Forums › Forums › Farktography General Chat › This week’s contest › 03-09-11 – Stars
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Plamadude30k.
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March 7, 2011 at 6:38 am #38650
Elsinore
KeymasterThat sounds like standard astrophotography exposure stacking to me.
Also, the Russians did something similar to create the first color photographs in the very early 1900s–filtered b/w film with magenta, cyan, and yellow on 3 separate exposures, then projected the three separate b/w exposures through the same color filters, stacked up in the projection so it created a color image. Was pretty damn nifty.
March 7, 2011 at 7:22 am #38651Plamadude30k
ParticipantHmm. Well, I’d better get to work then. I took a nice image of M3 last Thursday on the off chance I could use it for this contest. I hope it turns out well.
March 7, 2011 at 7:36 am #38652Farktographer
ParticipantDarn, wasn’t expecting stacked images to be allowed. Hopefully this rain clears up and I get a nice clear night to take shots before the deadline.
March 7, 2011 at 3:24 pm #38653chupathingie
ParticipantAnother technique that gets used is LRGB imaging… the normal R,G, and B filtered images plus one unfiltered for a Luminance channel. Normally this is done with a dedicated CCD imager, which is monochromatic (hence the need for filters and I think what Plamadude30k is speaking about), but I think if one has a DSLR the RAWs can be de-Bayered; leaving a luminance channel at twice the resolution of a color RAW… I need to dig into this yet, I’ve been wanting to try de-Bayering for a while now just for grins…
edit: debayering does not affect resolution (just found some info and trying to make sense of it…)
March 7, 2011 at 3:48 pm #38654
orionidParticipantThat sounds like standard astrophotography exposure stacking to me.
Also, the Russians did something similar to create the first color photographs in the very early 1900s–filtered b/w film with magenta, cyan, and yellow on 3 separate exposures, then projected the three separate b/w exposures through the same color filters, stacked up in the projection so it created a color image. Was pretty damn nifty.
I’m not planning on it for this contest, but whenever I figure out the operator-telescope communication error I’m having, one thing I want to try is false-color mapping by mapping each filter to the “wrong” channel, like this: http://www.flickr.com/photos/eifelsternwarte/3188478317/in/faves-orionid/
March 7, 2011 at 9:50 pm #38655ParticipantAnother technique that gets used is LRGB imaging… the normal R,G, and B filtered images plus one unfiltered for a Luminance channel. Normally this is done with a dedicated CCD imager, which is monochromatic (hence the need for filters and I think what Plamadude30k is speaking about), but I think if one has a DSLR the RAWs can be de-Bayered; leaving a luminance channel at twice the resolution of a color RAW… I need to dig into this yet, I’ve been wanting to try de-Bayering for a while now just for grins…
edit: debayering does not affect resolution (just found some info and trying to make sense of it…)
Yes and yes. De-Bayering has been in the back of my mind for a while, but I’ve never found a program that can do it. If you work out some nifty interpolation routines, you can see how it’s possible to get the original resolution back (loosing only some edge pixels, which I believe is why DSLRs always list ‘effective’ megapixels in their stats). With science CCDs, that’s not much of a concern, though. We’re less concerned with prettiness than with data.
By the by, here’s a picture of the Montreal 4K CCD imager that I use for all my science observations (and for the odd pretty picture when I’m bored):
http://flic.kr/p/4MUVkj
It’s 16.7 Mp, the chip is 2″ on a side (actually two chips, 2″x1″ side-by-side), LN2 cooled, and backside thinned for increased blue spectral response. Also bit more expensive than your run-of-the-mill 16 Mp digital camera.ANYway…stars. I actually bought a couple of star filters especially for this contest. I took an entire set of images from the top story of a high building in Albuquerque last time I visited my parents, only to find out that none of them were usable due to internal reflections from the double-paned windows up there. ARRRGH.
March 8, 2011 at 1:04 am #38656ParticipantOhman… that’s some drool-worthy CCD action, right there. Some of the folks I’ve been learning AP from won’t even mount a DSLR to a scope, and after seeing their images I can understand why. Even the low-end peltier-cooled CCDs take amazingly clean subs, making the trade-off for lower resolution and acquisition time well worth it. They’ve got some of the more mechanically dextrous hobbyists suffering from cooling envy…to the point of modding DSLRs for cooling. One guy has managed 20C below ambient in what amounts to a refrigerator with a DSLR stuffed inside and mounted to the scope. That’s gotta be fun to balance.
I’ve got an old 300D here that’s itchin’ to be torn apart and stripped of it’s IR block. I’m wondering if the sensor can’t be distanced from the rest of the camera to allow it to be bonded to a peltier unit. I’m gonna need a bit more free time before I can think about that.
On the de-Bayering front, I’m finding bits and pieces and some software… I’ll post some links when/if they pan out into anything usable (keep in mind that I’m one of those open-source types, so what I find may be less than user-friendly).
March 8, 2011 at 1:43 am #38657mopsy
ParticipantThis may be the first time I have to sit out a contest. I had given thought to trying the night time sky thing but it’s been cloud covered for days. I have a couple of mundane star pics but I’d actually be embarrassed to enter them with all of the fantastic things I see here! Damn, I really hate to miss a contest!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
March 8, 2011 at 1:54 am #38658U-Man
ParticipantMops, you’ve gotta have something with a flag. Or, take a nightime photo of a brightish light (like the fishing shed light or maybe some candles inside) using a long exposure and f/16 or 22 or something tight like that. The small aperture results in a star-burst.
Like these –
http://photos.imageevent.com/ulle17/fark/Rapids_2137.jpg
http://photos.imageevent.com/ulle17/fark/Tree_4254.jpg
http://photos.imageevent.com/ulle17/fark/Statue_9375.jpg
The stars in the last statue are parking lot lights.
March 8, 2011 at 1:58 am #38659ennuipoet
ParticipantThis may be the first time I have to sit out a contest. I had given thought to trying the night time sky thing but it’s been cloud covered for days. I have a couple of mundane star pics but I’d actually be embarrassed to enter them with all of the fantastic things I see here! Damn, I really hate to miss a contest!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Not a single star in any of my pics was in the sky. Just be silly, even if the votes don’t flow you might have a good time doing it.
March 8, 2011 at 2:01 am #38660ParticipantThis may be the first time I have to sit out a contest. I had given thought to trying the night time sky thing but it’s been cloud covered for days. I have a couple of mundane star pics but I’d actually be embarrassed to enter them with all of the fantastic things I see here! Damn, I really hate to miss a contest!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Not a single star in any of my pics was in the sky. Just be silly, even if the votes don’t flow you might have a good time doing it.
Yeah. What he said. I e-mailed you some other stuff. 🙂
March 8, 2011 at 2:02 am #38661ParticipantYes, I have flags and a couple of other things, but that’s just boring when there’s going to be shots of stars using the “Hubble.”
March 8, 2011 at 2:07 am #38662ParticipantEnnuipoet, that gives me a little courage. It just seemed this was going to be way beyond my abilities, but if there are others with limited means, then I won’t feel so dumb!
March 8, 2011 at 2:07 am #38663ParticipantThose will be top 10-15. Something cute or clever could easily do well. This is s’posed to be one of those ‘think outside the box’ themes.
March 8, 2011 at 3:52 am #38664ParticipantThose will be top 10-15.
That would be nice, but my original reading of the theme had me thinking astrophotography was only incidentally related. I’ve got lots of choices for this contest, but at MOST two will be nighttime stars. I’ve always thought using three different types of pictures (or three different interpretations of the theme) is the most interesting/fun way to do these contests, if not the most vote-intensive.
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