Summary, with embellishments, of tele-conference on Wednesday September 6 (9am MET = 5pm Qld 6pm ACT) Koen and Nigel on +31 50 363 4088 Ken and Gabe on +61 2 6249 0264 Damien Jones on +61 7 5442 8831 Magda on +39 081 5575549 We met to discuss problems with the optics, following acceptance testing. A) RELEVANT DOCUMENTS & MESSAGES: The test report from the CSIRO can be picked up from MISCELLANEOUS DOCUMENTS on the project page. email from Keith (date?) Dear Damien, Could I please ask you to take a look at Lindfield's acceptance test results and get back to me (CCed to the others) with an assessment of the as-built design. Achim tells me that the optics from Gabe look of high quality but that those from INAOE suffer a little from scratches and digs (probably not significantly impacting on scattered light). Most seriously, some of the INAOE surfaces have "stains" which Achim can't identify but which have eaten somewhat into the surfaces and hence cannot be washed off. These will most probably need re-polishing be INAOE to remove the stain. email from John Hart 05 Sep 2000 Hi Nigel, We have been looking at the CSIRO optics report lately and feeling a bit worried. Assuming that these measurements are correct, many of the edge diameters are out of specification, and the lenses will not fit well in the cells. In fact, some lenses are apparently oversize and will not fit at all! I plan to have our people measure the cells as the next step. (note added by Nigel: to my horror I do not see any diameter tolerances stated in the purchase orders!! This seems to me to be a blunder, considering the fact that 240.00 is a the mechanical tolerance for a lens cell designed to hold a 240 mm lens!) email from Achim Leistner 05 Sep 2000 Dear Nigel, I have been supervising the tests and dimensional measurements as well as quality inspections of the surfaces. I have made spot checks on the various problems that were reported. Dimensions such as center thickness, concentricity of surfaces (eg. concentricity of optical center/axis of lens to mechanical center/edge) and radii are clearly shown in tabulated form in the report supplied. Surface quality varied quite a lot. Across the board, all lenses have to a more or lesser degree residual grinding marks (pits). Four lenses have stains of a chemical nature, such as caused by water mainly. These type of stain is usually not removable with any kind of cleaning (we have tried) since they are actually etched in to the surface, the only real cure here is a repolish. How and where these stains occurred is somewhat of a mystery, because there was no evidence of water contact in the wrapping material when they arrived. Mainly because of their nature and appearance I would consider them to be water stains, for the cause to be condensation through thermal cycling in transit I would almost rule out. I must point out that some of the glass has a very low resistance to chemical attack (soft flint glass in particular)and better environmental protection during shipping is certainly advisable and necessary. email from Achim Leistner 06 Sep 2000 Dear Nigel, To your first question. I have really no good feel for what the exact loss or scattering is that is caused by the stains, pits (greyness)and scratches. I would however guess that the range is from the ppm to fraction of percent. I would also guess that say around 80% of defects are probably in the ppm range. I would certainly not recommend to repolish all of the surfaces that have defects, since most of them are within what is to be expected from commercially polished optics, although I have to say there is little excuse in my opinion for not completely polishing a surface. Unless you have extreme requirements, the scatter and light loss you would get from the great majority of the defects would be very small indeed. B) SUMMARY ( * = action item) 1 OPTICS Nigel summarised the situation. Optics were at the NML from mid-June to 18 August. Measurements, supervised by Achim Leistner, include radii, thickness, concentricity (* not clear), and diameter, as well as some sphericity measurements (* why not all? are these measurements useful anyway?). Gabe's impression of the described "digs and scratches" is that it is not too serious (agrees with Achim's comments above) "with exception of one of mine" (* which?). Nigel asked Damien to explain tabulated "Concentricity", he's discussed this with Achim and it's apparently the difference between mechanical axis and overal optical axis of a lens (* check with NML to be sure). Seems to ignore any possible difference between the two surfaces. So is a pure mechanical correction possible? (* at any rate we want to have the lenses edge-marked). A certain Frank (now retired) did the measurements. Gabe asks: is concentricity "total indicated runout". Damien offers to contact NML. Nigel: we'll need to check with John Hart about the difficulty of corrections (* at most 0.3mm) Gabe: quick check on cells indicates that "most of the lenses won't fit" due to lenses being too big or cells not round within spec. Only cells received are FL Coll, CL1, CL3 and first group of the Cam lenses and "all of them have problems". (note added: Coll lens cell 12478 and small lens cell 12554 are indeed still to be sent). Nigel: how do we quantify the probable