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09-06-2010, 12:51 AM   #16
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Thanks Everyone for your insight.

09-09-2010, 07:48 AM   #17
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I am also interested in astro-photography so I attended a siminar put on by a guy who does some really serious stuff.

From what he said any good DSLR without any adaptations can take reasonable shots of the moon or star fields or even star circles. Simple process of using a tripod, playing with the exposure settings and in some cases using Photoshop or other software to stack the images. He suggested that for star feild photos use the widest angle lens you have that is not a fisheye, set the ISO at 100, use as wide open F stop as you can (stop down to a crisp focus) and use long exposures. He also said that moon shots are really easy with a good telephoto lens. He also said good planetary images (mars, satern) isn't really possible with a zoom lens.

He said that planetary images and more complex star images were also possible with any good DSLR if you attach an adapter mount and use a telescope that tracks with the sky.

He then said that for serious deep space photography you need to have your camera adapted for that special purpose. It had something to do with de-activating or hyper activating the infrared sensor capabilities of the camera. He further said that Canon was the best camera brand to purchase for a camera to convert to this purpose. As I remember what he said, it had something to do with how that camera is designed that makes it much easier to convert. This was all well above my head and I quickly realized that I was unwilling to spend that kind of money to buy and convert a camera into something that could only be used for space photography (I think its cool but I'm not into it that much).

I can't vouch fore everything the guy said but his images were really amazing so obviously he knows what he is doing.

I have personally taken really cool shots of the moon and star fields using my K7 on a tripod. I have taken some fairly effective shots of shooting stars during a meteor shower. From my experience clear cool nights are best. I set the camera at ISO 100 and shoot for up to 1 minute exposure. The noise level is acceptable (with cleaning in PP) and at one minute the stars are still nice and crisp without obvious movement.
09-09-2010, 08:28 AM   #18
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QuoteOriginally posted by Ex Finn. Quote
Too bad the cn group does not have a Pentax section dedicated to people like me with limited funds..
They don't have sections for any particular camera, just film, digital or CCD.
Pentax users do show up.
Check my post titled "New Pics" # 3730774
I took those pictures with a Pentax Super Program using Fuji film.

William
09-09-2010, 03:40 PM   #19
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Nice shots William. All I was ever able to get out of Orion was a purple smudge.
Good tracking mount is paramount.

Cheers, Mike.

09-09-2010, 05:09 PM   #20
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Any good free stacking software for mac?
09-12-2010, 08:40 AM   #21
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QuoteOriginally posted by Jon in SC Quote
He also said good planetary images (mars, satern) isn't really possible with a zoom lens.
Although you can capture the position of Jupiter's moons with the kit 55-300mm. Over successive nights, you can establish that they orbit Jupiter and not Earth, and blow the whole heliocentric model out of the water. (Obviously not such big news today as it was when Galileo did it, but still kinda fun if you are that kind of person.)

I've seen photos of Jupiter in which you could make out some features, but I've not managed it myself yet. Apparently when you expose for Jupiter you lose the moons.
09-12-2010, 08:49 AM   #22
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I know it's the K-x - but this thread had some really good discussion not limited to the K-x:

09-13-2010, 09:13 AM   #23
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QuoteOriginally posted by Brangdon Quote
Over successive nights, you can establish that they orbit Jupiter and not Earth, and blow the whole heliocentric model out of the water. (Obviously not such big news today as it was when Galileo did it, but still kinda fun if you are that kind of person.)
What the Earth isn't the center of the Universe? I am crushed!

09-13-2010, 09:28 AM   #24
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QuoteOriginally posted by PentaxPoke Quote
Nice shot Nass. You really don't need stacking for a moon shot. The reason is that the moon is considered a "daylight object" and as such you can use low ISO. Stacking is most useful for deep-space objects where in the past we would have to use very long exposures, tracking, and high ISO. Stacking simply is a way to increase the signal to noise ratio of your pictures. I will spare the details, but there are some excellent reference on it. For those that are new, I think this site is very helpful: Catching the Light: Astrophotography by Jerry Lodriguss
Nice link thanks, that's a useful site. I take your point re-stacking, although it did seem to bring out more detail than any of the originals had individually, same reason I guess.
09-13-2010, 10:43 AM   #25
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QuoteOriginally posted by Brangdon Quote
Although you can capture the position of Jupiter's moons with the kit 55-300mm. Over successive nights, you can establish that they orbit Jupiter and not Earth, and blow the whole heliocentric model out of the water. (Obviously not such big news today as it was when Galileo did it, but still kinda fun if you are that kind of person.)
Galileo actually proved the heliocentric model . I believe what you're referring to is geocentricism.
09-14-2010, 05:57 AM   #26
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QuoteOriginally posted by kari Quote
Galileo actually proved the heliocentric model . I believe what you're referring to is geocentricism.
Ah so the Earth is the center of the Universe. I am much happier now!!!!
09-14-2010, 07:43 PM   #27
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OK, it is time for me to jump in. I've been doing astrophotography for many years including Pentax DSLRs.

"Jon in SC" received some good advice in his seminar in my opinion. Some things were lost in translation, I'll smooth the edges.

> From what he said any good DSLR without any adaptations can take reasonable shots of the moon or star fields or even star circles.

