Caveman Astrophotography

Adventures in el-cheapo astrophotography - please navigate back to Chapter 1 using the page links at the bottom of this page for the start of the journey...

With my laptop playing up and a bit of thought required before purchasing another, I went out and bought a cheap, unbranded 12.5mm illuminated reticle from Andrews in Sydney. Now there’s nothing special in using one of these, and in fact not so long ago they pretty much formed the only way of guiding telescopes while imaging, either as fully hand-guided using slo-mo knobs or for tweaking Dec drift while tracking with an RA motor drive. But nowadays of course it’s all you-beaut software & supa-dupa hardware blah, blah, blah…

Anyway, the reticle has an adjustable light and at low power, using reasonably bright stars, the amount of light was satisfactory (ie it didn’t swamp the guide star). I am using the reticle and a 2x Barlow in a home-built 80mm f5 achro refractor, on an unmotorised EQ1 mount with a flimsy aluminium tripod. The Canon 400D is piggybacked on top of the scope. Here’s the set-up:

To keep things as steady as possible, I sat on a stool at the eyepiece, and turned the RA knob with my arm ‘anchored’ to the top of a stepladder. First thing I noticed was that I didn’t seem to be able to exercise the same precision and degree of control as I did using the laptop, where the guide star appeared highly magnified on a ‘big’ screen. But would the control be enough? I tried the 400D at 55mm first, and by keeping the star within the small central square formed by the two crosses etched in the reticle I found that it was indeed OK. Stars were tight & round. The main difficulty was starting & stopping the camera with the wireless remote shutter release – very awkward (you need to be a contortionist or have three hands) and a cable release would work much better. It was so awkward that I eventually went to 30-sec exposures with ten-second shutter delay (maximum set exposure time of 400D without resorting to bulb). The 10-sec delay enabled me to grab the RA knob and settle the star down in the square before the shutter activated. Here's an actual pixel crop of 55mm shot - the tiny nebulae are Swan & Eagle, believe it or not!

What about 200mm? Well, strangely enough my very first attempt wasn’t too bad – stars not quite perfect, but hey! Here's an actual pixel crop - the marked object is comet C/2009 K5 McNaught:

I’ve tried a few times since at 200mm but the results have been very ordinary. With the flimsiness of this set-up and its susceptibility to the slightest of unwanted movement, shooting at 200mm is always a bit of a gamble, even using the laptop. It’s a zen thing, you need to be right in the zone, LOL! But one good thing about the flimsy mount, you don’t need to tweak the Dec knob as you’re shooting, as a slight pull on the RA knob one way or the other will correct any small Dec drift. Precise polar aligning? Er, what’s that?

Two great advantages with the reticle is that suddenly I’m not dependent on power and can move the scope anywhere I like in our big backyard (we lease a block at the back of our property) to take advantage of gaps between trees. Or chuck it in the car and go up a hill somewhere! And while the In-Camera-Noise-Reduction (ICNR) does its stuff I can look up at the glorious night sky, not having been blinded by the bloody laptop screen!