User talk:DrBob

Welcome back DrBob! I haven't seen you in Recent Changes for a while (although you may just be contributing at times I don't). --mav

Welcome to Wikipedia, Dr.Bob!

I see that you are making interesting additions, specially in electronics and optics related articles. -- AstroNomer---- Yes, welcome, Dr. Bob! Thanks for your good work here. --User:Larry Sanger

Thank you for the warm welcome, guys. -- DrBob

Talk

Bob, I'm with you on Prime Lens ≠ Fixed Focal Length lens. There is no way to logically defend limiting the description of a Prime Lens to an FFL lens. Don Williams 23:25, 15 February 2006 (UTC)[reply]

Hey, great to have you on board! Could you please check over color and refractive index? I wrote those but I'm not an expert, I just asked around on usenet. Thanks --AxelBoldt

They look OK to me, I may make some minor revisions to clarify a few points --- DrBob

Bob, I'm with you on Prime Lens ≠ Fixed Focal Length lens. There is no way to logically defend limiting the description of a Prime Lens to an FFL lens. Don Williams 23:25, 15 February 2006 (UTC)[reply]

Hey, great to have you on board! Could you please check over color and refractive index? I wrote those but I'm not an expert, I just asked around on usenet. Thanks --AxelBoldt

They look OK to me, I may make some minor revisions to clarify a few points --- DrBob

Hi, I did most of electromagnetic spectroscopy. Do you know why continuous spectrum arise? (I left a note where it needs to be explained). thanks - User:sodium

Hi, User:sodium recommended that I came to your with a question I have concerning cis/trans isomerism. Am I right is assuming that cis/trans isomerism is dependant on the atomic mass of the functional groups? For example, in the case of 1,2 dichloro ethene, would the fact that it exhibited geometric isomerism be dependant on the isotopes of the two chlorine atoms being equal? Thanks! User:Ddroar - Thanks for your answer, sounds logical to me, just something that bothered me, really.

Hi! I just saw the diagrams image:Holography-record.png and image:Holography-reconstruct.png that you uploaded. They look great! I'd love to be able to use them on the French and Esperanto sections of the wiki; would it be any trouble to upload versions without the text so they can be cleanly relabelled? --Brion VIBBER

Also, I like the fact that you've uploaded the "source" files for the illustrations as well, but it would be better if they were in some standard format like EPS or PDF instead of the Adobe-specific AI.

FWIW, these AI files seem to actually be PDF. Ghostscript can handle them. --Brion

It looked like some kind of PostScript, but GIMP and GV choked on the one I tried. I'll try running GS manually. --LDC

Hmm, Gimp does seem to choke. I can open media:Quadrilateral.ai with GSview with no problem, though. (Using Ghostscript 7.04) --Brion

Thanks for helping the flesh-out process for fluorine Dr Bob. I've been neglecting that entry of late. --mav --- Hi DrBob I'am interrested in writing an article about photographic lenses but I don't know how to insert it. Can you rework your disanbigation to make space for it ? It seems you also have contributed to Rainbow. I believe the photo is a fake. What's your POV ?

Thanks.

User:Ericd

I've added some comments of the rainbow in User talk:Ericd

Hi, Dr. Bob; very pleased to run across you.

On Talk:Diode bridge, in the second of the second-level bullet points, i criticized the diagrams of Diode bridge, but my graphics skill is about nil. I'm betting, based on your background, that you can read a simple circuit diagram and that you can infer what i would draw if i had your skills. Of course you may have your own ideas about what should be done once you see it. I'd be please if you even took a look. --Jerzy (t) 04:42, 2004 Mar 5 (UTC)

That's beautiful; besides the layout, i like your "graphic font" (if you'll permit that coinage) better. I didn't look at any of your work before requesting, but it's obvious now that you have a sense of what visual communication is about.

I think you will have already concluded that i prefer to defer to your judgement abt the color vs. monochrome issue and of course what exact monochrome symbology would work. That's now more the case than ever!

It's obvious to me how to substitute yours for the old ones, but do you also do page layouts? (I edited Alessandro Volta's text around some fancier layout of graphics than what Diode bridge has, and got a sense that either i was over my head even in that, or that fancier layout in HTML is inherantly a risky proposition as window sizes and shapes change.) If you wanted to edit the page layout of Diode bridge as it stands, it looks to me as if the sizes are close enuf that my substituting your graphics and editing the text to correspond to them, in the same edit, would work well. (Tho of course it's not "my" article, and your taking over from where i last stopped would be fine -- and odds-on an improvement as long as it's not a waste of your skills.) --Jerzy (t) 19:27, 2004 Mar 5 (UTC)

Thanks so much! Besides the straightforward virtues they exhibit, you were insightful enough to use grey in the color diagrams. Merely brilliant!

