Gso rc 10

[Loupy31]

Hi Guys,

OK, I have been given the green light to buy a new scope, I am seriously looking at the GSO RC 10, are there any problems with it that others have found and fixed or had fix.

Also, are they a good visual scope or are they just for astrophotography

Peter

[Star Catcher]

I think the first problem most people encounter is collimation. It is not a trivial matter and several methods can get you there. The simplest and fastest method and well worth the money is the Tak collimating scope. Visual views are ok but that is not what you want to use the scope for.

Ted

[brisen]

Hi Peter

I have had a 12” GSO RC truss for about a month and would agree the first thing to get your head around is the collimation of these and purchased a tak collumation scope to assists with this. The other thing is getting the back focus correct and getting the spacers correct has been a challenge. There doesn’t appear to be a manual for these and it took me a bit of searching to find something that actually gave me an indication of the spacers for various imaging trains.

They are also heavy - the 12 is close to 25 kg but the 10 would be a bit lighter. I have found it isn’t easy to get into the saddle on the mount but I am doing it on my own and can just manage it with care.

They are setup as an astrograph and don’t come with eyepiece or diagonal. I believe they do come with covers for the primary and secondary- mine didn’t and despite having chased this up immediately following delivery, I am still waiting for a response and supply of these.

Brian

[casstony]

Lots of interesting RC info including collimation guide here: http://interferometer-tests.blogspot.com/2013/06/2542000-10-ritchey-chretien-gso.html

[lazjen]

Unless things have changed in recent times, if you plan to do astrophotography, you will probably want to change the focuser. It's ok, but it's easy to do better.

[Stonius]

You'll need one of those things that allow you to adjust the tilt of the focuser (I think it's called a tilt plate?).
First collimation task is to use the tilt plate to make the laser hit the middle of the donut on the secondary. Then use the coincentric circle hologram or tak scope to adjust the secondary. It's actually not that hard, TBH, but it does like you to be accurate.

And as mentioned above, grab a moonlite focuser.

For visual, you'll need a 4" spacer to get the eyepieces into the focal plane, but as mentioned before, it's an astrograph and you may well not need or want to go visual.

Best,

Markus

[glend]

As a previous owner of a similar GSO RC, I would suggest the OP consider another scope. The learning curve is steep, and your wallet needs to be deep, in order to get them to a reasonable standard. It is easy to stuff up the collimation if you don't know what your doing, and terribly hard to get it back.

[Andy01]

As mentioned, be ready for a world of pain with collimation- it can be done but unless you’re an expert, you’ll likely be calling in favours from your tech savvy colleagues!

In addition to the Tak microscope- you’ll also need a decent focuser, counterweights (these things are butt heavy), secondary dew heater and the tilt adjustment ring.

The guys at sidereal trading are importing Korean robotic secondary focusers, nmight be well worth investigating as the focuser supplied is rubbish.

Good luck!

[Paul Haese]

Peter,

collimation can be a bit tricky but by comparison to the AG12 it is a breeze. Perhaps it fell into place for me. I am now using two pieces of equipment. One is a Howie Glatter laser to centre focuser to the secondary. Then I use a Tak scope to sort out the primary to secondary. Final tweak on a star.

You will need a better focuser. I am sure the new focuser is ok but it cannot hold much weight. My preference is for a 3" Feather Touch. It is very sturdy and more reliable than the standard Moonlite. Although I am currently using a Moonlite 3" Nitecrawler which is very good, but totally unlike a Crayford.

You will need a secondary heater and shroud to reduce dew and glare on the optical surfaces, especially at Clayton Bay as it is dew city.

I don't know if the 10" comes with a camera tilt adjuster but you will need one of those to perform collimation.

If you get stuck I am sure you will know someone in the area that can sort it for you quickly. ;)

[Loupy31]

Thanks guys,

I appreciate all the advice you have posted

It is certainly going to be a learning curve,

Regarding the Howie Glatter Laser and the Tak scope, are they suitable for other scopes, eg SCT's, Dobs, Refractors?

Cheers Peter :thumbsup:

[N1]

Interesting page, particularly this bit:

"As only about 50% of the light is concentrated in the Airy Disk, and the rest in the diffraction rings, the resolution effectively is just half the value the aperture size suggests. A 10" RC has the effective resolution of a 5" instrument without obstruction"

So my FC76 should resolve similar detail to what my RC6 can do. Sounds fantastic if unlikely. Must do a test sometime.

[Stonius]

Interesting - I guess this must apply to all those professional observatories too, then?

[Paul Haese]

Yes a Howie Glatter with Tblug is great for Dobs too.