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Re: PE with and Without the O-Vision NS Kit


Sep 29, 2009

 


----------------------------

#44072 Sep 29, 2009

I have a Losmandy G11 with Gemini 1.04.

I recently bought the O -Vision kit.

I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

-.28.7 Arc-Seconds peak to peak.

-.RMS : 5.8

-.With an awful 76s peak.

RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

-.4.4 Arc-Seconds peak to peak.

-.RMS: 1.1

-.The 76 s peak has quite disappeared.

I mounted the kit in the following way:

-.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

-.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

-.I locked tight both bolts.

-.I checked the worm gear was moving freely on 180. at least.

Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

Pempro PE and frequencies curves are given in the photo album:



PE on G11 With and Without the O - Vis O





I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

I would appreciate if somebody could give me a clear advice on this point.

Thanks in advance.

Regards.



----------------------------

#44084 Sep 29, 2009

r.claveyrolas,



Congratulations on an excellent improvement to your periodic error! That's a huge difference and it will certainly make a difference in your ability to guide and image.



Use PemPro or other methods to program PEC. You'll reduce your PE to less than half of the 4.4 arcseconds that it is now.



This will help in guiding. There's almost no truth to the story that you shouldn't use PEC while auto-guiding. Good PEC will improve your guiding, and result in sharper images and rounder stars.



Regards,



-Paul

--- In Losmandy_users@yahoogroups.com, "rclaveyrolas" r.claveyrolas@...> wrote:

>

> I have a Losmandy G11 with Gemini 1.04.

> I recently bought the O -Vision kit.

> I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

> RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

> -.28.7 Arc-Seconds peak to peak.

> -.RMS : 5.8

> -.With an awful 76s peak.

> RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

> -.4.4 Arc-Seconds peak to peak.

> -.RMS: 1.1

> -.The 76 s peak has quite disappeared.

> I mounted the kit in the following way:

> -.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

> -.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

> -.I locked tight both bolts.

> -.I checked the worm gear was moving freely on 180. at least.

> Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

> Pempro PE and frequencies curves are given in the photo album:

>

> PE on G11 With and Without the O - Vis O

>

>

> I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

> I would appreciate if somebody could give me a clear advice on this point.

> Thanks in advance.

> Regards.

>



----------------------------

#44087 Sep 30, 2009

Hello,

really good improvements after o-vision upgrade. I'm a bit curious about knowing if the improvements come from the new worm gear mounting or also from the new worm itself.

I think - but this is just a my ideas, not yet verified - that using a high precision worm with the right block mounting will help a lot in reducing the PE.



About the PEC you should use it: there're a lot of mis-understanding about the question, but a well programmed PEC can only improve greatly the roundness of stars and help you to have a better and easier guiding.



Best regards, Stefano

--- In Losmandy_users@yahoogroups.com, "rclaveyrolas" r.claveyrolas@...> wrote:

>

> I have a Losmandy G11 with Gemini 1.04.

> I recently bought the O -Vision kit.

> I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

> RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

> -.28.7 Arc-Seconds peak to peak.

> -.RMS : 5.8

> -.With an awful 76s peak.

> RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

> -.4.4 Arc-Seconds peak to peak.

> -.RMS: 1.1

> -.The 76 s peak has quite disappeared.

> I mounted the kit in the following way:

> -.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

> -.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

> -.I locked tight both bolts.

> -.I checked the worm gear was moving freely on 180. at least.

> Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

> Pempro PE and frequencies curves are given in the photo album:

>

> PE on G11 With and Without the O - Vis O

>

>

> I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

> I would appreciate if somebody could give me a clear advice on this point.

> Thanks in advance.

> Regards.

>







----------------------------

#44091 Sep 30, 2009

Some of the Brass Losmady Precision worms are very good and perhaps almost as good as the OVision? But the OVision is machined to a tolerance that is 10x better or smaller. This gives it a smoother PE as well as a smaller PE, which is why it seems to work so well. The mounting block certainly is a part of the fix and if there is a block that will take its place that uses the Brass Worm, I am sure that good results can be obtained.

The worm block should be made with stainless steel rather than aluminim however, as the Titan mounts learned this lesson when they first came with aluminum one piece blocks and had problems with temperature changes.

Floyd --- In Losmandy_users@yahoogroups.com, "stefanovezzosi" stefano.vezzosi@...> wrote:

>

> Hello,

> really good improvements after o-vision upgrade. I'm a bit curious about knowing if the improvements come from the new worm gear mounting or also from the new worm itself.

> I think - but this is just a my ideas, not yet verified - that using a high precision worm with the right block mounting will help a lot in reducing the PE.

>

> About the PEC you should use it: there're a lot of mis-understanding about the question, but a well programmed PEC can only improve greatly the roundness of stars and help you to have a better and easier guiding.

>

> Best regards, Stefano

>

> --- In Losmandy_users@yahoogroups.com, "rclaveyrolas" r.claveyrolas@> wrote:

> >

> > I have a Losmandy G11 with Gemini 1.04.

> > I recently bought the O -Vision kit.

> > I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

> > RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

> > -.28.7 Arc-Seconds peak to peak.

> > -.RMS : 5.8

> > -.With an awful 76s peak.

> > RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

> > -.4.4 Arc-Seconds peak to peak.

> > -.RMS: 1.1

> > -.The 76 s peak has quite disappeared.

> > I mounted the kit in the following way:

> > -.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

> > -.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

> > -.I locked tight both bolts.

> > -.I checked the worm gear was moving freely on 180. at least.

> > Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

> > Pempro PE and frequencies curves are given in the photo album:

> >

> > PE on G11 With and Without the O - Vis O

> >

> >

> > I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

> > I would appreciate if somebody could give me a clear advice on this point.

