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11-15-2009, 05:44 AM   #46
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QuoteOriginally posted by LeoTaylor Quote
I'm very impressed with pti-andy's images. The new camera indeed does look good though the old lens may have something to do with it too.
The 67M*400 f/4 ED is working well here for sure, especially with the small sensor compared to 67 film. This lens is par excellence!

If only the DFS could be turned off, this camera would be the solution for those of us waiting for an acceptable camera for astrophotography, allthough some have done well with a few previous models.

Nice on the M31 LeoTaylor, and at F/10!


Keep at it gentlemen, I'm enjoying the thread and looks like I'll be trying a K-X in 2010.

Let's not forget film, I'm its last crusader: Legacy Astrohotography - Cygnus / Cepheus Region on Flickr - Photo Sharing!

11-15-2009, 07:59 AM   #47
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QuoteOriginally posted by pti-andy Quote
Ok, here are the dark frames from the K-x and just to compare the new sensor with the previous 10MP cameras I've added K200D frames. The results are quite astounding!

These are raw frames cropped and layed out in PS. The histogram was clipped on the high end by 75% (64 instead of 255) to bring out the noise. This was done on the final after tiling so that they would all be processed exactly the same.

It is clear that there is at least a 2 stop improvement over the previous generation sensor. The K-x ISO3200 is still a shave better than the K200D ISO800. There is also not nearly the hot pixel problem that existed in the CCD pentax cameras.

I'm so impressed with what Pentax has done here. I just wish I could turn off DFS. This camera is capable of 1-4 minute exposures without hot pixels taking over the shot. Please Pentax, uncripple this camera!
Thanks Andy. Yes, I agree the Sony CMOS sensor is a generation ahead of the CCD sensor in the K10, K200. The hot pixel and chroma noise are almost non-existent. But I still must ask is there no amplifier noise? You are after all shooting at ISO 1600 and 3200 well above the base of 200 so the amp is kicking in pretty heavily. Unless you were in really cold temperatures and let the camera equilibrate. Even when I do that with my K10 on a really cold winter night I still get very discernible amp noise in the upper left corner of the frame.
11-15-2009, 11:30 AM   #48
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QuoteOriginally posted by LeoTaylor Quote
It has been a long time since I've guided manually. In my K1000 days I used to call it the, "World's most boring video game!" Keep the white dot in the red square for 10 minutes at a stretch. I auto guided with an SBIG ST-7E for 7 years and will never go back to manual. That astro camera could do 15 minute exposures from my MAG 3 back yard. No Milky Way in my city. With the DSLR I gave up on guiding altogether, the exposures are too short to need it even at 2000mm. My LX200 Classic is pretty well aligned using PEMPro 2.

Here is an unguided Meade 2000mm f10 image of a Galaxy Cluster with reasonably round stars:

http://astrophotoleo.com/galaxy/n7619.jpg.
LeoTaylor: I just went back and visited your site after reading this again. I must say, you have an impressive array of astrophotos there. I've not come even close to imaging that number of deep space opjects. I really like the planet animations too. Great job!

Your home built observatory is also a testament to your dedication to this hobby. You really have done a first rate job here and make me envious of being able to use such a fine facility whenever you get a clear sky. I'd really give just about anyting to not have to spend the hours of drive, setup, and tear down time. BTW, is the flower pot still there?


QuoteOriginally posted by JackBak Quote
Thanks Andy. Yes, I agree the Sony CMOS sensor is a generation ahead of the CCD sensor in the K10, K200. The hot pixel and chroma noise are almost non-existent. But I still must ask is there no amplifier noise? You are after all shooting at ISO 1600 and 3200 well above the base of 200 so the amp is kicking in pretty heavily. Unless you were in really cold temperatures and let the camera equilibrate. Even when I do that with my K10 on a really cold winter night I still get very discernible amp noise in the upper left corner of the frame.
Oh yes... the amplifier glow. You'll be happy to hear that there really isn't any that I can find. My longest exposure so far is 4 minutes and I can stretch the histrogram as far as possible and not see anything at all.

When I stacked the Andromeda images I could just start to see a small amount of fringe across the very bottom of the image but this was only visible with extreme clipping of the image and was well below the level of anything in the photo and even the noise. All in all this camera is completely free of amplifier glow!

QuoteOriginally posted by nightfly Quote
The 67M*400 f/4 ED is working well here for sure, especially with the small sensor compared to 67 film. This lens is par excellence!

If only the DFS could be turned off, this camera would be the solution for those of us waiting for an acceptable camera for astrophotography, allthough some have done well with a few previous models.

Nice on the M31 LeoTaylor, and at F/10!


Keep at it gentlemen, I'm enjoying the thread and looks like I'll be trying a K-X in 2010.

