Whats the scope next to eyepiece?

Jabba (Keenan) · #1 18-01-2010, 09:13 AM

I apologise for my stupidity in advance.

Just bought my first ever telescope over the weekend which im ever so excited about, it's an 8" dob.
I want to find out what the small scope on the side next to the eyepiece is and what it's used for?

Anyway looking forward to clear skies to test run this baby

supernova1965 (Warren) · #2 18-01-2010, 09:25 AM

Quote:

Originally Posted by Jabba

I apologise for my stupidity in advance.

Just bought my first ever telescope over the weekend which im ever so excited about, it's an 8" dob.
I want to find out what the small scope on the side next to the eyepiece is and what it's used for?

Anyway looking forward to clear skies to test run this baby

Its for lining up on your target its called a finder scope its easier to use it to aim with.

jjjnettie (Jeanette) · #3 18-01-2010, 10:10 AM

To use your finder scope properly, you need to align it with your main scope. So what you see in the cross hairs is what you see in the centre of your eyepiece.
During the day, aim your scope at a far object. (not the sun obviously) the corner of a building, the top of a light post. Use a 20mm eyepiece in the scope and the 3 adjustment screws on the finders scope ring to centre it.
Once you have your object in the centre of both scopes, refine your adjustments by changing eyepieces to say a 12mm.
You can do this at night, but it can be a right pain if you're not familiar with your scope.

erick (Eric) · #4 18-01-2010, 10:13 AM

It's called a finderscope. It is a little refracting telescope - probably around 8x50 - ie. 8 times magnification and a 50mm objective lens (the aperture). It has a wider field of view than your main telescope/eyepiece combination, so it's easier to locate an object (or a location in a recognised star pattern) and centre it on cross hairs, then move to your main scope to see it. Of course, you need to align those cross hairs so that your main scope is pointing to the same location. Your manual will have instructions.

You'll see it comes off the telescope. Take it off and experinment with it - maybe during the day (WATCH OUT FOR THE SUN). You may need to get it focussed for your eye (or eye with glasses). That is done by winding back the locking collar on the objective lens end of the finder, and then winding the objective lens in or out until it is focussed on a distant object (a tree in the distance, a mountain top?), then winding back the collar to lock it there.

jjjnettie (Jeanette) · #5 18-01-2010, 10:42 AM

I forgot to say.
Congratulations on your new scope.

erick (Eric) · #6 18-01-2010, 10:50 AM

And remember - nothing is as it seems! The view through the finderscope is different to reality (upside down for a standard refractor) and the view through the telescope is sideways and back to front (or whatever). No it's not broken, that's the way it is and you'll get used to it.

Now, I may have to take that all back re your finderscope because you might have an RACI finderscope - right angle, correct image! A right angle bend in the light path to save your aching back and a prism inserted which corrects the image to the same orientation as you see with your eye looking at the sky.

mental4astro (Alexander) · #7 18-01-2010, 11:31 AM

Hi Jabba, congratulations on the new scope,

.

Sounds like your scope didn't come with instructions.

I'll PM you the two sets given to me by another IIS member. These two are very good. If the scope you got is the GSO 8" dobbie, then the 'Orion' set of instructions will show you how you can focus your finder too.

These instrutions are also quite good together as a starters guide.

Let me know if you need them.

Jabba (Keenan) · #8 18-01-2010, 12:32 PM

Thanks for all the help.
Alex, I think it's a GSO dob... I bought it off someone from this website so I didnt get any instructions

I would appreciate it if you could send me a copy of those instructions though

I asked everything I could think of on the day I bought it, but forgot to ask about that lol.

erick (Eric) · #9 18-01-2010, 12:40 PM

Just to check - which one is it? Here are pictures of the two common types.

Jabba (Keenan) · #10 18-01-2010, 01:22 PM

It's definately the first picture Eric. Although mine is a black model :p

mental4astro (Alexander) · #11 18-01-2010, 01:26 PM

PM sent re instructions.

Jabba (Keenan) · #12 18-01-2010, 08:52 PM

Using that finder scope really helps a lot wow.

holy s*^t im excited, clear skies tonight im all set up and ready to go!
... just checked out the moon even though it's a cresent, couldnt beleive how much of it I could see, and so clear too!!!

next I will wait till a bit darker and check out jupiter