Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

LX200 10" OTA mount?

  • Please log in to reply
18 replies to this topic

#1 Scoobs231

Scoobs231

    Lift Off

  • -----
  • topic starter
  • Posts: 9
  • Joined: 09 Apr 2019
  • Loc: UK

Posted 16 April 2019 - 04:15 AM

Hello...  I have just bought a classic Meade LX200 10" OTA.  It weighs 29.8 lbs (13.5 kg).  Probably add a couple of kg for a camera and Crayford focusser and I expect the weight to be about 34.2 lbs (15.5 kg)   Any suggestions for a mount ?  I was looking at the Meade LX85 mount but looks like it has a payload limit of 15 kg.  I'd like to do astrophotography with it.  Thanks.



#2 beanerds

beanerds

    Viking 1

  • -----
  • Posts: 947
  • Joined: 15 Jul 2008
  • Loc: Darwin Australia

Posted 16 April 2019 - 05:59 AM

I would look at at least a G 11 for this beast .

I have a C9.25 on the Celestron equivelent the older CI-700 and its very stable , the Meade 10 inch is a lot heavier but it will be a great scope on the above mentioned mount .

Beanerds .

edit : AP with a 10 inch f10 would be very hard , I would suggest say a 2nd hand ED80 on the G11 until you get experience ,,, lot's of experience . Just use the sweet Meade as a visual scope for now .

Edited by beanerds, 16 April 2019 - 06:02 AM.


#3 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 35444
  • Joined: 30 Apr 2003
  • Loc: NE Ohio

Posted 16 April 2019 - 06:01 AM

It is necessary to consider that more than weight is involved in this decision. At 2500mm focal length, that tube presents greater challenges to an imaging mount than the much shorter focal lengths generally used by casual imagers. The effects of tracking errors will by twice those encountered when imaging at 1250mm (already longer than most casual imagers use) - and four times those at 650mm (a much more commonly used imaging focal length). You'll want a mount that can easily handle the weight plus offer better tracking performance than that provided by most generally available mounts. I agree that something in the G11 class might be suitable.



#4 gotak

gotak

    Surveyor 1

  • -----
  • Posts: 1829
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 16 April 2019 - 06:13 AM

Cem60 would work. A Meade 12" was used with success on a cem60 by a member here at 3000mm.

Edited by gotak, 16 April 2019 - 06:13 AM.

  • beanerds likes this

#5 Scoobs231

Scoobs231

    Lift Off

  • -----
  • topic starter
  • Posts: 9
  • Joined: 09 Apr 2019
  • Loc: UK

Posted 16 April 2019 - 06:15 AM

Thanks for the quick replies!  To clarify it is the f/6.3 version....



#6 gotak

gotak

    Surveyor 1

  • -----
  • Posts: 1829
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 16 April 2019 - 07:40 AM

You mean you are using it with the reducer. I don't think a native f6.3 exists.

#7 Scoobs231

Scoobs231

    Lift Off

  • -----
  • topic starter
  • Posts: 9
  • Joined: 09 Apr 2019
  • Loc: UK

Posted 16 April 2019 - 07:44 AM

It's a native f/6.3... I think Meade stopped making these some time ago, but this is an older model.



#8 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 35444
  • Joined: 30 Apr 2003
  • Loc: NE Ohio

Posted 16 April 2019 - 08:38 AM

Many (perhaps all) of the LX6 models were natively F/6.3 . That helps, but the focal length is still pretty long for an economy mount.



#9 gotak

gotak

    Surveyor 1

  • -----
  • Posts: 1829
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 16 April 2019 - 08:48 AM

It's a native f/6.3... I think Meade stopped making these some time ago, but this is an older model.


Right just looked it up. Interesting beast. And I do prefer SCT format. Too bad they are extinct production wise and optics seems hit and miss.