Let's not forget film, I'm its last crusader: Legacy Astrohotography - Cygnus / Cepheus Region on Flickr - Photo Sharing!
Great job on the film work of the Milky Way swath! It is nice to see someone else shooting with a 67. Unfortunately I have to sell all of my 67 gear. It's ashame too because this was some of Pentax's finest gear they have ever produced and I just got a 67II when I had to give it up for a while so it only has a roll or two through it. The last one was when the photo lab cut through my negs becasue they thought there was nothing on them (they never saw astro photos before). I also still have an 67M* 800mm f/6.7 ED! It's a real monster! My next K-x shots will probably be with it.

It's really nice to see such dedicated people here. I had no idea you were all on this board.

-Andy

Last edited by pti-andy; 11-15-2009 at 12:34 PM.
11-15-2009, 11:50 AM   #49
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QuoteOriginally posted by pti-andy Quote
All in all this camera is completely free of amplifier glow!
Great news. Even with the forced DFS on Bulb if your G8 is aligned and tracking nicely you could go for longer exposures, you would just not be as productive during the evening's shoot session. Well you're eyes would hurt but then you could use that Orion Starshoot for a guider. No?

Thanks for all the great K-x astro info.

11-15-2009, 12:06 PM   #50
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QuoteOriginally posted by JackBak Quote
Great news. Even with the forced DFS on Bulb if your G8 is aligned and tracking nicely you could go for longer exposures, you would just not be as productive during the evening's shoot session. Well you're eyes would hurt but then you could use that Orion Starshoot for a guider. No?

Thanks for all the great K-x astro info.
Yes, I'm sure I could do some 5 and 10 minutes exposures if it wern't for waiting for the DFS! This camera is so darn impressive it just kills me that something this simple is diminishing it's use.

I'd love to use the Orion Starshoot as a guider but my G8 mount has loose bearings that causes it to shift a bit during guide corrections and it really messes with an autoguider. Through manual guiding I can anticipate it's behavior so I think it will be sore eyeballs for a while unless I can raise enough money from my 67 gear to buy a G11.

-Andy
11-16-2009, 07:21 AM   #51
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QuoteOriginally posted by LeoTaylor Quote
I'm very impressed with pti-andy's images. The new camera indeed does look good though the old lens may have something to do with it too. And his skill at imaging and guiding.

It has been a long time since I've guided manually. In my K1000 days I used to call it the, "World's most boring video game!" Keep the white dot in the red square for 10 minutes at a stretch. I auto guided with an SBIG ST-7E for 7 years and will never go back to manual. That astro camera could do 15 minute exposures from my MAG 3 back yard. No Milky Way in my city. With the DSLR I gave up on guiding altogether, the exposures are too short to need it even at 2000mm. My LX200 Classic is pretty well aligned using PEMPro 2.

Here is an unguided Meade 2000mm f10 image of a Galaxy Cluster with reasonably round stars:

http://astrophotoleo.com/galaxy/n7619.jpg

Below is my best M31 so far. It is with a filterless K110D but I was able color correct the stars to be white. Stellarvue 480mm f 6, ASA 800, RAW, Internal NR, 10 flat frames, 1 minute * 126 frames (Yes, 4+ hours unguided). I use Images Plus for all processing and it handles the slow polar alignment drift.
OK, I will admit I don't understand this well; are you saying that at 480mm you were able to get 60 second exposures without any elongation or other problems?

I'd love to be able to do something like this, but didn't think it was possible.... my 50D is supposed to be fairly decent for astrophotography, but I have barely a clue how to approach it!

So far my few "astro" shots have been simple 10-30 second exposures stacked in Deep Sky Stacker, wide angle:
11-20-2009, 06:19 PM   #52
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QuoteOriginally posted by pingflood Quote
OK, I will admit I don't understand this well; are you saying that at 480mm you were able to get 60 second exposures without any elongation or other problems?

I'd love to be able to do something like this, but didn't think it was possible.... my 50D is supposed to be fairly decent for astrophotography, but I have barely a clue how to approach it!

So far my few "astro" shots have been simple 10-30 second exposures stacked in Deep Sky Stacker, wide angle:
I don't think LeoTaylor has been on lately but I think I can help.

When we refer to "unguided" that doesn't necessarily mean it is not tracking with a motor drive. Many high quality Eq mounts can track accurately enough to not require quide corrections either manually or with an autoguider up to around 200-500mm depending on the exposure length. If you are using a tripod then you will be limited to wide-angle shots only.

Leo: Did you hit your head on the flower pot hanger again? We need you back.

-Andy
11-21-2009, 04:23 PM   #53
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Here is a single shot Iso 3200, f/2.0, 4s with the Pentax K-X. Sadly the focus was bad and I dont have the energy to go out again, I get strange from the antibiotics I eat



11-21-2009, 04:43 PM   #54
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QuoteOriginally posted by pti-andy Quote
I don't think LeoTaylor has been on lately but I think I can help.

