GSO RC8 and Feather touch FTF3015B-A

[Manav]

Hi Guys,

I'm thinking of getting the CF version GSO RC8 and use my existing Feather Touch 3.0" Dual Speed Focuser with 1.5" DTT.

Has someone used this combination and if so what adapter do I need to connect the scope and focuser?

Any other items that I need to consider for the QHY9M to work with this let me know. i.e. reducer, field flattener etc etc...

Regards

[Marke]

I thought the RC8 took a 2" focuser ? I have a 3" on the RC10

Mark

[Manav]

Should have checked that good thing you pointed it out! Not much of an option then for me upgrade.

[gbeal]

I have the 2" on the RC8, but am looking to see if the 3" will adapt easy enough, so if you do find a solution let me know please. The 2" is a godsend compared to the fishing sinker that is supplied as standard.
Gary

[bmitchell82]

hey yugent :D

I have had this battle myself, i too thought at such a cheap price it would be a great little scope just to play with some longer fl but it cannot take the 3" focuser which is a real shame! its a 10" or better and the price becomes inhibitive again :(
:thumbsup:

[Marke]

There is not a lot of weight saving between the CF and non CF tube but the price difference is such that you can afford to replace the focuser and add
electronic focusing with temp compensation if you are worried about that.
With the RC10 it was a $700 difference so it was easy choice to put a FT on it.

Mark

[bmitchell82]

I guess the thing is though Yugent already has the 3015B-A FT just like me and it doesn't fit the RC8 which is pointless because then you would have to A. get the 10"RC or B get a new focuser which defeats the $$$ aspect. if the 3" focuser fitted then it would be very attractive. and without building a whole new visual back for the RC then its not really worth it!

[Marke]

If you only had a 2" and wanted a RC10 you would be in same boat
The 3" would be very big on the back of an 8" and you may have issues
with backfocus and balancing.

[bmitchell82]

:) nothing a little bit of weight up the front couldn't balance out losmandy do a 2d system for that. A friend of mine on his VC200L has to do the same thing or the balance point would be under the focuser.

Really the 3" doesn't matter if it looks big. it works well! :) and allows alot of other practical things. Though at the end of the day its not a issue as the RC8 has a small visual back that would not accept the 3" and i think it would struggle with the 2.5" and a 2" focuser is small now days with the size of sensors avalible.!
Brendan:thumbsup:

[Manav]

Yeah Brendan you completely understood the reason why I looked at the RC8. If I was going to go towards any other type of scope it would be the RC and nothing else. Why?

1. Focal length at f8 is reasonable you could use a flattener/reducer and go f6 but that defeats the purpose for most people.
2. Aperture is quite reasonable and provides good resolution compared to refractors.
3. Cost.

Even the 10" CF is not a bad option but the weight is the main concern the CF version is 7.5Kg and with a QHY9+Guidescope the EQ6 will be on the edge. G11 is the other option but then we start the money burn cycle all over again! Damn you astronomy.......

Update:

Mark - Are you using a GSO 10" on a CGEM? I read somewhere that using an EQ6 or CGEM for RC10 CF is also possible as long as a very light weight guide scope is used.

[bmitchell82]

dude your 10 + guide scope is far bigger than the rc :D ahahaha plus the eq6 is more than capable of round stars at 15-20min subs :P hehehe

[Marke]

Update:

Mark - Are you using a GSO 10" on a CGEM? I read somewhere that using an EQ6 or CGEM for RC10 CF is also possible as long as a very light weight guide scope is used.[/QUOTE]

I tried it out and it is possible but I had trouble guiding toward zenith
the weight was starting to show and was responding erratically to
guide commands I use an OAG no guide scope. Otherwise it seems to cope ok just depends on the angle and weight balance . I now have a Mach1 :D it doesnt break a sweat with it.

[bmitchell82]

Mark i don't know what was wrong with your eq6 but mine guides with perfectly round stars loaded up with about >24kgs of weight and a big swing hanging off the top of its head, see 1.2m long 254mm astrograph I have to man handle that thing...

That RC is a feather compared this is from experience of actually playing around with the ally tube version it is about half the weight of my scope.

[ReaPerMan]

I have my GSO RC10 CF on my Brendan adjusted tuned and pimped EQ6 :D, and as he says it will do the weight and give good results all day long. Nothing to fear with the RC10 CF and you should be using OAG or lightweight finder guider as standard!

all the best

Paul :thumbsup:

[Paul Haese]

Just to weigh in, contact Wayne at Starlight instruments (be sure to mark attention Wayne) and tell him which scope and that you want to use it on an 8" scope. He will let you know what adapter and which focusor. The 2" is fine and will pull up a lot of weight. Tell him I sent you and then haggle for a discount. He is good like that.

[Manav]

Thanks Reaperman!

Brendan - What/how did you tune up/pimped the EQ6 exactly for Paul?

[bmitchell82]

By understanding what is actually happening within the mount and having experienced it many many times before. I know the pit falls I know the important parts. :) they are bullet proof inside if only they actually put some more work into their worm wheels and gears........

[bmitchell82]

Once again Paul, manav already has the 3" varient on this, and the scope stops being economical if you go and buy a 2" FT to go on it. Might as well go to a 10" and use his 3" as before then there is only a minimal increase in price for a big increase in size. :D

[Manav]

Brendan Im going to talk to andrewcomms and see if they can reduce the price of RC10 CF by taking the standard focuser out of the equation.

I will PM you regarding the PEC and backlash for the EQ6.

[bmitchell82]

I don't run PEC its just raw. I should possibly do it one day and see how it goes

[Manav]

Sorry guys back to the original question is the FTF3015B-A fine for the 10" RC? i.e there was backfocus complaints so I just wanted to doublecheck. I just saw the price for the adaptor for the FT from starlight and its quite expensive.

[ReaPerMan]

i know its horses for courses but i went with the moonlight focuser you can get the fully motorised version with the adapter for <$500. I also have FT on another scope and they are beautifully made and fantastic but $$$. Consider this if you will based on how you will use the RC and what features you want the focuser to have in relation to your camera of choice. Economically you could sell your FT and recoup enough $ to make the change over minimal.
hope this helps

I also have no backfocus complaints with the moonlight as i seem to have more backfocus than I can poke a stick at !!

Paul :thumbsup:

[Marke]

The FTF3015B-A is correct I have it on my RC10 there is no issue with backfocus its the same length as the original so I dont know where that
idea comes from . I also got the microfocus kit for mine as well . I considered the Moonlite but you cant change the motor to another focuser if you wanted to later on .
Other thing to remember is that the FT is not a crayford and as such will support much heavier loads and also accounts for its extra expense.

[gbeal]

And if you so desire a FT, like all of us, but want a R&P, but not any bigger than the 2" variant, they make a 2" sucker with R&P.
Yes it is very expensive, even more so, but it does have the R&P, and will fit the current setup perfectly I suspect.
I have a couple of the FT2" versions (non R&P), and one is on the GSO R/C8". I also have coming a 3" version, FT3035, to fit onto a refractor which sadly/badly needs an upgrade.
Gary

[RickS]

It may have been my comment about not having enough backfocus with the FT focuser to fit focal reducer, AO, OAG, FW and camera - which is a pretty big ask :) I have an Atlas focuser due to arrive any day now...