Trombone or taller tripod?

[GordonCopestake]

I prefer to sit whilst observing, however when viewing near the zenith my eyepiece gets uncomfortably low. One obvious solution is a taller tripod, however whilst messing around this evening in my shed i had the idea of combining a 45 degree erecting prism together with a 90 degree diagonal.

The result is a suprisingly versitle solution that actually seems to work! I wont tell you that the image quality is 100% as im using 2 cheap diagonals. My only problem is that due to the large amount of out focus the 2 diagonals take up most of my eyepieces dont reach focus as i dont have enough in travel. Does anyone know if a focal reducer or barlow (or some combination) would allow more infocus?

[The Warthog]

Barlow might work if you put it on the lower leg of the 45 diagonal. It would give you at least a 3x increase, though. Don't know about a focal reducer.

[The Warthog]

Barlow might work if you put it on the lower leg of the 45 diagonal. It would give you at least a 3x increase, though. Don't know about a focal reducer.

Sorry, meant to say that you should unscrew the lens from the bottom of the barlow and screw it into the lower leg of the 45 degree diagonal. If it is the lens from a long 2x barlow, the increase may not be much more than 2x. In effect, you are replacing the tube of the barlow with the diagonal. Should work.

[GordonCopestake]

I have purchased a barlow and when it turns up i'll see how it works. Thanks for the info WH

[The Warthog]

By all means let us know. I may try this out next time I get my frac out, as I have two 90 degree diagonals, now, and can try the same thing myself.

[GordonCopestake]

i think you'de need a 45 degree diagonal to make it work. 2 90's means that the eyepiece is right up against the OTA.

[The Warthog]

Nope. It gives you a universal jointed ep holder that can point any way you damn well want.

[GordonCopestake]

Fair enough :shock:

[Zeffer]

A commercial one would be good that can be moved without loosening all the bolts but has enough friction to stay put once released. Maybe it should be patented quick!

[The Warthog]

When I got home I went out and set up the tripod and scope in daylight, and did some eggspearmintayshun on what we've been talking about. I put the 2" diagonal in the scope, and aligned my finder, then I put the 1.25" diagonal in, and pointed it to a jaunty 45 degree angle away from the scope, and tried to focus. Naturally, I couldn't. So, I took the lens out of my Barlow, and tried to put it in the front end of the diagonal, and learned that this diagonal is not threaded for filters. So, I put the Barlow on the front end of the filter, and tried to focus, with my trusty 32mm Plossl in the far end. It worked just fine, with something like 3x magnification. The image was upside down and reversed. I imagine with your setup, Gordon, you'll have an upside down image that is correct left to right. It does limit the range of ep lengths you can use, though.

As one of the reasons I bought the 1.25" diagonal was to use it as a filter carrier when I am changing eps, and it won't carry filters, I now have a decent 1.25" diagonal for sale. £12 + postage.

I hope I can put filters in the 2" diagonal.