Quote:
Originally Posted by Jethro777
Thanks Bill, that sounds very helpful. It sounds like you are advocating for the QHY5 solution.
I understand that this requires some sort of an extension to connect/focus properly? I have heard of a 1.25" 2 x barlow without the lens being used as an extension tube, and a 62mm long male to female T2 adaptor which screws into the QHY5 at one side, and directly onto the ST80 with the diagonal removed. Can anyone shed any light on this/Which is simpler (Imagine instructing a 12 year old child to do it - I assume I have similar competence).. 
And given that a QHY5 is preferable/more flexible, can anyone advise on which variant they suggest?
As I have said, from a pure financial standpoint, the QHY5, QHY5 II, QHY5L II color, QHY5L II mono, QHY5V and QHY5T are affordable.
Thanks Bill et al  |
Jethro
I am not advocating the QHY5 over the SSAG - just that there are some foibles to note; it all depends on what you are really after and if you want one that can do both - guiding plus planetary - then the choice is a no-brainer; I ended with one of each only because the QHY5 came with another piece of gear in a deal; I have been satisfied with the performance of both when I was using them
As far as the methodology of fitting the QHY/SSAG to the finder, you'll see much clearer what I did to achieve that by looking at my first image; the one with the Lodestar - the silver colored ring (it's actually aluminium) is threaded to fit the thread/pitch of the end of the finder after you have removed the eye-piece fitting which is basically made of plastic - I made the hole 1.25" as that is what both the nosepiece of the QHY5 & the barrel of the Lodestar are sized at (Lodestar hasn't got a nosepiece, the whole tube of the body is it with a recessed C-threaded mount at the front end if you want to screw the Lodestar to a fitting instead)
Then I removed the knurled "focusing" ring of the finder at the front (see the SSAG pix and the knurled "focusing" ring is absent) - the one that you turn to obtain focus of the stars when using the finder as a finder - this is because the focus point is more backwards than in normal use when the QHY5/SSAG is installed at the other end thus the "focusing" ring of the finder actually impedes the backwards travel depth of the lens element up front
The Vixen VC200L + SSAG finder/guider was used to capture
this image
Yep, you do need to use an extension tube if you use the Orion ST80 short tube without the diagonal of course - you get all the necessary fittings that will work correctly if you purchase the kit from Bintel (I started with that originally) but then you're having to use guiding rings to hold the ST80 which will invariably cause you grief due to flexure/movements of the guide scope - the reason people use the finder is that it is 1) convenient and 2) light weight and does not produce flexure - not in my case anyway when I was using the finder-guider method as the linked image above proves, even though the VC200L was prime at 1920mm fl
IMO I think that the addition if a 2X barlows will reduce the light incoming to the guide camera and even though the QHY5/SSAG are quite sensitive you might in certain circumstances be missing out quite a fair bit of stars available to be used - I don't know if my thoughts are right or wrong since I never did it that way as I opined that it would be more of a disadvantage so to speak - YMMV
I might take some pixs of the finder-guider parts so you get a clearer idea of how the thing goes together - I still have the SSAG in hand for the times when I do not use the OAG system it being that for eg: the VC200L's back focus distance is so short that I cannot use the OAG+FW+CCD combo
For the QHY5, yes +1 what Laurie said - get in touch with Theo of Gama Electronics; he is the distributor for the QHY range of products and his service is ridiculously good - FWIW sometimes the way he says things might be off-putting but don't worry about that; he does the right thing by the customer and you will never tire him out asking questions before your purchase
BTW the QHY5/SSAG has a T2-to-1.25" nosepiece anyway
HTH
Cheers
Bill
Autoguider options - Orion Starshoot or QHY5_? Help!
