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04-22-2009, 03:06 AM   #16
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It is better to shot with analog cameras then digital because the sensor gets "hot" during long exposures and you might get some errors.

04-22-2009, 03:50 AM   #17
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QuoteOriginally posted by netuser Quote
Hi, is it possible to do this kind of pictures with k20d and only using lenses and/or adapter/extention tubes ??
Well, the photog used fairly standard equipment. And for most of the images on display he does not even need any tracking mount. All the star trail images and the night landscapes are simply shot with a stationary camera. (Probably mounted on a good tripod.)

Only shots like comet Hale-Bopp would require a tracking platform of sorts. This could either be a standard equatorial telescope mount (I use an old Vixen SuperPolaris for travelling.) or it could be a dedicated camera tracker, like the Astrotrak.

And only the few moon shots really require longer focal lengthes, which you could achieve more easily with a telescope or spotting scope. In this case (moon, sun etc.), even despite the short exposure times, you would also need a telescope mount for tracking.

I have added two recent images for illustration: the first is a night scene: The Jungfrau massif, lit by moonlight (Bernese Oberland, Swiss), stationary camera on tripod

and the second is a favourite among astrophotography beginners: M42 - The Orion nebulae. Both shot with the K20. Camera on telescope with tracking mount

Ben
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04-22-2009, 04:05 AM   #18
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Thanks Ben.

I think I better not learn anything else related or I will have to start saving for a scope lol
04-22-2009, 10:24 AM   #19
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how would something like this:

Orion 254mm f/4.7 Reflector Telescope Optical Tube - Telescope.com

mount to a k20d? 1200mm, f4.7 for a cheap price i think.

04-22-2009, 12:00 PM   #20
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QuoteOriginally posted by WerTicus Quote
how would something like this:

Orion 254mm f/4.7 Reflector Telescope Optical Tube - Telescope.com

mount to a k20d? 1200mm, f4.7 for a cheap price i think.
The Orion reflectors have a good reputation, considering their really good pricing. But for photography (you mean terrestial or astro?) you should also consider adding a corrector/field flattener, as Newtonian scopes are notorious for their coma at the edge of the field - especially these fast ones. Thats's an additional 200 bucks or so. And then you are still left with the question how to mount that beast.

Ben
04-22-2009, 08:02 PM   #21
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As Marc discovered, the Original Poster linked to an example photo that was taken with a 28 mm lens. On a Pentax DSLR it would be roughly like a kit lens 18mm.

People have offered several mount suggestions. A Barn Door mount is cheap, especially if you build it. OTOH it is single purpose. It can't do much else but wide angle astrophotos. Next step up is an equatorial camera mount, there are a few on the market. In my opinion they cost more than a small motorized telescope mount. Next step is a motorized, "German Equatorial Mount" for perhaps $150 that could be used for a camera and would also handle a small telescope in the future. Finally, you could buy a modest telescope with motorized mount to which the camera can be used "piggy back" with a lens as well as on the scope for high power. This is the most versatile and you might actually find you enjoy astronomy.

Hint about Equatorial mounts: They must be Polar Aligned. Be sure you get instructions for whatever mount you choose. OTOH the camera need not be precisely aligned to the mount. My camera mount is about 5 degrees off from the axis of the scope and it makes no difference.

Next obstacle is exposure time. Where I live the light pollution limits me to 1-2 minute exposures with my modified K110D. This is way to short to approach the example photo. To get a long total exposure you pretty much have to stack multiple images. Or image from a really dark location on a cool night.

Here is a Milky Way photo taken from my light polluted back yard using a K110D, Vivitar manual 19mm lens, PiggyBacked on an 8 inch Meade SCT. Eighteen exposures of 120 seconds using in camera Noise Reduction. Not nearly as good as the example. I hope to have another chance from a dark site.

http://henriscorner.com/leosfolder/mwupper.jpg

Astrophotography is very dependent on processing. Software designed for astro is preferred since the needs are very different than daylight photography.

