Caveman Astrophotography

Over Christmas/New Year, I took 2 weeks off and devoted (the evenings at least!) to a new stage of the imaging journey. My aim was to produce some deep sky images using very basic gear. I piggybacked my Canon 400D on the 4.5" reflector mounted on a Skywatcher EQ1 & tripod, and used the NexImage as a guider. Guiding was done with the "slow motion" control knobs. I could have just as easily used an "illuminated reticle" to facilitate guiding, but I don't have one!

Hardly ground-breaking stuff and let’s face it, the computerised mounts that most serious amateurs use are very recent. This method on similar gear (other than the webcam guiding) used to be a common way of film imaging not all that long ago! But I preferred to nut out the process and feasibility myself rather than consult the masses of info that must be out there.

First thing I did was calcs that showed that at 18mm in the 400D kit lens, a little wobble is insignificant but at 55mm it is maybe just starting to have an impact on star size/shape. And because of the focal lengths I'd be using, I strongly suspected that unless I took really long exposures, precise & exacting polar alignment wouldn't be a problem (ie it would remain within the "wobble bubble").

Looked good so I checked it out! Bright moon and light hazy cloud but I set up anyway. Didn't really polar align properly, just set the alt at 37 degrees (with the rough pointer and scale, could be +/- 2 deg!!!). Plonked a stick of wood on the ground and aligned it NS with hand-held compass (did allow for magnetic declination), then plonked scope over it, roughly aligning by eye & not levelling. Had a quick practice but had to use both slow motion controls to track (effectively using the EQ mount as an Alt/Az). When I thought I had it OK, I clicked the camera (delay on), grabbed the control knobs, and went for it!

The following were the results, and I was very pleased. Not that it was any different to what I expected, just that it was really testing my hand-eye co-ordination, in two directions at once because of the poor alignment (no good for longer exposures, but OK for this quick test)! Focus was way off on the second shot, but that was not that important. Sirius is the bright star - I was guiding on this.

Next night, with a bit better polar alignment, things worked much better and I could guide with just the RA knob. I actually measured the alt, it was 3 degrees out - correct setting is about 34 degrees on the scale, for 37 degrees! Cheap shit, LOL. Levelled everything too, and re-did celestial south orientation more carefully. Got markers down to plonk tripod on. At 55mm in the lens (max zoom), guiding with the NexImage on Rigel, there wasn't much movement in the shots (crop attached, slightly down-sized).

In later nights I played around with polar alignment, zoom, exposure time & settings. Even enlisted my Chrissie pressie lens, a basic Sigma 55-200mm, but shooting at 200mm turned out to be fairly ordinary (not unexpected!). A true babe-in-the-woods with EQ mounts, at times I was frustrated with RA control jammed against the counterweight, weird camera angles, red dot finder needing a contortionist to see through it, etc! I stiffened the RA control knob join, using a temporary folded-paper shim and it made it much smoother, with no unwanted torque. With practice, managed to guide successfully for as long as almost 4 minutes, which was OK for starters. Kept ISO at 800.

To guide, I plonked the cursor in the guide star's track across the monitor, and try to keep it on the arrow. Intended originally to make a cellophane cross-hair to lay over the screen, then a grid on the cellophane...... then stuff it, too much trouble!! Cursors are very flexible - it's a lot easier moving the cursor than aligning the star.

Well, it’s all packed away now, waiting for my next opportunity for a burst of activity! Top of the “TO DO” list is make a camera mount that I can rotate around the OTA to suit, rather than have it fixed on tube ring as it is at present. Second is drift aligning to get much better polar alignment. Third is to do hand/wrist exercises so I don’t get the shakes on long exposures – hmmm, drinking comes to mind!!!

Welcome to astrophotography on the cheap! This blog is about a journey through astrophotography, a journey that is not finished yet. Before I get to what I'm doing now, I'll bring you up to date on where I've been.

But be warned, if your own astrophotographical interest is in achieving technical perfection through advanced equipment and techniques, then don't bother reading further.

