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Which motor focus for a Moonlite focuser?


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I am currently looking at buying a Moonlite focuser for my CPC925.  I want to use a motor also and was set to but the Moonlite Hi Res Stepper Motor, but wanted to get some advice on whether there are any other good options for the motor that would work with the Moonlite focuser.  Think the mMoonlite motor is a bit ugly (yes I know that shouldn't be a consideration but I cant help it!)

I have assumed - maybe wrongly - that the focuser controller will work with Sequence Generator Pro - is that correct?

Many Thanks

John

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Well, I've got one with the DRO focus/rotator option on my C925 and been very.. very happy with it. Not ugly at all.. I love it, first class engineering although its heavy and adds a fair bit of backfocus, so you need to add counter weight to the front of the tube.It also has the option of fitting a reducer inside.

http://stargazerslounge.com/topic/212161-moonlite-with-new-rotator-option/

Has Standalone, Ascom & Linux drivers. It'll work with SGPro, I use FocusMax/Maxim/ACP with mine now.

I'd check you have enough clearance on the CPC mount though.

Another option would be to motorise the feather touch microfoccuser I guess.

http://www.firstlightoptics.com/starlight-instruments-feather-touch-sct-microfocusers/microfocuser-for-celestron-925-sct.html

http://starlightinstruments.com/store/index.php?route=product/category&path=41

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Well, I've got one with the DRO focus/rotator option on my C925 and been very.. very happy with it. Not ugly at all.. I love it, first class engineering although its heavy and adds a fair bit of backfocus, so you need to add counter weight to the front of the tube.It also has the option of fitting a reducer inside.

http://stargazerslounge.com/topic/212161-moonlite-with-new-rotator-option/

Has Standalone, Ascom & Linux drivers. It'll work with SGPro, I use FocusMax/Maxim/ACP with mine now.

I'd check you have enough clearance on the CPC mount though.

Another option would be to motorise the feather touch microfoccuser I guess.

http://www.firstlightoptics.com/starlight-instruments-feather-touch-sct-microfocusers/microfocuser-for-celestron-925-sct.html

http://starlightinstruments.com/store/index.php?route=product/category&path=41

Thanks for those links.

What is the rotator used for?

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I've got one on my CPC1100, fitted with a Lakeside motor and using Focusmax.  No problems at all - worked straight "out of the box", and that is carrying a filter wheel and Atik 4000 camera, as well as an off-axis guider and camera.

Chris

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Thanks for those links.

What is the rotator used for?

TBH I don't really need to use it much at all. My main reason for getting it was for ease of use as my Obsy is remote controlled. It rotates the entire imaging train so you can fit/frame the target on the sensor. Also, more often than not at these FL's you'd be using an OAG. So it also helps in finding a guide star if there's not one in the current FOV. Of course it also means taking flats for every angle you shoot at as the scope optics don't rotate. You may get away without if your optics are very clean & it's only vignetting you need to get rid of.

Now, I take it you are talking about imaging DSO rather than Solar System (planets/lunar) as you've mentioned SGPro. A rotator can also be used to help control the field rotation (look up de rotation, can also be done in software to some extent) you get with Alt/Az mounts such as your CPC. Although I've never tried that as all my mounts are GEM's.

So before splashing out on a focuser/motor my 2 concerns would be how to overcome the issue of rotation with an ALT/AZ type mount, (wedge?), and how much clearance you have once it's all loaded up with FW & CCD. With a fork mount you don't have much rear clearance when shooting around the meridian.

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TBH I don't really need to use it much at all. My main reason for getting it was for ease of use as my Obsy is remote controlled. It rotates the entire imaging train so you can fit/frame the target on the sensor. Also, more often than not at these FL's you'd be using an OAG. So it also helps in finding a guide star if there's not one in the current FOV. Of course it also means taking flats for every angle you shoot at as the scope optics don't rotate. You may get away without if your optics are very clean & it's only vignetting you need to get rid of.