When we refer to "unguided" that doesn't necessarily mean it is not tracking with a motor drive. Many high quality Eq mounts can track accurately enough to not require quide corrections either manually or with an autoguider up to around 200-500mm depending on the exposure length. If you are using a tripod then you will be limited to wide-angle shots only.

Leo: Did you hit your head on the flower pot hanger again? We need you back.

-Andy
OK, that makes more sense, I was trying to wrap my head around the concept! So you basically go from wide field tripod shots at reasonably long shutter speeds (15-20 secs or so for a 24mm lens?) to motorized tracking without guiding, to motorized tracking using a separate (and I presume mounted together with the camera) guide scope keeping some point of reference in a fixed position so that you know you're maintaining target... I guess the only thing you really worry about is Earth's rotation and not any other sort of movement.

Thanks!

By the way, would it be possible to mount say a webcam on the guide scope and have it control a tracking mount based on a point of reference? From a software standpoint it should be fairly easy to keep track of a bright single point and move things accordingly.... should make it more accurate than "blind" tracking right?
11-21-2009, 10:02 PM   #55
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QuoteOriginally posted by pingflood Quote
I guess the only thing you really worry about is Earth's rotation and not any other sort of movement.
Well yes the Earth's rotation is the major movement that one must counteract but that lovely shot you are creating has a way of showing ALL the accumulated errors. If your mount is not perfectly aligned with the Earth's rotation of axis (in the Northern hemisphere that would be just shy of Polaris) no amount of precise motor RPM will get you pin point stars and you must use a guide scope with either a human feedback loop or a computer feedback loop. Then there is the error always present due to imprecise gears on the RA and Dec axis of the mount. Then there are bearing bumps and shaft inaccuracies throughout the mount... the list goes on and on.

QuoteOriginally posted by pingflood Quote
By the way, would it be possible to mount say a webcam on the guide scope and have it control a tracking mount based on a point of reference? From a software standpoint it should be fairly easy to keep track of a bright single point and move things accordingly.... should make it more accurate than "blind" tracking right?
So yes a computerized guiding mechanism is the way out of all these irritating little gotchas. And what you have described has been around for at least 15 years in the form of the Santa Barbara Instrument Group ST-4 guider. The control pins via an RJ-11 socket have been standardized throughout the mounts one can purchase because of the success of the ST-4.

And yes the software to follow a star is not trivial but not particularly mind bending either. I have written said software for a webcam application but never driven the ST-4 pins themselves.

Last edited by JackBak; 11-22-2009 at 07:34 AM. Reason: Typo
11-22-2009, 08:11 AM - 1 Like   #56
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I'm back.

I was away one night on short notice: a friend with a second home and observatory in the Berkshires asked if I'd like to join him for a night under a dark sky. I dropped everything I was doing and drove 80 minutes to join him. I imaged 9 hours (384 RAW Frames, almost filled a 4 GB memory card) with my modified K110D using an old manual Sigma 70-210 mm and CG-4 tripod. I had a slight cold when I started and ended up with frost on the equipment and a worse cold. I'm just now recovering but for me one night at a dark site is worth a couple of nights coughing...

I've been too sick to finish processing, just the first step with Images Plus ran for 8 hours. I did stack one small trial set of 24 frames and it looks promising. Perhaps tonight I can tackle the rest.

Scrolling though the messages:

I think I confused some people. The photo I linked to was at 2000mm f10 but the photo I embedded was 480 mm f6.

Both were unguided. Both were on a well aligned mount.

I've had real flowers hanging from both 4*4 in observatory beams every summer for 9 years and leave the pots up year around. If I leave a beam un-potted I will strike my head within a week or two! In hindsight I could have made the walls 2 inches higher and save many a head injury.

Here is a list of "tracking and guiding" examples to try and solve the confusion:

1. No and No. Camera on a fixed tripod. Can take short exposure Full Moon shots and star trails.

2. Yes and No. Camera on a motorized, equatorial tripod in the field. Can do most low and medium power astrophotography. Must be "polar aligned." This is what I did early in the week, I aligned the CG-4 on Polaris by sighting through a tube. Since my longest focal length was 210 mm and only exposures were 30 seconds I could get away with alignment within perhaps 1 degree.

2. Yes and No. Camera on a motorized, equatorial, permanent pier. This is what I'm doing in my little home observatory with novel wooden pier. My friend spent more on each of his piers than I spent on the whole setup. My Meade LX200 Classic mount (bought used for $600 in 2005), Meade LX3 2000mm f10 optical tube (also bought used as a scope for $900 in 1997), and Stellarvue 480 mm f6 (new $400) all ride on the pier. I have stopped guiding and just rely on the accuracy of the polar alignment for which I use PemPro software to get within 2 arcminutes of the Celestial North Pole. The short (2 minutes or less) exposures of the DSLR make any drift less than the other quirks of the Classic mount.