degredation due to digs and scratches? Damien: only after visual inspection. Recommends sending optics to MSO. Nigel: see also Achim's comments. Damien confirms that if collimator spacer is adjusted (as agreed by John) then no detectable degradation will occur due to radius error (note: refers to CL3, both sides are too flat). Nigel: raised question of diameters. Ken: it's still in the measurement area, so best to put the optics with the cells and see. Nigel: raised question of stains. Repolish here. Gabe: more cost-effective in Mexico as they have the existing tools. No chance of polishing just locally - out of question. Ken: check diameters BEFORE optics go to Mexico. Magda: agrees. Ken reminds us that other jobs are putting pressure on MSO workshop, and extra work would have to be financed. Ken asks about timescale for remainder of cells (* to check). Concensus that we ship all the optics asap to MSO. Nigel: make sure that we have all we need from the NML before we get them to ship optics to MSO. Timescale 1-2 days. (* discuss with Damien to agree on issues to raise with Achim). 2 COATINGS Nigel: asks Gabe to revisit the Phase B quotes including special collimator coating. Gabe (* will check on Rofin and F. Lord Optics). The latter did not quote earlier as their plant was not running. 3 FILTER Magda: Roger Netterfield still to give quote - maybe one more week. Barr quoted $US11700 per filter. The Halpha filters can be smaller (about 140mm) so these quotes will change, especially as this diameter falls in the standard (160mm max) range. Nigel: 3 x $US11700 is about equal to budget ($56000) Magda: (* needs to check on price of smaller order, and whether 5% discount applies for a set of three as opposed to six filters. Notes that the UK rep quoted GBP 33,000 for the same filters. Nigel: asks about the +/- 6 wavelength flatness spec, why does it only apply to central 120mm? Gabe: an estimate from ray tracing Nigel: but this will only be correct for on-axis beam. Suggests we continue with the restricted spec (120mm) on CWL but specify whole surface for the flatness spec. Damien (* will give second opinion). Magda: Netterfields quote will give us a guide to the impact on price Nigel: disagrees, as optical flatness is probably easier to attain than a tight spec on the CWL Nigel: given the fair Barr order, let us not delay too much. Koen: asks about delivery time Magda: ca 3 months. Gabe and Damien thanked for their participation. Continuation with Koen, Magda, Ken and Nigel: 4 WHO IS TO TAKE RESPONSIBILITY FOR THE OPTICS? Ken: does not have any relevant expertise but will undertake to continue the administrative and contact aspects, with help of Gabe and John. 4 WPD30 - INTEGRATION AND TEST? Nigel: asks whether involvement from PN.S team is still feasible now that this takes place in Australia (help setting up star tests, and in evaluation) Ken: the one person at MSO is overcommitted. Will undertake to keep an eye on it himself. Ken: notes that quote for WPD50 is based on everything being right, it will now be "a little more expensive" - we'll know more when the stuff arrives and can be remeasured. 5 FINANCES Nigel: $27000 deficit, when $56000 is earmarked for filters. Magda: still waiting for info on Italian bid for grant Nigel: strongly suggests making a Magda: try Gilmozzi (for the initial grant a proposal was required, * will initiate another one this time). Restatement of situation is the PN.S is approaching integration and testing, that bids are out for filters, but that there is a shortfall to have the PN.S at La Palma for the commissioning of $27000. Nigel (* will check this figure). Magda: let's say we are looking for something like DM 35000 as last time. All agree that this is a positive step. But Nigel thinks that for the timescale in question we should make a project-wide approach for at least "underwriting" i.e. our institutes will pick up the bill for a limited overrun on the proviso that we'll repay it later. General agreement that we should try this but Ken is reluctant (chances slim). Ken points out that just ordering one filter might get us there, Koen echoes that a subsequent request for extra filters might be viewed positively. 6. PENDING COMMISSIONING Nigel: We (NL) have asked for commissioning time as early as Jan 2001, will we make it? Koen: this includes the financial Ken: asks about gratings Nigel: "estimated shipping date" from Richardson is August 18 2000. Ken: is more worried about the state of the optics. Nigel: reiterates concerns about financial situation. Ken: worth approaching the optics manufacturers to finance small mechanical alterations, though it'd be their call. Koen: go as quick as we can with one filter Magda: this might impact quotation which was requested on the basis of a whole set - price of one might be 50% more (* but will check, also whether they would acccept ordering in instalments). There was in the end agreement that we'd at least try to get financial guarantees. Ken: what's immediate plan of action? Nigel: clarity on what NML has done, then send optics to MSO. Get remaining cells to MSO a.s.a.p. Get feedback from John on what to do next and costs. (note added by Nigel: I'll need to rewrite WPD30 a bit). Ken: we'll get Gabe to inspect the (Mexican) surfaces and get his advice.