September 2007: Integration of VEGA on CHARA

• Extensive visit of the Mt Wilson treasures conducted by Steve (thanks a lot for this great time, especially on the bridge....).
• Accurate preparation of the observing program for the night as well as modifications in the communication and tracking process.
• Unfortunately the seeing is very poor and we can only conducted tests of pupils and images on W1,W2,E1,S1.
• This is the end of a very great run. Thanks a lot to CHARA and congratulations to all the participants. Rendez-vous next time on the mountain!

• During extensive software tests on the automatic control, we discover problems on the background of the detectors. The configuration files have been corrupted. Great care has to be taken in the dark process to be sure of the correct operation of the detector.
• We prepare the night which appears to be very good.
• First fringes 'night'
  
  We spent almost all the night on Gamma Cas for checking different configurations of the spectrograph and of the real-time processing for fringe tracking.
  
  - Images and pupils recorded on W1, W2, S2 and E2 and the beginning of the night. S2 looks very faint, E2 almost ok. Images on E2 and S2 look good, pupils too.
  - Fringes are found at -3 mm (on W2) wrt the CHARA Classic offset obtained at the beginning of the night. We should say that it occurs after many strange things (bad star, bad delay, 4 beams in the spectrograph....).
  - Record data at different time (from HA=-0.5 to HA=+1.5h) with different gratings.
  - Record data with the SPIN device (polarimeter): fringes on one polarisation for the fringe tracking ar emuch easier to detect than on natural light....
  - Try on BK Cam (HD20336, mV=4.7, B2.5Vne): fringes detected at medium spectral resolution with the largest slit. Data recorded.
  - stop at 4:15am
  
  Notes:
  We have a lot to do on software control and a lot to learn about CHARA.
  It was also really great to see how stable CHARA is: stars, delays.
  We have to check the data tomorrow of course but it's really a great night after all this work!
  
  Chris+Antoine
  Aurelie, Jean -Michel, Yves and Denis

• Metrology measurements inside the lab through the optical paths of VEGA to measure the internal OPD errors of VEGA. The results are in perfect agreement with the theory within an uncertainty of +-5mm.
• Beginning of the cover building.
• Software aspects (central control, tracking)
• The forecast for tonight are not good, unfortunately.
  

• VEGA report
  lot of clouds at the beginning of the night.
  
  deneb (HD 197345)  W2 POP4 on beam1, W1 POP1 on beam 2
  W1 needs to be restarted (pb with the Dome)
  W2: not possible to align M10 (look as X and Y are in the same direction...)
  Record of pupils and stars images: W2 pupil not good (M10 pb), W2 image pretty good. W1 pupil nice, W1 image is double!
  Alignment seems very good. Images are centered on our reference position, pupils are a little bit translated. We decide to not move the M2-M6 mirrors
  We record photon data on the red detector: Neutral Density=1, more than 3000 photons! It's really great and much more than what we had in the past on GI2T....Good news.
  tip/tilt=5ms
  
  gam Cas (HD 5394) same configuration
  tip/tilt=2ms
  Record of images and pupils (see attached images W1-Im, W1-Pup, W2-Im, W2-Pup) and the movie with W2 on the left and W1 on the right). W2 pupil was not correctly aligned.
  Nice Halpha emission line on red detector: more than 3500 photons again!
  Stop for a while (alignment in the lab + restart of GW)
  Record of pupils and images. Try to center images and pupils with M2 and M6: works perfectly. News records. With M2 we can center the pupil whereas with M6 it's easy to center the image on the reference positions of VEGA.
  On red detector: gamma Cas (R=2.3) around Halpha with density=1.5 gives about 1600photons (600 on W2, 900 on W1, 100 of thermal noise)
  Start the scan but new crash of GW
  New scan from 0 to +10mm and then from +0.5 to -10mm by step of 250µm on the delay line with the medium resolution.
  Start a new scan with the high spectral resolution (without density 2000 photons per frame on gamma Cas) from -20mm by step of 1mm on the delay line but it appears that we have lost the reference signal from a while...(no fringes on classic also).
  Humidity has greatly increased and condensation appears.
  Close....at 4h50am.
  
  Nils, Antoine,
  Aurélie, Yves, Jean-Michel and Denis

• The four beams of VEGA have been co-aligned with CHARA and with the use of corner cubes our beams have been seen in the tip/tilt sensor of CHARA. The alignement is ready.
• Laszlo has helped us for solving the repeatability problem of the periscope.
  
• New tests have been done concerning the recording of the data from the  image and pupil sensors.
  
• Yves made the drawings for the protection cover of the interface table.
  
• Preparation of the first night.
  

• BCP#3 and #4 are aligned. All BCPs have been installed on the interface table and aligned with the periscopes. It was not possible for us to terminate the fine alignement with CHARA tonight due to the preparation of observations. Anyway we were really very tired! Have a look to the nice pictures of the 4 BCPs: really great job made by Nice+Atlanta+MW...
  
