Today’s digital SLR cameras are able to capture astonishing celestial images. All they need is a small equatorial mount to compensate for the Earth’s rotation and keep tracking the stars. The camera then images the stars as pleasing points of starlight rather than nonstellar hyphens. Tracking allows more than just an aesthetic touch. It also brings several distinct advances to your personal astrophotographic repertoire.
To avoid star trailing on nontracked tripod-mounted images, photographers are limited to wide-angle lenses (typically, 28mm or shorter) and exposures under 25 seconds. Tracking mounts open imaging opportunities to lenses up to 200mm focal length, which greatly widens the choice of celestial targets. Equally important, exposures can be increased from seconds to several minutes. And, if desired, sequential tracked images of the same object can be digitally stacked for increased density and reduced digital noise.
In the era of film-emulsion photography, tracked astrophotography was more difficult for a multitude of reasons. I won’t list the frustrations, but there were many, which was probably the main reason that very few commercial portable tracking mounts specifically designed for SLR cameras were ever marketed.
Tracking Mounts Emerge
That changed about a decade ago, and today, several are available. Three recent ones have been reviewed in SkyNews (Vixen Polarie, July/Aug. 2012; iOptron SkyTracker, May/June 2013; Sky-Watcher Star Adventurer, Nov./Dec. 2014). The iOptron SkyGuider shown here was supplied by iOptron for review. At a glance, it appears like a scaled down equatorial mount, but unlike most mounts, this size is designed expressly for travel astrophotography. To try it, I took it with me on a trip to the Enchanted Skies Star Party in southern New Mexico in late September. As seen above, the SkyGuider is being readied for action as darkness falls. For airline transport, everything disassembles and fit easily into my full-sized checked bag, with plenty of room for clothing and other astro gear. The semidesert conditions about an hour south of Socorro, New Mexico, proved to be ideal for astro-imaging.
Some essential accessories that are not part of the standard SkyGuider package are the iOptron ball head, between the camera and the mount, and the 12-volt holder (for eight AA batteries) on the tripod leg. There are many ball heads that will do the job, but the iOptron ball head is as good as any I have used. The important thing is to get one that is beefier than you might think it needs to be because it has to rigidly hold the camera and lens at an angle during the exposure — sometimes a steep angle. As for the 12-volt power source, several choices are detailed in the instructions. I paid a visit to my local hobby store, where the owner quickly found a five-dollar plastic holder that houses eight AA batteries, which you can see taped to the tripod leg. This added insignificant weight and powered the mount for five three-hour sessions, and it was still offering juice.
Using the Skyguider
I have some advice for anyone getting into astro-imaging or upgrading to better imaging equipment. If you don’t already know an astrophotographer, find an astronomy-gear dealer with a staff member who’s actually taken celestial images with a DSLR during the past few years. Astro-imaging is, in many ways, a hobby within a hobby. Viewing and imaging have overlaps, but imaging has its own learning curve. Going deeper, there are DSLR imagers and CCD imagers with their own overlaps. It helps to have someone who has done it successfully to explain some of the equipment. Your local astronomy club may have just such an individual.
I’m not trying to scare anyone away. I’m simply suggesting that finding the right dealer can be a wise investment of your time. Here’s another tip directly relating to the SkyGuider, which I thoroughly enjoyed using. The sturdy but teensy tripod supplied with our review unit (28 inches high where it clamps to the mount) requires the user to kneel way down to sight the reticle in the polar-alignment scope and to adjust the knobs to get Polaris in the exact correct spot. As a septuagenarian, I found the crawling and crouching somewhat demanding. Fortunately, a 44-inch iOptron tripod I use with another scope solved my problem. This tripod can be purchased with the SkyGuider mount.
So what’s the verdict? Is it worth investing about $500 for the mount alone and
another $150 for the taller tripod? I say yes for several reasons: (a) I proved to my satisfaction that this mount reliably does what a portable astro-camera tracker is supposed to do; (b) the whole kit fits in a full-sized airline suitcase; and (c) the entire SkyGuider outfit costs less than the lens I used to take the Andromeda image above. This is a quality product that works.
What about the auto-guiding capability? Although there is an ST-4-compatible guiding port, I didn’t need it. To my mind, the advantage of the SkyGuider is its simplicity and accuracy: quick setup and alignment, no electronics, small batteries and accurate gears. For remote imaging anywhere, this is the formula. Simple, mechanical, largely foolproof. Colleagues who make a living as photographers in the news business say again and again that the best equipment to get the shot is reliable “no excuses gear” that won’t let you down.