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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: DaveJ]
#5026559 - 01/19/12 11:02 AM

Dave/Martin, sorry, my mistake; thanks for point it out. I have edited the original post regarding aperture for LX200 14". Sorry again. Regards, Mike

Edited by mmalik (01/19/12 11:08 AM)

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: mmalik]
#5027824 - 01/20/12 12:17 AM

LX800 ACF secondary mirror obstruction is something that has been exhaustively discussed in this and other forums; following are some summary figures (Note: Some of the figures are approximate and are intended for better understanding than mathematical precision; any corrections to calculation errors are welcome though.)

Another request; since we are dealing with numbers, please feel free to point out mistakes ‘without quoting numbers’ so that original post can be edited and doesn’t lead to ambiguity and speculation for follow-up readers. Thanks!

LX800 f/8 ACF Secondary Mirror Obstruction (by diameter=obstruction/diameter*100)
10"............4.05"/10"*100= ~40.5%
12"............4.36"/12"*100= ~36.33%
14"............TBD

LX800 f/8 ACF Secondary Mirror Obstruction (by surface area)
10"............20.95%
12"............16.86%
14"............TBD

Edited by mmalik (01/20/12 12:23 AM)

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Mark Costello
Carpal Tunnel

Reged: 03/08/05

Loc: Matthews, NC, USA
Re: Meade's new LX800... [Re: mmalik]
#5028335 - 01/20/12 10:12 AM

Quote:

LX800 ACF secondary mirror obstruction is something that has been exhaustively discussed in this and other forums; following are some summary figures (Note: Some of the figures are approximate and are intended for better understanding than mathematical precision; any corrections to calculation errors are welcome though.)

Another request; since we are dealing with numbers, please feel free to point out mistakes ‘without quoting numbers’ so that original post can be edited and doesn’t lead to ambiguity and speculation for follow-up readers. Thanks!

LX800 f/8 ACF Secondary Mirror Obstruction (by diameter=obstruction/diameter*100)
10"............4.05"/10"*100= ~40.5%
12"............4.36"/12"*100= ~36.33%
14"............TBD

LX800 f/8 ACF Secondary Mirror Obstruction (by surface area)
10"............20.95%
12"............16.86%
14"............TBD

Hi mmalik, the obstruction percentages by diameter and area don't seem to be equivalent. If the diameters are correct then the fraction of obstruction by area would be (about)

10" diameter fraction = 40.5% -> area fraction = 16.4%
12" diameter fraction = 36.33% -> area fraction = 13.2%

If the area fractions are correct, then the equivalent diameter fractions become

10" area fraction = 20.95% -> diameter fraction = 45.8%
12" area fraction = 16.86% -> diameter fraction = 41.1%

Best regards,

Edited by Mark Costello (01/20/12 10:13 AM)

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Alph
Carpal Tunnel

Reged: 11/23/06

Loc: Melmac
Re: Meade's new LX800... [Re: Mark Costello]
#5028908 - 01/20/12 03:34 PM

Quote:

If the area fractions are correct, then the equivalent diameter fractions become

10" area fraction = 20.95% -> diameter fraction = 45.8%
12" area fraction = 16.86% -> diameter fraction = 41.1%

Good catch. This is so because 16.86% = 0.1686 and sqrt(0.1686) = 0.4106 = 41.06%

The 12" RCX is on my shortlist. The ultimate hi-res astrograph.

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: Alph]
#5029868 - 01/21/12 05:17 AM

Mark/Alf, surface area figures I listed are actual Meade specs; I was trying to calculate diameter based figures according to my understanding (and not directly deriving from surface area figures). I think both approaches, yours and mine, should be ok since method you are using is bit different than mine.

Alph, on a side note, I would suggest going with 14" LX800 instead of 12" RCX. Thanks, Mike

Edited by mmalik (01/21/12 05:19 AM)

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ewave
Pooh-Bah

Reged: 05/16/09

Loc: northwest NJ
Re: Meade's new LX800... [Re: mmalik]
#5030090 - 01/21/12 09:49 AM

Funny, the new 12" OTA has the least obstruction and I remember seeing that from the pics on their site. Perhaps the 12" IS BEST!

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Jared
Post Laureate

Reged: 10/11/05

Loc: Piedmont, California, U.S.
Re: Meade's new LX800... [Re: mmalik]
#5030186 - 01/21/12 10:56 AM

Quote:

Mark/Alf, surface area figures I listed are actual Meade specs; I was trying to calculate diameter based figures according to my understanding (and not directly deriving from surface area figures). I think both approaches, yours and mine, should be ok since method you are using is bit different than mine.