It's only bcz i am so sure it's such a trivial further suggestion that i note the inconsistency of omitting "conductor junction" dots at the capacitor's connection points.

I don't write that much about circuitry, but when i do, you should expect to hear from me again. And i'll trust in your willingness to be "he who first cries 'Hold, enough!'" when appropriate. --Jerzy (t) 21:46, 2004 Mar 6 (UTC)

Non-sensical Sellmeir coefficients

First, the BK7 demonstration of the Sellmeier equation is a nice illustration of its primary use. However, the primary advantage of using the Sellmeier equation over other equations such as a simple power series expansion is its physical significance. For glasses, the first two terms are typically assigned to oscillators in the UV with the third in the IR. In your notation, the Ci coefficients represent the oscillator wavelengths. You assign C2 a negative value of -1.18225x10-2 which is nonsense. This is probably the result of not constraining the values of Ci to physically meaningful values greater than zero during the non-linear regression or it could be the regression converged on a local minima instead of the absolute minima of the fit.

You're right, negative C_2 doesn't make a lot of sense, does it? I've no idea where I looked up the original coefficients, but I've changed them to the values for BK7 from the Schott catalogue. Graphing those gives a near-identical curve, so you're probably correct about how the originals were found. -- DrBob

I think the evolution of the Faraday effect page is a very strong example of the power of collaborative development. In particular, I am really glad that you contributed the diagram. I may be wrong, but could you double check the direction of rotation shown for beta, because I think it might be reversed. AJim 18:43, 12 Mar 2004 (UTC)

Answered at User talk:AJim.

Thanks. and my reply is there. AJim 14:56, 13 Mar 2004 (UTC)

No problem. :) I might get to more of them later. - Hephaestos|§ 21:47, 15 Mar 2004 (UTC)

Hi again,

I was just admiring your picture collection, going through the list you added. Seeing them all in one place, I am even more impressed. I love those colors.

I think there may be a small error in the Sellmeier equation diagram, the x axis is labelled nm but I think it may be micro meters.

AJim 04:21, 18 Mar 2004 (UTC)

Hi DrBob,

I bet you could make a really neat schematic of a Czerny-Turner monochromator. I saw one in Photonics Spectra July 2003 p21 I don't believe. The world could use a good one. AJim 04:15, 22 Mar 2004 (UTC)

I was right! Thank you very much. AJim 01:39, 24 Mar 2004 (UTC)

--- DrBob - I am the Guilty One who changed lens to lens (optics). There is now a certain amount of discussion at Talk:Lens (optics). Awaiting yor input! -- Hugh2414 09:32, 8 Mar 2004 (UTC)

"Well, well, well...What have we here?..." - I nearly died laughing. Thank you! fabiform | talk 19:10, 1 Apr 2004 (UTC)

Hi DrBob, re the Pine and Scots pine articles, the old name 'fir' was mentioned before all this blew up (in the Scottish form Scots fir, rather than with the English spelling 'scotch', which causes offence to many in Scotland, being percieved as a English invader's imposition). True that use of 'fir' specifically for pines did take a long time to die out, but it has now, and pine has been the majority use for at least the 250 years I cited (it may have been long before then, but I don't have data; the OED cites e.g. Turner's 1562 Herball as using pine). I would agree that a reference to 'Fir' or 'Scots fir' as a historical usage does have a place in the article. - MPF 00:32, 7 Apr 2004 (UTC)

I noticed your addition of the chemical structure diagram to Mirtazapine. It's great. Thanks! Defenestration 04:33, 7 Apr 2004 (UTC)

So what do you use to make these diagrams, anyway? - Omegatron 20:05, Apr 8, 2004 (UTC)

Hi again, Doc. I thought of you almost immediately on reading Vesicle pisces and then Vesica piscis (oh, and now Ichthys, and hmm, Darwin fish). And not just because the "almond shape" is more precisely the cross-section of a double-convex lens of optics. Not a project that requires your skills, nor one of great weight, but by the same token, probably not one that would take much of your time. So i thought it might be worth letting you be aware of the graphic deficit. Thanks again. --Jerzy (t) 15:43, 2004 May 11 (UTC)

thanks for editing the Magnifying glass article, I tried a few times to get the second photo alignment right with no results. - wolfenSilva

