Mystery objective with crosshairs/fixture on front lens

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
Post Reply
Message
Author
microcosmos
Posts: 252
Joined: Fri Jun 18, 2021 9:05 am
Location: Singapore

Mystery objective with crosshairs/fixture on front lens

#1 Post by microcosmos » Sat May 14, 2022 11:04 am

I recently came across this objective while looking at a disused GE DeltaVision OMX TIRF-SIM super-resolution microscope.
Front of the objective. Notice the crosshairs
Front of the objective. Notice the crosshairs
Screenshot 2022-05-14 at 18.47.33.png (231.84 KiB) Viewed 1081 times
Screenshot 2022-05-14 at 18.47.13.png
Screenshot 2022-05-14 at 18.47.13.png (210.69 KiB) Viewed 1081 times
Screenshot 2022-05-14 at 18.46.38.png
Screenshot 2022-05-14 at 18.46.38.png (213.45 KiB) Viewed 1081 times
View of the front lens through the back lens
View of the front lens through the back lens
Screenshot 2022-05-14 at 18.45.47.png (306.62 KiB) Viewed 1081 times
Has anyone seen this before and do you know what it is? It has no labels that I can see. It has a crosshair that appears to be on the recessed front lens, and a thin translucent squarish thing that seems to be affixed on the front lens and has very faint stripes when held to the light. Is it some sort of calibration device related to the laser and/or the SIM grating?

Unfortunately the OMX was completely inoperational and there was no other microscope available to screw on the objective to take a look. Unfortunately I didn't bring my loupe.

There's a slight possibility that this objective has nothing to do with the OMX, but it was sitting near the nosepiece although it wasn't screwed in.

User avatar
FatBassPlayer
Posts: 93
Joined: Sat Mar 26, 2022 1:49 am
Location: Warwickshire, UK
Contact:

Re: Mystery objective with crosshairs/fixture on front lens

#2 Post by FatBassPlayer » Sat May 14, 2022 4:06 pm

I wonder if the faint stripes you mention could be some sort of diffraction grating? No idea what it might be used for.
Picasso is dead,
Mozart is dead,
Einstein is dead,
And I ain't feeling great.

Scarodactyl
Posts: 2775
Joined: Sat Mar 03, 2018 9:09 pm

Re: Mystery objective with crosshairs/fixture on front lens

#3 Post by Scarodactyl » Sat May 14, 2022 6:17 pm

Maybe an interferometer objective?

microcosmos
Posts: 252
Joined: Fri Jun 18, 2021 9:05 am
Location: Singapore

Re: Mystery objective with crosshairs/fixture on front lens

#4 Post by microcosmos » Sun May 15, 2022 1:47 am

Thank you all for your inputs! I think it is probably an interferometer objective as Scarodactyl suggested. It looks like a Mirau-type objective as shown in Figure 5 at https://www.microscopyu.com/microscopy- ... rferometry

Scarodactyl
Posts: 2775
Joined: Sat Mar 03, 2018 9:09 pm

Re: Mystery objective with crosshairs/fixture on front lens

#5 Post by Scarodactyl » Sun May 15, 2022 5:06 am

You'd need coaxial epi illumination to use it. Great for detecting vibrations as they will be dramatically illustrated in the interference figure. I could never get my reference surface level enough to get a bullseye with one.

microcosmos
Posts: 252
Joined: Fri Jun 18, 2021 9:05 am
Location: Singapore

Re: Mystery objective with crosshairs/fixture on front lens

#6 Post by microcosmos » Sun May 15, 2022 6:08 am

Thanks for the additional information. It does seem to me that this kind of objective was initially developed for measuring the topography of microscopic surfaces but it turns out to be very useful for detecting external vibrations affecting a microscope as well.

microcosmos
Posts: 252
Joined: Fri Jun 18, 2021 9:05 am
Location: Singapore

Re: Mystery objective with crosshairs/fixture on front lens

#7 Post by microcosmos » Sun May 15, 2022 6:16 am

I notice that the square patch stuck on the front lens is translucent and doesn't look like a mirror, while the Mirau objective described in the link I gave earlier (https://www.microscopyu.com/microscopy- ... rferometry fig. 5) shows and labels it as a mirror that reflects all of the light. And my objective doesn't seem to have the half-mirror in front of the front lens that is shown with the Mirau objective, although the half-mirror might have been a separate component. Maybe it's a design variation.

Scarodactyl
Posts: 2775
Joined: Sat Mar 03, 2018 9:09 pm

Re: Mystery objective with crosshairs/fixture on front lens

#8 Post by Scarodactyl » Sun May 15, 2022 9:17 pm

There are a couple types. Maybe it is a Michelson(sp?). Many seem to add an external attachment onto an existing objective (plus maybe an aperture in the back) while Nikon sells some that are built in to the objective. Both worked the same when I tried them.

Post Reply