Hello guys,

I am seeking  a little help / ideas with a small problem I'm having.  I'm looking to build my first telescope.  I decided to do this because I saw a primary mirror on ebay and decided to buy it at a lower price (I know it probably isn't the best mirror in the world but for my first build I dont want to invest a lot of money).

Anyway, the mirror is a 8" f/4 mirror.  With that mirror by my calculations using a low profile focuser and a 2" secondary mirror my tube length would be aroudn 34.5 inches.  Now the problem I have with this is that I was going to make a dobsonian scope, but that short of a tube on a dobsonian would give one heck of a krink in the back to look through when your 6 feet 1 inch tall.

Any ideas / suggestions on what I can do here?  I thought about just changing up and using the tube on an equatorial mount but I can't seem to find a good tripod + mount with tube rings to fit a 10" OD tube (thats the size sonotube I plan to use for the tube itself).   

I wanted to do a dobsonian and stay away from electronics for now so that I can learn the night sky better, as I've always had electronic scopes in the past and never really learned anything.  But an equatorial if I can find the equipment, with motor drives would not be bad either if I can use them for tracking, I wouldn't mind toying around with some astro photography if I can set something like that up.

Thanks for any help you guys can give me!

You could make a Dob with a tall central pedestal that will boost the height of the optical tube to a more comfortable height.   You could also use a longer than needed tube and place the mirror a third, or even half, the way up the tube.  This approach will require a counter weight at the bottom of the tube to ballance out the weight.  Good luck...

also you could buy or make an adjustable viewing chair, makes viewing a true pleasure.

Al

I was wondering how this turned out, since I'm looking at the same mirrors.

 Has anyone looked at the specs for these mirrors and what do you think of them?

 

I saw a great, easily made, simple equatorial mount that you could use for this application here:

http://home.fuse.net/astronomy/gem.html 

I havn't made much progress with it as I've been busy with work and school and havn't had much extra money to spend on it.  But I think I'm going to end up going with a CG-5 Type Equatorial mount, I see them on ebay every now and then for between 150 to 200 dollars with both axis motors and tracking capabilities.  This would be the optimum solution for me to start off with I think because I'd like to get a deep space imager to play around with.  I know I wont get anything to great off a set up like this but just something to toy with :)

I bought the same mirror from ebay, and the fl is actually 750 mm (approx 29.39"). Remember that you must also take into account the distance from your secondary to your actual focal point in the focuser, so it will be even shorter in the end. You can always add extensions to your tripod to make it a little taller. By the way, my mirror turned out to be quite good, which was a nice surprise.

 You could build a platform to raise it up off the ground. Friend of mine set his travel case for his scope as a platform. Check it out.

http://www.inskysd.org/gallery/details.php?image_id=858