#10 DuncanM

DuncanM

    Mercury-Atlas

  • -----
  • Posts: 2512
  • Joined: 03 Nov 2009
  • Loc: Arizona Sky Village or the rain forest

Posted 16 April 2019 - 01:19 PM

Hello...  I have just bought a classic Meade LX200 10" OTA.  It weighs 29.8 lbs (13.5 kg).  Probably add a couple of kg for a camera and Crayford focusser and I expect the weight to be about 34.2 lbs (15.5 kg)   Any suggestions for a mount ?  I was looking at the Meade LX85 mount but looks like it has a payload limit of 15 kg.  I'd like to do astrophotography with it.  Thanks.

I have used the Meade 10in SCT successfully, on the:

 

EQ-6

CI-700

EQ6-R

CEM60

CGE-PRO

CEM120

 

I'd say the CEM60 is the sweet spot in terms of weight vs accuracy, while the EQ6-R should be OK, but for the CW bar, which is a bit flimsy. 


Edited by DuncanM, 16 April 2019 - 01:20 PM.


#11 DuncanM

DuncanM

    Mercury-Atlas

  • -----
  • Posts: 2512
  • Joined: 03 Nov 2009
  • Loc: Arizona Sky Village or the rain forest

Posted 16 April 2019 - 01:31 PM

Right just looked it up. Interesting beast. And I do prefer SCT format. Too bad they are extinct production wise and optics seems hit and miss.

I have a Meade LX200 10in F6.3 OTA and it works quite well. Mine has a defect in the corrector plate, that causes a flare on bright stars, but past that it has really excellent optics. I've paired it with the Starizona .75x SCT reducer and I get F4.9 with good illumination of an APSC sized frame:

 

M42FF 23x240s F49
 
 
The above was 23 x 4min subs @ F4.93 (flat fielded) on the CEM60. Reducer spacing is critical and I think I can get a bit better off-axis stars with some trial and error. I have another 10in F6.3 OTA and I intend to swap corrector plates to see if I can fix the flare issue.

Edited by DuncanM, 16 April 2019 - 03:16 PM.


#12 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 02:53 PM

Hello...  I have just bought a classic Meade LX200 10" OTA.  It weighs 29.8 lbs (13.5 kg).  Probably add a couple of kg for a camera and Crayford focusser and I expect the weight to be about 34.2 lbs (15.5 kg)   Any suggestions for a mount ?  I was looking at the Meade LX85 mount but looks like it has a payload limit of 15 kg.  I'd like to do astrophotography with it.  Thanks.

Hi Scoobs231,

 

I have used both GM8 and G11 under my deforked 10" Meade LX200 f/6.3 OTA. The GM8 is great for visual use but even upgraded with Michael Herman's much grippier clutch pad material, upgraded clutch knobs and larger ADM DV saddle the GM8 mount is at its limit with my heavy 30+ pound M10" f/6.3 OTA  with 2.5" Moonlite focuser, Losmandy "D" bottom dovetail and Losmandy "V" top dovetails, Rigel QuickFinder on top and Stellarvue 50mm RACI in the finder bracket.

 

IMO the larger G11 is a much better choice for imaging with the M10" f/6.3 SCT OTA. My 2002 vintage G11 was fully updated to current specs 2 years ago and after adjustment consistently autoguides well under 0.5 arcseconds RMS (0.47-0.34 RMS) using PHD2. I think to carry this heavy OTA well you will need something in the G11 range payload and quality for best results. 

 

Chip  



#13 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 02:58 PM

Many (perhaps all) of the LX6 models were natively F/6.3 . That helps, but the focal length is still pretty long for an economy mount.

But the OP's and my own M10" f/6.3 OTAs were from LX200 classics. In any case at 1,600 mm fl a "better" class of mount class is needed. 

 

Chip



#14 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 03:13 PM

Right just looked it up. Interesting beast. And I do prefer SCT format. Too bad they are extinct production wise and optics seems hit and miss.