> > Thanks in advance.

> > Regards.

> >

>



----------------------------

#44094 Sep 30, 2009

Thanks a lot for your advice concerning PEC and autoguiders.

I am not able to tell you if the improvements come from the new worm gear mounting, or from the new worm itself.

I think however it's both.Indeed,when reading the O-Vision manual when mounting, I realised that I could miss some points, and I phoned to Franck Valbousquet.

He told me that the best way was to process was as mentioned in my first mail, provided the assembly worm + RA wheel was able to turn freely on 360..He was considering that some excentricities might exist on the RA wheel. He told me that I would get the best results with a good centering at the Oldham coupler level, and a play as small as possible between the worm gear and the wheel.

Moreover, He had told me previously that a great part of the 76. peak was due to non orthogonalities between the 2 bearings of the Losmandy worm gear assembly (they are not mechanically and precisely linked, as it is the case in the O-vision kit).

So as far as I understood :

- Part of the improvement is linked to a correction of a design problem at the level of the Losmandy worm gear assembly(the 76s peak ). In my case, this peak was quite huge.

- Part of the improvement is linked to a better precision machining of the worm gear itself.

- Part of the improvement is linked to the gap between the worm gear and the RA wheel.



Best regards.

Robert Claveyrolas --- In Losmandy_users@yahoogroups.com, "stefanovezzosi" stefano.vezzosi@...> wrote:

>

> Hello,

> really good improvements after o-vision upgrade. I'm a bit curious about knowing if the improvements come from the new worm gear mounting or also from the new worm itself.

> I think - but this is just a my ideas, not yet verified - that using a high precision worm with the right block mounting will help a lot in reducing the PE.

>

> About the PEC you should use it: there're a lot of mis-understanding about the question, but a well programmed PEC can only improve greatly the roundness of stars and help you to have a better and easier guiding.

>

> Best regards, Stefano

>

> --- In Losmandy_users@yahoogroups.com, "rclaveyrolas" r.claveyrolas@> wrote:

> >

> > I have a Losmandy G11 with Gemini 1.04.

> > I recently bought the O -Vision kit.

> > I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

> > RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

> > -.28.7 Arc-Seconds peak to peak.

> > -.RMS : 5.8

> > -.With an awful 76s peak.

> > RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

> > -.4.4 Arc-Seconds peak to peak.

> > -.RMS: 1.1

> > -.The 76 s peak has quite disappeared.

> > I mounted the kit in the following way:

> > -.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

> > -.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

> > -.I locked tight both bolts.

> > -.I checked the worm gear was moving freely on 180. at least.

> > Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

> > Pempro PE and frequencies curves are given in the photo album:

> >

> > PE on G11 With and Without the O - Vis O

> >

> >

> > I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

> > I would appreciate if somebody could give me a clear advice on this point.

> > Thanks in advance.

> > Regards.

> >

>







----------------------------

#44095 Sep 30, 2009

Thank you very much for your advice. I will try it.

Best regards.

Robert Claveyrolas

--- In Losmandy_users@yahoogroups.com, "paulkccd" pkane2001@...> wrote:

>

> r.claveyrolas,

>

> Congratulations on an excellent improvement to your periodic error! That's a huge difference and it will certainly make a difference in your ability to guide and image.

>

> Use PemPro or other methods to program PEC. You'll reduce your PE to less than half of the 4.4 arcseconds that it is now.

>

> This will help in guiding. There's almost no truth to the story that you shouldn't use PEC while auto-guiding. Good PEC will improve your guiding, and result in sharper images and rounder stars.

>

> Regards,

>

> -Paul

>

> --- In Losmandy_users@yahoogroups.com, "rclaveyrolas" r.claveyrolas@> wrote:

> >

> > I have a Losmandy G11 with Gemini 1.04.

> > I recently bought the O -Vision kit.

> > I made PE measurements using Pempro on a Meade DSI 2 mounted on a C8.

> > RA PE with Losmandy Worm Gear (Average on 17.5 worm cycles - No PE correction):

> > -.28.7 Arc-Seconds peak to peak.

> > -.RMS : 5.8

> > -.With an awful 76s peak.

> > RA PE with O-Vision Kit (Average on 11 cycles . No PE correction):

> > -.4.4 Arc-Seconds peak to peak.

> > -.RMS: 1.1

> > -.The 76 s peak has quite disappeared.

> > I mounted the kit in the following way:

> > -.Alignment setting at the level of the Oldham coupler. I slightly blocked the corresponding bolt in order to fix the kit on this side.

> > -.Then, I applied firmly the other end of the kit on the 5.626" wheel (no noticeable play at the end of the CW shaft-or, let's, I was unable to make the distinction between a flexure or the Shaft and RA Head and a play due to the teeth of the gears).

> > -.I locked tight both bolts.

> > -.I checked the worm gear was moving freely on 180. at least.

> > Following recent mails of the Group I read on the ball bearings quality, I noted that the NS kit ball bearings were making a kind of noise, or not appeared to turn very smoothly. A friend of mine told me it was normal. He is using a motor with high precision ball bearings turning at 18,000 rpm. Although the ball bearings are making this kind of noise when placing them near the ear and turning the shaft, the whole works perfectly.

> > Pempro PE and frequencies curves are given in the photo album:

> >

> > PE on G11 With and Without the O - Vis O

> >

> >

> > I read on some posts that there are sometimes some problems trying to use an autoguider on a mount with PE correction.

> > I would appreciate if somebody could give me a clear advice on this point.

> > Thanks in advance.

> > Regards.

> >

>



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