Testing out the barn door tracker

Looking to test the newly improved ‘barn door’ tracker to its limit, I dusted off my old Sigma 75-200mm/f3.8 with 2x tele-converter. But with a hefty 600mm 35mm equivalent focal length, I was prepared for the worst.

barn door tracker image of M13 Globular ClusterAfter less than a minute of polar alignment, and unable to frame the shot through the viewfinder (due to an awkward angle), I pointed the camera vaguely in the direction of the Great Globular Cluster in Hercules, and opened the shutter for a 30 second shot. Without a watch to count the seconds, I manually moved the dial round, counting the seconds off in my head.

Checking the screen, to my amazement, there it was! Not only had I centred the cluster first time, but there were virtually no trails. I know the shot is pathetic compared to most, but for a home-made, hand guided barn door tracker, cobbled together for under £10, I was blown away by the result.

Shown here is a single 30 second exposure (iso 2000) without the didymium filter, giving it much more colour than the final stacked image.

Details: Nikon D7000, Sigma 75-200mm/f3.8 (at 400mm with 2x converter). 5 minute exposure (10 x 30 seconds) at iso 3200 with didymium filter. Stacked with Deep Sky Stacker and tracked with barn door tracker.

The Milky Way

First attempt at shooting with the home made ‘barn door/scotch mount’ star tracker – I’m amazed how well it works!

This single 3 minute exposure was taken using a borrowed lens in the amazingly clear skies of the North York Moors. The detail shown in the shot at full resolution is amazing (click here for a larger view). The Tokina 11-16mm also worked extremely well. Much sharper and faster, with less distortion and vignetting than the Sigma 10-20mm.

I’m hoping a new ‘didymium’ filter/red enhancer I recently bought from eBay (for £15) will help bring out the nebulosity, while also combating light pollution at the same time. I’ll give it a try near my over illuminated home town in the nights ahead.

Details: Nikon D7000, Tokina 11-16mm f2-8 at 11mm and f4. Single 3 minute exposure at iso 1600. Tracked with barn door tracker.