Work Items and their results done at Kottamia Observatory during Nov. 14- Nov.25 by Takeshi Noguchi, Hisashi Koyano, and Toshiyuki Sasaki 1. adjusted Axial Support system (ASS) of the mirror to get good image quality of Kottamia 188cm telescope. Current image quality has been measured as 0.7 arcsec of Hartmann constant using Hartmann test images taken on June 21, 2009. This Hartmann constant is not goood compared to initial data of 0.12 arcsec presented by Carl-Zeiss. 1.1 measured Heights of ASS (Initial height measured on Nov.15, 2009) Treatment plans shown below is adopted according to compare to an average height, 3.588 mm, of ASP#2 to #6. ------------------------------------------------------- Outer ASP Treatment Plan ------------------------------------------------------- #1 3.455 mm to be added a sheet spacer of 0.1mm #2 3.555 mm #3 3.519 mm #4 3.565 mm #5 3.664 mm #6 3.638 mm #7 2.834 mm to be added a sheet spacer of 0.8mm #8 2.535 mm to be added a sheet spacer of 1.0mm #9 2.718 mm to be added a sheet spacer of 0.8mm ------------------------------------------------------- Inner ASP Treatment Plan ------------------------------------------------------- #10 3.390 mm to be added a sheet spacer of 0.3mm #11 3.670 mm #12 3.733 mm to be enlarged limiter by 1mm #13 3.734 mm to be enlarged limiter by 1mm #14 4.084 mm to be enlarged limiter by 4mm #15 3.686 mm ------------------------------------------------------- Axial Fixation Treatment Plan ------------------------------------------------------- AFP#1 2.853 mm should be changed to be 3.6 mm AFP#2 3.335 mm should be changed to be 3.6 mm AFP#3 3.980 mm should be changed to be 3.6 mm ------------------------------------------------------- 1.2 enlarged the limiter hole using a bit machine for ASS points (ASP) #12, #13, and #14 by 1mm, 1mm, and 4mm respectively, shown above (Nov 16). 1.3 inserted thin plastic sheet(s) between an ASP pad and pad's base for ASP#1, #7, #8, #9, and #10 by 0.18mm, 0.75mm, 1.0mm, 0.93mm, and 0.18mm, respectively. (Note) In order to equalize their heights of ASS pads, we adopted the average values of 3.588 mm out of ASP#2 to #6, as we may not have enough sheets for all ASS pads to rise up to 4.1 mm of the highest ASP#14. We adjusted the heights of Axial Fixation Point(AFP) equal to 3.6mm. Other ASPs (ASs Points) should be adjusted to nearly the same height by adding some plastic sheets between ASP pads and ASP pad's base. We used two sets of plastic sheets; transparent sheets of 0.18mm thick, and colored sheets of 0.25mm thick. The final height after inseting the sheets or enlarging the limiters on Nov. 17, 2009 ----------------------------------------------------------- InitialHeight Treatment (thickness added) FinalHeight (Nov.15) (Nov.17) ----------------------------------------------------------- Outer ASP #1 3.455 mm added Tx1 (thickness of 0.18mm) -> 3.79 mm #2 3.555 mm + -> 3.51 mm + #3 3.519 mm | -> 3.55 mm | average #4 3.565 mm |=> 3.588mm -> 3.52 mm | <== 3.558 mm #5 3.664 mm | -> 3.63 mm | #6 3.638 mm + -> 3.58 mm + #7 2.834 mm added Cx3 (0.75mm) -> 3.88 mm #8 2.535 mm added Cx4 (1.0mm ) -> 3.56 mm #9 2.718 mm added Tx1 + Cx3 (0.93mm) -> 3.71 mm Inner ASP #10 3.390 mm added Tx1 (0.18mm) -> 3.68 mm #11 3.670 mm -> 3.65 mm #12 3.733 mm enlarged limiter by 1mm -> 3.85 mm #13 3.734 mm enlarged limiter by 1mm -> 3.86 mm #14 4.084 mm enlarged limiter by 4mm -> 4.19 mm #15 3.686 mm -> 3.69 mm AFP#1 2.853 mm -> 3.58 mm AFP#2 3.335 mm -> 3.58 mm AFP#3 3.980 mm -> 3.62 mm ----------------------------------------------------------- Final heights show nearly the same values instead of specially high ASP#12, #13, and #14. But some high values are shown for ASP#1, #7, which should be recovered by replacing their sheets adopted this time to new sheets of exact thickness requested in next treatment, planned in 2010. 