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Finders Keepers

adamsp123

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adamsp123

adamsp123

Posted
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Hi folks,

Has anyone tried or know of using a finder scope for autoguiding?

I have a QHY5 and wondered if it could be used with appropriate frigging to work as a lightweight autoguider combo.

I can think of a couple of potential downsides ie light gathering lack of focal length but would it work?

Cheers Pete

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blinky

blinky

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In thoery Yes! I think there may be a couple of people who autoguide or at least experimented autoguiding like this. I think the lack of focal length would be the biggest downside but hey it's worth a go!

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Merlin66

Merlin66

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The focal length of your average finder is about 200mm, using this ( even with QHY5/ PHD) to guide a 10" scope will be problematic.

You may be able to fit a x2 or x3 barlow infront of the guide camera, that would be better, or "upgrade" to a ST80 (500mm fl) with the QHY5, which CAN guide even my 12" Lx200.

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Psychobilly

Psychobilly

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I use a 500mm f8 T-mount telephoto lens that I picked up for about £30 on eBay as my guidescope these days...

I just needed to add a t-extension between the lens and the DSI II C to be able to get it to focus properly at "infinity"...

Works a treat...

Peter...

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adamsp123

adamsp123

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I use a 500mm f8 T-mount telephoto lens that I picked up for about £30 on eBay as my guidescope these days...

I just needed to add a t-extension between the lens and the DSI II C to be able to get it to focus properly at "infinity"...

Works a treat...

Peter...

That is very interesting nice idea!

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beamish

beamish

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See here :)

http://stargazerslounge.com/diy-astronomer/79000-lathe-anyone.html

Hope that helps !!

There are one or two links re doing the mod too, I'll see if I can find them. The SW 50mm finder is approx' F7 , and, if you go the way I did it utilising a 2"-1 1/2" adapter you could of add a barlow :D however I've not had to do this as yet always find plenty of guide stars even down to 0.5 sec exp !! DSO's show up well too

post-13438-133877387118_thumb.jpg

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adamsp123

adamsp123

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See here :)

Hope that helps !!

There are one or two links re doing the mod too, I'll see if I can find them. The SW 50mm finder is approx' F7 , and, if you go the way I did it utilising a 2"-1 1/2" adapter you could of add a barlow :D however I've not had to do this as yet always find plenty of guide stars even down to 0.5 sec exp !! DSO's show up well too

Thats the sort of thing I will be doing.

Having spoken to one of our Mechanical CAD people plus we have a prototype machine that can make plastic parts using polysomething or other he will make me an adaptor to hang the QHY5 onto which will slide into the finder tube. Bit like your set up, good to know I won't need a barlow by the looks of it, well here's hoping it works....now for some clear skies.

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beamish

beamish

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You'll find it's a relatively easy mod and yes it will work and of course once you've focused it up you don't need to touch it again-focused every time. I currently keep my cam in the holder on the the finder and keep the finder in place on the scope. Soooo much time time saved- can be up and running as soon as you like !!:):)

You will be very surprised at the results at short exp as well as longer ones. :D

Good luck and don't forget to post some pics when your done :p

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adamsp123

adamsp123

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Finally I managed to try my finder guider.

Once I had calibrated the gotos using a normal finder I swapped it over with the Adams Finder Guider (patent Pending LOL).

It took a fair bit of time to get a reasonable focus by manually sliding the QHY5 back and forth and then taping it in place, I ended up with somewhat fuzzie stars on the screen but PHD worked.

I ended up doing a whole load of 4 min subs on my non polar aligned Vixen Sphinx Yippeeee!

Cheers Guys!

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GazOC

GazOC

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I'm in work so I can't test it but IIRC if you unscrew the dew shield a couple of turns you can then turn the collar below it to move the lens. Obviously it'll only move upwards but it might be in the direction you need (50/50 chance!!).

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adamsp123

adamsp123

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I'm in work so I can't test it but IIRC if you unscrew the dew shield a couple of turns you can then turn the collar below it to move the lens. Obviously it'll only move upwards but it might be in the direction you need (50/50 chance!!).

Yes I tried that and ended up with the lens cell in my hands so I had to slide my patent QHY5 to finder tube adaptor out a bit then used the front focusing thing, but trying to slide the adaptor in and out was tricky and the cam is very sensitive to focus, plus I have a bit of slop in the current adaptor, will have a further fiddle today.

Bottom line is now I know it will work and I will save a hell of a lot of weight to my rig and it is so much less cumbersome to set up.

BTW below is a 1x4min jpeg totally untouched except to reduce the size so I could attach.

post-15319-133877387611_thumb.jpg

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