A bit of a nerve-wracking moment...

[JamesF]

I mounted up the C9.25 this afternoon only to discover when I took the lens cap off that about a quarter of the corrector lens was covered by water stains on the inside

Not much choice but to take the corrector out, then.  Eeek!

So, I marked the orientation of the parts as I took them off so I could put them back the same way.  Fiddling the outer retaining ring past the pins that are presumably there to prevent it falling out was actually the most awkward part.  I then discovered that the secondary was also pretty filthy so got the blower on that and did the needful on the corrector with Baader OW fluid.  It now looks much healthier.

Interestingly, the edge of the corrector had both a "V" mark etched into the glass and a pen arrow drawn on, about 40mm apart.  It wasn't obvious that these two marks lined up with anything on the OTA though, so I ignored them and just reassembled it using my own marks.

All in all it was far less stressful than I expected.  I don't want to do it again, but I shall feel less worried about it if I have to.  Now I just need to check the collimation...

James

[JamesF]

Hah!  Just realised that the two pins are not there to stop the retaining ring falling out at all.  They're the pins that hold the lens cover on!  Bizarre that I kind of forgot what they were there for as soon as I took the cover off and only realised once I had to put it back on again.

James

[Kev M]

Are you sure it was water, has been known for grease to drip on them if stored face down.

Cleaned my ED80, still didnt work through 2 miles of cloud....🙁

[JamesF]

As sure as I can be that it was water.  It was dry and not at all smeary.  All gone now though

James

[Alan White]

Good job James, is this all for scoping up the observatory?

Not been fully engaged of lately as have been and still am a tad unwell.

[JamesF]

It is indeed, Alan.  I have been moving stuff in over the course of the weekend and uncovering things I need but don't have, such as suitable 1/4" UNC bolts to fit Skywatcher scope rings.  And in fact things I have but surely can't need, like seven(!) Skywatcher tripods.  I might have to make a parallelogram binocular mount or two just to put them to use

Sorry to hear you're not in the best of health.  GWS.

James

[Peter Drew]

10 minutes ago, JamesF said:

It is indeed, Alan.  I have been moving stuff in over the course of the weekend and uncovering things I need but don't have, such as suitable 1/4" UNC bolts to fit Skywatcher scope rings.  And in fact things I have but surely can't need, like seven(!) Skywatcher tripods.  I might have to make a parallelogram binocular mount or two just to put them to use

Sorry to hear you're not in the best of health.  GWS.

James

!/4" Whitworth will do if no 1/4" UNC  available.   😀

[ollypenrice]

It's stressful the first time you pull anything apart, I think. The stress comes from a healthy desire to be able to put it all back the same way. If you feel no stress you are either a genius or a complacent numpty awaiting a fall!

Olly