 

The later production M10" f/6.3 OTAs used in the LX200 mounts were all very good optically. The rumor that the native f/6.3 optics are poor is an old wives tail. Most of the issues I have seen with many scopes is poor alignment of the glass optics to the mechanicals, tubes baffles front and rear cells. Once corrected virtually any SCT will perform as they should. After modification of the primary mirror mount to allow adjustment of the primary mirror tilt and centering of the secondary body my dumpster saved LX200 M10" f/6.3 SCT is just as good optically (if not cosmetically) as my very good, very pretty, Celestron carbon fiber tubed NexStar-11 GPS OTA. 

 

Chip 



#15 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 03:17 PM

 

I have a Meade LX200 10in F6.3 OTA and it works quite well. Mine has a defect in the corrector plate, that causes a flare on bright stars, but past that it has really excellent optics. I've paired it with the Starizona .75x DCT reducer and I get F4.9 with good illumination of an APSC sized frame:

 

The above was 23 x 4min subs @ F4.93 (flat fielded) on the CEM60. Reducer spacing is critical and I think I can get a bit better off-axis stars with some trial and error. I have another 10in F6.3 OTA and I intend to swap corrector plates to see if I can fix the flare issue.

 

Don't swap the corrector plates unless you have to, they are somewhat sensitive to rotation. Have you tried using a black Sharpie on the corrector defect? It should be unnoticable in the data. 

 

Chip



#16 DuncanM

DuncanM

    Mercury-Atlas

  • -----
  • Posts: 2512
  • Joined: 03 Nov 2009
  • Loc: Arizona Sky Village or the rain forest

Posted 16 April 2019 - 03:42 PM

Don't swap the corrector plates unless you have to, they are somewhat sensitive to rotation. Have you tried using a black Sharpie on the corrector defect? It should be unnoticable in the data. 

 

Chip

I think the secondary mirrors are more sensitive to rotation that the corrector plate, but I'm sure some trial and error will be involved.

 

The corrector plate is not cracked but seems to have a defect in how it was ground as there are no apparent physical defects. I bought the OTA just before I moved and it ended up sitting in the box for several years before I had a chance to test it.



#17 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 04:03 PM

I think the secondary mirrors are more sensitive to rotation that the corrector plate, but I'm sure some trial and error will be involved.

 

The corrector plate is not cracked but seems to have a defect in how it was ground as there are no apparent physical defects. I bought the OTA just before I moved and it ended up sitting in the box for several years before I had a chance to test it.

Duncan,

 

Is the issue a flare across the image that changes direction based on the angle to the bright object or more like a ghost image shaped like the primary mirror? Some people have had a reflection that is caused by the primary not being well centered. The effect is significantly reduced or eliminated when the secondary mirror is well centered. At least that's what I recall reading anyway. 

 

Chip 



#18 DuncanM

DuncanM

    Mercury-Atlas

  • -----
  • Posts: 2512
  • Joined: 03 Nov 2009
  • Loc: Arizona Sky Village or the rain forest

Posted 16 April 2019 - 04:11 PM

Duncan,

 

Is the issue a flare across the image that changes direction based on the angle to the bright object or more like a ghost image shaped like the primary mirror? Some people have had a reflection that is caused by the primary not being well centered. The effect is significantly reduced or eliminated when the secondary mirror is well centered. At least that's what I recall reading anyway. 

 

Chip 

You can see the issue in my image in post 11, above.  The flare acts identically to a single vane spider, but is some type of chromatic error and the flare is always in exactly the same orientation from image to image. I can remove it post processing, but I usually don't bother.



#19 YAOG

YAOG

    Apollo

  • *****
  • Posts: 1050
  • Joined: 12 Oct 2015
  • Loc: SoCal of course!

Posted 16 April 2019 - 04:37 PM

You can see the issue in my image in post 11, above.  The flare acts identically to a single vane spider, but is some type of chromatic error and the flare is always in exactly the same orientation from image to image. I can remove it post processing, but I usually don't bother.

Oh, well that's a puzzler! It almost looks like a fine crack or glass flaw, maybe the corrector swap is a good thing to try. I'm interested in any progress on this topic!

 

Chip




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics