4 replies to this topic

[Paul McC]

When I recently cleaned the oil stain off of the internal surface of my CPC 1100's corrector (long story covered on another thread here) I noticed a rubber ring (after reassembly of the corrector) on the baffle tube. The ring is on an angle- one side closer to the mirror and one side is closer to the corrector. I can't remember if this was there before or if it slipped out of some other place in the scope's internals. As it is now, it seems to serve no purpose- whether the scope's mirror is all the way forward or back, it never comes in contact with the ring when sliding down the tube. It also doesn't seem to effect the scope's performance. (In fact, the performance has never been better since cleaning the optics- two year's of dust and pollen sure did make an impact)

If it wasn't there before, I'm wondering where it was and what purpose it served? See the picture here along with the red line pointing to what I'm talking about. My real worry here is that it is in the wrong location and could slip off and stick to the mirror or corrector. I can't help but wonder if the reason an oil drip occurred is that this ring became dislodged somehow- perhaps it used to be a seal of some sort?

Anyone else see this in their scope, and if so, is it on an angle?

Cheers,
Paul

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[Digital Don]

Hi Paul,

Are you sure it's rubber? There's no room between the baffle tube and the mirror tube for anything that thick.

My first thought when I looked at the picture is that it's lubricant. If you've owned your scope for some time, you've moved the mirror back and forth hundreds of times when focusing. If it is lubricant, it may be getting 'squished' out from that movement.

Try moving the mirror all the way to the front and see if it comes close to the 'ring'. If so, that may be the answer.

Don

[gb_astro]

Hello Paul.

Mine has the ring, it is meant to be there and it has not come from somewhere else.

At a guess its function seems to be to restrict the baffle grease to where the baffle actually slides.
Or perhaps, if it is strong enough, it is meant to stop the primary mirror falling onto the corrector when the focus
knob is disconnected.

gb.



CPC1100

[Paul McC]

Don,

Yes, it's definitely a ring- and it's on an angle. In other words, if you were able to go inside the OTA and look at the ring from the top of the baffle, it would be like this "\" rather then this "|". In other words it's skewered. I have rolled the mirror all the way forward and it doesn't come close to this ring. My thought was that perhaps there's an indentation inside there that it use to fit in- say between the baffle and the part of the mirror that slides over the baffle- and that it perhaps served to smooth out the lubrication with the mirror's movement. (If it wasn't captive somewhere, I can't see what it would do...)

gb,

Fascinated (and a little relieved) that your CPC has the same ring- but is it skewered as I describe it above? (It's hard to see this in the photo) Your guess that it might restrict the baffle lubrication is interesting.

Anyone else see this in their CPC 1100s?

Cheers,
Paul

ps- Celestron was sent the same picture... they responded that they'll get back to me on this. (Probably being sent to their tech dept)

[gb_astro]

Paul,

It's hard to tell from outside but mine does not look skewered.

I think you will find that is meant to be where it is
and being a bit skewered will not make a difference to anything.

gb.