flickr photos: http://www.flickr.com/photos/24719437@N03/
Quote:SSAG is probably the least sensitive autoguider in the market. I use to own one and never liked it so I replaced it with a high sensitivity Lodestar autoguider and I have never had to hunt for guide stars with OAG. I have guided to as low as 0.2 second.
Not only it's not an easy hobby but an expensive one!!!
I do not know enough about Newtonian scopes so I am not sure how much I can help you. I do know that in order to handle a large scope requires a strong mount with very good tracking and it's not going to be cheap. Try downsizing to smaller scope and go from there.
Modded C9.25, Vixen SP retrofitted with DS motors and Autostar My pics
Stars light the world without, to give us purpose
They light us within to give us reason
We live in a well-lit abyss.
Quote:I found this link from another CN thread. He uses 8" Newt on the same mount as yours. Take a look at his pictures from his web site:http://webpages.charter.net/paastroman/I think his scope is F/4 which is quite a bit shorter than yours.You might want to contact him and you might get better advice than me.Peter
Quote:I would guess the ST-80 is causing the flexure , that focuser tube with an extension is notorious.I would put a block and a strap between the SSAG and the Newt so it cant move , once the focus is set it wont need to move anyway.
Quote:For the screws in tube rings, I wouldn't recommend metal screws touching the guide scope. I suggest screws with special tip material like Delrin so they won't scratch the guide scope. Here is a sample:http://www.admaccessories.com/Miscellaneous_DTTS.htmPeter
Quote:Alpal,That looks much better. The dovetail plate for the ST80 will give the tube rings an extra bit of stability. With the setscrews on the ST80 extender tightened down, see what you get. Await your results curiously.Ajay
Quote:What kind of dovetail are you using? Standard NEQ6 (Vixen style) or Losmandy "D" style? If you are using Vixen style, I highly recommend getting "D" style since it's quite a bit wider and will provide much greater stability for a heavy tube.http://www.admaccessories.com/D_Series_Universal.htmYou will also need "D" saddle.http://www.admaccessories.com/D_Series_Saddles.htmI am a little concerned of your tube rings. They look a little thin. They may flex differently depending on where the scope is pointing to.Parallax makes great tube rings. They have 10.3" and 11". http://www.parallaxinstruments.com/ring.htmPeter
Quote:After receiving new equipment, let us know the outcome. It may take a while since you live down under and shipping from USA may take a while. From ADM web site, it listed one Australian dealer, hopefully they will have what you need in stock.Good luck.Peter
Quote:That's great news. Hopefully this will solve your flexure issues and your NEQ6 mount is beefy enough for your big scope and astrophotography.Peter
Quote:I am curious of the real source of the flexure in your setup. You are pretty much replacing more than one component which makes it difficult to really track down the source of the flexure. I kind of would like to know but that would waste your time and not worth the effort. I would be mad after replacing all the components and you still see image shifting in between frames. That would be very annoying and I hope that won't happen. It happened to me when I was using a guide scope guiding an SCT with moving primary mirror. I spend extra money on trying to get this system to work by getting stiffer components and none of them worked because the source of the flexure was the moving primary mirror and the guide scope cannot be in sync with moving primary mirror. So I threw out the guidance system and replaced it with OAG and that solved everything.If you do still see image shifts in between subs with new parts, probably the next place to look at is the primary mirror mount which I hope that won't happen.That's the price of this hobby.Peter