereof. Reckon something like this will do me:
No guiding. Not for 90 secs or so. Mount was just tracking sidereal rate on its own.
> Suburban location? Country?
Centre of Brisbane. Don't think you could find a much more light polluted location in Queensland :(
Fortunately light pollution doesn't seem to affect planetary imaging so much because the targets are so bright. I'm talking Jupiter, Saturn, Venus, Mars, even Mercury here. For Uranus and Neptune you use more deep sky imaging techniques I think - longer exposures and light pollution does come into it a bit.
This sort of stuff it's more about atmospheric conditions, the jetstream, and scope focus and collimation. I have yet to come to terms with tweaking all that.
Troy Piggins wrote: > * Jeff R. wrote : >> Cooled camera?
> Nope. This one: > http://www.theimagingsource.com/en_US/products/cameras/usb-ccd-bayer/... > I'm considering (don't tell my wife) a cooled CCD for longer > exposure, deep sky stuff. They're the duck's nuts. But won't be > getting the top of the line ones. They go for $10k or multiples > thereof. Reckon something like this will do me:
Long time since I knew much about them things. ISTR colour didn't exist, and you had to use filters and three exposures with a mono unit. I have patience, but not that much.
Waddy'a reckon that unit would retail for? (Any point in asking if you've tried a DSLR ?)
>> Hand or auto-guided?
> No guiding. Not for 90 secs or so. Mount was just tracking > sidereal rate on its own.
Fairy nuff.
> This sort of stuff it's more about atmospheric conditions, the > jetstream, and scope focus and collimation. I have yet to come > to terms with tweaking all that.
Even with all that, don't neglect widefield stuff. Point your camera somewhere around Crux, and do a wide-angle shot for a few minutes (piggy-backed, of course) and the results will astound!
I couldn't believe how much I could see in a short exposure, even here in the 'burbs where the clouds light up like fireworks from the streetlights.
>The astrophotography has been keeping me occupied lately. This >is my first attempt at planetary imaging. Lots to learn, I know. >Don't see much astrophotography here so thought I'd share.
>Taken with a 8" f/10 scope with a 2.5x powermate (like a >teleconvertor) giving it an equivalent focal length of around >5000mm. Camera was a DBK21 CCD camera.
>The dark spot is the shadow of one of the moons, and you can just >make out the Great Red Spot at the top.
On Sat, 24 Oct 2009 07:21:39 +1000, Troy Piggins <usenet-0...@piggo.com> wrote:
>How does one stop down the aperture of a fixed aperture scope? >The bare scope is f/10. With the 2.5x powermate it becomes an >equivalent f/25. I haven't heard of people using those masks >you're referring to. I'll look into it. Thanks.
A simple round hole cut into some opaque plastic, cardboard, or thin aluminum sheeting will suffice. Placed over the opening of your telescope. For a refractor this is easy (no central obstruction). Just place it concentric with the optical axis.
For a reflector the choice is not so easy. The secondary mirror's size is optimized for the light path and f/ratio.
Larger reflector telescopes can use an aperture mask offset to one side, so as to use an unobstructed region of the mirror between the outside diameter of the primary and the outside diameter of the secondary, and situated between the spider-vanes. Consider too the number of spider-vanes you have. If 4 vanes you will have to cut your mask smaller so its diameter fits within an open quadrant between any two spider-vanes.
The huge plus of this for planetary imaging is that now you have an obstruction-free telescope. Of reduced aperture but for bright subjects and due to "seeing" problems this can be a huge plus too. Many people buy 12" or larger reflectors with the intent to only use it as a stopped-down off-axis planetary imager. (8"-10" telescopes too, but you then start to lose resolution due to primary size alone when stopped-down off-axis.) There is a huge cost-savings in buying pre-fabricated easy to make manufactured telescopes much greater than the size needed, as opposed to buying or building an off-axis (asymmetric) reflecting telescope design (see below), or prohibitively expensive refractor of those diameters which is now fraught with CA problems.
