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Old 10-08-2019, 10:29 AM
Startrek (Martin)
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Startrek is offline
 
Join Date: Dec 2017
Location: Sydney and South Coast NSW
Posts: 5,990
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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