BTW: the K20D's not being able to turn off NR is not a show stopper. It doubles how long it takes to get the same total exposure, but it is simpler than working with dark frames. Taking multiple dark frames would be a little better. I tend to use in camera NR for the Pentax vs a few dozen 15 min darks for my SBIG camera.
04-22-2009, 10:56 PM   #22
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QuoteOriginally posted by netuser Quote
So, where can I start a thread "Marc Sabatella to forum moderator" ?

Thanks for the education :P
(again lol)
Marc does a great job of educating to the best of his knowledge and is a great example of what ths forum represents. He may be a moderator in disguise!
04-23-2009, 07:08 AM   #23
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I guess no one here has even cared to look at the picture's specs.

Photographer claims shot was taken with Pentax ES, 500 iso film and a 28/3.5 Takumar. Of course, location (Atacama Desert in Chile) means is from very high altitude which means super clean atmosphere and no city light contamination.

Anyway, this same photographer has several "astronomical" pictures, among which he claims some specs hard to believe. In no one single picture he claims using an equatorial tracking base for the camera, but he claims exposures as long as 10 minutes. Hmmm?

04-23-2009, 07:41 AM   #24
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QuoteOriginally posted by rburgoss Quote
I guess no one here has even cared to look at the picture's specs.

Photographer claims shot was taken with Pentax ES, 500 iso film and a 28/3.5 Takumar. Of course, location (Atacama Desert in Chile) means is from very high altitude which means super clean atmosphere and no city light contamination.

Anyway, this same photographer has several "astronomical" pictures, among which he claims some specs hard to believe. In no one single picture he claims using an equatorial tracking base for the camera, but he claims exposures as long as 10 minutes. Hmmm?
Why should he? He only gives camera, lens and film details. I guess he simply thinks, that giving details on image acquisition is not really that important in a normal photography gallery. I would not think, that this is fraud. I mean, he does not state the use of a tripod for the star trails, because we simply all know, he needs to use one. So we all know, he needs some kind of tracking for the deep sky and moon shots.

Ben
04-23-2009, 08:41 AM   #25
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Again, thanks to all.

This is a super forum with a great sharing and willing to educate community.

Leo Taylor, since I'm in the Azores Islands, pollution and light are not quite a problem. I will, "one of these days" check about some astronomers club so I can learn the basics before buying (even) more gear. Initial point is that I really like the pictures.

[offtopic]

res3567I took the time to write to Adam by pm proposing Marc for forum moderator and explaining why. Who knows, when new moderators are needed, he can become one ?

Ben_Edict, don't forget the pictures (when possible). I "kind" of have one FA 24mm on reserve.

Have to unplug myself from internet. LBA is very very bad even because now my kids are also enjoying photography so much.
The good point is everybody in the family is very happy with the images I have been taken. Lots of images being printig etc
[/offtopic]
04-25-2009, 08:38 AM   #26
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Here are some forums that you might want to check out......

Telescope Reviews: Viewing forum: Beginning Imaging
04-25-2009, 12:42 PM   #27
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QuoteOriginally posted by netuser Quote
res3567I took the time to write to Adam by pm proposing Marc for forum moderator and explaining why. Who knows, when new moderators are needed, he can become one ?
Hmmm, thanks! As long as it doesn't require any real work, I'm certainly open to it :-).
04-25-2009, 02:07 PM   #28
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QuoteOriginally posted by Raybo Quote
Here are some forums that you might want to check out......

Telescope Reviews: Viewing forum: Beginning Imaging
Thanks, I will
04-25-2009, 02:08 PM   #29
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QuoteOriginally posted by Marc Sabatella Quote
Hmmm, thanks! As long as it doesn't require any real work, I'm certainly open to it :-).
Taking into consideration the time you already give to the forum, don't thing more time is needed
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