Beiträge von Steve_mt

  • Stated magnification versus real magnification

    Would be nice if someone can test the same procedure and calibrate the measurements with oil and without oil for the x100 objective and see if there are same results. Because if one measures spores under oil immersion and applies a 1:1 scale, there might be some 15% error in the measurements!!!! --- or is it just me here with this anomaly ?!?!

  • Stated magnification versus real magnification

    this morning tried the calibration without oil and I got 96-97 units for 100um (everything same setup but no oil on stage). The focusing and sharpness was quite good actually! That makes 100/97 = 1:1.04 which is a good match.


    Replies:

    I second Peters opinion that the problem is the measuring scale in the eye piece. >> Same eyepiece reticule for all objectives (which gives expected values)


    You should have the same unusual multiplication factors also in the other magnifications, means 1:4,25 with the 40x objective (instead of 1:2,5) and 1:17 with the 10x objective (instead of 1:10) - correct? >>> For the other 'air' objectivesI get a close value to the expected magnification.


    Your eyepieces are 10x?

    Yes E-Pl 10

    Or you can buy a "real microscope" from Olympus right away.:saint:

    You need real money too!

  • ​ Diderma sp. (hemisphaericum?) on leaves of Juglans and other deciduous trees

    hilmgridd , dont worry about the English, what's important is that we communicate .... (although I couldn't get the joke about the egg lol!). I attach two more photos of this Diderma species from a previous collection which was more typical (well-developed stipe) for you to admire. Yes it is a lovely slime mold looking like tiny satellite radar discs.

    Agreed eith LG Ulla, the species is not specific to Juglans (I found it earlier on carob leaves and Rubus ulmifolius decaying stalks) but I think it requires a lot of humidity and likely a thick layer of leaf detritus.

  • Stated magnification versus real magnification

    Thanks - but have I posted in the microscopy section already? I start thinking what happens without oil immersion ...and also if users here calibrate the magnification (for measuring) compensated for oil immersion! ! !

  • Stated magnification versus real magnification

    Hi there,


    I don't really believe that the lens delivers such a clear change in the image scale.

    - Was it really readable 1: 1 before?

    No, always 1:1.17 (oil mount)


    - Is the measuring eyepiece the same as before?

    Eyepiece original of microscope (Zeiss Axioscop 20) but reticule different.


    - Is the measuring scale in the eyepiece the same? (There are so many different scales)

    yes


    - Has the graticule slipped in the measuring eyepiece?

    No


    - Is the microscope micrometer inserted the right way round?

    \yes, if not the numbers of the micrometer will be inverted and I would know


    The easiest way is to screw in the two 100 lenses side by side and compare them directly.



    Peter, maybe you are misinformed, but the lens always gave this 1:1.17, that is, it was not like it was giving 1:1 and now all of a sudden 1.1.17. If I remember the previous x100 objective did the same.


    regards

    Peter



    I wonder if you guys have your x100 objective giving 1:1 or 1:>1? when using oil (that is you put a drop of oil on stage micrometer)

  • Stated magnification versus real magnification


    Hi Andreas, I bought it from ebay and there is one like it here:

    Zeiss Plan-NEOFLUAR 100x/1.30 Oil Objective


    I was told infinity objectives made by Zeiss should work on Zeiss microscopes so I had a budget and this objective looked really good. However I am a bit disappointed with the resolution, and often the lens has to touch the cover slip to have focus. I don't know if, If it does work well for transmitted light application.


    Maybe u r right re used ONLY for fluorescent microscopes, but websites selling the exact obj are saying that it could be used both for light and florescent applications ! As far as I know, such a specific lens should be colour coded . where black it means for transmitted light





    Zeiss Plan-NEOFLUAR 100x/1.30 Oil Objective



    I also have this objective : Zeiss Plan Neofluar 100x/1.30 Oil Pol Microscope Objective Lens 440483 for sale online | eBay

  • Stated magnification versus real magnification

  • Stated magnification versus real magnification

    But then the 630x objective at same conditions (except not oil) does not suffer from any discrepancy.

  • Welche Pilze sind das?

    nobi_†: So true, but then a genus name is already very good for newbies .


    @ Fungi : Agree with the above, there are quite some Psathyrellaceae in the bunch. For better expectations, ideally you post species pre post and take several pics from different angles including scent. In several other fora or social media you want be helped from such a photo.