• Some modifications have been done in the electronic cabinets for integrating the ICCD rack as well as the new protected power that is just arrived today.

• BCP#2 is aligned and installed on the interface table. For BCP #3 and #4, fine adjustements of the M4 supports have been done today in order to have a correct position for this reference mirror. Thanks to Bob that gives us time in the lab, we have been able to prepare everything for #3 and #4.
• All the spectral calibrations are done. We have also finely adjust the reference positions for the pupils and images on the ICCD for a correct coalignement between CHARA and the interface table and between the interface table and the spectrograph.
  
• The software is now almost ready for the observations.
• It's a long way but we are almost ready for the sky!
  
• Sorry for the pictures but they will come back tomorrow!
  

• BCP #2 is now ready for optical alignment. BCP #3 and #4 have been mechanically verified and are almost ready also. We have not been able to complete the optical alignment of BCP #2 due to important work in the optical lab, especially with the metrology system and the MIRC alignment (observations in progress).
• The spectral calibration of the two cameras are made for the low and medium resolution. The calibration of the highest (R=30000) resolution is more difficult and we are almost done with it for the red camera.
  
• Some difficulties appear for the time synchronization of the different VEGA machines. Jean-Michel is working on that point before the observations. The automatic control has been tested in version 2 and some work are necessary to stabilize all the softwares.
• We decided to not wait for the MIRC stars tonight so that we can start early tomorrow morning in the lab for BCP#2 and others if possible.

• BCP #1 is now correctly aligned after the modifications made by Laszlo and Yves. It has been installed on the interface table and thanks to the M6+M2 motions (thanks to Nils/Theo and Jean-Michel)+the adjustment screws on the M1 (thanks Laszlo), the beam 1 of VEGA is now correctly aligned with the CHARA targets, both in position and direction! It's a first step but really a great progress after these hard working days!
• On the spectrograph side, the fine focusing of the detectors (shape of the photon-events) is done. Aurelie has made the accurate calibration of the slit's positions. We are also ready for the spectral calibration. At least a few spectral lines have been visually identified and the full process can now start.
• We also recorded internal dispersed fringes, with the pointlike source on the interface table. The fringes were recorded with the realtime processing of the red (see the spectral density) and blue (see the spectral density) detectors.
  
• More in-depth tests of the software V2 have been done and a certain number of problems have been solved by Jean-Michel.
• Today's conclusion: Yeah, we will break for the week-end....

• Software control for the VEGA-M6s mirrors (BCF) is ready. We have also used the software control of the VEGA-M2s mirrors and it works successfully.
• We succeeded to make the optical integration of the first BCP and the results are very good, both in internal alignement and in image quality. The mechanic is very nice and the adjustment's motions are very smooth.
  
• We have installed the first BCP at its theoretical location on the interface table but we discover first an error of about 20mm on the lateral position (with respect to the periscope) but hopefully there is enough place for moving the BCPs in the direction of the CAU.
  
• The main problem we have had is that, although the BCP is correctly aligned internally, its optical axis has a large vertical tilt (10') with respect to the base plate. In fact in the alignement procedure, the reference of direction is the M4 mirror but we found a small problem with one of the piece supporting the M4, with a tilt of about 10' (1/10 of mm over 40mm). As all the BCP is aligned on this axis it explains why we obtain this large tilt. Laszlo will fix that tomorrow. In spite of this we decided to continue the co-alignement with CHARA by tilting the beam from M6 to the BCP and we finally succeeded to go through the periscope and to align the beam up to the CHARA targets after the switchyard. With the different DoF on periscope and on M6 the alignement is very easy. Of course this is not the final alignement because, due to this tilt we are clearly non centered on the M3 and M5 mirrors of the BCP.
  
• Today's conclusion: we are progressing more slowly but we are now in the phase where the new things appear and where we should find the solutions! Anyway we are optimistic and impatient to go on the sky! Also, it's really nice to see John Monnier preparing MIRC for the next run and ready to coherence our visible beams!
  

• The spectrograph is fully aligned: the polarimeter has been installed and tested. The cover is now installed. We recorded new distorsions grids and spectral calibrations files for determining correctly the distorsion and rotation of the detectors. The data processing is in operation.
  
• The VEGA-M6 mirrors (BCF) have been successfully aligned. Finally, Jean-Michel succeeded to communicate with the new controllers for the M6 picomotors.
• The first and second BCP have been mechanically integrated. We have started the optical alignment of the first BCP: the mechanic works correctly and the alignement is almost done. We should do it again tomorrow because we have skipped one step near the end of the procedure...
• The VEGA software Version1 has been successfully tested and Version2 is now installed and tested. This second version corresponds to developments made after the shipment of the materials and not tested in Grasse.
• Weather is changing at MtWilson with a lof of fog and temperature going down!