Alph, on a side note, I would suggest going with 14" LX800 instead of 12" RCX. Thanks, Mike

How can both approaches be OK when you got very different results for obstruction as a percentage of diameter? What method were you using? I don't know of a way to calculate obstruction other than the one outlined by Mark and Alph.

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: Jared]
#5038051 - 01/25/12 09:56 PM

Jard, sorry for the late response; as I stated earlier, both approaches are OK. Reason for the disparity is what I stated in my original post, “Some of the figures are approximate and are intended for better understanding than mathematical precision”.

If you need to know exactly why both calculation methods are OK, let me give you EdgeHD example instead since we have actual figures to work with instead of approximates; here is how:

Example:
EdgeHD Aperture = 14”
EdgeHD Secondary Mirror Obstruction = 4.5"
Area of entire aperture = pi*r^2 = 3.14*(14/2) ^2 = 153.86
Area of secondary mirror obstruction = pi*r^2 = 3.14*(4.5/2) ^2 = 15.90
By area = 15.90/153.86 = 0.10 = 10%
By diameter (my method) = 4.5/14 = 0.32 = 32%
By diameter (your method) = sqrt (15.90/153.86) = sqrt (0.10) = 0.32 = 32%

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: mmalik]
#5041983 - 01/28/12 02:32 AM

I have been wondering about the weight of LX800 14" f/8 ACF optical tube; my main concern/question is if it would be feasible at all for one person to mount/un-mount the OTA onto an LX800 mount or would it be absolutely 2 person job? Meade LX200 14" f/10 ACF was fork mounted and weighed quite heavy (110 lbs.); given there are no forks now, would it be reasonable to assume that bare bone OTA (mounting plate only and NO viewfinder or other equipment) weight would be roughly the same as the Celestron’s 14” EdgeHD (which is 45 lbs.)? Plus adding the factor of lower LX800 saddle and assuming properly placed handles on OTA, is it reasonable to presume LX800 14" f/8 ACF could be handled by one person?

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Alph
Carpal Tunnel

Reged: 11/23/06

Loc: Melmac
Re: Meade's new LX800... [Re: mmalik]
#5042593 - 01/28/12 02:05 PM

Quote:

have been wondering about the weight of LX800 14" f/8 ACF optical tube; my main concern/question is if it would be feasible at all for one person to

I would be concerned about it too. I mount the C14 on the CGE few times a week, and I sometimes wish I had a lighter OTA. The M14 is significantly heavier than the C14 and the side-by-side saddle makes it even harder. If you are into pretty picture taking then there is no benefit of going with the 14” The 12” matches most CCDs much, much better.

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: Alph]
#5042973 - 01/28/12 05:23 PM

I am actually interested in both, visual as well as photographic performance of a telescope. I have heard that when it comes to visual observing there is big difference between say 8” or 10” and 14” or 16” apertures.

When it comes to astrophotography, aperture to some extent really doesn’t matter in my opinion. I have seen folks taking stunning pictures with 5” (I mean, five inch apochromatic) aperture as long as one has a decent mount, a decent camera, and takes long exposures. Reason I am thinking about 14” is actually to see stuff yet have the ability to capture the same in decent quality. I think, most ‘common’ apochromatic apertures are around 5” and I consider that to be a decent aperture for astrophotography, and where one doesn’t have to contend with factors like secondary obstruction, etc.

While we are on the subject of APO, my dilemma actually is between LX800 14" f/8 ACF telescope or LX800 130mm ED APO telescope. 5” APO weighs only 25 lbs. and would be great for long exposure astrophotography but it loses visual resolving power to great extent against 14”. I am interested in deep space observing (I don’t like the term deep sky) as well as in astrophotography.

Coming back to my original point, being able to mount 14” OTA by myself is quite important consideration for me if folks can chime in on their experience with non-fork mounted 14” OTAs of similar sort? Real answers about 14” OTA handling by one person or not will become available when folks have a chance to review it.

On a side note, I am also interested in knowing what folks think about LX800 130mm ED APO telescope in terms of both visual and photographic performance; and sorry for another speculative question, thanks to Meade’s delays!