Very nice figures! You seem very talented in this area. Latitudinarian 01:38, 22 May 2004 (UTC)[reply]

diagrams

Yes, It would be great if you added some new diagrams (and old diagrams from wikipedia) to Wikibooks. Take a look at the wikibooks:Physics Study Guide. Optics could use some nice light ray diagrams. Latitudinarian 15:58, 22 May 2004 (UTC)[reply]

Hello DrBob, I am gearing up to fix up the ice page to include a phase diagram, and fill in pages for all of the various ice phases. I could use some help making figures for the various crystal structures as well as the phase diagrams. I have admired your many and beautiful figures, so a) could you help make figures for ice or perferably b) could you show me your magical techniques?! Do you use open source software to create these figures? I've heard rumors about latex packages for crystalography, but I don't do crystalography, so I don't know. Is it pstricks for us open source users? --dikaiopolis

math-ising

Thanks - I presume you are thinking of photon? I was only repeating what I had seen someone else do in lighter than air since I thought it looked better and was more consistent. Inline maths usually seems to get rendered as html anyway, but I see the error of my ways and will revert to ''-ing. -- ALoan (Talk) 16:14, 8 Jun 2004 (UTC)

Hey - where did that go? -- ALoan (Talk) 16:19, 8 Jun 2004 (UTC)

Gain-switching

Hi DrBob, thanks for your additions to Gain-switching. I'd appreciate your having a look at Laser diode rate equations too. Whilst these equations are correct, I recall that the equations can be presented in many different ways. I've been out of it for a while so the equations may not be ideal ;)

ChanningWalton

Periscopes & binoculars

Thanks for all the diagrams you've done. If you're still offerring to do diagrams, the periscope article could use an optics diagram. Also, thanks for the binoculars diagram. As a minor suggestion can you make the porro prisms in the binoculars diagram more like the diagram in the porro prism article? They currently look more like lenses. Thanks! Samw 16:42, 4 Jul 2004 (UTC)

Kudos! and, of course, requests.

I noticed your illustration on pentaprism. Nice work! I was thinking that there was no way someone had gone to the trouble of illustrating that, but there it was---not just an illustration, but a really nice one to boot. Thanks!

I've been working on some of the photography articles. Since you're knowledgeable about optics, I was wondering it you could have a look at wide-angle lens, prime lens, normal lens, zoom lens and telephoto lens. I don't know if they could all benefit from illustrations, but I think zoom lens definitely could. I don't actually know how these things work internally, however, so I can't be of much help.

Any change of a diagram for view camera or rangefinder camera while I'm at it? (If you can only do one, the first would be preferable.) If you want some non-free diagrams to work off of (I've found a few around the web), just ask and I'll provide. grendel|khan 03:30, 2004 Sep 13 (UTC)

redlinks

Oh my! That will teach me to meddle in articles I'm unfamiliar with. I apologize for putting you to the trouble of fixing my mistakes. Joyous 01:01, Oct 20, 2004 (UTC)

A Bridge Too Far?

DD, S Story: i never write, never call, until i want something. Diode bridge again; the addition of the three-phase material to the end of Diode bridge included Image:New tridge rectifier.jpg, whose style is quite different from your fine one on that page. In my phant'sies of graphic competance, i imagine a diagram that is slightly pictorial (while remaining schematic) in that it would use the same layout as the photo Image:Tridge rectifier.jpg -- tho i would also rejoice to see some clever or obvious adaptation (extra input & diodes) of a cross (AC labels but no capacitor, since no hint of one in photo) between Image:Diodebridge1.png and Image:Diodebridge4.png.

In a closely related matter, Three-phase electric power (which i haven't bothered to link Diode bridge to yet, bcz of its, uh, non-encyclopedic style), needs a diagram with either one three-color graph of sine curves staggered by 120 degrees, or a stack of three single-curve graphs. (I don't know if there's a convention for whether the "next" phase mentioned lags or leads the previously mentioned one, so if it were me, i'd probably label them α, β, & γ rather than either "AC1", "AC2", "AC3", or A, B, C, to be as noncommittal as practicable. [Strikes own forehead in a stunning blow] If i'm so smart, how come i ain't thot of this earlier? Label the curves Rd, Gn, Bl (or whatever colors you choose). Afterthot: OK, i just read the 2nd 'graph of Three-phase electric power. [shrug])

TIA, again.
--Jerzy (t) 19:26, 2004 Nov 4 (UTC)

Thanks so much!

