-----Original Message----- From: Toshihiko Kimura Sent: Thursday, November 24, 2011 2:11 PM To: Vik Dhillon Subject: Re: Result of examination(ULTRASPEC) Dear Prof.Dhillon, Thank you for the reply. Could you just confirm that your optical designers did their modelling with the filter in that position? Absolutely. That is why he asked me to get the Zemax data from you. I talked with him (=our optical engineer) this morning, and I found he really did. 3)Predicted the thickness of epoxy-glue He also says the thickness of epoxy-glue doesn't have the "repeatability", so this uncertain value is probable to affect the parfocality slightly. However, we must live with this uncertainness. Just to confirm - we want 50mm x 50mm *SQUARE* filters. Yes. I believe the tolerance, +/-0.1mm is acceptable for ULTRASPEC. We made ULTRACAM filters also with +/-0.1mm tolerance. Best regards, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Wednesday, November 23, 2011 11:38 PM To: Toshihiko Kimura Subject: Re: Result of examination(ULTRASPEC) Hi Toshihiko, Thanks for your email. The specifications look very good to me: our filter wheel can accommodate a maximum depth of 5.5mm, so all of the filters will fit with no problem. Just to confirm - we want 50mm x 50mm *SQUARE* filters. [I think I discussed the possibility of circular filters in a previous email - please ignore this]. I attach a drawing showing the layout of our optical design, which shows where the filter will be placed in the beam. The zemax file I sent you had the filter included - it was the 6th optical element in the beam. Could you just confirm that your optical designers did their modelling with the filter in that position? (I am sure they did, but I just want to check with you to be sure). Otherwise, please do go ahead and manufacture these! Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon On 22 November 2011 12:46, Toshihiko Kimura wrote: Dear Prof.Dhillon, Our engineer finished the examination of each physical thickness. He calculated in consideration of the followings: 1)ULTRASPEC optical design 2)Actual physical thickness of ULTRACAM clear filter: 5.43mm 3)Predicted the thickness of epoxy-glue 4)Our best polishing tolerance: 0 ~ 0.05mm 5)We should not adjust the thickness of colored glass of which transmittance is sensitive for the physical thickness. For example, UG, BG or KG... especially UG11. The result was, u': KG3(2mm) + UG11(1mm) + Fused silica(2.05mm) g': GG400(2.05mm) + BG39(1mm) + Fused silica(2mm) r': OG550(4.05mm) + Fused silica(1mm) i': RG695(3.9mm) + Fused silica(1mm) z': RG695(3.05mm) + Fused silica(2mm) Sincerely, Toshihiko -----Original Message----- From: Toshihiko Kimura Sent: Wednesday, November 16, 2011 5:59 PM To: Vik Dhillon Subject: Re: Zemax file Dear Prof.Dhillon, Thank you for the Zemax file. I forwarded the data to our optical engineer. He examined optical thickness of all ULTRACAM filters we made before. He is now very busy. I asked him to calculate each physical thickness by 28 November. Once you've had a chance to come up with your design, please could you tell me the final thicknesses of the filters? Sure, I'll do so. Because we need your final check about the maximum physical thickness for your filter holder. Thanks, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Tuesday, November 15, 2011 8:05 PM To: Toshihiko Kimura Subject: Zemax file Hi Toshihiko, Please find attached the final zemax file of the ULTRASPEC optical design. One thing you'll notice is that the beam the filters are in is very slow - in fact, it is not far from being collimated. Once you've had a chance to come up with your design, please could you tell me the final thicknesses of the filters? Thanks, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon ---------- Forwarded message ---------- From: Tully Peacocke Date: 14 November 2011 15:41 Subject: Re: Zemax file To: Vik Dhillon Hi Vik, Attached are a telescope model and the final fitted version of the ULTRASPEC optics on the telescope. It'll be interesting to see what Spanoptic quote. Regards, Tully. On 14 November 2011 14:47, Vik Dhillon wrote: Hi Tully, Would you mind emailing me the final zemax file? I need to send this to Asahi so that they can design the filters properly (as they adjust them depending on the focal ratio of the beam). Thanks, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon Vik Dhillon 13 Feb to Toshihiko, duncan.brealey Hi Toshihiko, Thanks for letting me know - looking forward to receiving them! Toshihiko Kimura via sheffield.ac.uk 20 Feb to Vik, duncan.brealey Dear Prof.Dhillon, We shipped to Uni. of Sheffield by DHL freight-collect as the PO instructed. DHL tracking number is 999 3895 052. According to DHL web site, the package has already arrived in UK. I will send the actual transmission data later. Best regards, Toshihiko -----Original Message----- From: Toshihiko Kimura Sent: Friday, February 10, 2012 8:50 AM To: Vik Dhillon Cc: duncan.brealey@warwick.ac.uk Subject: SDSS filter set for ULTRASPEC Vik Dhillon 20 Feb to Toshihiko Hi Toshihiko, The filters have just arrived - many thanks! I won't be able to test them on the telescope until the end of this year, so I'll contact you again then to tell you the news. Please could you send me the data files containing the transmission curves? Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon Toshihiko Kimura 22/11/2011 to Vik Dear Prof.Dhillon, Our engineer finished the examination of each physical thickness. He calculated in consideration of the followings: 1)ULTRASPEC optical design 2)Actual physical thickness of ULTRACAM clear filter: 5.43mm 3)Predicted the thickness of epoxy-glue 4)Our best polishing tolerance: 0 ~ 0.05mm 5)We should not adjust the thickness of colored glass of which transmittance is sensitive for the physical thickness. For example, UG, BG or KG... especially UG11. The result was, u': KG3(2mm) + UG11(1mm) + Fused silica(2.05mm) g': GG400(2.05mm) + BG39(1mm) + Fused silica(2mm) r': OG550(4.05mm) + Fused silica(1mm) i': RG695(3.9mm) + Fused silica(1mm) z': RG695(3.05mm) + Fused silica(2mm) Sincerely, Toshihiko -----Original Message----- From: Toshihiko Kimura Sent: Wednesday, November 16, 2011 5:59 PM To: Vik Dhillon Subject: Re: Zemax file Dear Prof.Dhillon, Thank you for the Zemax file. I forwarded the data to our optical engineer. He examined optical thickness of all ULTRACAM filters we made before. He is now very busy. I asked him to calculate each physical thickness by 28 November. Once you've had a chance to come up with your design, please could you tell me the final thicknesses of the filters? Sure, I'll do so. Because we need your final check about the maximum physical thickness for your filter holder. Thanks, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Tuesday, November 15, 2011 8:05 PM To: Toshihiko Kimura Subject: Zemax file Hi Toshihiko, Please find attached the final zemax file of the ULTRASPEC optical design. One thing you'll notice is that the beam the filters are in is very slow - in fact, it is not far from being collimated. Once you've had a chance to come up with your design, please could you tell me the final thicknesses of the filters? Thanks, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon ---------- Forwarded message ---------- From: Tully Peacocke Date: 14 November 2011 15:41 Subject: Re: Zemax file To: Vik Dhillon Hi Vik, Attached are a telescope model and the final fitted version of the ULTRASPEC optics on the telescope. It'll be interesting to see what Spanoptic quote. Regards, Tully. On 14 November 2011 14:47, Vik Dhillon wrote: Hi Tully, Would you mind emailing me the final zemax file? I need to send this to Asahi so that they can design the filters properly (as they adjust them depending on the focal ratio of the beam). Thanks, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Tully Peacocke Experimental Physics NUI Maynooth Mob: +353 (0)87 94 000 66 Office: +353 1 708 3863 Vik Dhillon 23/11/2011 to Tully.Peacocke Hi Tully, I've just received the email below from Asahi about the filters. Based on your Zemax file, they've come up with a final design for the filters. These should be parfocal with each other, and with the other ULTRACAM filters that we've ordered from them in the past. The max depth the filter wheel can accommodate is 5.5mm, apparently, so these look like they should all fit with no problems. They will be 50mm x 50mm, by the way. I'm going to give them the go-ahead to make these, but I just wanted to check with you first in case you can see any problems? Cheers, Vik Dhillon 23/11/2011 to Toshihiko Hi Toshihiko, Thanks for your email. The specifications look very good to me: our filter wheel can accommodate a maximum depth of 5.5mm, so all of the filters will fit with no problem. Just to confirm - we want 50mm x 50mm *SQUARE* filters. [I think I discussed the possibility of circular filters in a previous email - please ignore this]. I attach a drawing showing the layout of our optical design, which shows where the filter will be placed in the beam. The zemax file I sent you had the filter included - it was the 6th optical element in the beam. Could you just confirm that your optical designers did their modelling with the filter in that position? (I am sure they did, but I just want to check with you to be sure). Otherwise, please do go ahead and manufacture these! Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon On 22 November 2011 12:46, Toshihiko Kimura Layout_nominal.jpg 177K View Download Tully Peacocke 23/11/2011 to Vik Hi Vik, All sounds good. Lets just hope that there are no surprises from the Thais. The information that they supplied was not quite complete, but I do not expect any problems. Regards, Tully. Toshihiko Kimura 24/11/2011 to Vik Dear Prof.Dhillon, Thank you for the reply. Could you just confirm that your optical designers did their modelling with the filter in that position? Absolutely. That is why he asked me to get the Zemax data from you. I talked with him (=our optical engineer) this morning, and I found he really did. 3)Predicted the thickness of epoxy-glue He also says the thickness of epoxy-glue doesn't have the "repeatability", so this uncertain value is probable to affect the parfocality slightly. However, we must live with this uncertainness. Just to confirm - we want 50mm x 50mm *SQUARE* filters. Yes. I believe the tolerance, +/-0.1mm is acceptable for ULTRASPEC. We made ULTRACAM filters also with +/-0.1mm tolerance. Best regards, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Wednesday, November 23, 2011 11:38 PM To: Toshihiko Kimura Subject: Re: Result of examination(ULTRASPEC) Vik Dhillon 24/11/2011 to Toshihiko Hi Toshihiko, > Absolutely. > That is why he asked me to get the Zemax data from you. > I talked with him (=our optical engineer) this morning, and I > found he really did. Excellent! > He also says the thickness of epoxy-glue doesn't have the > "repeatability", so this uncertain value is probable to affect > the parfocality slightly. > However, we must live with this uncertainness. Yes, I understand. >> Just to confirm - we want 50mm x 50mm *SQUARE* filters. > > Yes. > I believe the tolerance, +/-0.1mm is acceptable for ULTRASPEC. > We made ULTRACAM filters also with +/-0.1mm tolerance. Yes, that is fine. So, I think we are ready to proceed! Regards, Vik. Dear Prof.Dhillon, Though your first and second contact (i.e. Sloan and clear) were ten years ago, I remember the "history" of ULTRACAM filter. In conclusion, clear filter became the basis of parfocality in ULTRACAM. That is, we should calculate each optimized physical thickness (u'g'r'i'z') in consideration of fused silica 5.4mm +/-0.05mm and optical system of ULTRASPEC. Perhaps you and me now understand what we should proceed correctly, however just in case let me clarify again; 1)SDSS u'g'r'i'z' made in 2001. They were not parfocal each other. 2)Clear filter Fused silica 5.4mm +/-0.05mm was parfocal for each u'g'r'i'z' band. Fused silica 5.4mm +/-0.05mm was not calculated to be optimized for specific band, e.g. g'-band only. Fused silica 5.4mm +/-0.05mm was calculated to be optimized for all band *averagely*. 3)Narrow bandpass filter The physical thickness was all calculated in consideration of fused silica 5.4mm +/-0.05mm. One thing I know is that all of the filters you have made for us (e.g. the narrow band ones) HAVE been par-focal with the original set of SDSS filters that you made for us. It seems to me that it is quite natural in terms of 1), 2) and 3). Again in conclusion, I predict new SDSS filters for ULTRASPEC will be approximate e.g. 5.3x mm ~ 5.4x mm. That is, they are parfocal for fused silica 5.4mm +/-0.05mm and also parfocal for *each other*. *Each other* is the difference from ULTRACAM. I also told him that you would like his zemax file when it is ready so that you can optimise your parfocal calculations. I will be able to send you this in late September/early October. > And could you tell me the maximum acceptable *physical thickness* for ULTRASPEC ? I have asked Tully Peacocke this question - I shall let you know his answer when I get it. We don't rush, please let me know both information. Best regards, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Friday, August 26, 2011 10:05 PM To: Toshihiko Kimura Subject: Re: Filter thickness Hi Toshihiko, OK - I have been thinking some more and I think I can now clarify what we want. - I would like a set of u'g'r'i'z' filters which are par-focal WITH EACH OTHER. - I would also like this set of u'g'r'i'z' filters to be par-focal WITH ALL THE NARROW-BAND AND CLEAR FILTERS you have made for us in the past. Is this clear? Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon On 26 August 2011 14:01, Vik Dhillon wrote: Hi Toshihiko, I have just realised that all of my other emails on this subject are printed out on paper - I no longer have the electronic copies. My apologies. If you do still have your old emails on-line, please look at the email you sent me during November 2002-February 2003. Reading through these emails, it looks like we came to the conclusion that you would make clear filters of thickness 5.4mm for use in all three arms (to save money). One thing I know is that all of the filters you have made for us (e.g. the narrow band ones) HAVE been par-focal with the original set of SDSS filters that you made for us. So if you make these new SDSS filters in exactly the same way, there will be no problems. Have I explained this clearly? Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon Vik Dhillon vik.dhillon@sheffield.ac.uk 05/09/2011 to Toshihiko Hi Toshihiko, Thanks for your email. > Again in conclusion, I predict new SDSS filters for ULTRASPEC > will be approximate e.g. 5.3x mm ~ 5.4x mm. > That is, they are parfocal for fused silica 5.4mm +/-0.05mm and > also parfocal for *each other*. > *Each other* is the difference from ULTRACAM. Yes! I understand you perfectly and I confirm that this is what we want! I think you can now proceed with the filter manufacture. Vik Dhillon vik.dhillon@sheffield.ac.uk 06/09/2011 to Toshihiko Hi Toshihiko, Sorry - I forgot to answer one of your questions: > And could you tell me the maximum acceptable *physical thickness* for ULTRASPEC ? >> I have asked Tully Peacocke this question - I shall let you know his answer when I get it. I have now had a response from Tully - he said that filters of 5.4mm thickness is ok. So I think we are now ready to proceed. Toshihiko Kimura t-kimura@asahi-spectra.co.jp 06/09/2011 to Vik Dear Prof.Dhillon, Now I intended to ask you about it. It's timely response. I have now had a response from Tully - he said that filters of 5.4mm thickness is ok. We can not say the predicted maximum physical thickness *correctly* at this moment in consideration of polishing tolerance or the epoxy- glue thick. If it is difficult to get the information about the correct (not rough) maximum thick for filter wheel, we should calculate the number and show you. Because if the actual number exceeds the thickness the filter holder can accept, you would have the problem. That is why we would like to proceed carefully and know the correct (again, not approximate) maximum thickness you can accept. I also told him that you would like his zemax file when it is ready so that you can optimise your parfocal calculations. I will be able to send you this in late September/early October. Finally, our optical engineer tells me that he can simulate the better physical thickness with actual optical system. (Needless to say, we will refer the Zemax data only to supply the best filter for ULTRASPEC !). However unfortunately, if it is difficult for us to check it, could you tell us the information about f ratio in ULTRASPEC ? Sincerely, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Tuesday, September 06, 2011 5:07 PM To: Toshihiko Kimura Subject: Re: Basis of parfocality Vik Dhillon vik.dhillon@sheffield.ac.uk 09/09/2011 to Toshihiko Hi Toshihiko, I think the maximum filter thickness is going to be set by the filter wheel that we use. At the moment, I'm thinking of using an OPTEC IFW-3 filter wheel. I've emailed the company to ask them the maximum filter thickness that it can accommodate. As soon as I get an answer, I'll let you know. (I'm worried that the maximum thickness might only be 5mm. I'm also thinking it might be better to go for circular filters of diameter 50mm, as we can then fit 9 filters in the IFW-9 filter wheel. If we use square filters of size 50mm, we can only fit 6 in! I shall confirm all of these points with you once I have heard back from OPTEC). Our optical designer is still finalising the optics for ULTRASPEC. At the moment, it looks like the filters will go in a near-collimated beam. As soon as I have the final design, I'll forward you the Zemax file. Regards, Vik. Vik Dhillon phone: +44 114 222 4528 Dept of Physics & Astronomy fax: +44 114 222 3555 University of Sheffield email: vik.dhillon@sheffield.ac.uk Sheffield S3 7RH, UK web: www.shef.ac.uk/physics/people/vdhillon On 6 September 2011 09:52, Toshihiko Kimura Toshihiko Kimura t-kimura@asahi-spectra.co.jp 09/09/2011 to Vik Dear Prof.Dhillon, Thanks for keeping me of the update. Actually, our optical engineer has many experience to examine parfocal filters for observatories. So we don't rush the information. I suppose it will not take much time for him to calculate the optimized thickness. I'm worried that the maximum thickness might only be 5mm. If it is so, we should change the recipe. For example r filter, I think we have a option as below: AR*OG550(4.xx mm)*Interference film Thanks, Toshihiko -----Original Message----- From: Vik Dhillon Sent: Friday, September 09, 2011 6:21 PM