SCT Autoguider Finder Advice

[Suffolk Chris]

Hi 

Just looking for some advice on a decent auto-guiding scope and camera for a SCT 10". From what I am researching, I am seeing that I shouldn't really be going with anything under 80mm to avoid not being able to keep a good guide when capturing subs longer than possibly 2 minutes, am I correct thinking that, or am I reading too much in to guide issues for the bigger SCT with F8s and F10s? 

Maybe someone who has gone through this pain already could save me the pain and the cost of learning the hard way.

I am currently running a Meade LX200 Classic 10" F10 FL=2500mm on a SkyWatcher EQ6-R-Pro mount  but have only done visual up to now and I would like to try some photography. I have been looking at going down the Orion ST80 Clone refractor or something similar as an auto-guider scope using probably PHD with a ZWO ASI1200 camera or something around that money in mono for auto-guiding. Would this be wise for my Meade LX200 10".

I will be imaging with a DSLR EOS D6 for now to see how it goes.

Any advice appreciated.

Cheers

Chris

[Davey-T]

Better off using an OAG with a long focal length SCT although I have guided mine with a variety of refractors at one time or another, they need to be bolted directly to the main scope, so preferably no adjustable guide cope rings.

Dave

Edited September 8, 2020 by Davey-T

[Suffolk Chris]

Thanks Dave,

im not too keen on OAGs to be honest, I would much prefer a dedicated guidescope really. I have read that OAGs do work well with longer focal length SCTs. I’m currently looking at the 80ED With a 1.25” camera of some sort, hard railed to the underside of the losmandy dovetail if there is enough room to get it on there. If not, I will get a second rail and mount the guide to the top to reduce slop.

[Davey-T]

Better mounted on top, depending on the time of year it can be tricky finding guide stars in OAG and can lead to not ideal framing for the target, never any problem finding guide stars with piggy backed refractor.

You can always stick a cheap Barlow in the ST80 to get a more approximate matching image scale to the SCT, you'll need a short 1.25 extension to reach focus.

Mirror flop can be a problem if your scope hasn't got a mirror lock, mine has and never had a problem but it is over exaggerated by folk without any actual experience .

I use a piece of flat aluminium bar with tube rings bolted to it bolted to the top of the scope, doesn't need to be anything fancy, you'll need some sort of counter balance system on the bottom of the scope.

Dave

Mine guided with 80mm f/9 refractor with wobbly guide scope rings 

 

Balance system

 

[Suffolk Chris]

That’s a nice setup Dave, WOW!!

my Meade is the LX200 without the mirror lock but I don’t have any mirror slop issues really. I have a crayford refractor type focuser on the back which works very well for fine focus as the main Meade scope focus can be tricky sometimes, I get the scope focussed best I can then use the crayford to fine focus, works fine for visual, I will see how it does when I get my 6D back from being Astro modified and see how I get on with that focus setup on the next clear night we have.

so I’m guessing your guiding okay with the refractor, no guide slew issues with longish exposures? 
 

Your setup is great, is that the 10” scope or 12” I would love to see some DSO snaps from that setup if you have any?

Edited September 8, 2020 by Suffolk Chris

[Davey-T]

3 hours ago, Suffolk Chris said:

so I’m guessing your guiding okay with the refractor, no guide slew issues with longish exposures? 
 

Your setup is great, is that the 10” scope or 12” I would love to see some DSO snaps from that setup if you have any?

Generally tracked ok but had some issues aiming at high dec' still only using Win XP Pro and PHD1 in the obs'y on the, if it aint broke principle.

It's 10" LX200R  before people complained and they changed the name to ACF, mines got the Meade electronic microfocuser which works fine.

Dave