Edited by mmalik (01/28/12 06:20 PM)

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Alph
Carpal Tunnel

Reged: 11/23/06

Loc: Melmac
Re: Meade's new LX800... [Re: mmalik]
#5042996 - 01/28/12 05:36 PM

14" SCT vs 130mm APO? Geez! apples and oranges and confusion.

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: Alph]
#5043025 - 01/28/12 05:53 PM

Sorry, but this is LX800 forum; I consider the APO comparison relevant. Even Meade has 3 ACFs and an APO compared side by side at http://meade.com/lx800/specifications, just click 'Compare Models'.

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Wil2010
super member

Reged: 08/17/10

Loc: Millville, CA
Re: Meade's new LX800... [Re: mmalik]
#5043267 - 01/28/12 08:41 PM

Good Day.

I have a C14 Carbon Fiber mounted on a CGE mount. I dont have a backyard observatory, so I have to mount OTA each time I set up. The OTA weighs in at 43 lbs, which isnt all that bad, however the size of the OTA is bulky like lifting a trash can..akward. Up to this point no real issues..it's just a chore that I get nervous about doing..lol

WiL

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: Wil2010]
#5046286 - 01/30/12 04:32 PM

Thanks Wil for your feedback; reason I keep bringing up handling of a large OTA is that I would like to hear from folks who may have handled a 14" OTA on day to day basis; I don’t have observatory either and if I went large OTA route I’ll be setting it up each time. Currently I am in 5" OTA range but would like to make a leap to 14", instead of gradually incrementing aperture (say 10”, or 12”) when I know deep space is better seen with larger aperture in the end. My goal is to maximize on visual as well as astrophotographic performance in one equipment, which I can setup/mount by myself. Not sure if a 14” OTA is asking for trouble from mounting/dismounting effort perspective?

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sphelps
member

Reged: 07/03/10

Re: Meade's new LX800... [Re: mmalik]
#5047129 - 01/31/12 12:36 AM

With a good scope cover like the one I use from Telegizmos on my 14" RCX400, you won't have to haul your scope in every night. The 14" LX800 will weigh considerably less than the RCX due to not having those heavy forks so I wouldn't worry about the weight so much. I've pre-ordered the 14 LX800 and am looking forward to it's hopefully much easier ease of use, and weight.

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budman1961
Pooh-Bah

Reged: 02/25/11

Loc: Springfield, MO
Re: Meade's new LX800... [Re: sphelps]
#5047177 - 01/31/12 01:30 AM

I had a chat with the folks at OPT.....still no definitive info/ship dates on the LX800 or LX80.

Auto manufacturers ofter do the same thing Meade is (IMHO), show early product, create a boatload of buzz, then bring it out when it is right.

I am intimately familiar with this practice (former european auto dealer). The stuff we had to deal with after the Paris...Detroit...LA auto shows was overwhelming. The press at the shows had to know when.....the folks that saw the pix on the web always thought it was headed to the showroom, when in fact, many show-cars never hit the showroom.

I dont think Meade is doing this. I think, again, in my humble opinion, they have a product that will hit the market soon, they are beta testing it hard, with users that have very strong non-disclosure agreements.

I may be wrong, I have seen companies with a market cap many hundreds of thousands more than Meade, do the same thing, and bring a great product to the market.

Be patient. Flame on if you want....conjecture is a two-sided sword.

Andy

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yweln
member

Reged: 08/05/11

Re: Meade's new LX800... [Re: budman1961]
#5047935 - 01/31/12 01:22 PM

Meade has just posted a pic from the LX800 on their facebook page:

It says from final beta testing. I'm thinking that means shipping is somewhere on the near horizon.

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budman1961
Pooh-Bah

Reged: 02/25/11

Loc: Springfield, MO
Re: Meade's new LX800... [Re: yweln]
#5048181 - 01/31/12 03:16 PM

You beat me to it! What kills me are the FB comments, after clearly staing the picture was taken with the LX-800 mount and 130mm ED APO, with a 6.3 reducer....

Q-Did you take this with a LX800?
A-Yes, with the 130mm ED APO

Q-Curiously, what mount was used?
A-The LX800 mount

The patience of the Meade folks is pretty good!

Andy

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mmalik
Post Laureate

Reged: 01/13/12

Loc: USA
Re: Meade's new LX800... [Re: budman1961]
#5049254 - 02/01/12 05:08 AM

I wonder where LX800 f/8 ACF beta testing stands? Good news though on APO!

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