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Old 05-05-2007, 03:31 AM
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Adding a second finderscope

Hi everyone!

I recently purchased a Skywatcher SK1025AZ3, which came with a red dot finder. Now I found the red dot finder extremely easy to use, far easier then a normal finder for pointing at bright objects.

But since I live in the suburbs, I can only see pretty bright objects - so to find fainter DSOs I have to guess where they are in what appears to be dark swaths of the sky.

I need a finderscope, to give me magnification, and also to show me stars that I can't see with the naked eye.

So thats why I am here - I want to add a mount for another finderscope, so I can go red dot -> finder -> OTA. I have no idea how to do this, I am pretty crap at any kind of machining, and I certainly don't want to be drilling into my OTA. The rings holding the OTA in place though, have holes for mounting a camera and such - can these be used some how?

Any advice would be much appreciated!

Cheers,
Steve
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Old 05-05-2007, 09:47 AM
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Omaroo (Chris Malikoff)
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Steve - I have the long tube version of yours, and I'm mounting a red dot finder in addition to the included finderscope today. I plan the remove the rear focuser assembly, drill two holes and mount the standard Synta-style dovetail bracket. It's no biggie to drill the holes, and if you keep the bolts short they won't interfere in the path of the light cone at that point.

I wouldn't mount one to the rings as there is too much inherent movement between the scope and rings if you want totally repeatable mounting each and every time.

Photo 1 is the end of the tube with the focuser assembly removed. As you can see, the quality of these things is nothing to write home about. They are basically a steel toilet roll with a lens at one end. The chipped paint is from their manufacture - not of my doing. I drilled the holes and vacuumed the insite of the OTA to make sure that all swarf was removed.

Photo 2 is the new dovetail monted, with the whole thing reassembled. Now I have both the original finderscope and new red dot to guide me. The distance up the tube that the new red dot is mounted is perfect - such that when you go between them you don't have to refocus your eyes as the red dot is far enough away to see the dot at infinity.
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Last edited by Omaroo; 05-05-2007 at 11:04 AM.
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Old 05-05-2007, 10:48 AM
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Garyh
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Hi Steve, just buy a little dovetail base plate for a finder, which you will have to drill 2 holes to screw it down. You`ll get a few crumbs in the OTA so if you are fussy you might have to remove the focuser to get them all out.
Then you can have a 8x50 finder with a dovetail bracket fit straight on in a few seconds and just as quick to remove...Places like bintel or Andrew etc should sell the finder with a matching baseplate..
Cheers
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Old 05-05-2007, 04:41 PM
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Thanks Omaroo, Garyh. The pictures make it look pretty easy, and yeah, I was a little disappointed by the quality of the OTA, but I suppose as long as it does the job, it doesn't have to be brushed alu. Pretty happy with how it performs optically though, but then this is my first real scope, and I have nothing to compare it against.

Omaroo, I have some questions, in fact quite a few of them, sorry!

*do you have any tips for drilling the holes so when the dovetail base plate is mounted its more or less aligned with the telescope? I don't want to just guess where the holes up and mess it up so badly I can't align the finder.

* did it take much pressure to drill through?

* Did you start with a smaller drill bit, drill through, then enlarge it with a bigger one? Also what diameter are the holes?

* Would I run the risk of distorting the OTA

* Is the focuser hard to remove? and is it easy to re-attach properly?

* Could i accidentally jiggle the primary lense out of alignment due to vibration?

* Any tips at all?

Thank you both again for your replies, hopefully I can implement this next weekend with a more drill-competent friend.

Cheers,
Steve
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Old 05-05-2007, 04:56 PM
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Steve the dovetail plate should have a couple of holes in it already, just place it where you want it and get a fine pointed texta or similar and make your holes.

I would start off with an smaller drill, and drill a pilot hole first, then go to the correct size you need for the screws, or bolts.

It is not a problem, and you wont do any damage to your scope, however if your not sure about it all, by all means get some help.

Leon
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Old 05-05-2007, 06:05 PM
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Quote:
Originally Posted by leon View Post
Steve the dovetail plate should have a couple of holes in it already, just place it where you want it and get a fine pointed texta or similar and make your holes.
Ah ok, that should make things a little easier.

Quote:
I would start off with an smaller drill, and drill a pilot hole first, then go to the correct size you need for the screws, or bolts.
Ok, I will do that then.

Quote:
It is not a problem, and you wont do any damage to your scope, however if your not sure about it all, by all means get some help.
Now I feel a bit better :-)

My thanks leon. I expect to do this next weekend, hopefully I won't have ruined my b'day present
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Old 06-05-2007, 07:25 PM
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Na, You'll be right, soon you will be doing all sorts of repairs and adding stuff to your set-up.

Cheers Leon
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  #8  
Old 06-05-2007, 08:10 PM
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Here is a thought - why not use epoxy? Then no holes required. In fact, why don't we use epoxy?

I am sure I am missing something, it seems too easy...

Cheers,
Steve
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Old 06-05-2007, 09:55 PM
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Quote:
Originally Posted by freespace View Post
Here is a thought - why not use epoxy? Then no holes required. In fact, why don't we use epoxy?

I am sure I am missing something, it seems too easy...

Cheers,
Steve
Hi Steve,
Epoxy is a good idea, I used it a lot... but when you want to remove what you just glued a day ago for some reason, then you may have a problem :-)
Also, epoxy takes some time to set, so you still need to hold your item fixed while glue is still liquid.
Good old mounting holes and screws are still better, and faster method, whenever you can afford them :-)
Also, avoid 5 minute epoxy... this stuff refuses to be glue when you need something glued solid the most...
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Old 06-05-2007, 10:47 PM
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Quote:
Originally Posted by bojan View Post
Hi Steve,
Epoxy is a good idea, I used it a lot... but when you want to remove what you just glued a day ago for some reason, then you may have a problem :-)
Also, epoxy takes some time to set, so you still need to hold your item fixed while glue is still liquid.
Good old mounting holes and screws are still better, and faster method, whenever you can afford them :-)
Also, avoid 5 minute epoxy... this stuff refuses to be glue when you need something glued solid the most...
I knew there was a reason why every one used mounting holes and screws

I think I like the flexibility of mounting holes / screws is better. Cheers mate

Never used epox either, so once less unknown

Cheers,
Steve
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  #11  
Old 08-05-2007, 03:42 PM
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Poo :/

I lost half a tooth, and now its going to cost 2k to get it all fixed up. This will have to wait now

Sorry every one, there will be no pictures/stories of my attempt until much later.
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