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Finder scope aiming


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Hi,

I am a new stargazer with an 8 inch dob.  I've recently replaced the red dot eyepiece with an 9 x 50 finder scope.  The scope works wonderfully once I get to the approximate place I want to look.  My problem is that I have a hard time lining up the scope in the first place to get 'in the neighborhood'  (for example Orion's belt).  Most of the time I end up taking off the 9 x 50, putting the red dot scope on, aligning the dob, and putting the 9 x50 back on to fine tune.  Any suggestions on the initial lining up of the dob?

thanks!

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Get an Orion double finder mount (Amazon) then you'll have your RACI and rdf side by side. Or cheaper, buy a Rigel Quikfinder or Telrad (both FLO), either mount can be stickied on using the tape supplied...works like a charm with a RACI (I have the Rigel/RACI combo - it's superb in use).

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Similar issues myself, though I have no red dot finder. Usually I use the (out of alignment) finder to point in generally the right direction, stick in a 2" 32mm eyepiece to centre a known object (I find Jupiter helps here, even when it's out of view you know where it is!) and then align the finder based off of that. Usually the finder gets my close enough on the first attempt.

Is your finder wildly inaccurate when you starting setting up?

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My finder scope is pretty well aligned so if I know what I'm looking at then I can find it. My main problem is in the clear skies which I mainly have, I can' t distinguish if I looking at the star I think I am. So then I can't star hop. Is this a question of understanding magnitudes better or just practice? I'm also trying to use the RA and Dec scales to help

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+1 for the Rigel or Telrad - I have both and would give the Rigel the edge over the Telrad because it is much smaller and I find the flashing red circles help when locating dimmer objects.

I used to have exactly the same problem as danteexplorer when I got my first Dob so bought a Telrad. After using the Telrad for a while I got a much better sense of where my scope was pointing and now find it very easy to use the standard finder scope.

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If you have a straight thru finder , keep both eyes open and line up the dots - try it you will see what I mean , you will then have the correct star in view . I lined my finder up using the moon . You should have it quite accurate , in the skywatcher finders there should be a rubber O ring around the finder before it is pushed into the holder so that it can be easily adjusted.

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Set up your telescope in Daylight, and focus on something way off in the distance. When your  satisfied that the target is central and in focus. lock down the scope. Now adjust the finder scope to locate that same target, and once centralised, you should be able to now find your targets with the finder scope, with the telescope matching what the finder  sees.

The Finder scope has an adjuster on the field lens, to bring things into sharp focus, and at night, as scuffer suggests, keep both eyes open when using a straight through finder.

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I dismantled my red dot finder and neatly taped the body of it to the end of my RACI, so I can point roughly with the RDF and then use the RACI. I do have a double finder holder , but it does raise the finder level a bit so that I whack my head on it in the dark.....

Chris

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I dismantled my red dot finder and neatly taped the body of it to the end of my RACI, so I can point roughly with the RDF and then use the RACI. I do have a double finder holder , but it does raise the finder level a bit so that I whack my head on it in the dark.....

Chris

Good idea.  :laugh:

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If you really want to be accurate and align all the optical axis, keep a look out for s/h cross hair ep to go in the main scope, can be had from AB/Sell and the bay from time to time, at a reasonable cost. You can then set up during the day on a distant focal point, or use a bright star at night to align the optical axis of your scope, finder and RDF. may be a bit OTT, but I found it useful, as I had a spare c/h ep in stock :)

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If you are really struggling the cross hair idea from John is very handy.

If mine gets knocked I simply use a distant object during the day or the moon at night to get it close and then move to Polaris to get it really accurate.

As Polaris does not move you can get everything aligned bang on. Just use something like a 32mm and work your way down making adjustments as you go.

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FWIW, it took me a while to adjust to a 9x50 finder after using the 6x35 (?) that came with the scope. The larger finder showed many more stars and a larger circle of sky: things looked quite different. After a few nights out, you'll get more comfortable with it.

I'll pile on with the recommendations to stick a Rigel or Telrad on there as well. Use the red dot finder to line up on something visible to the naked eye, the finder to zero in on what you're after and then enjoy the view.

One of the first things I do at night is zero in on an easily seen star, get it centered in the eyepiece, and then center it in the finder and (in my case) the Rigel. Takes less than a minute and I can stop worrying about whether the finder(s) and scope are aligned.

Have fun! -- Joel.

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