Getting your support vote on my RFA really meant a lot, especially since you had to clean up a big glob of my errors. Happy editing! Joyous 00:07, Nov 16, 2004 (UTC)

Image copywrite

Hi! Thanks for uploading Image:Orthorhombic-body-centered.png. I notice it currently doesn't have an image copyright tag. Could you add one to let us know its copyright status? (You can use {{gfdl}} if you release it under the GFDL, or {{fairuse}} if you claim fair use, etc.) If you don't know what any of this means, just let me know where you got the images and I'll tag them for you. Thanks so much, Edwinstearns 16:16, 9 Dec 2004 (UTC)

Article Licensing

Hi, I've started a drive to get users to multi-license all of their contributions that they've made to either (1) all U.S. state, county, and city articles or (2) all articles, using the Creative Commons Attribution-Share Alike (CC-by-sa) v1.0 and v2.0 Licenses or into the public domain if they prefer. The CC-by-sa license is a true free documentation license that is similar to Wikipedia's license, the GFDL, but it allows other projects, such as WikiTravel, to use our articles. Since you are among the top 2000 Wikipedians by edits, I was wondering if you would be willing to multi-license all of your contributions or at minimum those on the geographic articles. Over 90% of people asked have agreed. For More Information:

Multi-Licensing FAQ - Lots of questions answered
Multi-Licensing Guide
Free the Rambot Articles Project

To allow us to track those users who muli-license their contributions, many users copy and paste the "{{DualLicenseWithCC-BySA-Dual}}" template into their user page, but there are other options at Template messages/User namespace. The following examples could also copied and pasted into your user page:

Option 1

I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions, with the exception of my user pages, as described below:

OR

Option 2

I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions to any [[U.S. state]], county, or city article as described below:

Or if you wanted to place your work into the public domain, you could replace "{{DualLicenseWithCC-BySA-Dual}}" with "{{MultiLicensePD}}". If you only prefer using the GFDL, I would like to know that too. Please let me know what you think at my talk page. It's important to know either way so no one keeps asking. -- Ram-Man (comment| talk)

Acetone | your user-page

Minor edit to your user-page, please check to see that I'm not mangling your intent.

Please check the figure on Acetone, and I'd like more information on the tidbit you mentioned in the Acetone talk page added to the article (if you can find it).

-- ~ender 2005-02-12 12:17:MST

Organic Molecule Image

Hello! It was pointed out on the talk page for IUPAC nomenclature that a name in the text 4-(1-methylpropyl)octane, which also had an illustration created by you, was incorrect. I examined the situation and came to the same conclusion. The molecule should instead be named 3-methyl-4-propyloctane. The image is linked below so you can see which one I mean:

I've commented it out of the IUPAC nomenclature page for now, and I made a slight tweak to the text beneath the image so that it would be correct (the incorrect name was replaced with 4-(1-methylethyl)octane, which doesn't have a substituent of length equal to the "end" of the molecule as shown). Please feel free to triple-check my changes if you wish (although I have absolute certainty they're correct), and could you make another version of the image so we have the correct version shown? Thanks! --Waldo

Holography

Hi, I want to add some text about digitial holography. Do you have an editable version of your holography diagrams? Basically I want to replace the object with an lcd display.

Be nice to show both a reflective LCD (so diagram looks pretty much exactly the same) and a transmitive LCD(the light goes through it instead, then hits a mirror or plate)

I did have the original Adobe Illustrator files as image:Holograph-record.ai and image:Holography-reconstruct.ai, but they've been deleted, probably due to changes in WP file policy since I uploaded them. If you want them, email me (see my user page).--Bob Mellish 17:06, 17 October 2005 (UTC)[reply]

Question

Say... you wouldn't happen to be the same person who does Star Trek: Rennaissance, would you? Erre 02:07, 9 Mar 2005 (UTC)

Picture move

Though you do not seem very active anymore I just thought I'd tell you I have moved your Pulteney Bridge image to a new location Image:Pulteney Bridge, daytime, from weir.jpg. I have updated your /Figures link. --Oldak Quill 09:27, 1 Apr 2005 (UTC)

Category:UK Wikipedians

Hi, just to let you know that the list of UK participants at the UK notice board was getting rather long, so I have replaced it with the above category which I have added to your user page. -- Francs2000 | Talk 30 June 2005 19:18 (UTC)

Lens groups and elements

I see you're into optics so I hope you can answer my question. :)

I'm trying to find an article about lens construction terms: groups and elements. I've looked through a number of articles and can't find anything about them.

