Wow !!

[vlebo]

Got my Pentax XW30 today and put it on my Flextube 300 and took it out for the first time tonight for a quick look.

When there was a break in the clouds the field of view and the clarity edge to edge was amazing.Crystal clear and pin sharp stars all around, where with the naked eye, I could see nothing. Unfortunately it clouded over quickly so I have just packed up and come inside.

One thing did worry me was that I shone a torch onto my secondary mirror in the dark and found a large W shaped smear going across the mirror which I never noticed in the day during collimation. I tried to get it off with a fine make-up brush but it would not budge and I did not want to rub too hard in case I made it worse. Do I need to clean the secondary or is it best left alone.

Thanks in advance for taking the time to answer

Vlebo

[DaveGibbons]

Shine a torch on any newtonian mirror and a heart attack will always ensue! They all look terrible. Unless you can detect an optical defect with your MK1 eyeball at the eyepiece leave well alone. Mirror cleaning is to be avoided, not to say it can't be done every year or two but it is very easy to cause much more damage and therefore performance reduction than even a fair amount of crud will ever do.

cheers

Dave

[barkis]

Vlebo, the best thing to contact your mirrors with, is water. I wouldn't risk touching that precious coating with anything else. The optics of a Newt have to be fairly grubby before cleaning needs doing. Then they are best removed from their cells and done properly.

You may think that lightly rubbing with a soft cloth, or brush is harmless. Wrong, you can leave minute scratches and or sleeks on the coating.

There have been many discussions here on cleaning mirrors. the techniques described have varied widely, but my philosophy about touching the surface is a simple one. DON'T!.

You can find lots of methods by searching the Internet, or even looking back to the post here on SGL. Select the method you are happiest with.

And I will repeat another Maxim.

A Dirty Mirror, will perform Better Than a Badly Cleaned One.

[supernova]

WOW :shock: I have just cleaned my dob mirror and it is looking good.

just finnished at midnight I need sleep.

[barkis]

I hope you took great care then Bernie. That big 16" mirror is a precious thing.

Did you take it out of the scope to do it. I hope you just didn't just shove a wet mop down the tube. :laughing2:

Ron.

[supernova]

I hope you took great care then Bernie. That big 16" mirror is a precious thing.

Did you take it out of the scope to do it. I hope you just didn't just shove a wet mop down the tube. :laughing2:

Ron.

I took some very good advice and it is looking great.

It is not easy, the mirror cell was loose so I gave the whole thing a make over.

[barkis]

Well that's great Bernie, I hope to get a look through the Cannon someday.

Especially with the Ethos plugged in.

Ron.

[supernova]

Well that's great Bernie, I hope to get a look through the Cannon someday.

Especially with the Ethos plugged in.

Ron.

Come to the Salisbury star bash Ron.

[barkis]

It would be nice Bernie, but it is just a bit too far to drive from way up here in the far North.

I think there will be a venue one day which won't be as far away as Salisbury, and I will be there.

I would really have liked to get to Kelling, but I couldn't make that either. I think I will get over to Kielder this Autumn, it is not far from me. I need to get to meet as many SGL members as I can,

And Kielder is a good opportunity to do that, although the stay will probably just be the one day.

I know Darren was trying to get more northerners to go to Salisbury, but as I say, It is a bit too far for me. I'd get lost anyway. I have no Sat. Nav :mrgreen:

Ron.