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Old 10-08-2019, 10:29 AM
Startrek (Martin)
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Proposal - Orion 60mm guide scope

Orion 60mm guide scope with helical focuser- Proposal

I’ve been using an Orion 50mm guide scope with helical focuser and a ZWO ASI120MM guide camera for over a year now on both my 6” and 8” newts and works well
The only problem I have is after slewing Goto and finding my object ready for imaging ( using my finder scope as part of the procedure ) , I have to remove my 50mm finder scope and replace it with the guide scope then plug the guide camera in and start PHD2 etc
If I was to buy and fit the Orion 60mm guide scope on a dovetail bar along the centre axis of my main scope OTA tube rings ( they have provision for mounting ) then I don’t have to touch a thing all night . I have my finder and my guider on board and can do anything , especially if I change targets and I need to use the finder again to find objects again ( this is rare as EQMOD is really accurate but I have that back up if I need it )
Also my image scale on the 50mm guide scope is currently 4.77 arc sec / pixel but with the new 60mm guide scope it would now be 3.22 arc sec / pixel , therefore the image scale ratio between the main Scope ( say my 8” f5 newt ) and guide scope would go from currently 5.4 times to now 3.6 times which would be better
Plus the 60mm has a wider field for greater selection of guide stars in PHD2
With the 60mm guide scope bolted piggyback along the centre axis of the main scope ( very close ) it may reduce any movement or flexure compared to the 50mm guide scope which sits in a little shoe bracket off to one side sticking out 120mm from the OTA
As far as additional weight goes , leaving the finder scope in place and adding the new proposed 60mm guide scope it only adds 900grams to the payload which is acceptable for my 6”f6 newt and HEQ5 and not a problem at all with my 8”f5 newt and EQ6-R mount
Appreciate any advice or thoughts on the above proposal as I’m getting a bit sick of swapping equipment on the scope during imaging sessions
Also addition cost not a problem for me
I not looking for alternatives to the above or re invent the wheel but to ask whether anyone finds any issues with doing the above both in a technical and practical sense

Thanks in advance !
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  #2  
Old 10-08-2019, 01:27 PM
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xelasnave
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https://www.google.com/url?sa=t&sour...wawQDG907uU5YA

I use one of these on my 80 mn.
Alex
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Old 10-08-2019, 02:09 PM
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LewisM
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Been using a Tak 7x50 finder converted with a helical focuser riding on top centre line in adjustable rings for years. I use a regular finder for alignment of the mount (or use the guide cam as an electronic finder) then remove the offset regular finder to remove asymmetric yaw and imbalance.

Use a Lodestar, so absolutely zero issues finding a guide star ever. Been using the guidescope with Lodestar much more frequently lately as a finder, not even bothering to mount the regular finder.
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Old 10-08-2019, 09:39 PM
RyanJones
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Hi Martin. I have one of these http://www.astroanarchy.com.au/teles...er_80x400.html
On a dovetail on top of my 8” f/4 Newt mounted on a HEQ5 Pro and it handles it perfectly. At 400mm with 80mm apature, it is incredibly easy to find good guide stars. $99 is an absolute bargain, so much so I’ve bought 2. One for my Newt and the other for my SCTs so I don’t have to swap them over when changing scopes. They are a rack and pinion focuser which I find easy to use and easy to adjust without disturbing the guidescope. They have a pretty decent dew shield built in to the front which rarely fogs up too. Personally I feel it’s a great option for guiding.
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Old 11-08-2019, 07:50 AM
Startrek (Martin)
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Thanks all for your advice !
Cheers
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Old 11-08-2019, 01:29 PM
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peeb61 (Paul)
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Quote:
Originally Posted by RyanJones View Post
Hi Martin. I have one of these http://www.astroanarchy.com.au/teles...er_80x400.html
On a dovetail on top of my 8” f/4 Newt mounted on a HEQ5 Pro and it handles it perfectly. At 400mm with 80mm apature, it is incredibly easy to find good guide stars. $99 is an absolute bargain, so much so I’ve bought 2. One for my Newt and the other for my SCTs so I don’t have to swap them over when changing scopes. They are a rack and pinion focuser which I find easy to use and easy to adjust without disturbing the guidescope. They have a pretty decent dew shield built in to the front which rarely fogs up too. Personally I feel it’s a great option for guiding.
This looks like a doer! Thanks Ryan.

Did you need an extension tube to bring your guide camera to focus?

Paul

Last edited by peeb61; 11-08-2019 at 02:23 PM.
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Old 11-08-2019, 07:20 PM
RyanJones
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Quote:
Originally Posted by peeb61 View Post
This looks like a doer! Thanks Ryan.

Did you need an extension tube to bring your guide camera to focus?

Paul
In my particular setup, I’m using a 1.25 diagonal which probably isn’t the suggested way to use it but it works well for me and keeps my wiring over one side of the OTA. If I didn’t use the diagonal then I’d have to use an extension yes. Astroanarchy sell those too.
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