Got any ideas? Cburnett July 1, 2005 07:22 (UTC)

Photographie

Thanks for the link ! I had seen yet your gallery where there are lots of interesting drawings !

I'm now writing a big Wikibook about photography.

Sorry for my bad english !

Jean-Jacques MILAN from the french Wikipédia and Wikibooks.

Bezier curve image

Could you please reupload so the control points are labeled as P₀, P₁, P₂, P₃, instead of A, B, C, D'. The article can then generalize much more successfully, and reads more elegantly. Thanks Dysprosia 11:24, 10 September 2005 (UTC)[reply]

Thanks, that's great :) Dysprosia 07:16, 11 September 2005 (UTC)[reply]

Copying drawings to the Dutch Wiki without mentioning the author

Apparently in the Dutch Wikipedia it is a growing habit to copy drawings without mention any meta information or the name of the author.
Though I protested, because is is not according GFDL they are not taking any action. One of the most active user in copying is:
http://nl.wikipedia.org/wiki/Gebruiker:MADe
I just give one example:

Your picture: http://wiki.riteme.site/wiki/Image:Binocular-optics.png
"His picture":http://nl.wikipedia.org/wiki/Afbeelding:Verrekijker-onderdelen.png

The only information he added: onderdelen verrekijker, wiki en; GNU fdl; zelf vertaald So I is saying that he is the translater. But I know two translations of the three words are not used in the Netherlands.

The picture he uploaded last months:

http://nl.wikipedia.org/w/index.php?title=Speciaal:Contributions&target=MADe&limit=500&namespace=6

I protested but with no result of the user nor the Dutch Wiki. http://nl.wikipedia.org/wiki/Gebruiker:Ed_Stevenhagen Ed Stevenhagen 17:20, 10 September 2005 (UTC)[reply]

Dear DrBob,

While looking whether you have answered my question below (see #Anti-reflective coating), I happened to come across the above discussion. May I draw your attention to the fact that the mere existence of so many language versions of Wikipedia is based on the fact that not everybody in the world speaks English? So in order for drawings to be usable(!) in other languages as well, use of full words in the drawings should be avoided. Better is using letters and/or figures, and providing a key in the "comment" field. By way of example, see my images Transverse magnification.png or Lens apertures.png in WM Commons (I don't make correct links here, to avoid the images unnecessarily consuming space here). This way, anybody who uses the image, can provide a caption in his own language, based on the info in the comments field.

--HHahn (Talk) 14:14, 10 January 2010 (UTC)[reply]

Bot

Thanks for the warning of the bot, i will revert the changes and look forward. Thanks --KnightRider 19:48, 15 September 2005 (UTC)[reply]

Potato chips and such

The most common brand for salt and vinegar chips is Lay's but this flavor may be a regional thing. Also, prawn or more commonly shrimp cocktail is usually found under the Sau-Sea brand (Sau-Sea Foods Inc.). Cheers, --hydnjo talk 19:57, 20 September 2005 (UTC)[reply]

You might want to take a look at TasteUK.com -- lots of Walkers and Tayto flavo(u)rs available. LarryMac 17:44, 21 September 2005 (UTC)[reply]

Black watch image

Image:Sinclairblackwatch.jpg was obtained from [1], I was unsure of the Copyright status, Sorry. Seems like you were right, it is a scan from a magazine (the full scan of the mag advert is also at that link) — Wackymacs 18:28, 30 September 2005 (UTC)[reply]

Thanks for clarifying on which licensing to use on the image, I have changed it to use the promotional one. — Wackymacs 18:37, 30 September 2005 (UTC)[reply]

Admin?