This blog is for the punter who has limited equipment, who might want to get a few lasting souvenirs of his/her night sky travels, who might want to push his/her gear to the limit to get some reasonable astro photos without major investment, who has a child-like fascination with the fact that photons can travel millions of light years across the cosmos and be captured by relatively basic means......

And so who died and made me an expert on budget astrophotography? Nobody, I'm just a punter too, who's fighting against the rampant consumerism that's driving this hobby to more and more expensive realms (= tight-arsed, penny-pinching Scrooge, hehehe).

So whaddaya need? Camera helps, duh-uh! You can start off with nothing more than an ordinary point-&-shoot if you want - you can zoom in and capture little moons, you can photograph planetary & moon conjunctions at twilight, you can even capture bright stars......

Solar? Well, don’t point your camera at the sun. But here’s images of the transit of Mercury in 2006, shot using a cheap Kodak camera and a long cardboard box with binoculars set at one end – called “eyepiece projection”, this projects an image of the sun through one of the binocular lenses (other masked) onto a sheet of white paper on the bottom of the box. You just photograph this projected image, then darken up the image to bring up details. Works on eclipses too, and very safe.

If you’ve got a telescope, any telescope, a cheap webcam is a good investment. My telescope is a 4.5” f8 Tasco reflector on an alt/az mount, now that’s pretty small and basic! My webcam is a Celestron NexImage, bought cheap in the States, but you can also pick up ToUcams on eBay for well under $AU100. Of course you do need a laptop computer, but I doubt that many people buy these just for astrophotography. I didn’t. Anyway a webcam then brings bright solar system objects into your realm – moon, planets, even the sun but only if you purchase some approved solar filter film and make your own full-aperture filter. A cheap Barlow increases magnification, but don’t bother with the cheapest plastic rubbish. A perfectly acceptable 2x short Barlow can be purchased new for around $AU30. Processing is by stacking the frames from the videos (AVIs) with freeware such as RegiStax.

To compensate for the limitations of your cheap scope, you can do interesting stuff like moon mosaics. These are lots of shots put together to form pictures of the whole moon, at different phases.

With a telescope, you can use your point-&-shoot camera to take afocal shots by just holding your camera up to the eyepiece and shooting. Pretty rough, fiddly method and you will get lots of failures. But you can also get the odd good one. Limited to bright stuff, moon & planets. You can even shoot through binoculars if you want! Try your camcorder through the eyepiece too, splitting the useful sequences and using stacking for processing (as with the webcam)

Want a better camera? Entry-level manual cameras can open up a whole new world. Here you’ve got control over the settings, and extra exposure time. Now you can photograph starfields, bright comets, perhaps even the biggest and brightest Deep Sky Objects (DSOs), just off a tripod. But for the latter, you also need to develop some basic image processing skills. Photoshop (expensive), Photoshop Elements (cheap), or similar processing software are good investments at this stage.

Which brings me to now. Wanting to grab some more of the thin stream of photons from distant places in the universe, I made my only ‘decent’ purchase to date. A Canon 400D digital SLR. Mind you, it’s still only an entry-level DSLR, purchased for under a $AU1000 with kit lens. At the start, I was limited to using it off a tripod because I didn’t have tracking, so it was mostly conjunctions and widefields initially where star movement was not a great issue.

Tripod imaging can also suit photographing satellites (eg flares from Iridium communication satellites), or the movements of the brighter asteroids (m.p.'s). You can even create animated gif files where there is orbital movement!

I needed to track. Now you can spend a fortune on tracking mounts, auto-guiding software etc, but I preferred a more hands-on (and cheaper!) approach. So I bought a second-hand SkyWatcher EQ1 mount for $AU70. This saw ‘first light’ only a week or so ago, and I am still wrestling with it. And that wrestling will be covered in the next instalment. But here’s a few images from my early experiments, in advance…..

All images posted in "Caveman Astrophotography" were taken by the Caveman himself, and remain his property! However, any may be copied and used for non-commercial purposes, provided acknowledgement is given - © R Kaufman 2008