<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Here are some pictures of the results of Bernards tests covering one of the aux filters in dome flats. Clearly some light does leak through in this way. With the dome lamps the peak contamination of the flat fields are are <div><br></div><div>u ~ 30%</div><div>v ~ 5% (Stroemgren)</div><div>z ~ 1.2%</div><div>r ~ 0.2%</div><div><br></div><div>They affect at least the two ccds near the aux ccds.</div><div><br></div><div>r106, r107, r107-106: r filter from night 217 (ie FLAT217_0106 etc)</div><div>u01,u02, u02-01: u filter from night 214</div><div>v29,v30,v30-29: v stroemgren from night 216</div><div>z27,z28,z28-27: z from night 216</div><div><br></div><div>Notice also how in a few cases dust specs on the filters came and went: they cause a <0.05% effect.</div><div>Certainly for u this is going to make data reduction even more complex. </div><div>Koen</div><div><br></div><div><img height="690" width="540" apple-width="yes" apple-height="yes" id="4407a34d-07d8-4868-9ad5-e2d8b9d548ea" src="cid:D236EB54-48B3-4555-AB47-3C9FA6C95A70@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="0c98a078-45b9-4a7e-a8c3-97474a99dfb1" src="cid:92A7DAFD-1EA4-45EE-82E2-E3FA20218E4A@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="1d2d9695-6365-47e5-b6b2-3b6ebf28b6df" src="cid:7341A0CD-B642-49F5-9AAF-FEAA6F2A381F@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="5b393fec-b983-44d9-8295-508667a22903" src="cid:19F7D582-406E-4574-AFEA-783857DDFAAB@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="0f03951a-ea73-4230-a2fc-8dd8a0dcfbb9" src="cid:EFDA3F53-4249-4BC5-A2C1-E3FC03637D11@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="033f0ac7-c588-4abd-aca4-25627730f122" src="cid:747F1485-1AA9-4CE4-96EB-4831FD4FB9B2@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="410ac3e3-e2cd-490b-b84f-ccbaa4afea59" src="cid:354E8524-0EA6-4155-8B6F-7B313E3E17DD@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="f28863ad-9fc4-4a08-9e9a-e27ab2885d3d" src="cid:FA0FC88C-FBE5-4172-A4F1-67EB3A53AD2E@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="a4c1c8de-aa11-41c7-b62e-489e51451ecf" src="cid:371625C1-6716-44D0-9855-C498368CD072@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="9ba4fdc1-1377-4fae-a358-09a66afea6df" src="cid:1B11D770-6618-4CC0-9A98-4460A9B29367@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="fe699b59-49f3-42b5-a116-db50c8cee3ea" src="cid:D52F1B9E-06BD-4AA0-9851-043FF05B7CD2@pl.eso.org"><img height="690" width="540" apple-width="yes" apple-height="yes" id="b1b697c2-c344-42cc-bec5-bd948aa54d07" src="cid:E9669102-A1B0-4A9C-AB7F-013705811C24@pl.eso.org"></div></body></html>