Hi DrBob, I'm a big fan of your work here. Can I nominate you for adminship? --Duk 17:08, 30 October 2005 (UTC)[reply]

OK, good! Indicate your acceptance here and let me know, then I'll add it to WP:RFA. --Duk 03:16, 31 October 2005 (UTC)[reply]

Congratulations, you are now an administrator. If you haven't done already, now is the time to read Wikipedia:Administrators' how-to guide and the Wikipedia:Administrators' reading list. All the best, Warofdreams talk 18:11, 7 November 2005 (UTC)[reply]

Congratulations! --Duk 18:14, 7 November 2005 (UTC)[reply]

Congrats on adminship Dlyons493 Talk 00:32, 9 November 2005 (UTC)[reply]

User pages

Is there any particualr reason you are leaving messages on A. Maddy's user page, rather than a talk page? It seems a bit odd. JPD (talk) 16:16, 31 October 2005 (UTC)[reply]

Papers

Hey there! I was able to obtain a copy of it just today, so I guess it won't be necessary for you to make that trip to the library. I really appreciated the thought. Have a great day! :-) --HappyCamper 01:13, 11 November 2005 (UTC)[reply]

DYK

Did you know? has been updated. A fact from the article Schmidt-Pechan prism, which you recently created, has been featured in that section on the Main Page. If you know of another interesting fact from a recently created article, then please suggest it on the "Did you know?" talk page.

1037C articles

Hi, you might be interested in Wikipedia:Centralized discussion/Federal Standard 1037C clean up and its associated talk page, if you aren't already aware of them.--Srleffler 05:08, 30 November 2005 (UTC)[reply]

Franchise spammer

For the heck of it I decided I would let the franchise spammer get all the way to "Z" before I blocked him. Maybe if I let him expend all his energy in vain he wouldn't come back... :) - Tεx τ urε 17:19, 7 December 2005 (UTC)[reply]

I guess that would have been pretty funny, but you can't expect people like that to act at all rationally anyway. Quick related question: I know there's a URL blacklist built into the MediaWiki software. Do you know if this is admin-accessible so that I can add this "thefranchisemall" URL to it? --Bob Mellish 17:34, 7 December 2005 (UTC)[reply]

If you find out please let me know the answer. Sorry I couldn't help. - Tεx τ urε 17:36, 7 December 2005 (UTC)[reply]

Aspheres

Re: aspheric lens: Can't aspheric surfaces be used to correct aberrations other than spherical aberration?--Srleffler 19:34, 9 December 2005 (UTC)[reply]

The Wolf Effect

I noticed that you had contributed to the Wikipedia article on the Wolf effect. There is no doubt that the term "redshift" has a specific meaning in astronomy, but I've also seen the term used extensively with regard to the Wolf Effect.

One of the other editors has decided to remove the term "redshift", claiming that the Wolf effect does not produce a redshift, and that to suggest that it does is merely a Point of View. You can see our dialogue on the Wolf Effect discussion page.

This issue has got quite out of hand, as the same editor refused to just mention the Wolf Effect in the article on Redshift, for exactly the same reason. Consequently for this, and other reasons, I have started a Request for Arbitration:

If you can make a statement confirming that "redshift" is indeed used when discussing the Wolf Effect, it might help the arbitration committee make up their minds. --Iantresman 23:01, 19 December 2005 (UTC)[reply]

Photoelasticity

Hi DrBob,

I saw your edits on the Photoelasticity article. They were great. I belive that u have great interest in the subject. I had started the article and I feel that it definitely requires some diagrams and pictures. If you have any of fair use images of the experimental setup or diagrams to explain the concept, please upload them. Gaurav1146 18:23, 22 December 2005 (UTC)[reply]

Image:Binocular-optics.png

Hi I've re-drawn your Image:Binocular-optics.png and uploaded as Image:Binocularp.svg. Would you mind if I nominate your original diagram for deletion since it's redundant? Thanks. --antilived ^{T | C} 04:27, 25 February 2006 (UTC)[reply]

Caustics

Hi DrBob. Do you know anything about optical caustics? I tried to clean up the article, but it could really use a going-over by someone more familiar with this term. --Srleffler 02:57, 3 March 2006 (UTC)[reply]

Focal length

Yes, I got those definitions from Greivenkamp, and now that I look I see that, indeed, Hecht defines ffl and bfl the way you said. I'll try to adjust the focal length article to better reflect both usages. One difficulty: I notice that Hecht (2nd edition) shows, in figures 6.4-6.6, the distance from the principal planes to the focal points as f. If Greivenkamp is correct, this should be true only if the optical system is in air. In general, the distance between corresponding focal and principal planes is nf, where n is the index of refraction of the medium in front of or behind the optical system, as appropriate. I'm not sure whether it would be better to try to deal with this in the article, or just specialize the article to the case of an optical system in air. --Srleffler 23:56, 7 March 2006 (UTC)[reply]