With the aperture offset you are no longer plagued with diffraction from secondary mirror and its spider supports. Since this is a reflector, you now have a telescope that is free of all chromatic-aberration, making it much better than a refractor of the same size (large and astronomically expensive refractors bought with planetary imaging in mind). Special asymmetric reflector telescopes are designed this way, but grinding and figuring the offset curvatures are extremely difficult and many ingenious methods were tried and found to try to circumvent this fabrication problem. One of the more ingenious is to grind an achromat corrective lens for use with a standard parabolic mirror set at an angle. This achromat ground to the proper figure by using a creative method found for the home telescope builder, but then you introduce CA problems. Often, to simplify things, they'll just buy a much larger pre-figured mirror and then cut it up into 2 or 3 smaller offset-telescope primaries. (I don't think I could bring myself to do that, even though I have the means. It would be like cutting a favorite child into 2's or 3's.)
By using an offset aperture mask on a large telescope you now have the best of 3 worlds. An exceptional planetary imager (the same as a prohibitively expensive asymmetric reflector telescope), no CA problems as exists in all refractors, and when the mask is removed you now have a very very nice deep-sky light-bucket.
Aside: This is precisely why I chose the size telescope I now have (16" dia.). The 16" also not chosen arbitrarily due to costs nor other issues. When researching I found that due to even the most pristine seeing conditions (unless I am on a mountain-peak), that without adaptive optics the resolution of this size telescope is the same as that of Mt. Palomar's 200" telescope. The weakest link now being caused by the atmosphere itself. There was no appreciable gain in resolution by buying larger. Light-grasp yes, resolution no. (Keep in mind too, this was before image-stacking became popularized to increase resolution. And since I was going to primarily use it for visual astronomy this didn't enter into my decision-making equations. Then, nor now.)
Another plus to an offset mask is that you can rotate the aperture-mask to find a "sweet spot" of your mirror where the figure is the most pristine. This can greatly improve on its 1/8th to 1/20th wavelength of light tolerance across its whole surface.
For smaller telescopes you can try an aperture reducing mask placed concentric with the axis of the telescope, but then the smaller you stop down the aperture the more that diffraction becomes an issue due to the larger percentage of central obstruction vs. the useful light path.
>* Rich wrote : >> On Oct 23, 11:43 am, Troy Piggins <usenet-0...@piggo.com> wrote: >> [---=| Quote block shrinked by t-prot: 14 lines snipped |=---] >>> tweaking of the collimation which should give a sharper image. >>> Will have to try that next time, haven't done it before.
>> You need at least 25,000mm to really shoot Jupiter. Nice shot at >> 5000mm though.
>Anthony Wesley, the guy who discovered the that most recent >impact scar on Jupiter, takes these sort of shots with an >effective focal length of around 9000mm.
>I'd be extremely happy if I can get anywhere near as good as >that. Have you ever tried to image with something of the sort of >focal lengths you're suggesting with back-yard amatuer gear? I'd >love to see examples.
Don't mind Rich, he's just a troll that regurgitates what he's read other trolls invent, or he himself invents. He doesn't even own a camera, much less a telescope. Proved many times by many people. He's only here to play "pretend" with his role-play life, using bits and snippets of info that he happens to find anywhere on the net. He believes anything he reads on the net, with no real-life experience to know the difference of when he's being bullshitted.
Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, eh? :) Sometimes I wish I could retire in a place like Maree or Oodnadatta and enjoy clear, cloudless skyes all year round. I do recall reading a newspaper in the campsite by starlight alone, no moon! Beer (Red Back) ain't half bad over there either... ;)
> Yes, this image was stacked from around 2500 frames of an avi > file using Registax. Suspect that's the technique you're > referring to.
Did you get that size image from the 8" scope and sensor alone or did you add a converter and/or digital resize?
I'm toying around with the idea of a 8" or 10" dobsonian, want to get a feel for what's possible and what's needed. Kids have been bugging me to get back into this stuff...
On Sat, 24 Oct 2009 22:17:05 +1000, Noons <wizofo...@yahoo.com.au> wrote: >Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, >eh? :)
Inland is worse, but then you'd know this if you knew the least bit about photography and astronomy. Another piss poor attempt of yours to try to look like you knew something. Trolls never do.
Outing Trolls wrote,on my timestamp of 24/10/2009 9:24 PM:
> On Sat, 24 Oct 2009 22:17:05 +1000, Noons <wizofo...@yahoo.com.au> wrote:
>> Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, >> eh? :)
> Inland is worse, but then you'd know this if you knew the least bit about > photography and astronomy. Another piss poor attempt of yours to try to > look like you knew something. Trolls never do.
