Building & Using a Tracking Mount for Astrophotography

Some Astrophotos Made Utilizing The Tracking Mount

All the photos on this page were obtained using this mount with a Sony NEX-5N camera.  The lens used is an old 1971 Mamiya-Sekor 55mm f/1.4 stopped down to f/3.5. These images are composed of single JPEG shots with no stacking, flat frames or dark frame noise reduction (except where noted). Post processing was mostly just histogram stretching. So there is lots of room for improvement in these areas. The panoramas were assembled using Microsoft's ICE (Image Composite Editor, a free download).

The first three photos shown here were taken at a site in the Blue Mountains of northeast Oregon at  just over 3000 feet elevation. Exposures were around 2 minutes at ISO 1600. There was some light pollution from cars and trucks on a nearby highway as well as from a town (about 17,500 population) just over 10 miles distant and about 2000 feet below. Also the air was dimmed by a lot of smoke from forest fires. Still the results are quite nice.

The view here is in Sagittarius, showing a region in the direction of the center of our Milky Way galaxy.
This image shows a nice star field between the star Vega in the constellation Lyra on the right to Gamma Cygni on the left.
This panorama of multiple images covers a span of the Milky Way from Cygnus on the left to Sagittarius on the right. The change in color from left to right is due mostly to smoke pollution, which is thickest low in the sky to the right. Click to expand image.

 The following panorama consists of parts of 13 photos taken from an elevation of just over 1200 feet in the Coast Range of southern Oregon. Some clouds and  light pollution  affected  the images. Exposures were 2-1/2 minutes at ISO 1600. Long exposure noise reduction (dark frame subtraction) was activated on the camera. This resulted in considerably less noise as compared to the first panorama above.

 This view of the Milky Way extends from the Double Cluster in Perseus on the left through Cassiopaeia and Cepheus to Cygnus on the right. Click to expand image.

 Here's wishing you success in astrophotography with this mount.

Its easy to build and fun to use - give it a try!

The views and opinions expressed in this article are those of the author and do not necessarily reflect the views and opinions held by dpreview.com or any affiliated companies.

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Comments

Total comments: 4
NancyP
By NancyP (Jan 17, 2013)

What is the maximal load the home-made barn-door mount can accommodate?

What is the minimal wattage on the green laser? I understand that these green lasers often emit eye-cooking infrared, and would like to use the least powerful laser that can be used for polar alignment. I know some people use more powerful lasers for group lectures during star parties, but that capability I don't want.

0 upvotes
RustierOne
By RustierOne (Mar 25, 2013)

Hi Nancy,
I don't know the minimum wattage, since that would depend on circumstances. The visibility of the laser beam depends not only on its wattage, but also on the amount of particulate matter in the air available to reflect the laser beam. I purchased my Laser from Orion Telescopes for around $40 US PPD. It's rated at <5mW, which seems to be very bright in a dark sky. One important use consideration is to be very sure not to point the laser beam at anyone's eyes or at any aircraft. To do otherwise would risk eye injury and would be violation of the law.

Best Regards,
Russ

Comment edited 2 minutes after posting
1 upvote
Leif Goodwin
By Leif Goodwin (Dec 25, 2012)

This mount was invented by George Haig of Glasgow, and originally known as the Scotch or Haig mount. In North America it became known as the barn door mount. The original version had a straight drive arm which accumulated tracking error, which was corrected in later versions with various modifications. The original article appeared in Sky and Telescope, April 1975 according to Wikipedia, where there is a discussion of some of the variants.

0 upvotes
the jimmy
By the jimmy (Dec 20, 2012)

Good article, thanks

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Total comments: 4