set up skyline 200p

[O2B3]

I am new to this and have just got the dobsonian skyliner 200p telescope.

There are some questions I need help

With.

1. How do I know if I need to collimate my telescope.

2. I have tried to focus on a bright star and can not see anything through the EP.

I do hope that someone out there can help me this...

[knobby]

1- look at a bright star (when the scope has cooled to match outside temp) if you defocus slightly you should see concentric rings around the star.

2- is the finder scope aligned with the main scope?

have you put the 2" adaptor and the 1.25" adaptor in together? If so the scope won't achieve focus...

[itmo]

When in doubt, collimate. Basically if you look in the focuser tube and all the reflections look nice and mostly  symmetrical , then you cant be too far off. For rough aiming and testing, do it in daylight , look at a very far away objects to confirm everything works as they should. And to aim your finderscope. 

[ronin]

I would leave the collimation, at least for now.

As to not finding a star well scopes have an amazingly narrow field of view, what you think is pointing at a star can easily be way off.

Need to set up the finder first if possible. Which means getting something distant in view (distant = 2 miles away or more) then coersing the finder to look at the same thing. Liable to take some time, much coffee and much bad language. :grin:

Then other thing is unless focused right a star will not produce an image so again you would not see anything even if pointed at one. :eek:

If you know Casseiopia aim at that. It lies in the milky way and the stars of the milky way will hopefully drop into focus at some stage of adjusting the focus. Use the longest focal length eyepiece you have - bigger view. If you can see the milky way then aim at that. Idea is the milky way is big enough to not miss.

[itmo]

A good way to find _something_ with a scope is to take the eyepiece off and turn the tube until you see some light from the focuser hole, try to center that light, then put a long focal length eyepiece in and focus. then switch to shorter ones. When I am on a lazy mood and operate my (goto) dob without electricity and/or finder this is what I do and I can quite easily find jupiter or moon and focus on it.

[jason.p]

Just a thought. If you can't see anything it might possibly be dewing up which can be a big problem at this time of year. Quick fix for this could be a hairdryer set low.

Sent from my GT-P5110 using Tapatalk

[Moonshane]

most likely problem is as above that you have added the 2" and 1.25" adapters. I have answered your collimation question in the other thread. personally I check before every session with a cheshire/sight tube combo to see if adjustment is required. sometimes yes sometimes no and usually just a small tweak to the primary.

[Rob63]

The two most common problems are

1: using both 2" and 1.25" adapters at the same time.

2: make sure you haven't tightened the focuser lock screw !

This catches a lot of people out because if it's locked the wheels will still turn but the focuser won't move in and out therefore no focus.