3. Yes and Yes. Camera mounted on a motorized, equatorial, tripod or pier. Manually guided by a person watching a guide star and correcting for drift. I did this a couple of years with my old LX3 scope. It had Periodic Error of 45 arcminutes that would destroy long film exposures at 200mm if not corrected by guiding.

4. Yes and Yes. Camera mounted on a motorized, equatorial, tripod or pier. Computerized guiding with separate camera on another scope. I tried this using an SBIG and Pentax. The flexure between the two scopes, mirror sag in the SCT, focuser sag in the refractor, and other problems caused more drift than then I had with guiding off! With very sold equipment the pros do this method.

5. Yes and Yes. Camera mounted on a motorized, equatorial, tripod or pier. Computerized guiding with one scope. This can be done with an "off axis" guide camera. This would work well but I don't have or want the equipment needed. Since both cameras are on the same scope most of the problems of item 4 vanish.


6. Yes and Yes. Camera mounted on a motorized, equatorial, tripod or pier. Computerized guiding with one scope using a camera with internal guide chip. To me this is the ultimate, my SBIG has both an imaging sensor and guide sensor side by side. There can be no differential error between the two sensors. Scope errors like mirror shfit are corrected by the guide sensor. I did this for seven years. I got tired of the small sensor (0.4 MP) and the difficulty of doing color. I bought my first DSLRs (K100D for daytime, K110D for astronomy).

I think I covered all the combinations of Tracking and guiding!
11-22-2009, 09:44 AM   #57
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Wow, thanks for all the information!

Jack: figures that whenever I think I have a good idea somebody's beat me to it, by a couple of decades...

When we move overseas in the spring we will be in a fairly dark area in Sweden, so would like to invest in a decent setup for both observation and astrophotography at that point. With a budget of say $3k, what would you guys recommend? I have a good camera (50D) already so should be ok at least for hobby purposes.
11-22-2009, 10:28 AM   #58
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QuoteOriginally posted by pingflood Quote
Wow, thanks for all the information!

Jack: figures that whenever I think I have a good idea somebody's beat me to it, by a couple of decades...

When we move overseas in the spring we will be in a fairly dark area in Sweden, so would like to invest in a decent setup for both observation and astrophotography at that point. With a budget of say $3k, what would you guys recommend? I have a good camera (50D) already so should be ok at least for hobby purposes.
Big subject and I don't know your preferences (you might not know them yet either). Here are a couple of thoughts, pick up a few copies of say "Sky and Telescope" magazine to familiarize yourself with equipment that is out there, and remember that the mount is extremely important in astrophotography. I might use this breakdown $1k for the telescope and $2k for the mount - yeah it's that important.

Good luck and trust me $3k won't be the end of it if you go down this road.
11-22-2009, 01:22 PM   #59
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Thanks -- I kind of figured the mount would be key; my only experience so far with astro stuff is a Meade 70mm refractor. The optics are certainly decent enough to resolve a lot of detail, but the mount and tripod are absolute garbage. Was thinking about mounting it to my Bogen 393 gimbal style head that I use for my long teles since it's very solid and can be adjusted smoothly.
11-22-2009, 07:10 PM   #60
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I went back and collected the the subjects from pti-andy I missed the last few days.

Yes, there are a lot of DSOs on my web site, mostly galaxies. These were the objects I was most fond of and the ones my little SBIG was best at. With my SCT, location, and K1000 I was limited to eight galaxies. In 2000 I bought an SBIG and as you can see I have exceeded 25 galaxies in one tiny frame. I imaged galaxies as fast as I could.

Thank you for mentioning the Planetary Animations. They took awhile to do and you are the first to mention them! The Moons and Shadows passing across Jupiter are my favorites.

You are too kind in your comments about my observatory. My friend's observatory in the Berkshires cost more for one Astro Physics 1200 mount (list price $9800) then all my equipment together. but he takes far better photos.

I'm glad you did not have amp-glow with the new camera. A red area in the upper left quashed my hopes to use a istD for non-nebula astro. My Modified K110D is a poor choice for stars since it is near impossible to get the red out. In hind sight I should have brought a K100D to the dark site since the color would be more natural. I made another mistake, I'm so used to using an IDAS light pollution filter I took all 9 hours with an LP filter at a place that did not need it. The LP filter tinges the colors toward blue. At 3 AM my friend asked, "Why did you use an LP filter on a night like this?" I did not have a good answer! So I have some tough color correction to deal with.

Last edited by LeoTaylor; 11-22-2009 at 07:12 PM. Reason: fixed typo
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