  • ​ Diderma sp. (hemisphaericum?) on leaves of Juglans and other deciduous trees

    I found an interesting myxomycete, rather abundant on fallen leaves of Juglans regia and few other exotic trees. Initially, they looked like small flour sacks or pouches, quite large (2mm perhaps), and quite cute. On further development, there were some slimy droplets oozing (maybe damaged during transport) and finally, they solidified into irregular flattened disks and dehisced in a particular way. Must be a Diderma sp. and maybe globosum or more likely D. hemisphaericum. However, the latter should be distinctly stalked! On careful examination, the myxocarps were subsessile (neither distinctly stipitate nor sessile). For me, it looks more like hemisphaericum unless there are other species that I have not considered. I am aware micro is needed but for this I might be lucky to decrease the workload!

  • Congo Red

    I was about to write that 3g/100mL = 3% is too concentrated (usually literature suggests 1%). I opt for 0.8% in my preparation and see if it works well.


    And just for fun, I found a thesis on colours of Congo Red written in 1927 by Robert S. Radcliffe.


    RICE1273.pdf?sequence=1&isAllowed=y


    Thanks Andreas and Andreas

  • Congo Red

    Thank you Andreas, what % is the Ammonia, around 10% maybe?


    I am preparing new solution from the powder now, that Congo Red is strange.


    I take the long cut, I dissect and put the section in congo red. Leave for a minute or so, then I absorb the extra stain with a cotton bud or kitchen roll strips and add plenty of 3%KOH and wash the dissection in it (sometimes leave it to stand for another minute if the tissue is robust/hard). Then I pick the washed section and place it in a drop of KOH+Glycerol mixture, sometimes a dissect further in smaller pieces and space them out. I place the cover slip over, press with a rubber over tissue paper and ready to go. The glycerol mixture prevents the slide from drying.


    Cheers :S

  • Congo Red

    The one on the right is Congo Red Powder C.I. 22120 dissolved in water and filtered (I asked my friend who gave it to me) and remains red in KOH. Actually, when searching for my stuff, I just realised that I have bought a bottle and forgot about it - so at least this post was very beneficial !!! The one on the left was bought a few months ago from a commercial Lab Supplies and they provided it as a solution (1%). Well, I can make my own Congo Red solution from 22120... I guess 1% is a good concentration or a bit less is better? Since my Lab is home-based I prefer to avoid Ammonia.


    P.s. Does it really expires 🤷‍♀️😁 ?

  • Congo Red

    Hi guys, tomorrow I show you a video of what's happening. Thank you so much for your replies. I am a bit more relaxed with regards toxicity. The other (old) congo red do form some minute crystals and I know the notorious feeling under the microscope. Sometimes it goes away by heating it in water bath at 70C until water cools down gradually

  • Congo Red

    I have had a stock of Congo Red donated by a friend and recently I bought a new stock from a local Lab supplies shop. The second one is a different kind!

    In alkaline solution, it becomes purple and somewhat leaches out stain when a stained section is placed in clean KOH.


    Are there different types of Congo Red because I may buy again this time from abroad.


    Another point, it is really toxic and carcinogenic? Sometimes my fingers are stained and then I nibble my nails! : blow:

  • Cortinarius sp. ? under Cistus (and Thymus) from calcareous soil

    Dear Uwe, I just wrote this morning to Unite / Estonia and I see what they are gonna tell me. I will keep you informed with everything. Thank you for your help and I see no objection on sharing the sequence with serious colleagues like your kind self. I have no experience with the sequencing of fungi so I am glad to read your offer of helping.


    Apart this I have other fungi that are crying for sequencing such as a Cosmospora (?) sp. [ Cosmospora species , Central Mediterranean region - Forum ASCOFrance] and a Talaromyces growing specifically on Washingtonia seeds. [ https://mushroomobserver.org/262509 ]

  • Helvella ephippium - new record for our island of Gozo

    I recently found dozens of Helvella sp. which would correspond to a new record for the island of Gozo and most likely the whole archipelago. It was growing from very damp and shaded ground coved with Juglans leaves (and some twigs). I read the teeth on the lower surface is characteristic for the species, hence my determination to Helvella ephippium. Is it common in central and south Europe?

  • Cortinarius sp. ? under Cistus (and Thymus) from calcareous soil

    I see, so the infractus group can be confirmed at least! I wanted to add info (micro) perhaps it can lead to a narrower selection within the group. Ok then.



    Who do you think would be interested to follow a DNA analysis?

    Is a dry specimen enough to sequence or it has to be subcultured on special agar?


    Or to put in different ways, what can I do to sequence it? (with my own budget)


    Thanks.