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Run out of focus


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Hi, So I just know that there is a simple answer here but only in my 4th week and recovering withdrawl after 5 nights without seeing :)

Finally tonight was able to take my 8" Newtonian out for a spin and got some real clear views of the moon, and of saturn although disappointed with saturn expected to see more detail than in my 90mm scope :( Anyways the views of the moon were awesome so figured i'd take some pics with the webcam and here's the crunch I ran out of focus!!! It was coming into focus but 'clunk' i hit the end of the barrel :(

I tried a number of things from using a .5 Focal Reducer with or without my barlowx2 but just could not get focus. Tried my 6.5mm EP and sure enough same problem.

So I'm guess in need some kind of extender (no magnifing) to allow me to get proper focus. Am I right or just waaaaaay off?????

BTW I bought the FR specifically to use with my webcam as I want to get some shots of the moon with having to avi but i'm guess the addition of the lens and the small CCD are going to mean this is out too?

I do have some books on my B'day list but may have to bring them forward.:)

Justin

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Not sure, but I think that you will need an extension tube. Hopefully one of the forums imagers will come by and chip in with more/better advice.

You'll find a good starting point for anything to do with astro-photography is Making Every Photon Count, by SGL's very own steppenwolf. Easy to read, it's full of advice aimed at the imaging novice, including choosing the right equipment, tips 'n' tricks and lots of other vital stuff.

:)

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The normal problem with Newtonians and imaging is insufficient inwards focus travel. Assuming that this is your problem, i.e., you are unable to wind the focus tube IN far enough to achieve focus then the quick solution is to use a Barlow lens.

It would help to know if your problem is not enough extension or not enough inwards travel so that we can advise accordingly.

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David that book is at the top of my list :)

Great suggestion thank you will give that a try asap :(

You're assumption is correct I do not have enough 'inward' focus travel, let's hope the 1.5" on the barlow gives me enough.

Thank you all very much for your advice much appreciated.

Justin

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OK so I gave it ago (SPC900 and barlow) and I'm confused :)

I removed the lense from my Barlow and still could not focus on the blob that was Saturn, e.g. focuser was IN as far as it would go. I then piggy backed my other Barlow (with lense) and manged to get something I still needed to get IN more to be able to get more focus and I'm guessing the barlow with lense didnt help but at least I got something OK so this not particularly well processed in RS but it gives a could example of what I'm imaging.

post-24560-13387756629_thumb.jpg

But i don't understand why this combo would work and what I need to to do to fix it. maybe this is confirmation that my scope has the wrong mirror.

I also did a viewing of the moon and got some good views (no webcam) until I used the 6.5mm that came with the scope and again was not able to focus IN enough to get a clear image:(

And more thoughts or ideas on what to try next?

Thanks,

Justin

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