Now, I take it you are talking about imaging DSO rather than Solar System (planets/lunar) as you've mentioned SGPro. A rotator can also be used to help control the field rotation (look up de rotation, can also be done in software to some extent) you get with Alt/Az mounts such as your CPC. Although I've never tried that as all my mounts are GEM's.

So before splashing out on a focuser/motor my 2 concerns would be how to overcome the issue of rotation with an ALT/AZ type mount, (wedge?), and how much clearance you have once it's all loaded up with FW & CCD. With a fork mount you don't have much rear clearance when shooting around the meridian.

Well i am interested in both planetary and DSO objects, but am going to cut my teeth on planetary first.  For planetary I am using BYE to capture AVI's (more truthfully I would say I am 'trying'!).  SGP is something I want to learn for DSO as (I am assuming) its not the right tool for planetary as it has no video capture.

I have a wedge fitted to my CPC925 to use as an EQ mount.  I understand your point on the clearance - I was going to get the wider flange for the Moonlite but realised at 4.52 inches long with the drawtube fully in, it is not going to leave a lot of room!.  Think I will be going for the non focal reducer option. I can always add the FC in front of the focuser later if I want to with a 2" SCT adapter.  Total clearance on my CPC is about 8.5 inches.  The focuser I am looking at is 3.62 inches deep, which will leave c3.5 inches (with a fully extended draw tube on the focuser) of space to  clear the fork mount. Thats enough for my dslr or a filter wheel/ccd combo.  Planetary becomes more difficult I guess because of the need to use barlows - no way will the focuser/barlow/dslr clear the mount.

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Oh  I thought of another question regarding the focuser... what position is best for the OEM focuser when the moonlght is installed?  All the way in, all the way out, or somewhere in the middle?

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Well i am interested in both planetary and DSO objects, but am going to cut my teeth on planetary first.  For planetary I am using BYE to capture AVI's (more truthfully I would say I am 'trying'!).  SGP is something I want to learn for DSO as (I am assuming) its not the right tool for planetary as it has no video capture.

I have a wedge fitted to my CPC925 to use as an EQ mount.  I understand your point on the clearance - I was going to get the wider flange for the Moonlite but realised at 4.52 inches long with the drawtube fully in, it is not going to leave a lot of room!.  Think I will be going for the non focal reducer option. I can always add the FC in front of the focuser later if I want to with a 2" SCT adapter.  Total clearance on my CPC is about 8.5 inches.  The focuser I am looking at is 3.62 inches deep, which will leave c3.5 inches (with a fully extended draw tube on the focuser) of space to  clear the fork mount. Thats enough for my dslr or a filter wheel/ccd combo.  Planetary becomes more difficult I guess because of the need to use barlows - no way will the focuser/barlow/dslr clear the mount.

post-11176-0-30703300-1429985769.jpg

post-11176-0-83049000-1429985768.jpg

As you can see mine is 10 inches once the FW & CCD is hanging off the back .. :eek::grin:

The thing to remember with the version that takes the FR internal is that it moves with the focus tube. That means it stays at the same distance as focus changes. Using the reducer won't get you any more photons any quicker but will enable a wider FOV if thats what you need. I've left mine in as it suits most of the targets I've been after.

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Oh  I thought of another question regarding the focuser... what position is best for the OEM focuser when the moonlght is installed?  All the way in, all the way out, or somewhere in the middle?

Ah yes, mines not an HD, so has no mirror locks. What I did was move the focus tube to the middle position.. ie half way out. Then focused with a bahtinov using the celestron focuser. That way once I'd setup FocusMax it had equal travel either side and automated focus means it compensates for any mirror flop via the moonlite.