>> I'm considering (don't tell my wife) a cooled CCD for longer >> exposure, deep sky stuff. They're the duck's nuts. But won't be >> getting the top of the line ones. They go for $10k or multiples >> thereof. Reckon something like this will do me:
> Long time since I knew much about them things. > ISTR colour didn't exist, and you had to use filters and three exposures > with a mono unit. > I have patience, but not that much.
All of the high end, top astro imagers still use the mono sensor cameras with filters - the cameras are much more sensitive because each pixel is really a pixel, instead of divided into RGGB.
> Waddy'a reckon that unit would retail for?
It's around $3k for the one I want.
> (Any point in asking if you've tried a DSLR ?)
I've been using a 40D for deep sky stuff to date - galaxies, nebulae, globular and open star clusters. Much cheaper alternative to the above CCDs, but don't have the quantum efficiency, well depth, sensitivity, antiblooming, etc bells and whistles that the CCDs do. But coming from a photography background, much easier to translate over.
My 40D is modified - they remove the UV/IR filter off the sensor and replace it with clear glass. Makes it much more sensitive to IR light spectrum which is what a lot of deep sky, esp nebulae, emit.
If I get a chance to process and upload some of my deep sky images, I'll post links taken with 40D.
That DBK21 camera I took Jupiter with, would never use it for deep sky stuff, only planetary or using it as a guide camera.
>> No guiding. Not for 90 secs or so. Mount was just tracking >> sidereal rate on its own.
> Fairy nuff.
>> This sort of stuff it's more about atmospheric conditions, the >> jetstream, and scope focus and collimation. I have yet to come >> to terms with tweaking all that.
> Even with all that, don't neglect widefield stuff. > Point your camera somewhere around Crux, and do a wide-angle shot for a few > minutes (piggy-backed, of course) and the results will astound!
> I couldn't believe how much I could see in a short exposure, even here in > the 'burbs where the clouds light up like fireworks from the streetlights.
I've got some narrowband filters - Ha, OIII, SII (these refer to narrow bands of wavelengths of light emitted from certain nebulae). They cut out heaps of the light pollution because they only let extremely narrow band of wavelengths of light through.
My intention is to shoot planetary or narrow band shots from home here, and when I get to "dark" sites (remote and no light pollution) I'll do the colour imaging.
> Goos stuff as usual, Piggo. Pity you can't move all that gear > 300 miles inland, eh? :) > Sometimes I wish I could retire in a place like Maree or > Oodnadatta and enjoy clear, cloudless skyes all year round. I > do recall reading a > newspaper in the campsite by starlight alone, no moon! Beer > (Red Back) ain't half bad over there > either... ;)
I've been to a few dark sites this last year, at new moon, not a cloud in the sky. Got a sore neck from constantly gazing up at the sky.
>> Yes, this image was stacked from around 2500 frames of an avi >> file using Registax. Suspect that's the technique you're >> referring to.
> Did you get that size image from the 8" scope and sensor alone > or did you add a converter and/or digital resize?
The C8 8" f/10 schmidt cassegrain I have had a 2.5x powermate (like a teleconvertor) on it, which gave focal length of around 5000mm. Plus the image was slightly cropped to square it up from the sensor size of 640x480.
> I'm toying around with the idea of a 8" or 10" dobsonian, want > to get a feel for what's possible and what's needed. Kids have > been bugging me to get back into > this stuff...
"Aperture rules" - 10" lets in almost twice the amount of light the 8" does ;)
Do you want it for visual observing or taking photos? If visual, all good. If photos, slippery slope. Dobs/Newtonians might be fine for planetary imaging, but no good unless you mount them on equatorial mount for deep sky, long exposure shots.
Troy Piggins wrote,on my timestamp of 24/10/2009 11:06 PM:
> I've been to a few dark sites this last year, at new moon, not a > cloud in the sky. Got a sore neck from constantly gazing up at > the sky.
The dry air inland makes quite a difference: very little haze. Never cease to be amazed how clear the sky is in the desert: I've got photos of Mt Connor at nearly 30Ks that look like the blessed thing is just 5 away.
