Back to forums

10Micron GM1000 for Edge HD 9.25"

10Micron GM1000 HPS Equatorial Mount Refractors
5 replies•433 views
Jerry Gerber avatar
Jerry Gerber avatar
Hello,

I currently own a 10Micron GM1000 mount that is carrying a 130mm refractor at a dark sky site.  I am very happy with this mount and am getting excellent results shooting unguided 3 minute subs.  

I am planning on putting a 2nd scope, a Celestron Edge HD 9.25", at a dark sky site and also placing it on a 10Micron GM1000 mount.  

Will I still be able to shoot unguided (2350mm focal length) if I keep my subs at 5 minutes or less or, because of the longer focal length, would I need to guide?  The scope will be under Bortle 1 skies with often very good to excellent seeing conditions.

Sincerely,
Jerry Gerber
Well Written Respectful
andrea tasselli avatar
andrea tasselli avatar
With SCTs guiding needs (or lack thereof) have as much to do with mount performance as mirror flop. Thus, depending on your focusing arrangements, you might or might not  need to guide. My bet is that you'll need to guide.
Jared Willson avatar
Jared Willson avatar
Due to the combination of the longer focal length and the movable primary mirror (that you won't be able to lock down since it's a remote site), I would be surprised if you could get away without guiding for exposures over 2 min or so. The mount is excellent, and the pointing model accomplishes a lot, but you are also asking a lot. I would plan on an off axis guider–no matter how good the mount. I would say the same about my beloved AP1100GTO AE.

- Jared
Well Written Helpful Insightful Concise
Jerry Gerber avatar
Jerry Gerber avatar
Jared Willson:
Due to the combination of the longer focal length and the movable primary mirror (that you won't be able to lock down since it's a remote site), I would be surprised if you could get away without guiding for exposures over 2 min or so. The mount is excellent, and the pointing model accomplishes a lot, but you are also asking a lot. I would plan on an off axis guider--no matter how good the mount. I would say the same about my beloved AP1100GTO AE.

- Jared

I will be able to lock down the mirror permanently as the PrimaLuce Esatto 2" electronic focuser will be installed.  That will take care of image shift and mirror flop as I won't be touching the stock focuser.  All focusing will be done by the Esatto 2".

I'll also attach the Celestron OAG with a guide camera, but prefer to use the outstanding absolute encoders on the mount to guide.   The GM1000 manual says that no guiding is necessary up to 10 minute subs (my subs will be 5 minutes max) but it doesn't specify up to what focal length this is applicable.  So I guess I'll have the option ready to guide but will try to go unguided when possible.
Well Written Helpful Insightful
astro10micron avatar
astro10micron avatar
hello ,
You will find attached a beginning of answer to your question
http://www.astrosurf.com/blogs/blog/11-astro-10-microns/?page=4

It is compulsory beyond. I had gone out with a 3000mm focal tube
http://www.astrosurf.com/blogs/entry/663-suivi-10-micron-avec-le-vmc260l-focale-native-de-3000mm/

bonne journée
bon ciel
BBRAUNCCP avatar
BBRAUNCCP avatar
Hi Jerry,

I have a similar setup with Esatto/Arco with an Edge 11 and is reduced to F7 1960mm. I have had good results most of the time. I have the primary locked down as best as I can with the standard mirror locks. Usually I have an RMS of around 4-6 when modeling with Mount Wizard 4, and mostly round stars at 300 seconds.

CS,
Bruce
Helpful