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attachicon.gifFullSizeRender.jpg

attachicon.gifFullSizeRender-2.jpg

As you can see mine is 10 inches once the FW & CCD is hanging off the back .. :eek::grin:

The thing to remember with the version that takes the FR internal is that it moves with the focus tube. That means it stays at the same distance as focus changes. Using the reducer won't get you any more photons any quicker but will enable a wider FOV if thats what you need. I've left mine in as it suits most of the targets I've been after.

Thats longer than I thought!  I will be going for the non FR version which is about an inch shorter but still that would mean just less than 9 inches with a FW and CCD...

Guess I will have to look for a narrow FW!

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Oh  I thought of another question regarding the focuser... what position is best for the OEM focuser when the moonlght is installed?  All the way in, all the way out, or somewhere in the middle?

A very good question.  I set the moonlight at halfway, and then adjusted the Celestron focuser to achieve focus on a distant hill (daytime set-up).  Then after dark it was relatively close to good focus on stars enabling me to then set up Focusmax.  I didn't use the mirror locks but I did mark the position of the celestron focuser so I could easily return to it after any changes without re-running the v-curve for setting up Focusmax.  As you can see from the attached pic, and as indicated by Sp@ce_d above, the moonlight does make for a fairly chunky rear load.

Chris

post-23286-0-85870700-1429987620.jpg

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A very good question.  I set the moonlight at halfway, and then adjusted the Celestron focuser to achieve focus on a distant hill (daytime set-up).  Then after dark it was relatively close to good focus on stars enabling me to then set up Focusmax.  I didn't use the mirror locks but I did mark the position of the celestron focuser so I could easily return to it after any changes without re-running the v-curve for setting up Focusmax.  As you can see from the attached pic, and as indicated by Sp@ce_d above, the moonlight does make for a fairly chunky rear load.

Chris

Thanks for that Chris and space_d... i will try that when the moonlite arrives ( I went ahead and ordered it!)... so half way on the moonlite, focus using the Celestron focuser and then use moonlite as required.

Chris, are you using a FR in that set up?

One thing I noticed is that you guys above are also using OAG's which is also adding some length to the imaging train...I am aiming to use a seperate guide scope as I read that OAGs are difficult for beginners... of course the guide scope adds its own problems which I am finding out!

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Thats the SX FW with OAG on there. I've tried guiding with my Esprit 80 which is mounted on top for wider field imaging (it has a finder/guider) but to be honest at this FL, OAG really is the way to go to avoid flex.  Longer FL imaging has its challenges & is not really recommended for starting out as it's rather frustrating to get going on. Shorter length imaging tends to give you more pleasing results with less frustration. You don't want to be put off trying this but be aware I imaged at shorter FL for some years before tackling longer FL and it's took me nearly a year before I started to feel I could post some of my results.. :embarassed:

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Thats the SX FW with OAG on there. I've tried guiding with my Esprit 80 which is mounted on top for wider field imaging (it has a finder/guider) but to be honest at this FL, OAG really is the way to go to avoid flex.  Longer FL imaging has its challenges & is not really recommended for starting out as it's rather frustrating to get going on. Shorter length imaging tends to give you more pleasing results with less frustration. You don't want to be put off trying this but be aware I imaged at shorter FL for some years before tackling longer FL and it's took me nearly a year before I started to feel I could post some of my results.. :embarassed:

Yes I agree it IS very frustrating LOL.  I have been at it just a month after a year of research prior to that  (yes a year!) to go for the CPC925.  I am very realistic about how long it is going to take to learn.  Expectations are low for the first 12 months. . Only just now able to get even a bright star in view consistently with the finder and main eyepiece in the CPC and only just been able to image a star properly, let alone anything else!  Learning to use PHD ('push here dummy' - yeah right!) , SGP, BYE, TheSkyX etc is a lot of fun if a little difficult. The learning curve is incredibly steep but for me personally that is part of the fun of it...  I get as much enjoyment out of the journey as the result. 

So i ended up ordering the moonlite (non FR flange version) and the motorised focuser with it - will post some pics of the set up for both DSLR and CCD when it arrives.  Cant wait :)

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