Barlow lens problem

[HeavenlyHiLites (Dave and Chris)]

Hi I am new to this site and new to astronomy!! I have a skywatcher dob goto 10" and have had it for 3 weeks. I am having trouble focusing with a barlow lens attached to a 10mm. I can find the object such as Jupiter ok but as soon as I attach the barlow I am unable to get any focus, it is just one big blurry object! Does anyone out there have the same scope as me and has anyone had similiar issues?

Also I am having trouble slewing to an ojbect accurately with the goto. It will go to the general direction but then I have to try and refine the search. Any solutions?

Thank you ....

[jenchris (Jennifer)]

For a good go to, the base must be perfectly level or it won't be very accurate.
With the Barlow - the 10mm with a x2 will be the equivalent of a 5mm lens - presuming you have 1200 focal length then 240x is your magnification - which should be reasonable in a 250mm mirror.
It may be that your Barlow is not too good or that the atmosphere is pretty turbulent - either will give you a blurry image - but I reckon the atmosphere is more likely

[AndyK (Andy)]

I have a 2 x Barlow which came with my 8" dob when I bought it (used) and it has exactly the same problem.

Although I haven't had the chance to experiment, I suspect that the Barlow in my case is simply too long, and that the focuser doesn't have sufficient range to reach focus with the Barlow in place. I think maybe one of the "shorty" Barlows would be more suitable. In my case the construction of the Barlow lends itself to shortening the extension tube somewhat and if it proves to be overly long, that's what I'll try.

In your case I'm wondering if you have another eyepiece. The range of focuser movement either side of focus can be very small and can easily be missed at high magnification. Rather than trying at the high magnification of the 10mm, perhaps you have something like a 25mm or longer you can try?

If you can't find focus with any eyepiece, try undoing the screws holding the Barlow and Eyepiece in the focuser and slowly pull it out to see if you can then reach focus. If you can then you may be able to fix things with an extension tube.

Did the Barlow come with the telescope or was is an accessory you bought separately?

[HeavenlyHiLites (Dave and Chris)]

Both great bits of advice. I will try and see if I have any success. Thanks once again.

Andy, the barlow was bought seperately to the scope.

[Stu Ward]

Hi

I have the 12" Goto Dob
With regards to accuracy of the Goto.
Ensure your Co-ordinates are as accurate as possible
Time must also be spot on
As mentioned, the base to be level is also a very important setup check.
To make this easy, i bought a round Bubble level and glued it on the front of the base.
Then to adjust the level i bought a Pack of Plastic builders levelling chocks from Bunnings

I can get objects to appear in view in a 15mm eyepiece every time

Stu

[Suzy]

Hi Christine,
I see you've re-posted this question here so I will copy and paste what I said in your other thread here, in keeping with collective information for your question....

I had a bit of trouble as well with my barlow a while back.
Worked fine on my 6" dob, but when I put it into my Saxon 10" dob, it rendered my 2 inch Celestron barlow useless. I was incredibly annoyed as it cost me $175. Just would not come into focus. Would not go the full way into the focusser- the stop for it was shorter than my 6" dob.
Kev, good man, came to the rescue and sent me a spare 2" barlow that he had and all is good now.

My now rendered useless barlow came in handy a while back- I lost a screw in the grass on the Barlow Kev sent me- spent half the next day running a magnet across the grass and separating blade by blade by blade of grass - lucky I have a high fence- I must have looked a sad site . But, no luck so I took the screw off the Celestron barlow . Needless to say, I shake like a leaf whenever I change my eyepieces now.
A carpet square under the dob has it's place here and not just to keep your feet comfy and dry. Bunnings are actually selling the perfect sized squares of carpet for under $30 at the moment.

I hope you sort out your issues soon, Christine.

[HeavenlyHiLites (Dave and Chris)]

I love this site and how so many people are prepared to take time out to sort out all the newbies ?'s! Thank you so much both of you for your advice, I will try all mentioned.

[jenchris (Jennifer)]

Suze -Would you like to borrow my metal detector?

[Suzy]

I think it's too late...
It was about 12mths ago, so I think the mower and whipper snipper would have finished it off.