Ruminations, Haunts, and Errors

My camera’s working fine, I finally stopped stalking a lens and actually bought it, and now Flickr dropped their pro-account pricing. I guess I had better start shooting some more pictures now…

Last night I started playing with some night-sky pictures from my camera, using dcraw and then ImageMagick to convert from RAW to PPM to FITS format so I could do proper reductions with IRAF. It occurred to me how far digital imaging technolgy has come in recent years. Back on my first trip to Mt. Laguna in 1995, I was impressed by their recently installed imager: a 2048x2048 CCD, thinned and cooled to 148K (fun with liquid nitrogen!) to achieve great sensitivity. Combined with custom control software, it was state-of-the-art and still an top-notch imager through my last observing run in 1998. To my knowledge they’re still using it, as it performs its intended job quite well.

I realized that the CCD in my Pentax is bigger (3038x2022), full-color, has better on-board readout and processing firmware…and was bought at retail for probably a fraction of what the MLO detector cost! (On my first night at the observatory, as my advisor and I were picking up the massive dewar-detector combo to attach it to the ’scope, he reminded me to be careful with the instrument ‘because…well, I have tenure…’) Wonder what this camera could do if cooled and let loose on dark mountain skies…

A unified image is also available. All images were taken outside my apartment using only a tripod and a 200-mm f/4.5 lens with my Pentax *ist D operating at ISO 800, with exposure times ranging from 1/180 to 1/4 second. The images were composited using The GIMP; they were adjusted slightly for intensity variations but no processing was performed beyond that done by the camera itself.

A digital camera is great! It’s not only a precision optical gadget, with its own quirks and terminology…it’s also a small computer! Fun for several facets of my geekiness.


Hey, I can even use it to record the goings on in my life, maybe I should try that now…

After my earlier trials and tribulations with my recently acquired Pentax *ist D, I finally received it back today and in working order. Hooray! So nice to be able to test out various things rather than simply reading the manual. The funny thing is that I believe I will need to unlearn much that I took for granted with my old K-1000: the new camera has lots of buttons and settings that either take care of exposure settings automatically or allow me to tweak them with fingertip controls.

I especially like the ability to not only ratchet up the detector sensitivity (all the way to ISO 3200, if I’m willing to deal with extra noise) but also automatically adjust the color balance, for that allows me to actually take some decent indoor photos where a flash would be bad:

As an added bonus, it was almost trivial to set things up to get the images off the camera…on Linux! Why not go the easy route and use Liz’s Windoze box and the software that came with the camera? Well, the two-processor Linux machine in the closet is the only one that has USB connectors on the front. So, that machine is now set up to automount the camera CF drive when it’s plugged in (thanks to the mass storage driver hich appears to work flawlessly), and a few more minutes of configuration set up my other Linux box to automount that partition. Then, a quick munge of the Samba configuration and voila! Plug the camera in, access the files from anywhere on my network.

Finally, I took a quick set of test photos of the night sky using the camera’s RAW image format and was able to convert them to FITS format using Dave Coffin’s dcraw program and ImageMagick. Gotta love open source! And, while the camera’s on-board processing of images is quite good, especially for general-purpose photography, it’s nice to know that when I want to do some fancier processing–especially for astrophotography–I can manipulate the pixel values however I see fit.

After years of yearning and a week of waiting, I finally recieved a brand-new toy today. All looked well: a full-featured digital camera, lots of bells and whistles for a perfectionist control freak like me, and a K-mount to fit the lenses for my current K-1000. Score! I come home a bit early, take it out of the box, start playing around. All is well. Not so fast. After checking out my 50mm and 75-200mm lenses with no problems, I decide to pop in my 28mm wide-angle. Drop-in, twist…uh-oh, that’s not right. Try to remove it…DOH!! Jammed! I have to send the damn thing in for service before I even get to use it for anything legitimate! Oh yeah, since the lens wasn’t made by Pentax, I can forget about this being an under-warranty servicing. Sigh. Oh, well, at least there’s a Pentax-certified repair shop in Bensenville. After the credit-card glitch last week that delayed shipment in the first place, this camera seems star-crossed.