• All computers are installed and operational. The different softwares have been tested, excepted for the central control.
  
• The spectrograph is fully aligned excepted for the polarimetric device. Distorsion grids have been recorded and first fringes from the white light source have been recorded. The data reduction processing will be started rapidly. The internal calibrations of the spectrograph have to be done now and especially the calibration of the dispersion.
  
• Concerning the cooling of the detectors, we are not able to reach -30°C for the red detector. In permanent regime we reach -20°C for the red and the nominal value of -15°C for the blue. The problem is that the chiller is not able to stabilize at +5°C (its current value with the two VEGA detectors reach +17°C). The red detector at -20°C has a thermal noise of about 30 photons per exposure (20ms) which is too high (compared to 1 or 2 photons at -30°C).
  
• The BCF (M6s) are ready for alignment. The software control for the M6 will be inspired from the one written for MIRC.
  
• Concerning the BCP, Laszlo and Yves have continued the adaptations. One BCP should be ready tomorrow morning.
  
• The periscopic optics (M1 and M2) are now connected and the software control will be adapted from existing routines from CHARA.
• As a conclusion, we should be ready tomorrow to start the coalignement of VEGA and CHARA.
  

• The first phase of the spectrograph alignement is finish. It means that all the mirrors (except for those of the blue camera) are at their location and orientation. The second phase consists in installing the cylindrical mirrors and then to check the image quality on the detector.
  
• The alignment between the spectrograph and the interface table is done: the laser going backward from the detector, through the spectrograph, to the interface table is co-aligned with the laser coming from the CAU to the spectrograph. It looks better than what we obtained in Grasse! Ok it's the third or fouth time that Aurélie does this alignement...
• Finally the slit viewer has been installed and fringes from the laser diode installed on the interface table are seen at the entrance image plane of the spectrograph (the entrance image plane is located on the slit of the spectrograph.)
• Thanks to Judit and Jean-Michel, the water is now circulating correctly in both VEGA detectors and in the CHARA CCD. We will check tomorrow for the cooling. The detector's electronic racks have been modified by Laszlo and we have now a switch on the front panel, which is really much better.
  
• Yves and Laszlo have finished the modifications for mounting the picomotors on the M6.
• A great news also: the parts for the third and fourth BCP have arrived from Atlanta: Thanks to Charles!
• Our computers are progressively coming onto the net, thanks to complicate operations by Jean-Michel and Nils.
• Steve, the early bird, at our surprise already had machined the parts we needed for the day and had put them on our breakfast table!
  
• Last but not least, we had a great experience this morning with an excellent american breakfast prepared by Yves that succeeded to make the smoke detector go off!!! Sorry for that...
  

• Alignment of the interface table subsystems (CAU, CSM, IPM, IPS). The ICCD are working well: the four images and four pupils (of the CAU) are in place. We do not see any big electric or electronic noise on the video signals. The remaining work on this table concerns the integration of BCF (M6) and BCP (beam compressors).
  
• The spectrograph table has been accurately positionned with respect to the beams coming from the CAU. All the subsystems of the spectrograph are now ready to be aligned.
• The detectors have been tested successfully. The high voltages work correctly and photons are seen on the cameras (after some inversions of cables...). The red detector can not reach the -30°C temperature: it looks like the water circulation is not sufficient and to hot. As yesterday, only one detector at the same time could be cooled. Let's see tomorrow.
  
• A large part of the pinning of the BCP pieces is done. Some problems occur with the Belleville washers and the change of M8 to M10. New washers have to be ordered.
• The integration of the picomotors on the M6 mounts is not possible: the diameters are not coherent. Some modifications are foreseen.
  

• The spectrograph table is now installed at its location and its new height. Thanks Steve for the additional 1 inch plates and all the clamps!
• The cooling system of the detectors has been tested. At that time it looks like we have enough water for one detector. More on this issue on Monday. Both detectors are working well and the Detector Control Softwares have been started successfully..
  
• All the subsystems of the interface table are now ready to be aligned.
  
• The ICS (Instrument Control Software) is in operation.
• The preparation of the BCP integration (pinning process) is in progress.

• All the boxes have been unpacked and the reassembling of VEGA has started.
• All the cables have been installed and the electronic cabinets are almost ready.
• Aurélie has prepared the alignement of the spectrograph table with respect to the interface table.

June and July 2007

1) Tests (software, optic, electronic) with all components in manual and automatic mode.

2) Some pictures during packaging:

Moving the spectro optical table

Moving the spectro chassis

4) Some boxes pictures:

Detectors, Spares parts, Tools boxes

 Paperboard pallets containing the electronic, computers and optics/mechanics