Telescope operational limits apr10

Last mod: 29apr10



Section links:

Intro
Memos, tables, presentations from Amman & whitney
Min td tensions required vs za
Allowable za range vs temp
Minimum tensions required for various dome, ch configurations.
Summary

Plots

The minimum tiedown tension required vs za (.ps) (.pdf)
Allowable dome za range vs temperature (.ps) (.pdf)
Astronomy observing with the dome: ch sits at stow (.ps) (.pdf):
Astronomy observing with the ch: dome sits at 8.469 degrees (.ps) (.pdf)
Aeronomy observing with the ch: ch sits at za=0 (.ps) (.pdf)
Aeronomy observing with the ch: ch sits at za=15 (.ps) (.pdf)
Aeronomy observing with the ch: dome sits at za=12 (.ps) (.pdf)
Testing: astronomy using the dome with ch tracking dome above 8.83 degrees za (.ps) (.pdf)
Testing: astronomy using the dome with the ch sitting at 19.9 degrees za (.ps) (.pdf)

Other pages:




Intro

 
   A broken beam was found on the telescope 03feb09. A splint was installed and verified on  23mar10 to bring the beam back to its original strength. An analysis using the current weights and operational motion of the telesecope performed by the engineering firm ammann & whitney resulted in new operational limits for the telescope (see email sent 29mar10). The summary of the new limits are:
    An analysis was then done for most of the beams on the platform and azimuth arm using full telescope motion. The beams similar to the one that broke (6 sets of 2) showed stresses above the allowable limit. A few other beams were overstressed (but to a lesser amount). The plan is to reinforce the 6 sets of 2 beams similar to the one that broke so they are no longer overstressed by full telescope motion.
     A further analysis is in progress checking that the cable tension safety factor is within the allowable range.

The sections   contain:
Memos, tables, presentations from Amman & whitney
Min td tensions required vs za
Allowable za range vs temp
Minimum tensions required for various dome, ch configurations.
Summary


Memos, Tables, presentations from Amman & whitney:


Platform reinforcement sep10:

Platform reinforcement jun10:REINFORCEMENT U1-L2-SK-3.pdf

17may10: procedure for re-enforcing broken member (u2-u2l3) (.pdf)
29apr10: A&W presentation from 29apr10 meeting (.pdf)

21may10: A&W non-linear analysis of cables:
27apr10: tensions from A&W modelling for 29apr10 meeting in NY.
29mar10
Ammann & whitney email describing the new limits
Plot of maximum unbalanced moment vs tiedown corner tension (.pdf)
table of member tensions capacity at maximum unbalanced moment (.pdf)


Min tiedown tension vs zenith angle

    To figure out the minimum tiedown tension required vs za:
The plots show the minimum tiedown tension required vs za (.ps) (.pdf):


Allowable dome  za range vs temperature.

    Using the A&W limits of ap10, compute the za range vs temperature for the gregorian dome for the configurations:
To compute the allowable range for each configuration:
    The plots show the allowable dome za range  vs temperature for various ch configurations (.ps) (.pdf)

processing: public_html/talks/vc10/tel_limits3.pro


Min tensions for various dome , ch configurations.


    To figure out the az, za limits i:
The computations were done for 4 configurations of the ch with the dome moving, and 1 config of the dome with the ch moving. All of the computations assume that the platform is in focus:


Summary :


Allowable az, za, temp ranges (*see note below)
mode
dome za
ch za
temp
Time
Astronomy using Dome
3.5 - 12
8.834
< 76F
after 7pm,before 7am
daytime above 85 you should probably move dome to za=8.4
Astronomy using ch
8.469
0-20
< 80F
at 85F ch > 4 degrees
Aeronomy using Ch
8.4-10
0
<76F
daytime probably best to move dome to 8.4 za and az to 60,180, or 300 degrees.

processing: x101/100329/tel_limits.pro


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