Gaussian Beam

If it is not too much trouble, would it be possible for you to upload a revised version of your "Gaussianbeam.png" image with a very minor change? The revision would be to change the lowercase "w" symbols to uppercase "W" to match recent changes to the article. IMO, uppercase is the way to go because lowercase "w" is too similar to the Greek letter omega (ω), which is commonly used to represent angular frequency. Thanks. -- Metacomet 01:49, 16 March 2006 (UTC)[reply]

But see talk:Gaussian beam first. There has been some disagreement over which notation is best, and your input would be appreciated. I'm not sure how best to achieve consensus on this (admittedly minor) issue.--Srleffler 02:07, 16 March 2006 (UTC)[reply]

Science fiction genres

I see you have an interest in treating the topic of SF genre theory. I recommend you head right over to Science fiction genres and related topics and introduce the topic there, because there isn't one. [[[User:Simonapro|Simonapro]] 21:12, 26 April 2006 (UTC)]

General Beer Lambert Law

I'd appreciate the help of someone with more expertise than I (which wouldn't be hard) at Talk:General Beer Lambert Law. Andrewa 15:56, 28 April 2006 (UTC)[reply]

General Beer Lambert Law/AfD

I’ve nominated the General Beer Lambert Law article for deletion. This is a notification in case you wish to comment or vote on the issue, because you commented on the article’s talk page. —xyzzy_n 23:17, 2 May 2006 (UTC)[reply]

antireflective coating

Thanks -- sorry I didn't notice the original (hyphenated) article. zowie 17:47, 13 June 2006 (UTC)[reply]

Marked Pentaprism diagram for deletion

Just wanted to give you a heads up that I marked your Pentaprism for deletion when I added a SVG version. I wasn't exactly sure what license to give it since I copied your diagram exactly with a few alterations. Didn't exactly feel like I could say it was self-made.--Bobarino 05:41, 27 July 2006 (UTC)[reply]

Fresnel equations

It looks like your revert on the fresnel equations page (of aug 17 2006) was in error, at least according to other sites such as World of Physics:

http://scienceworld.wolfram.com/physics/FresnelEquations.html

Maybe undo your revert?

The two formulations are identical (try plotting them). --Bob Mellish 19:55, 24 August 2006 (UTC)[reply]

Image:Cone-response.png

Ist it possible to upload it as SVG file? It would be great (smaller file size and better printing quality). Additionally the SVG file could be uploaded directly to Commons. :-) --89.55.240.162 17:52, 14 September 2006 (UTC) (de:Benutzer:RokerHRO)[reply]

Image:Lens5.svg

Hi,

I wants to re-use your image for french wikipedia and other language. Do you think it possible to delete the text "spherical aberration" and to put it on commons, maybe with the name "lens-spherical-aberration.svg"

--Leridant 12:43, 3 October 2006 (UTC)[reply]

Total re-write of the main Physics page is in progess

You might like to join us at Physics/wip where a total re-write of the main Physics page is in progess. At present we're discussing the lead paragraphs for the new version, and how Physics should be defined. I've posted here because you are on the Physics Project participant list. --MichaelMaggs 08:04, 11 October 2006 (UTC)[reply]

Image:Dxm-struct.png listed for deletion

An image or media file that you uploaded or altered, Image:Dxm-struct.png, has been listed at Wikipedia:Images and media for deletion. Please look there to see why this is (you may have to search for the title of the image to find its entry), if you are interested in its not being deleted. Thank you. Nv8200p talk 04:39, 30 October 2006 (UTC)[reply]

wonderful drawings

I admire the wonderful drawings that you do.

I tried to do (far simpler) drawings in SVG with software "Inkscape" but it cannot even draw colored arrows.

Would you please tell me the software you use for SVG drawings?

Thanks. LPFR 10:36, 31 October 2006 (UTC)[reply]

Graphics Lab

I saw your name listed on Wikiproject Illustration or the list of graphic artists, and I thought I'd let you know that a Graphics Lab has been created on EN. Based on the highly successful French and German graphics labs, it seeks to better organise and coordinate our graphic design and photo-editing efforts. Up until now, there has been no common space on EN where users could ask for maps, charts and other SVG files to be created. What's more, the Graphics Lab has discussion boards, tips, tools and links; in sum, a good common workspace. Come help us out! The infrastucture is already in place, and now we need participants. :) --Zantastik talk 00:36, 12 December 2006 (UTC)[reply]

Hello

Since you are obviously an expert in the field of optics would you be so kind as to review the accuracy of the description I provided for the image Image:Hafnium lump thin film effects.jpg to see if I totally screwed it up or if its ok?--Deglr6328 04:20, 24 December 2006 (UTC)[reply]

Beer-Lambert Law

Dear DrBob: I had checked the history of the article back to the first of this year, and the word was spelled "traveling," which is US English.

