Getting Started With Skywatcher 250px

[Quenzer]

Greetings all! 

Having recently purchased, recieved and assembled a Skywatcher 250px Dobsonian telescope I wanted to create a thread to ask experienced users of the model (or similar) for general help and advice.  I have chosen to do so largely because, beyond assembly of the mount, I find the included instructions to be severely lacking. 

So without further ado: 

Inserting an eyepiece into the focus tube. 

The included instructions lead one to believe that one simply removes the plastic end-cap on the focus tube and inserts the desired eyepiece. 

Removing said plastic end-cap it becomes immediatley obvious that this is not the case (for the desired eyepiece would fall into the telescope tube...and knowing my luck, smash the primary mirror!) 

Taking stock then of the other included bits and bobs (for which there are no instructions) I find what is vaguely listed in the manual as a 2" Eyepieces adapter.  I get the notion that this is maybe what one inserts into the focus tube first, then the desired eyepiece into that.  So I do just that.  I point the telescope at the sky and hey presto, I can see stars!  But the eye piece isn't tight.  It moves around.  That can't be right. 

Taking further stock I find a second Eyepieces adapter shaped object (not listed in the instructions at all) and get the notion that this is inserted into the first adapter.  I give it a try and it fits beautifully.  The desired lens then fits into that with equal beauty.  My eye piece is now tight.  Brilliant, I think.  I take a peek as before but this time, NO STARS.  The horror. 

So where am I going wrong? 

I remove the second Eyepieces adapter type thingymabob (not the technical name for the object, I'm sure) and sit the lens inside the first Eyepieces adapter like I did before.  It's loose, but I can see stars, all be it blurry* stars!  (Procyon / Alphard / lots of others that I have never seen with my naked eye before....) 

FOCUSSING the telescope once all the above eyepiece business has been sorted out. 

The focussing knobs thus far don't seem to do anything at all.  Perhaps this is because I've not got all the above sorted out yet.  Perhaps there is something else that beginners don't generally do correctly.  Perhaps it's broken!  OMG OMG OMG!  Send it back to FLO immediatley!  Arghhhh!  It's probably all as it should be and my brain is what's broken.  Best to ask before summoning the courier. 

Anyway. 

Beneath  and between the focussing knobs on the focussing tube there is a large screw which in the instructions is pictured on the opposite side of the focussing tube as to where it is in actuallity.  Does this have anything to do with the focussing process or is it merely a lock of some description? 

Any advice / sound thrashes on the back of the head with the atronomy teacher's stick welcome. 

Regards,

Quenzer.

[Paul73]

Yes. That is a locking screw. Can't see the point really as, on my scope, the action of tightening the screw actually changes the focus!

There is a far more useful Alen key type stud next to this bolt which adjusts the tension of the focuser. When I first got the scope, the focuser slipped and wobbled. A quick turn of this sud tightend things up beautifully.

Paul

[BritAngler]

You should have two adapters, one for  1.25" eyepieces and one for 2" eyepieces, only use one of these at a time otherwise you will not be able to get things in focus. And yes, there is a locking nut under the main eyepiece holder to lock focus. In addition, each of the eyepiece adapters should have two finger screws to hold your chosen eyepiece in place.

Is a good 'scope you have there, but being a Newtonian it will need collimating at times, for that you will need a collimating cap and a Cheshire eyepiece. There are dozens of threads on this forum that take you through the steps you need to do that

Happy viewing

[Dave In Vermont]

Is there a screw, or bolt, attached to the focuser? And so, it is likely a tension-bolt that should be loosened a bit so the focus-knobs allow the focussing-barrel to slide up & down easily. I am looking at a photo of the scope - and the tension-knob appears to be in the center of the focuser in between the two focus-knobs you turn to focus. On some Dobs and Newts they are in back of the focus-knobs. That should sort you - for now.

Sounds like someone should give Skywatcher a kick in the pants for not supplying detailed instructions with their Dob. Ah ha! Here we go.....

This should help you. And there's a plethora of others here.....Look at the menu of films on the right. You can disregard the film of the Moon:

Have fun!

Dave

[Quenzer]

Thank you Paul73 & Britangler! 

Very helpful indeed. 

 it is likely a tension-bolt that should be loosened a bit so the focus-knobs allow the focussing-barrel to slide up & down easily.

Good call Dave in Vermont! Said bolt was extremely tight and now that I have loosened it I can see the focussing-barrel slide up and down (which it wasn't doing at all this morning, which explains why turning the focussing knobs made no difference whatsoever.  Glaringly obvious now that I know )

[Gazabone]

These scopes have focus units that can take 1.25" and 2" eyepieces. If I remember correctly it comes with 10mm, 25mm eyepieces and a 2x Barlow in 1.25" fitting. The plastic cap should come out for your ep to fit into. There is a lock screw which enables you to remove the next stage and use a 2" ep.

The supplied ep, in my opinion, are not good and I can never understand why quality scopes like this aren't either supplied with good quality ep (I know this would push the price up) or no ep at all so the user can select what they want.

With my 250p, the 2" fitting wasn't 2" but a friend of mine at my Astonomy Society very kindly fabricated one from a spare part I got on eBay. Which brings me to the last thing I was going to say; I would recommend getting in touch with a local Astonomy club/society; there is so much more to this hobby than pointing a scope skywards and a club will help you find out what interests you most as well as how to get the most from the very nice scope you have - it's a fairly serious bit of kit that is perfectly capable of giving you decades of enjoyment. Your next challenge will be to find the interesting objects that you can't see naked eye.

Good luck with it and happy viewing

[DevonSkies]

Great scope you have there. I got mine recently and I love it (apart from the weight!). You've had good advice so far. Mine came with adapter tubes for 2" and 1.25" eyepieces. The 1.25" tube has to be inserted before you can use the supplied eyepieces. Tighten it with the two thumbscrews. You have already discovered the focuser locking knob I think!

Just take things slowly and don't panic! These scopes are quite simple and robust, so there's not much to go wrong really! Have fun with it.

[Quenzer]

The supplied ep, in my opinion, are not good and I can never understand why quality scopes like this aren't either supplied with good quality ep (I know this would push the price up) or no ep at all so the user can select what they want.

What eyepieces would you recommend, Gazabone? 

I've not enjoyed many clear skies, of late, but the few brief moments of clarity I have encountered have led me to the conclusion that there is a lot more possible with my scope than what I am -nevertheless very much enjoying- at the moment. 

Any eyepiece recomendations (and indeed Barlow recommendations, or similar) most welcome! 

I would recommend getting in touch with a local Astonomy club/society

I have just had my login details confirmed with the Central Scotland Observers forum.  I hoping to make some contacts there. 

Just take things slowly and don't panic! These scopes are quite simple and robust, so there's not much to go wrong really! Have fun with it.

It's not in my nature to panic, Devonskies...and I'm generally patient (except when it comes to clouds and street lamps). 

Thanks for your advice. 

Indeed - if you have any eyepiece notes for me that would be great. 

[knobby]

Before you start fiddling with collimation screws and buying Cheshire's ... Use a high power eyepeice like the 10 mm you have with the scope and when the scope has cooled for maybe an hour slightly defocus on a bright star , you should see concentric rings , if off centre then you need to 'fiddle' if OK then just enjoy the views

[Lorne]

Don't rush and buy new eyepieces, if you get out to any of our meets you can try out a few different types - then decide which you prefer. The downside of that advice is, as of typing this reply, its been 14 nights of cloud/rain/wind/sleet since our last group meet - and it doesn't look like improving soon. Where have all our clear frosty nights gone!!!