> The C8 8" f/10 schmidt cassegrain I have had a 2.5x powermate > (like a teleconvertor) on it, which gave focal length of around > 5000mm. Plus the image was slightly cropped to square it up from > the sensor size of 640x480.
Cool. Good luck with convincing the other half for the better camera!
> "Aperture rules" - 10" lets in almost twice the amount of light > the 8" does ;)
Yeah, I know. But it also increases the size and weight of the thing a lot! :(
> Do you want it for visual observing or taking photos? If visual, > all good. If photos, slippery slope. Dobs/Newtonians might be > fine for planetary imaging, but no good unless you mount them on > equatorial mount for deep sky, long exposure shots.
> If you're really keen, email me for more chats.
Mostly visual to start with: can't afford all the imaging stuff at the moment. There are a few suppliers of eq mounts I can use later on once I can afford the photography side. Figured the Dobsonians are a good priced entry point for wide aperture visual and can be used as a base for more advanced stuff. Thanks, I'll definitely ping you later on.
On Sat, 24 Oct 2009 23:56:56 +1000, Noons <wizofo...@yahoo.com.au> wrote: >Outing Trolls wrote,on my timestamp of 24/10/2009 9:24 PM: >> On Sat, 24 Oct 2009 22:17:05 +1000, Noons <wizofo...@yahoo.com.au> wrote:
>>> Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, >>> eh? :)
>> Inland is worse, but then you'd know this if you knew the least bit about >> photography and astronomy. Another piss poor attempt of yours to try to >> look like you knew something. Trolls never do.
>What an idiot...
Inland *is* worse, because inland air is more unstable, has higher fluctuations in humidity levels, often contains more dust and particulate pollutants, and is downright turbulent compared to areas near ocean air. All are enemies of "seeing" conditions. The weakest link when you have a decent telescope optics.
Some of the most stable pristine skies can be found in less-inhabited regions of places like Florida, where any part of the land is only a couple hundred miles from either coastline. The skies deep in the Everglades for example, easily rival the night-skies you will see in some remote national forest at the very top of the Rocky Mountains. (Viewed and photographed the night-skies at both, so I have first-hand experience with these locations for night-sky seeing conditions.) Ocean water has generally laminar air-flows, most of the pollutants have dropped out of the sky--any coming from other land-masses when airflow direction is inland. The fluctuations in humidity levels (a killer of air quality and seeing for astronomy), are usually much more gradual when dealing with ocean air as opposed to inland continental air.
This is why the most favored large telescope installations are built furthest from large land masses, as high as possible (when possible), and surrounded by or very near the largest bodies of ocean water with prevailing inland air-flows. This is precisely why they choose the Hawaiian Islands for some of the larger and more advanced observatories not too long ago. The upcoming mega-telescopes now in construction are being built near the ocean in places like the coastal deserts in Chile near the Pacific shore.
Since he is doing planetary imaging, light-pollution is not much of a concern, unless he gets into the outer planets (which won't show much in a telescope of that size anyway). Or if he'd be trying to do long exposures in place like downtown Times-Square New-York City.
Had you said, "Pity you can't move all that gear to a coastal region further from light pollution." Then you might have been perceived as having an iota of credible experience with either subject, photography or astronomy. Since you gave him the worst advice possible concerning this field of interest, there's only one conclusion possible.
Did you learn anything today? You useless fuck of an ignorant troll.
>>Outing Trolls wrote,on my timestamp of 24/10/2009 9:24 PM: >>> On Sat, 24 Oct 2009 22:17:05 +1000, Noons <wizofo...@yahoo.com.au> wrote:
>>>> Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, >>>> eh? :)
>>> Inland is worse, but then you'd know this if you knew the least bit about >>> photography and astronomy. Another piss poor attempt of yours to try to >>> look like you knew something. Trolls never do.
>>What an idiot...
>Inland *is* worse, because inland air is more unstable, has higher >fluctuations in humidity levels, often contains more dust and particulate >pollutants, and is downright turbulent compared to areas near ocean air. >All are enemies of "seeing" conditions. The weakest link when you have a >decent telescope optics.
