Building a Scotch Mount (barn door tracker)

Well.
For the craic I decided to build one of these
(here is a fine example from the Shropshire AC website)
www.astro.cf.ac.uk/sas/barn.jpg

There was plans for it in the current issue of the S@N magazine.

So far the materials have cost me around 20 Euro.

Thing is though, you have to fix the latitude.
Which is making me think I need to fix it to the latitude
of the dark sky site I will take the shots from (53.02)
as opposed to where I live (52.42)

How much of an effect would that difference have on say
a 20 min shot with a widefield lens?
Too much?

ive noticed that a lot of them fix the latitude, but wouldnt it be fairly easy to make it adjustable. I remember protractors we used in metalwork in school that were quite heavy, made of stainless steel and when you set it to the required angle you locked it in place with a bolt. it wouldnt budge until you released the bolt.

if you had one of those each side, or a similar idea on each side of your tracker couldnt it be adjustable?

could even use a screw mechanism such as in a compass ( draughtman's compas i think its called) so that you could have fairly fine grained tuning of the angle.

ive been thinking about this for quite a while so have been rolling ideas around for when i get home to my dads garage to try to hammer something together.

Your reading my mind.
I like the idea of it's simplicity.
(No motorized parts / drives)
To make it adjustable just makes sense.
I guess you just need an adjustable 'protractor' to bolt the
barn doors onto.

But what.

I'm surprised that more people around here don't make these.

Given our high latitude (Approx 53 degrees north.) it should be relatively easy to convert even a Dob mount into an equatorial!

Hi,

Frank, 0.6 deg offset from the pole for a widefield short will have very little effect, but could be a different story for a long-lens.

I made one many years back for IAS Halley's Comet expedition to La Palma (before I had a small equatorial), but in cold weather, high on a mountain, manually moving can be off-putting.

S&T have featured designs for a motorised Scotch Mount,

John

Frank,
I don't know if you have heard of it, but they have a new fandango called an Astrotrac mount.