Is my telescope collimated?

[Adam1234]

Hi all, I briefly tried out my telescope for the first time last night just to check it's set up and working ok. I couldn't see [removed word] all, everything was out of focus no matter how much I turned the focuser - turned out I hadn't fully extended the telescope!, So tried again today with a 10mm eyepiece and got a nice view of Jupiter and 3 of its moons, and even could make out Jupiter's belts.

Now that I know that I can actually see things through the telescope, I'd like to make sure the collimation is correct to get the best views I can. As this is not something I've done before, I'm a bit nervous about adjusting anything unless I know it's definitely out of collimation, so I've taken a couple pictures with no eyepiece, and with Cheshire eyepiece. From the research I've done, it doesn't look obviously out of collimation like in some of the example pictures I've seen, but I thought I'd check with you guys who have been doing this a lot longer than myself.

View with no eyepiece in focuser: (the primary mirror is actually more centred in the secondary than it looks in the photo due to angle of my camera phone)

 

View with Cheshire collimating eyepiece:

 

And a picture of my telescope for anyone interested:

 

Thanks

Adam

 

 

[Ignoro]

This helped me: 
https://garyseronik.com/a-beginners-guide-to-collimation/

When you put a star a bit out of focus it should be evenly bright from all sides... Polaris is best as it doesn't move.
It all isn't very complicated, it's easiest if someone more experienced helps you in person...

Congratulations on your scope, I think you'll be able to see a lot with it. I opted out for it's micro-brother and I still can see stuff...
 

Edited July 21, 2019 by Ignoro

[jetstream]

The secondary might not be exactly centered under the focuser, a piece of paper to block the primary can help to see it well and the crosshairs aren't exactly centered on the primary dot. That being said the views would most likely be sharpish, with the collimated beam slightly off center in the eyepiece.

[Alkaid]

Looks alright, not bang on, but not out enough to warrant adjustment.  Get a bright star in a high power eyepiece. Rack the focuser in a bit, then back out. Does the star evenly expand and does it contract back down to a nice point? If it does, collimation is ‘in’.  For ‘out’ look for the star expanding & contracting unevenly, on one side. 

It’s easy to get hung up on this.  If you’re targeting small lunar features or planetary, then yes it’s important, especially in an F5 scope. But if you’re using your 250 for DSO’s and sky sweeping, it’ll be absolutely fine at low power, even if it’s a little bit out.

Have fun!

[cletrac1922]

Adam

Assume from your comments, us have a flex Dob

Have to make sure, support rods click in, when extending

Also do not over loosen the three locking nuts for extension tube, as can come out, and then loose the small spring and ball bearing inside

Straight out of the box, scope should be collimated.

I am out a couple of times per month with my club doing presentations in primary schools, scouts groups

Very rarely have to collimate 

When trying to image down the tube, you will never get it perfectly centered

John