Yes, you can do astro without an expensive motorized mount. My wife took many Moon shots at using a $199 Orion 400 mm f5 telescope as a lens with a Bogan Tripod. She kept her Moon exposures under 5 seconds at 400mm. Any longer and the craters smeared. The same could be done with a 300-400 mm lens. The Moon will move and the tripod will need to be re-centered between shots. Focus is ALWAYS hard with astro, so take a lot of shots and hope to get a good one.

Star fields are doable with a wide lens. Wide field can expose longer before the stars smear. You can take multiple frames and stack them. I don't know what a Star Circle is!

> use as wide open F stop as you can (stop down to a crisp focus)

Using one or two stops short of wide open is good advice. Most lenses look worse wide open then a average telescope which does not have aperture control.

> He said that planetary images and more complex star images were also possible with any good DSLR if you attach an adapter mount and use a telescope that tracks with the sky.

To get any detail on planets you need a lot of focal length. I use 6000mm and at that FL you need a good motorized mount. But, I use a cheap web camera. The reason is you want to stack hundreds of frames and that is torture on a shutter based camera. Any camera that can do video with the shutter kept open can take hundreds of frames without wear and tear.

> It had something to do with de-activating or hyper activating the infrared sensor capabilities of the camera.

Daytime cameras have an IR filter to prevent excess IR from overwhelming the visible red. It is a lousy filter which also cuts off visible deep red which happens to be the color of many nebulas. So you can remove the filter (I did on my K110D) or replace it with an expensive filter that cuts IR but keeps deep red. My filterless K110D does pretty well on nebulas. If you don't plan on imaging nebulas then don't worry about the internal filter.

> He further said that Canon was the best camera brand to purchase for a camera to convert to this purpose.

Canons are the most popular DSLRs for astro, but not because they are easy to convert. There is more support for Canons but at least one vendor that will change filters in a Pentax.

> I quickly realized that I was unwilling to spend that kind of money to buy and convert a camera into something that could only be used for space photography

Everyone seems to think astrophotgraphy is expensive! I bought my K110D new for $349, used they must be dirt cheap. I bought that model since it does not move the sensor like my K100D making filter removing easier. Besides, my filterless K110D doubles as a super daytime IR camera. Exposures with a Hoya 72 are 100 times faster!

I presume the seminar mentioned dark frames. To get the noise out of long exposures you need to subtract dark frames. You can use the camera's NR but that takes away 50% of your evening. If your camera allows you to turn of NR than you can take a few dark frames after the imaging session and use software to subtract them. Most Pentax CMOS cameras do not allow you to turn off the long exposure NR, another reason to buy a used camera for astro!

BTW: I'm imaging now out in my observatory, but I went back to using an SBIG Astro camera after 3 years with DSLRs.

Last edited by LeoTaylor; 09-14-2010 at 07:52 PM. Reason: Fix Typos
09-15-2010, 07:04 PM   #28
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Leo
Thanks for helping to clarify the information I gave. I learned alot from that seminar and have used that info to take some really good mood and star field shots, but you certainly have more knowledge than I do and helped explain the parts that I didn't understand.

I see you are in CN, if you were closer to SC I would be hitting you up for a visit to your observatory to see what you are doing. I did visit a really good observatory operated by the Charlotte NC Astronomy club and loved what I saw. It was really cool to get the opportunity to look through the telescopes and actually see the rings of Saturn and to see a nebula. It's one thing to see them on TV or on line and another to actually see them in a telescope!
09-25-2010, 07:51 PM   #29
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QuoteOriginally posted by Jon in SC Quote
Leo


I see you are in CN, if you were closer to SC I would be hitting you up for a visit to your observatory to see what you are doing. I did visit a really good observatory operated by the Charlotte NC Astronomy club and loved what I saw. It was really cool to get the opportunity to look through the telescopes and actually see the rings of Saturn and to see a nebula. It's one thing to see them on TV or on line and another to actually see them in a telescope!
It would be a long ride to visit a small Observatory. At 6 * 7 feet it will fit my 8 inch scope, one visitor, myself, not much else.

I would be delighted to show you some objects through a telescope, but I rarely, "look through" my telescopes except at public outreach events. Once you have taken astrophotos you can't go back. The following Lagoon Nebula (taken with a K110D) looks faint and gray when I use an eyepiece. I'm spoiled!
Attached Images
 

Last edited by LeoTaylor; 09-25-2010 at 07:52 PM. Reason: fixed incorrect dimension
09-29-2010, 10:54 AM   #30
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Here is another Pentax astrophoto, this time with a K100D Super I bought used on this forum's Marketplace.

Jupiter is the bright object on left, Uranus the dim one on the right. In September they were in opposition during the same week and less than one degree apart. It was the chance of a lifetime.

Jupiter's moons from top to bottom: Europa, Io, Ganymede, Calisto.

Taken 9/21/2010.

I had a problem with the wide dynamic range: MAG -2.7 in the same frame as
MAG 5.7 but was successful by letting Jupiter overexpose.

Meade 2080 SCT, f6.3 Reducer (think 1250 mm f 6.3 lens)
Ten exposures of 0.1 sec.
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