© Reeth Informal Astronomy Group unless otherwise indicated

  Reeth Informal

 Astronomy Group

covering the Northern Yorkshire Dales

Anyone got a Heritage 130P Dobsonian?

This is a fantastic little reflector and comes with 25mm and 10mm eyepieces, with a focal length of 650mm that’s 26x and 65x magnification and it’s so easy and quick to set up and start using. Recommended price around £140 - £150.

It comes with a red spot finder which I find quite good, however, this is also where I found a problem. To see the red spot you need to align your eye parallel to the tube and at the mirror end so that you can line the spot up with the object you want to see. This is fine when the object is low down near the horizon but not so easy when you want to look more towards the zenith. It usually means kneeling or lying on the floor and performing all sorts of contortions. You may decide to stand it on a table to raise the telescope from the floor, which I normally do anyway, but to elevate it to a position that is easy to see through the red spot finder usually means that the eyepiece, which is at the other end of the telescope, is then too high to look through without standing on tip-toe or employing the use of a small set of steps. – Most inconvenient!

Wouldn’t it be nice if the image through the finder could be projected back along the line of the tube so that it could be seen whilst looking from around the position of the eyepiece. I looked around all the usual sites on the internet and in magazines but could find nothing. Right I thought I’m going to have to sort this out myself. I had a rough idea of what I wanted to do; a mirror at 45O should do the trick - but what mirror and how to fix it?

Luckily my wife had recently bought a travel make-up mirror from Boots the Chemist for the modest  sum of a Fiver. Next came the problem of fixing it to the telescope. I didn’t want it to be a permanent fixture but only to be connected on these odd occasions when I needed to look almost vertically. I had ideas of manufacturing some sort of a clamp to hold the mirror and then some sort of way to attach this to the telescope tube. This might mean drilling the tube and fastening it on with self tapping screws, which I wasn’t too keen to do. Then it struck me that I had some old bits of Meccano in the garage, surely I must be able to put this to good use!

In the Meccano bits were some U shaped brackets and it occurred to me that they would suffice to hold the mirror vertically and laterally. I was prepared to drill the telescope tube but I thought as a first step I’d glue the brackets in place and if the whole idea worked then maybe drill and screw later.