Re: [ccp4bb] suggestions on a microscope for Crystallography

2018-03-07 Thread Georg Mlynek 
Dear Chandra, we are also currently getting quotes for a new microscope. 
I recently worked at Oak ridge with a Zeiss SteREO Discovery.V20 
https://www.zeiss.com/microscopy/us/products/stereo-zoom-microscopes/stereo-discovery-v20.html 
(everything motorized, which is not really needed) and at diamond with a 
leica M205 C Stereomikroskop. Both are high end machines and I can't say 
which one is better, the quality was perfect for both. However the Leica 
at diamond has a very flat base. If you keep the plate on the glass 
everything is fine. But the frame get's warm and fried my crystals. 
However all mentioned microscopes are modular and you can also get a 
base with external light source. So contacting your local dealer or 
looking at synchrotrons or a microscope facility helps a lot for the 
right decision.


What*we are still looking for is a light source for intrinsic 
flourescence and **trace label flourescence*. We just found one vendor 
http://xtal-concepts.com/index.php/en/xtallight-100.html


We would also build it from parts of an electronic store if we get a 
good plan. Nowadays with LED's in all colors that can't be too difficult?



I asked now for quotes for a Zeiss

SteREO Discovery.V8    magnification 10x … 80x

SteREO Discovery.V12magnification 8x … 100x

and the
leica M205 C, because they have sales representatives here in Vienna and 
I can test the microscopes before buying.


A recent post on the bulletin summarizes well on what to focus:

In my opinion, the main features/specs to "focus" on:

   ○ Full Working Distance (FWD) - how much space is there between the
   front objective lens and the tray - anything less than ~55 mm and
   you will likely be frustrated when harvesting crystals

   ○ Magnification - for screening & harvesting anything less than a
   total magnification of ~80x will leave you wanting more, ideally
   120x or more will let you resolve those <10 µm crystals

   ○ Base Size - how large is the working area of the base - anything
   less than 250 mm (deep) x 300 mm (wide) can leave your plates
   dangling off the edge when harvesting from the perimeter columns

   ○ Light Source - a bright external LED cold light source, with a
   fiber optic transmitted feed into the microscope base, will give the
   light you need while preventing your trays from heating and drying
   out during viewing

Of course, quality of optics, ergonomics, cross-polarization 
attachments, and camera/trinocular mount are also important factors to 
consider.


Best regards, Georg.


Am 07.03.2018 um 11:18 schrieb Patrick Shaw Stewart:


Hi Chandra

My only comment is be careful of modern microscopes that have a 
frosted glass screen with LEDs behind it, just below the plate.  For 
looking at crystals you need /directional /light. I've seen some very 
expensive modern microscopes with illumination that just doesn't work 
for crystallization.  If I come across that situation I normally make 
a platform and raise the plate up by a few inches - it can 
dramatically improve the quality of images.  You can also cut a round 
hole in e.g. a piece of aluminium foil and use it to make the area of 
the light source smaller.


On the other hand illumination mustn't be /too /directional because 
the drop itself acts as a lens.  If you have a light source that is 
small and too far from the sample you'll get black regions around the 
outside of the drop where you can't see crystals.


It's all about the solid angle of the light hitting the sample - I'm 
sure others can explain better than I can.


Good luck, Patrick


On 7 March 2018 at 02:06, Chandramohan Kattamuri 
<1c5b7cb6c764-dmarc-requ...@jiscmail.ac.uk 
> wrote:


Hi

I'm looking for suggestions on a good microscope for looking at
crystals, which includes polarization, light source (fiber
optics), crosshairs and camera mount.  What Models and make?

Thanks in advance

Chandra







--
patr...@douglas.co.uk     Douglas 
Instruments Ltd.

 Douglas House, East Garston, Hungerford, Berkshire, RG17 7HD, UK
 Directors: Peter Baldock, Patrick Shaw Stewart

http://www.douglas.co.uk
 Tel: 44 (0) 148-864-9090    US toll-free 1-877-225-2034
 Regd. England 2177994, VAT Reg. GB 480 7371 36

Re: [ccp4bb] suggestions on a microscope for Crystallography

2018-03-07 Thread Patrick Shaw Stewart 
Hi Chandra

My only comment is be careful of modern microscopes that have a frosted
glass screen with LEDs behind it, just below the plate.  For looking at
crystals you need *directional *light.  I've seen some very expensive
modern microscopes with illumination that just doesn't work for
crystallization.  If I come across that situation I normally make a
platform and raise the plate up by a few inches - it can dramatically
improve the quality of images.  You can also cut a round hole in e.g. a
piece of aluminium foil and use it to make the area of the light source
smaller.

On the other hand illumination mustn't be *too *directional because the
drop itself acts as a lens.  If you have a light source that is small and
too far from the sample you'll get black regions around the outside of the
drop where you can't see crystals.

It's all about the solid angle of the light hitting the sample - I'm sure
others can explain better than I can.

Good luck, Patrick


On 7 March 2018 at 02:06, Chandramohan Kattamuri <
1c5b7cb6c764-dmarc-requ...@jiscmail.ac.uk> wrote:

> Hi
>
> I'm looking for suggestions on a good microscope for looking at crystals,
> which includes polarization, light source (fiber optics), crosshairs and
> camera mount.  What Models and make?
>
> Thanks in advance
>
> Chandra
>
>
>
>
>


-- 
 patr...@douglas.co.ukDouglas Instruments Ltd.
 Douglas House, East Garston, Hungerford, Berkshire, RG17 7HD, UK
 Directors: Peter Baldock, Patrick Shaw Stewart

 http://www.douglas.co.uk
 Tel: 44 (0) 148-864-9090US toll-free 1-877-225-2034
 Regd. England 2177994, VAT Reg. GB 480 7371 36

[ccp4bb] Fwd: [ccp4bb] suggestions on a microscope for Crystallography

2018-03-06 Thread Daniel M. Himmel, Ph. D. 
-- Forwarded message --
From: Daniel M. Himmel, Ph. D. <danielmhim...@gmail.com>
Date: Wed, Mar 7, 2018 at 12:23 AM
Subject: Re: [ccp4bb] suggestions on a microscope for Crystallography
To: Chandramohan Kattamuri <kattamuricha...@yahoo.com>


My best experience was with Leica microscopes, such as the S6E.
Leica microscopes have optics that are at least as good as
Zeiss, Olympus, and Nikon, with a larger working distance
between the specimen stage and the objective lens.  That made
it much easier to manipulate, harvest, and flash cool crystals.  For all
the accessories that Leica supplies (light source, camera mount,
etc.), you'll have to check the web site and speak with a Leica
rep. to customize the microscope for your purposes.  -Daniel


On Tue, Mar 6, 2018 at 9:06 PM, Chandramohan Kattamuri <
1c5b7cb6c764-dmarc-requ...@jiscmail.ac.uk> wrote:

> Hi
>
> I'm looking for suggestions on a good microscope for looking at crystals,
> which includes polarization, light source (fiber optics), crosshairs and
> camera mount.  What Models and make?
>
> Thanks in advance
>
> Chandra
>
>
>
>
>

[ccp4bb] suggestions on a microscope for Crystallography

2018-03-06 Thread Chandramohan Kattamuri 
Hi

I'm looking for suggestions on a good microscope for looking at crystals, which 
includes polarization, light source (fiber optics), crosshairs and camera 
mount.  What Models and make?

Thanks in advance


Chandra