help aligning finderscope:/

[met0001 (Brad)]

Hi guys
first off sorry for such a silly question, i have been reading up on how to get it right but that issue i am having is trying to focus the telescope!"
i see people focusing their scope on objects a few hundred of meters away, then adjusting the finder scope.

i have a 25mm ep in the scope and am trying to focus on some trees approx 3kms away but i cant get it to focus. Everything is just a big blur!
Then i thought trying the 35mm extension tube i got with the scope which helped but i still cant get anything in focus to align my finder scope.

please help guys i know im doing something wrong.
scope is a 8"newton on a heq5 pro.

brad.

[graphworlok (James)]

You should not need the extension tube, unless the Newt is built for astrophotography. (in which case you will use the extension tube when using an EP, and no extender when using a DSLR or similar) - This is due to the sensors in DSLR's being set relatively "far back" in the body

Also, are you sure it is an extension tube, and not a barlow? Are there any optics inside it?

As far as focusing, all i can suggest is to start with the focuser all the way in, and slowly change focus while looking through the EP.

One possibility is that the blur you see is actually something much closer than what you think the scope is pointing at?

james

[asimov (John)]

I would also suggest you are trying to focus on something a lot closer than what you think you are. Try Going above the treeline until you see blue shy/cloudy sky (BEWARE THE SUN!!) *looking through your scope not finder* & slowly pan down with your eye at the EP until it gets a bit darker, in which case you should now be at the treeline..Now try to focus. Once at focus you can revert back to trying to align that finder.

[met0001 (Brad)]

Originally Posted by graphworlok

You should not need the extension tube, unless the Newt is built for astrophotography. (in which case you will use the extension tube when using an EP, and no extender when using a DSLR or similar) - This is due to the sensors in DSLR's being set relatively "far back" in the body

Also, are you sure it is an extension tube, and not a barlow? Are there any optics inside it?

As far as focusing, all i can suggest is to start with the focuser all the way in, and slowly change focus while looking through the EP.

One possibility is that the blur you see is actually something much closer than what you think the scope is pointing at?

james

thanks james, yes 100% its a 35mm extension tube.
and i have used that technique to where the syk and the tree tops in the ep yet i still get blur.
it seen almost like i need another inch of focus to get the image in to focus.

brad.

Update: I can get focus if i dont slide my 35mm extension on all the way. If i tighten it before the grove on the 35mm extension i can focus fine (grove is about an inch in length)
But why would this be? arnt i ment to slide the extensionon all the way? and the screws are ment to hold onto the extension grove?
Also my scope is f/4 im not sure if this has any effect.

[Joshua Bunn (Joshua)]

If you think you need another inch or so of focus, maybe try to pull the eyepiece out of the holder to get that bit more once you reach full travel with the focuser.
Maybe try panning around at far and near terrestrial objects while the focuser is in one place to see if you can get focus, again - watch out for the sun!

Josh

[Meru (Michael)]

Hi Brad,

Does it matter if the trees are in focus or not from the reflector? As long as a tree is roughly in the middle of the EP, then it wouldnt matter if its blurry. You can just align the finderscope to that tree, as long as you know which tree is being viewed through the EP. I used to align my finderscope like that but it usually ended up being considerably off anyways, and required fine tuning regardless. So dont waste too much time on it during the day!

By far the easiest method is to use your 25mm EP, look at an actual star cluster or bright nebula, and then align the finderscope. Also not sure if you know this but finderscopes themselves also have a focus adjutsment (Something I only realised a long time after wondering why my finderscope was crappy!)

[graphworlok (James)]

Sounds like you have an newt thats set up for imaging rather than visual use. Thats no bad thing, as you also have a mount capable of carrying it.

In my case, i have an 8" newt that i want to use for imaging, but i'll need to cut my tube or reposition some mounting hardware for it to achieve focus (And my mount isnt really strong enough to cope with it anyway..)

This is not a bad thing - you can start imaging with some adaptors and a DSLR. Its slightly strange that you didnt get an extension tube suited to visual use however. You can get then for under $50 from most astronomy shops, depending on size/length.

Do you have a 1.25 or 2" focuser?

[met0001 (Brad)]

Yes i do believe my scope is set up for photography which is why i believe it came with a 35mm extension.
The scope i got is http://www.bintel.com.au/Telescopes/...oductview.aspx

Thanks guys it just looks like im worrying over nothing as the moon isnt quit as close as them trees over there!

[dannat (Daniel)]

the moon will be increasing & by tomorrow you should be able to get back your scope with widest ep & try & get it on the for -then align the finder or vice versa

[barx1963 (Malcolm)]

Which make of scope is this? If it is a Skywatcher this seems to be a consistent issue with the way they put together their focusers.
They have a 1.25 and a 2" adapter and I believe they are supposed to be used individually.
It was discussed in this thread http://www.iceinspace.com.au/forum/s...137#post962137

Hopefully that is the issue.

Malcolm