Posts Made By: Leslie Hess

I recently purchased parts from Surplus Shed to make a 85mm x 900mm refractor. After making a tube and focuser I eagerly assembled the telescope and waited for a clear night.

Finally the clear night came, I trained the scope on Saturn and focused it. I was sorely dissapointed but not ready to give up.

I am not fully understanding what the problem is, perhaps you good folks can help.

With Saturn focused at fairly high magnifications about 90x the planet is surrounded by a ghosting effect. Picture the planet focused and a surrounding area about 4 times the planet size has a bright haze around it.

My tube is blackened on the inside, I have used 2 inch and 1 1/4 inch eyepieces with simalar results.

Please help.

Thanks,

Leslie Hess

I guess I am just strange?

OH well, I can live with that, it is nothing I did not already strongly suspect anyway....

leslie

Thank you all for the quick response. Astromart is just super! <3

Yes the objective is an air spaced doublet. When I take the front lens out and flip it over it contacts the back lens. The back lens has a double convex surface. The front element appears flat on one surface (facing in)and slightly convex facing forward.

I can eliminate the variables such as atmosphere and eyepieces. I went directly out back and checked the view from my 10 inch dob and it was crystal clear using the same eyepieces.

"Most two element objectives are made with a double convex lens in the forward position."

If that is true it sounds like the entire objective is mounted backwards? I will try reversing the objective, too bad it is cloudy or I could check the results right away.

Thanks so much for your input!

Leslie