Astro Tuesday: A few of my favorite things

(I took the top photo of the Moon last fall from my back yard, through the trees. Really like how it turned out!)

Hi folks! 

Because this is sort of an introduction week (rather, week two of these Hello World! posts), I figure a good way to kick off the first astro post is with a few of my recent astrophotos. At some point, I'll scan in a few of the very first black & white space images I took in junior high and high school - on film, developed and printed in a home-brew darkroom in my parents' basement. Waaay more work for far less interesting results. 

Anyhow, let's start off with a couple of my top space subjects. First up, my favorite (and the most-dramatic) star nursery in the sky: 

Great Orion Nebula, November 20, 2018.

And here's what it looks like when the Hubble Space Telescope puts together a mosaic of many images (public-domain NASA image) - see how many details you can decipher in my shot when comparing to this best-ever image of the place: 

The NASA image required 105 Hubble orbits to complete, and the resulting mosaic is about the size of the full Moon from our perspective. Yes. This place is HUGE. Lots more info about the Great Orion Nebula and this image on the NASA website.

On the other hand, my amateur photo is a single 30-second exposure at ISO 100 using a Canon EOS T6i camera (digital SLR) and the telescope described below. I experimented with longer and shorter exposures, different ISO speeds, and different (basic) processing, and this is about as good as it gets without taking and stacking several images from a proper dark-sky location... I took this in my back (small Midwest city) yard! 

Earlier last year, I took a ton of Moon photos. Here's one:

Crescent Moon, March 21, 2018.

This is the first prime-focus astrophoto (no eyepiece, essentially using the telescope as a camera lens) I took using a the same camera mated to an Orion Skyview Pro 100mm f/9 (900mm focal length) rare-earth-glass apochromatic refractor. (That is, the telescope's primary lens is made of special glass that prevents color distortion when looking at bright objects.) Typically, a low-cost, standard-glass-lens refractor creates false-color halos around bright things (basic lenses bring each color of light to focus at slightly different focal lengths, but ED glass (Extra-low Dispersion), multi-lens-element setups like this produce almost as perfect color-correction as a reflector (mirror-based telescope)! 

A super-short scope-to-camera adapter mounts the camera to the telescope focuser to prevent vignetting (the sides of the adapter don’t obscure the light path).

Everything is mounted on an iOptron IEQ30 Pro German equatorial mount with built-in through-the-mount polar-alignment telescope for countering Earth’s rotation (plus a leveling bubble so it sits perfectly flat). I can also manually operate (via a hand-held controller) the clock drive to follow sidereal motion (speed 1), and I can bump it up all the way to speed 8 to quickly slew across the sky, or interim speeds to center objects. This thing is a huge leap over mounts I’ve used in the past, and would heartily recommend it. HEAVY, but that also means STABLE. And so smooth. 

I set up for these photos in my back yard with very little polar alignment - didn’t need super-accurate sky tracking for such short exposures. The more setup time invested, the better the resulting images.

I’m still learning how to use this camera, and tried a bunch of different exposures, ISO speeds, and so forth, plus figured out how to set a delayed multiple exposure so the vibrations from pushing the shutter release wouldn’t mess up the shot. 

This shot of the crescent Moon is at ISO 100 and 1/25th of a second. Faster ISO speeds got grainy, and slower shutter speeds were overexposed, so this seems perfect for the subject.  

Here's the mounted scope:  

(That chock-full firepit houses at least one family of California Wrens among other urban wildlife, so it keeps growing deeper, alas. The teeny tree surrounded by landscape bricks beside it is a baby apple tree I just planted last summer, and its partner tree stands right behind me - bees oughta appreciate their proximity, which I hope makes 'em more productive, too!)

Here's my large-format eyepiece collection (for when I want to use organic human optics rather than the camera) and some other gear: 

The biggest of these weighs almost five pounds! 

The fingerless gloves are a lifesaver on cold winter nights, the red-filtered headlight allows me to see without ruining night-vision, and the eyepatch preserves that vision in the covered eye (and prevents squinting, also helping astro-vision). Without a camera, most deep-space objects like nebulae or galaxies are very faint and diffuse, so preserving one's optimal vision is key to seeing anything.

The longer you do astronomy, the better your collection of gear gets, because it lasts forever if you take care of it and you can tailor your setup with small improvements over time. Maybe more info than you wanted - if you read this far, I hope you found it useful! 

Pretty happy with the results for my first attempts! If the upload doesn’t ruin the resolution, you should be able to open the image and zoom in on the Moon's craters and the Orion Nebula's vast detail.

I hope you enjoyed this little amateur astrophoto intro! If y'all like, I'll probably post more as I take 'em. Regardless, I'll use more to illustrate my writing as I post those, too.

Like these? Want to see more? 

Ad Astra!
Chris

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