I have had 3 cloud free nights this week to find my way around the sky and the scope. Found saturn, Jupitor and the Nebula in Orion I'm hooked.
Started out using the 32mm EP then the 25 and 15 I can't use the 9 or 6 properly yet because the scope moves too much. Also moves while I change the EPs, especially from the 32 to the 25 - but working on it. Is this where magnets are best to balance it?
Barlows are used to increase magnification - how do you decide which is best? do they come in different sizes?
What are the screws that are near the focusser where the Eps go in - told you these are newbie questions - haven't noticed them until today in the light!!
The little fan is broken and I have to return it to Lee - otherwise all was well with the telescope
One other bit of exciting news
I'm going to Parkes with the Coonabarabran Astronomy Group to meet John Dobson - the inventor of the Dob.
Hi Margo
If the spring tension is correct between your OTA & base, you should not get any balance problems.
Check that first, I dont find the need for any magnet weights with my Dob.
Margo, If your focuser is the same as mine (8" Dob), this is what you have.
There is one screw for regular (1.25") EPs. You've obviously found this one..
Then there is two identical screws 90 degrees apart, just behind the EP screw. These are for 2" EPs, and are actually holding a 1.25" adapter in your 2" focuser. Undo the two screws and lift out the adapter just to see how it all fits together. (It took me several days before I was brave enough to touch anything but the regular EP screw )
Finally, there is a larger screw (black and plastic on my scope) closest to the body of the scope (OTA). You can use this to adjust how snug or sloppy the focuser is. If it feels too stiff, loosen it; if it feels wobbly, tighten it. You can safely play with it all you like.
You have the Crayford Focuser. These are the parts below. (thanks to Geoff for assistance)
If your tension adjustment is too loose your eye will push the EP out of focus. Too tight and it becomes hard to turn the focus knob. Find a spot where you are happy with the movement.
Your scope should not move changing EP's. Which way is it moving? Up & down or Sideways?
Last edited by ballaratdragons; 07-03-2005 at 01:36 AM.
Actually Ken with the crayford, the screw closest to the OTA is the focus lock. If you tighten it the tube will lock and the focus knob shaft becomes disengaged and spins freely.
The top one is focuser tension.
Aahhrgh that Crayford looks so good Ken! ...but yours looks like it was made for a smaller scope... maybe an 8" ... i'd be happy to help you out and take it off your hands ...
If you are having problems with the Crayford focuser in changing eyepieces then I could swap you for my rack and pinion, it works perfectly
It takes a bit of time and practice to change the higher powers without moving the scope too much. Just give yourself some time and enjoy.
If you are having problems with the OTA balance with your range of eyepieces that would suggest that the spring tension system is not set properly and needs checking. On my 8" scope I only use one spring and that handles all my eyepieces so I would be surprised if you need magnets for this range of eyepieces.
Thanks guys
It was the focus lock and the tension adjustment screws - I wasn't sure what they did - many thanks
I will try only one spring tonight and see if that is what my problem is. I'll also notice if it moves up & down or sideways. Could be I just need to practise to change them smoothly
Thanks again
You may also find on the GS 12" dob bases that if the Azimuth bolt (the one that goes through the bottom) is not kept fairly tight (not too tight though) the base swivels too easy and even a light wind will move it.
The 12" Deluxe (mine and your model) has roller bearings and they are very sensitive. Other model GS's have Teflon pads and don't move in the wind (or slight knocks) as much.
I have noticed that the bolt on the bottom of the base needs tightening each time I've used it
Plenty to think about tonight!!
Thanks again
Dark sky outside
Bye
Try getting a nylon locking nut for the azimuth middle bolt, it will not come undone like the simple nuts do when you turn the scope in the counter-clockwise direction.
Things improving - either I'm getting the hang of it and/or the azimuth bolt was tighter and/or no wind. Using the 15mm and 25mm EP more frequently now rather than using the 32 to find things first, and even saw Saturns moons last night
Thanks again