Newbie questions

[blackpearl]

Hi All

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.

[Striker]

I wouldn't worry about the Barlow for the time being Margo...you have enough eyepieces to cover the full spectrum.....

The screws hold the eyepiece in place...just gently tighten after you have the eyepiece in the focuser, but dont over do them...their is no need.

The balancing...um someone else can help you with this....

[gaa_ian]

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.

[janoskiss]

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.

[ballaratdragons]

Margo,

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?

[ballaratdragons]

Also Margo,

tell John Dobson "Thank you" from all of us dobbers.

[Starkler]

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.

[janoskiss]

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 ...

[ballaratdragons]

Thanks Geoff.

Picture is corrected now.

[ving]

no dont giv eit to steve, give it to me!! :)

cant imagine why you scope would be moving too much margo, unless you are being too heavy handed. give us more info :)

[rmcpb]

Margo,

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.

Cheers

[blackpearl]

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

[ballaratdragons]

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.

[blackpearl]

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

[iceman]

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.

[ving]

or add just a drop of locktite to the tread. works for me :)

[ballaratdragons]

It should've been supplied with the scope! If not, like Mike said, get one and that should stop it from loosening.

If you do have one, tighten it up enough for the bolt to bite into the nylon inside the nut.

Or as David said, use Locktite.

[Thiink]

Glad to hear everything is smooth sailing (bar the fan) for you blackpearl! Good luck with the viewing sessions, I was wondering how you were going.

[blackpearl]

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

[RAJAH235]

Margo, clear nail varnish works well as a thread/nut lock, and is cheaper than Loctite. :D L.

[ballaratdragons]

Margo,

Azimuth. EP. You're starting to sound very professional.

Doesn't take long to pick up the lingo does it.

Great that you are getting your eye in the sky and learning the scopes capabilities.

Have fun.

[blackpearl]

It is like learning another language.

John Dobson is touring Australian and New Zealand astronomy clubs, so he may be at a club nearby. I'm going to Parkes on Sat 2nd April to see him.

Lee has offered to excahnge the OTA because of the broken fan, I'm very pleased with that - so a quick trip to Sydney coming up.

saw the Tarantula Nebula and the Eta Carinae Nebula last night.

Not much sleep these days!!!
Thanks again

[ving]

yup that scope will keep you up late if you arent careful! :)
isnt the tarnatula neb just one of the most beautiful things in the sky :)

[gaa_ian]

Hmmm ... now I already have a 10" Dob:astron:
So which newbie in the club can I convince that they NEED ! to buy a 12" GSO dob as their first scope :P