>Some of the most stable pristine skies can be found in less-inhabited >regions of places like Florida, where any part of the land is only a couple >hundred miles from either coastline. The skies deep in the Everglades for >example, easily rival the night-skies you will see in some remote national >forest at the very top of the Rocky Mountains. (Viewed and photographed the >night-skies at both, so I have first-hand experience with these locations >for night-sky seeing conditions.) Ocean water has generally laminar >air-flows, most of the pollutants have dropped out of the sky--any coming >from other land-masses when airflow direction is inland. The fluctuations >in humidity levels (a killer of air quality and seeing for astronomy), are >usually much more gradual when dealing with ocean air as opposed to inland >continental air.
>This is why the most favored large telescope installations are built >furthest from large land masses, as high as possible (when possible), and >surrounded by or very near the largest bodies of ocean water with >prevailing inland air-flows. This is precisely why they choose the Hawaiian >Islands for some of the larger and more advanced observatories not too long >ago. The upcoming mega-telescopes now in construction are being built near >the ocean in places like the coastal deserts in Chile near the Pacific >shore.
>Since he is doing planetary imaging, light-pollution is not much of a >concern, unless he gets into the outer planets (which won't show much in a >telescope of that size anyway). Or if he'd be trying to do long exposures >in place like downtown Times-Square New-York City.
>Had you said, "Pity you can't move all that gear to a coastal region >further from light pollution." Then you might have been perceived as having >an iota of credible experience with either subject, photography or >astronomy. Since you gave him the worst advice possible concerning this >field of interest, there's only one conclusion possible.
>Did you learn anything today? You useless fuck of an ignorant troll.
Hardly ever any wind. Hardly ever any rain (those clouds are exceptional). Hardly anyone or anything for many many miles in any direction. Lovely flat terrain over which the air flow stabilises. Oodnadata is not an entirely silly suggestion, except for the thought of living there.
>>Outing Trolls wrote,on my timestamp of 24/10/2009 9:24 PM: >>> On Sat, 24 Oct 2009 22:17:05 +1000, Noons <wizofo...@yahoo.com.au> wrote:
>>>> Goos stuff as usual, Piggo. Pity you can't move all that gear 300 miles inland, >>>> eh? :)
>>> Inland is worse, but then you'd know this if you knew the least bit about >>> photography and astronomy. Another piss poor attempt of yours to try to >>> look like you knew something. Trolls never do.
>>What an idiot...
>Inland *is* worse, because inland air is more unstable, has higher >fluctuations in humidity levels, often contains more dust and particulate >pollutants, and is downright turbulent compared to areas near ocean air. >All are enemies of "seeing" conditions. The weakest link when you have a >decent telescope optics.
>Some of the most stable pristine skies can be found in less-inhabited >regions of places like Florida, where any part of the land is only a couple >hundred miles from either coastline. The skies deep in the Everglades for >example, easily rival the night-skies you will see in some remote national >forest at the very top of the Rocky Mountains. (Viewed and photographed the >night-skies at both, so I have first-hand experience with these locations >for night-sky seeing conditions.) Ocean water has generally laminar >air-flows, most of the pollutants have dropped out of the sky--any coming >from other land-masses when airflow direction is inland. The fluctuations >in humidity levels (a killer of air quality and seeing for astronomy), are >usually much more gradual when dealing with ocean air as opposed to inland >continental air.
>This is why the most favored large telescope installations are built >furthest from large land masses, as high as possible (when possible), and >surrounded by or very near the largest bodies of ocean water with >prevailing inland air-flows. This is precisely why they choose the Hawaiian >Islands for some of the larger and more advanced observatories not too long >ago. The upcoming mega-telescopes now in construction are being built near >the ocean in places like the coastal deserts in Chile near the Pacific >shore.
>Since he is doing planetary imaging, light-pollution is not much of a >concern, unless he gets into the outer planets (which won't show much in a >telescope of that size anyway). Or if he'd be trying to do long exposures >in place like downtown Times-Square New-York City.
>Had you said, "Pity you can't move all that gear to a coastal region >further from light pollution." Then you might have been perceived as having >an iota of credible experience with either subject, photography or >astronomy. Since you gave him the worst advice possible concerning this >field of interest, there's only one conclusion possible.
>Did you learn anything today? You useless fuck of an ignorant troll.
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