The edit of 15 June 2007 by 147.156.97.214 made a single change, viz US English spelling of this one word to British English. Other words which have differences between British and US spelling adopt the US spelling, e.g., "normalize." Per WP:ENGVAR, the US English spelling is preferred for this article. (See "Retaining the existing variety".)

If you truly feel that its so vitally important that all of a sudden this one word be in British English, I shall yield, but it is contrary to Wikipedia policy. Lovibond 15:54, 26 June 2007 (UTC)[reply]

Thank you for your amplification on this issue. I stand corrected; I only went back to the first of this year. We were both trying to uphold the same policy; I just got the "existing variety" incorrect. Sorry! Lovibond 23:07, 28 June 2007 (UTC)[reply]

Curved mirror

This article needs some love, stop by some time. I am making new images, but it needs a physicist's eye. Cheers--Cronholm¹⁴⁴ 14:15, 2 July 2007 (UTC)[reply]

Cone Absorbance Spectra

Hi Dr. Bob,

 You posted a graph showing the 3 human cone absorbance spectra.  I'm trying to track down the raw data needed to generate this graph for a video project I'm involved in.  Is there any way you could send me the 'x,y' data for the cones, or direct me where I should look?  Thanks in advance for your reply.

--Ulight 06:42, 26 July 2007 (UTC)[reply]

Cardinal-points-2.svg‎

Hello Dr. Bob
You've got some nice images!
Would it be possible for you to load them up on Wikipedia commons? So I could them use in the german Wikipedia.
Thanks a lot in advance
Marc

Single-slit diffraction pattern

Hi DrBob,

Please let me know if it is possible to use your Single-slit diffraction pattern image on the Physics educational CD for A level students in the UK.

Thank you in advance, Anastasia anastasia.ireland@iop.org

Image:Quadrilateral.ai listed for deletion

An image or media file that you uploaded or altered, Image:Quadrilateral.ai, has been listed at Wikipedia:Images and media for deletion. Please see the discussion to see why this is (you may have to search for the title of the image to find its entry), if you are interested in it not being deleted. Thank you. Papa November 19:09, 10 August 2007 (UTC)[reply]

Uploaded Optical-cavity1.png to wikicommons

Hello Dr Bob, I uploaded Optical-cavity1.png to wikicommons because there was a broken link at b:Quantum Mechanics/Waves and Modes. Maybe, you could look if it is OK. Arjen Dijksman 20:00, 19 September 2007 (UTC)[reply]

Image of a Fabry-Pérot interferometer

Hi DrBob, I really like your schematic image of an etalon, however I feel it is missing something significant. By my understanding, the reason why you don't get equal amounts of light emitting from either side of the cavity (in fact you get almost no back reflection) is because the initial reflection off the front face (not included in the diagram) is π out of phase with all subsequent components emitting from the front face. Reflection off a medium with higher refractive index leads to a π phase shift (see Reflection_(physics)#Reflections). If, as is generally the case, the etalon has a higher refractive index than the surrounding medium, the initial reflection includes a π phase shift. In the case that the etalon has a lower refractive index than the surrounding medium, the initial reflection does not include a phase shift, however all reflections off the back face do.

I'd be interested to know your thoughts on this, and if you conclude that you agree then it would be great if you could retouch the image to include the initial reflection, maybe with a label to indicate the phase difference.--DJIndica 00:59, 7 November 2007 (UTC)[reply]

BLEVE

You wrote, "In the event that a gas cylinder is venting, BLEVE's can be avoided by cooling the cylinder invloved with water or foam, taking care not to extinguish the flame, until the cylinder is empty, or the leak is plugged." But this scenario is not a BLEVE. Do you mean the tank should be cooled if the tank is being exposed to an external fire, reducing the chance of a BLEVE, and not putting out a gas vent flame will mitigate the chance for a vapor cloud explosion outside the tank? Thanks in advance for your reply. 06:50, 8 November 2007 (UTC)

Thanks for the re-direct. Fireproeng 22:35, 9 November 2007 (UTC)[reply]

Lens Pictures