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Noob question regarding taking the finder scope on and off.


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So, this question may have a really obvious answer, please don't point and laugh!

I'm playing with my Skywatcher 150p and EQ5 mount and looking for good cases to store and transport both units, as I'd like to take the rig to France this summer, and I have two tiny children who have very inquisitive little hands.

I think I've found a good deal on an aluminium flight case which can hold the scope, but it'll be tight if I have to leave the finder scope attached.

Here is the question: I presume that if I take the finder scope off each time I store the main scope, I'll have to re-align it when I set up again; it won't somehow retain it's setting and be accurate?

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It depends on the quality of the finder mounting to a large extent. If it re-locates into exactly the same position it will be perfectly aligned but its likely to be slightly off. It shouldn't be too far out though. If you can set it up during the day and tweak the alignment you should be ok.

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It should still retain enough accuracy for the object to be in the finder, a quick tweak, specially if your finder has the spring loaded adjustment feature, will soon have it lined up    again.  :smiley:

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Unless it is a really tight sqeeze, finder scopes usually retain their alignment, esp. if it is screwed on tightly as you have a really secure mounting on the telescope.  You may have to tweek it at most.

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You could do away with the Finder scope and stick a Telrad on there, these retain these alignment regardless of the amount of times there removed and replaced, and are a much better finder than and Finder Scope could ever be, if you're not sure find somebody that has one and test it, your be converted...:)

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You could do away with the Finder scope and stick a Telrad on there, these retain these alignment regardless of the amount of times there removed and replaced, and are a much better finder than and Finder Scope could ever be, if you're not sure find somebody that has one and test it, your be converted... :)

yup would recommend a telrad, save my life when i first started, was much easier to locate and take on and off.  It retained the alignment well 

velvet

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I take my finders off every time and just need to give them a slight tweak each time. it's very easy to do and as you have to wait for the scope to cool anyway, it loses no observing time. once you have done it a few times it takes seconds.

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My concern is that I'll most often use the scope in my back garden, where I can either adjust the finder scope on something very very close, like my house, or something far far away, like the moon. There's no in-between.

I am intrigued by the Telerad; from what I've read about it that method of star-hopping really appeals to me. How come the Telerad can be moved and still retain it's accuracy, is it to do with the solidity of the mount?

Not that I'm looking to buy more equipment before I've even used the telescope in anger for the first time; I'm still trying to figure out how I can pan the finder scope in one direction and have the view move in that same direction, shouldn't a 180 degree pan mean I end up looking at the back of my own head!

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The Telrad base has sticky pads these hold it on the tube, the base is machined so the unit can only fit in the same position every time.,..there are Telrad maps as free downloads and Stellarium features the Telrad circles as a option.....

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So, this question may have a really obvious answer, please don't point and laugh!

I'm playing with my Skywatcher 150p and EQ5 mount and looking for good cases to store and transport both units, as I'd like to take the rig to France this summer, and I have two tiny children who have very inquisitive little hands.

I think I've found a good deal on an aluminium flight case which can hold the scope, but it'll be tight if I have to leave the finder scope attached.

Here is the question: I presume that if I take the finder scope off each time I store the main scope, I'll have to re-align it when I set up again; it won't somehow retain it's setting and be accurate?

The problem with the SW finder scope is the spring loaded third support- adjuster. If you see fit to take that off and replace it with a suitable plastic screw similar to the other two then once the finder has been aligned with the scope,  it will stay aligned as the SW finder base is actually not too bad. People who use the finder a guide scope too always do this mod otherwise the guider would be  wobbly and useless. 

A.G

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Thanks lensman, the finder scope did seem slightly wobbly. I'm getting the sense that the finder scope doesn't have to have a razor-sharp alignemet in any case though, it's not like a rifle sight which has to be corrected for every small knock.

A different question occurs to me though: what is the difference betweena  finder scope and a guide scope, or are they the same thing?

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I take my finder off each time. The alignment stays the same, you just have to wiggle the support in the shoe 'til it's in the same position.

-1 for the telrad!  :grin: I don't wear my glasses for observing, I'd be lost without some magnification. And I've now got a RACI to reduce the neck ache! Each to their own.  :wink:

A guide 'scope is a finder 'scope to which you add some electronic gizmo allowing the 'scope to be more accurately guided as far as I'm aware. AP stuff I think.  :p

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Thanks lensman, the finder scope did seem slightly wobbly. I'm getting the sense that the finder scope doesn't have to have a razor-sharp alignemet in any case though, it's not like a rifle sight which has to be corrected for every small knock.

A different question occurs to me though: what is the difference betweena  finder scope and a guide scope, or are they the same thing?

As Thinker posted they can be one and the same but you just replace the EP of the finder with an adapter to attach a guide camera and it becomes guider . I have 4 of these SW 50mm finders and a 30mm, the 30mm keeps the alignment best of all because that rubber O ring in the front is quite a tight fit in its housing, the rest are at different state of wobble. Telrads are fine if u have a dark sky otherwise they are as good as your eyesigth, it will not pick up a dim star like a 50mm finder and this is necessary if you get into imaging.

A.G

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I've got the 50mm SW finder and I take it off each time. Not had many issues with the spring screw. It does need some minor adjustments but is more or less spot on each time.

Sent from my HTC One using Tapatalk

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Thanks lensman, the finder scope did seem slightly wobbly. I'm getting the sense that the finder scope doesn't have to have a razor-sharp alignemet in any case though, it's not like a rifle sight which has to be corrected for every small knock.

A different question occurs to me though: what is the difference betweena  finder scope and a guide scope, or are they the same thing?

They can be physically the same thing but are not necessarily so. The important distinction is between their purposes. A finder you know about. A guidescope is used for correcting tracking errors in real time, as they occur, for taking long exposure photographs. This used to be done by a dogged soul peering through a guidescope and keeping a star bang on the corsshair by sending corrections to the mount manually. It is now done by an 'autoguider' - a camera which sends the position of a chosen star to a computer which calculates the drift and sends a correction to the mount. So accurate are these devices (once you have the blessed things working) that you can keep errors down to 0.1 pixel quite regularly.

Olly

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Thanks for all the responses. I've now mounted my finderscope and aligned it, and indeed it keeps it's alignement when you remove the scope and box it back up again which is a Brucey Bonus.

If you're only using it for finding stars, get a Telrad so much quicker........

http://www.firstlightoptics.com/finders/telrad-finder-astronomy.html

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I've heard that a Telerad isn't all that good if you live in a light poluted area and don't see all that many stars out at night?

You can only see visible stars, but there will be some, i found a finder scope very hard to get on with as bright and dim stars appeared all the same, if you use Stellarium it has a Telrad option so the circles show on its screen and there are free to download Telrad maps so star hopping can be done even if its only bright stars.....If you have a Astro club close by go visit there will be one to look through....

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