Jump to content

740427863_Terminatorchallenge.jpg.2f4cb93182b2ce715fac5aa75b0503c8.jpg

Guide scope for 9.25


Recommended Posts

Hello,

Just wondering if anyone has a guide scope for their Celestron 9.25?

I am deciding what is the best route re-autoguiding and have pretty much ruled out any off axis stuff (unless convinced otherwise) and go the seperate guide scope route with an auto guider to the cpc mount. However want something ideally that complements the CPC design.

Any help or point in the direction of scope/brackets etc on this would be great :)

Chris

Edited by Space Bat
Link to comment
Share on other sites

I like the Star Sky 90 scope. It's an achro but has very good optics and comes with a crayford focuser and retracting dewshield and is very light weight and reasonably cheap. Style wise it would look right on a CPC scope as it's nicely finished and in black.

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Ascension.asp?p=0_10_1_6_110

For guidescope rings the ADM system would be the best, yes it's not cheap but top quality.

http://firstlightoptics.com/products.php?cat=123

John

Link to comment
Share on other sites

Thanks guys....

Have ordered the bits I need now :)

Celestron OAG and an Orion StarShoot autoguider....coupling to set up with Canon DSLR :)

Just need to sort the camera out now.....Oh and how to hide the reciepts....:mad:

Chris

Link to comment
Share on other sites

OAG is definitely the best bet for an SCT unless you have mirror locks and use a rear cell focusser...

Just remember all this has to fit through the forks or at least make sure you set the slew limits up properly or your risking soem serious damage to the drive train...

Autoguiding with that setup wont work in Alt/Az either so your really looking for a wedge to "equatorialise" the CPC as well...

Oh forgot once you start adding stuff to the top of the OTA ... you really should consider counter-balancing it all with something like a "3d" counterbalance setup...

And then you'll want to replace the standard nylon Azimuth Beraings invalidating your warranty....

I made the same mistakes going for a fork mounted AltAZ scope should have gone GEM in the first place... ALt/AZ if fine for quick setup visual use but is a PITA for imaging...

Fortunately I have made and modified nearly everything myself otherwise it would have cost a fortune...

wps1k.jpg

11848_large.jpeg

Billy...

Edited by Psychobilly
Link to comment
Share on other sites

Thanks Billy -

Still getting my head around the new science as it were....pretty much was all EQ and Alt - Az was for casual observers ages ago and am pretty amazed at how things have progressed in the Alt-Az mounts.....crikey a motorised Dob for god sake :) people would have laughed at the idea in the late 80's - I am pretty chuffed at how well I can get this mount to track in Alt Az

Found the best method is the Auto two star but to try and pick stars 180 degrees apart, that seems to improve things way more than two localish stars...unless I am imagining things.

Then had a play with some of the settings for backlash..etc

I can pretty much get this tracking for a fair period of time with a lot less drift...and is way more accurate in centering objects so haven't found the need for precise GOTO.

I dare say I may learn the errors of my ways when I do try some long exposure stuff..still on a learning curve :)

But god this is so much better than freezing to death with watery eyes trying to see if your guide star has drifted out of the illuminated reticule :mad:

Like your setup by the way are you single? or have a very understanding partner....?

My partner thinks I get alot of my stuff second hand.....:mad:

Chris

Edited by Space Bat
Link to comment
Share on other sites

It lives in and obs now as well...

AFAIK The CPC scopes will not autoguide successfuly guide in Alt/Az.... There are some scopes (Meade for one)that will and they use de-rotator to counter field rotation..

When considering a "guidescope" I would be more inclined to regard it as a wide field imaging scope and go for something half decent... I started out with a Skywatcher Equinoxe-66 but afetr it had an unfortunate accident its imaging days were over so I went with a Megrez72 to go with the WO FFIII that I had already purchased...

Then you realise that having an SCT especially one without a mirror lock in the duiding equation is a recipe for more grief and why waste imagign time with a decent OTA so I added the guidescope which is a cheap T mount 500mm f8 telephoto lens bought from the Bay of E fitted in some custom guide rings which I knocked up in the garage...

When its comes to wedges you will be suprised what you can get away with once you satrt autoguiding and there have been several decent designs for wooden free standing ones for SCT's made out of 18mm ply...

I made a ply wedge to get my head around the design then made a scrap aluminium one out of some HE-30 I just happened to have lying around before drawing up the combined Pier and Wedge which I had laser cut and Fabricated FOC :)

Look forward to seeing your progress and will be happy to help if I can...

Nearly all my attempts at imaging are through the Megrez72 as I prefer the Wider field of view- its also a lot less demanding on the guiding :)

Billy...

Edited by Psychobilly
Link to comment
Share on other sites

Thanks Billy,

As I am still getting to grips with CCD's CMOS, motorized ALT/AZ - My thought process was to keep the time frames down under a minute but collect more subs. I believe minimal rotation can be dealt with in the alignment process when aligning the subs.

Its a bit trial and error at the moment to see how long I can expose before field rotation becomes a factor and when I build up my skills and move on to more challenging DSO's that require long exposure subs, then I will be in the market for a second hand wedge.

First I need to get proficient in planetry/lunar - then Clusters and Bright DSO's such as Orion, when I can produce good images then move onto a wedge and go for feint DSO's

I am supposed to be moving in with my partner this year if she can sell her house, so if this happens and we find a dark site to live, I will then look at a permanent fixture where a small observatory can be made....

She wants a Sauna (being Finnish)...which I am happy to go with....so I am sure an observatory will provide some leverage :)

Thanks for your help and advise :)

Chris

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.