1.4 measured current weights of all the Axial Support System (ASS) with a precise weight/force-measuring tool. Compared to the previous document( Parameters_Kottmia74_2002.pdf) describing that weights for ASP#2, #7, #8 and #9 are a little bit heavier, more unbalanced weights are shown in figure. Counter Weights must be 90 kg according to nominal mirror weight of 1620 kg devided by 18 ASS points. ------------------------------------------------------- Outer ASP #1 103.47 kg, (re-measued after round =>) 102.69 kg #2 102.75 kg #3 99.16 kg #4 99.95 kg #5 100.9 kg #6 101.49 kg #7 108.56 kg #8 102.41 kg #9 106.95 kg Inner ASP #10 101.21 kg #11 100.67 kg #12 99.95 kg #13 97.16 kg #14 98.96 kg #15 99.16 kg ------------------------------------------------------- In total of 15 ASP weights is 1522.75 kg of 925.64 kg of Outer ASPs and 597.11 kg of Inner ASPs. So it may looks only 100 kg is supplied by three AFPs, which would be not good. These weights should be equalized all to 90 kg according to nominal M1 weight. 1.5 checked the Radial Supports which look work well. 2. checked Newtonian mirror support to be tighted stiffly to the telescope base, as we recoginized image shift between objects in northern sky and in souther sky when we observe several objects using Newtonian focus during the last stay at Kottamia. We have disassembled/assembled the Newtonian Cell. We checked and found no gap between Newtonian mirror and its cell, as last time we guess one of possible causes of image shift due to its gap. Stiffness of Newtonian mirror has been confirmed by no positional shifts of COMA free region between northern sky and souther sky by observing astronomical objects with Newtonian focus on Nov 23. 3. investigated where Dome Flat screen is implemented inside the dome. A lower part of the upper movable slit looks suitable with a distance from tube top to the screen of 1.85m. We are now contacting commercial companies to deal the SORIC screen in Japan. 4. checked Aluminizing proces of the mirror at Kottamia. We discussed the methods and timing to make a pre-wet process of Aluminum onto the filament which are used in an aluminizing chamber. Detailed schedule is discussed for next aluminizing at Kottamia. 5. measured length for hose from the dome floor to M1 about 7-8m for mirror cleaning tools with CO2(carbon dioxide) snow ( Nov.18). We are now searching for commercial companies to deal the CO2 snow implements. 6. Noguchi and Koyana looked around Laboratory at Kottamia to find good tools avilable there (Nov 23). 7. Koyana attached new cramps for M2 covers of Newtonian and Cassegrain. 8. Koyana made a wooden support in order to disassemble/assemble the newtonian mirror from/to its cell. 9. checked strange noise from declination-driving motor (Noguchi) 10. Noguchu measured sizes and positions for Cassegrain buffle. 11. Sasaki prepared and attached Marks saying "Don't Move AFP" back of M1 cell around three AFP. 12 Sasaki discussed with Ali for shielding plate for opposite side of the telescope tube to Newtonian focus position for protection of Newtonian imaging against stray lights. 13. Noguchi checked universality of joints for LN2 cylinder used at Kottamia; possibly universal. 14. We conducted Hartmann test after adjustments of M1 ASS and moving Newtonian focus to eastern portion of the telescope from southern. 15. We discussed on several topics with Dr. Hamed on Nov. 24. 15.1 Dr. Hamed wanted to solve optical problems on Kottamia 188cm telescope, especially possible astigmatism. He'd like to invite us to visit Kottamia again in Feb, 2010. We must negotiate our visit for these jobs. 15.2 Dr. Hamed prefered Coma corrector for Newtonian focus than focal reducer at Cassegrain focus. Then we will concentlate how to design and make Coma corrector for Newtonian focus in Japan. He expressed that he prefers to complete the Coma corrector in a year. Noguchi will prepare comparison table between Newtonian Coma corrector and Cassegrain focal reducer, which shall be opened on Web page. Sasaki discuss with Prof. Ohtani about Cassegrain focal reducer at Kottamia. 15.3 We should ask to Prof. Yoshida's correspondence of Spectrograph installation at Cassegrain. 15.4 We should make a work plan and schedule for installing Dome flat, CO2 snow, pre-wet aluminizing filaments, and M1 ASS thin plate. Then we negotiate with Prof. Sekiguchi about this plan and its funds. --- Over ---