Posts Made By: Gary Davis

Hey Mr. luna-tic I own an XT-8. I throw 400X at it and it holds well. In order to use my digital camera though I can only use a 15mm or below. Like you the reason is to small an exit pupil. I have used the 5.2 Orion Lanthanum with success as it has a large lens and big eye relief. You have to get close and shoot the pic fast. The rubber eye cup is a perfect distance from the lens. I do not think you can use a 2.8 or 3mm. Image breakdown is fast. And a Dob is to hard to guide. At that magnifacation the image will be out of sight before you can line up for the shot. For your camera I believe you will need EP's with large exit pupils in order to line up quickly. They do sell holders for digitals that will help alot.

Complete Collimation during daylight hours is not normally possible. You can get close with the proper settings "alighnment only". You will need a night time star to star test "the second step after alignment". A star is a point source of light not a reflection as in a planet "or ball bearing struck with a light source". When you do this you will see the difference of the two light sources. Before attempting to collimate, you should read all you can about what it is and what it does and then make a plan to attempt it. You may render your scope unusable "but recoverable" if you attempt this before educating yourself. Good luck !! Also look in the book that came with your scope it may show you how to alighn it.

By the way, i see my keyboard is sticking again and I keep getting an H after a G. Daytime focus may just be heat rising from your surroundings. Since your likely attempting to focus at a real low altitude the rising air currents blur your target. This is most pronounced during the summer with tempatures in excess of 90 degrees but can occur at anytime. If you live in a temperate zone it can render a terrible image. Those who live in the western deserts sometimes see this as moving, shifting waves of air, floating up and across the landscape.

Larry,

I live in Fresno and have the same problem. I have to wait for planets to be high in the sky before I can see them clearly. If you live on the west side of a city and are looking east you will have this problem "or vice versa". I have discovered not only light pollution but heat columns rising from the city until late at night. That rising heat makes the planets dance, wiggle, hop "really" and jump making focusing next to impossible. I don't know if anyone has really given thought to rising heat from major cities playing a role in image distorsion. Of course viewing through a window will cripple your viewing. If it is heat rising from the city your only recourse is wait until the planet is high in the sky. Or wait until its opposite of the side that presents the highest amount of heat columns. Make sure the jet stream is not over the valley "low pressure nearby". Light fog or thin clouds will mask some of these problems. Try to avoid looking over the city and see if it helps. It drives me nuts sometimes. On nights just before the fog develops "stagnent air and no currents" you should get your best views in winter. I hope at least one thing I listed will help.

As a last ditch effort to fix the very same problem I did the following. Found an unused plastic barlow. Took out the glass. Used the leftover tube to lengthen my focuser. Its cheap and has been used 23 years on my 10 inch f/10 refractor. There of course are other remedies, but this one is quick and not asthetic.

I have found out what the problem is. There is some kind of defect on the secondary mirror. I put in a new 1.5 inch secondary that I had here at the house and presto, it works even better than I had hoped for. Thanks to all of you for your input. I now have this scope working very well, I was suprised to find the secondary at fault. I can see that the premium coatings are brighter than my standard coatings. I can see finer detail than with the standard coatings. I am so happy you all talked me into being patient. Last night provided the best images of Jupiter I have ever seen. I really thought that the scope was a lost cause. Thank you to all.

I was looking at yours and mine and you do so much better ! But I think the real point is they resemble each other in many ways. Its fantastic to see that others see what I see and can verify my detail. Its great !!! Tonight, if all goes well, I will use my 10 inch f/10 refractor. I use the 8 inch Dob more because its easy to set up and get going. But I am ahead of the game tonight as I have the refractor all set and ready to go.

I had a Synta OTA that did the same thing. So, I added lead weights to the focuser and behind one of the baffles. I also used a large speaker magnet "easy to move up and down the tube" to help find the balance point. You do not have to live with what you have. You can change it what you want. Its real hard to live with a focuser that touches the ground. Not only did mine look stupid it was not even practical and a dumb overlooked problem by the manufacturer.

Yep, it makes it a private auction. Personally, I pass over them. I think everyone knows the value of something they want to sell. If they don't, there are many, many ways to find out what its worth beginning with an internet search.

There may be problems. See if you can find on the internet a free program called Newt !! Use Yahoo and search for "Newt". You will find it handy. As far as I can tell, you could use a 2.1 inch secondary with the right tube. Be sure to enter accurate numbers in the fields for Newt.