PH alignment without a CT

[Plasmid]

How effective or accurate is the PH alignment cheat cheat using the "sheet of paper method" when compared to using a CT? I ask because only because I rather spend the cash for a CT on something else like a dedicated DF condenser. I've never used a CT before, is there any other uses for it?

[MicroBob]

What is a CT?

[mrsonchus]

Hi, they're pretty cheap to buy and just about any one that fits your eyepiece-tube diameter will be fine. It's job is to allow you to focus on and inspect the back of an objective - which is where the alignment of the phase rings is seen. The telescopes are also focusable of course simply by use of a telescopic construction.
They're very useful I find for seeing clearly 'what's going on' at the rear focal plane of your objectives - great to see if there's any dust etc, not to mention phase alignment of course.

They really can be found very cheaply (£20-£30 ish) and are definitely worth having. Every now and again I come over all insecure re my phase alignment and the phase telescope gets dragged from the drawer to reassure me that all is still aligned perfectly (as it invariably is...). Alignment of those phase rings is a significant factor and correct alignment is very easy to set, stays set and ensures optimum performance for your system. Great also if using darkfield stops for example, or even oblique stops, as theirn 'fit' to the objective's size is able to be seen with a PT...

Here's an example...

[Plasmid]

What is a CT?

Centering telescope that is normally used to align the phase contrast annulus,

[Plasmid]

Hi, they're pretty cheap to buy

Here's an example...

Yes that is quite cheaper then the ones I was looking at, approx 150-170 USD
Thank you

[MicroBob]

They are also very useful to check:
- whether the back lens of the objective is clean
- whether it is fully illuminated by the condenser aperture
- whether there are delaminations or other defects in the lens stack of the objective

Some microscopes have a Bertrand lens built in, sometimes it can be focussed. My Zeiss Phomi 1 has such a function integrated into the Optovar assembly.

So they are useful to have and versatile. They give an enlarged view of what you see when looking into the tube without an eyepiece.
I think the go used for 20-50€ typically.

Bob

[hans]

Many are not clearly marked and show up with vague or incorrect descriptions, sometimes selling for quite a bit less than usual in those cases, like this for example:
https://www.ebay.com/itm/383776390801

[Plasmid]

Thank you Hans, I'll keep an eye out for it, just recieved my PH scope today, unfortunately it was damaged during shipping, so we'll see if I'll end up needing a CT.

[PeteM]

The phase telescope is worth having, as noted above. Lacking one, though, you can take a trashed eyepiece tube, cover the end, and put a pinhole in the center. Works a bit like a pinhole camera. This can be good enough to align phase rings. Not so good for the other uses Bob mentioned.

[carlh6902]

How to setup phase contrast without a phase telescope:

1) Buy a phase telescope.
2) Set up phase contrast in the traditional way.

Carl

[dtsh]

I have heard of people using one eyepiece atop the other to somehow align phase. I fooled with it for a minute or two, but as my scope has a bertrand lens I use that; might be worth looking into.

[Plasmid]

I was referring to this cheat method
At 5:19

[Plasmid]

I was wondering too if anyone could identify what style of screws this condenser uses for alignment.?
The closest I've seen that resembles what could possibly work are carburetor adjustment needle screws style.
https://www.ebay.com/itm/373354492850

[PeteM]

Can't clearly see what you have from the picture. One common type uses a male hex drive to fit the condenser. Another common type uses a female square drive - perhaps what you have?

[MicroBob]

The way the condenser is made I wouldn't expect any fancy type of screw head: Smaller phillips or allen screw driver would be what I would try first.

[Plasmid]

I'll try to get a better picture in the AM,.
So just to be clear the alignment screws are rotated right or left and once alignment is achieve they can be taken out?

[PeteM]

The alignment screws stay in. The (missing) keys that drives them can be removed.

[Plasmid]

So this will be my first time using phase contrast, I followed the instructions, aligned the two annulus ( still no CT , the two Eyepieces stacked up method that was recommended by @dtsh worked perfectly) the first thing that I saw was this Heliozoa during Telophase. My question is does the condenser stay wide open and raised all the way up or do I have to close the condenser iris a bit?

[deBult]

Condenser full up and condenser diaphragm full open.

[dtsh]

So this will be my first time using phase contrast, I followed the instructions, aligned the two annulus ( still no CT , the two Eyepieces stacked up method that was recommended by @dtsh worked perfectly) the first thing that I saw was this Heliozoa during Telophase. My question is does the condenser stay wide open and raised all the way up or do I have to close the condenser iris a bit?

I read the manual for my scope's manufacturer and they suggest setting up koehler lighting as usual, which will set the condenser as needed. Don't know if other manufacturers do the same or even if my understanding is correct though as I'm very new at this.

[deBult]

So this will be my first time using phase contrast, I followed the instructions, aligned the two annulus ( still no CT , the two Eyepieces stacked up method that was recommended by @dtsh worked perfectly) the first thing that I saw was this Heliozoa during Telophase. My question is does the condenser stay wide open and raised all the way up or do I have to close the condenser iris a bit?

I read the manual for my scope's manufacturer and they suggest setting up koehler lighting as usual, which will set the condenser as needed. Don't know if other manufacturers do the same or even if my understanding is correct though as I'm very new at this.

Correct Koehler the condenser (my previous condenser “full up” was a bit of a shortcut).

[mrsonchus]

It's correct that phase contrast requires the 'normal' Kohler set-up, i.e. the same as brightfield without phase.
In addition to this correct configuration of the condenser, the phase rings must be correctly aligned, a seperate and usually once-only task.

If you can put the phase condenser under a stereo microscope you should be able to 'peer into' the shafts/holes at the bottom of which the adjustment screws are located. The proper tools are a pair pf 'wrenches' that fit down these holes to adjust the screws, which move the annuli about to effect alignment. You may find that simply the correct size of allen-key will do the trick - once set, the alignment usually stays correct.