Jupiter and fine tuning

[mikemph]

Hi

Between the clouds had my first view of jupiter with my 150mm Dob and 10mm eyepiece (need to order a barlow I think)

very impressed especially Jupiters moons, full session lasted about 15 seconds before clouds moved in. But got to look at orion and venus in phase for a little while.

Anyhow i need fine tuning/nudging advice.

How tight/loose does the base bolt need to be and how much tension am I looking for in tensioner.

thanks

mike

[Zachariah]

I have a sw150 dob too and I find it very difficult to use at high mag. Its trial and error with the tension bars. Some swear that dobs are the best but my Russian Tal on on a eq mount is a joy to use.

[umadog]

If you find a Dobsonian hard to use at higher magnification then chances are it has bad bearings. People who've used a Dob with good bearings will swear by it; people who've used one with bad bearings will swear at it.

A lot of the mass-produced Dobs have crappy bearings to cut corners. You can replace the bad bearings. It's usually just the case that the Teflon blocks are riding on something sub-par, so you simply have to replace the surface they're in contact with. Surface that can work well include fibreglass and Ebonystar. A friend of mine recently upgraded his 8" Orion bearings and was shocked by how much difference it made.

[mikemph]

thanks

getting the ahng of it, so far tonight, juoiter, venus, mars and waiting for saturn, will be first time viewing saturn so really looking forward to it.

mike

[crashtestdummy]

ditto to viewing saturn,hoping it rises before i have to go to bed.i have similar problems to you with small inputs but ive done some mods to the base of my 200p that have made it better,still not perfect though so my next scope will have a motor drive for fine adjustments and apparently the bigger dobs are much smoother.good luck with saturn

[umadog]

Yes, I think the bigger Dobs are smoother but that's because they cost more and so they're more likely to come with good bearings. The Orion XX12 has Ebonystar on the azimuth, for example. I built my first Newt (an 8.75") and the bearings worked very well indeed. It's PVC/Teflon for elevation and Formica/Teflon for azimuth.

[mikemph]

stopped up for saturn and was well worth the wait. Had to take in turns with my 17year old though,Hes too old to send to bed anymore(damn)

Anyhow saturn was better than thought it would be, brilliant in factand thats with a 6" Dob with standard 10mm eyepiece.

good hobby and good forum/people

thanks

mike