Removing primary mirror from SW Flextube 350

[kerrylewis]

I am still thinking of cleaning the mirror of my SW Flextube 350. Has anyone removed the primary mirror from one of these? Looking at some video guidance online it is clear that the 350 mirror has a different fixing method compared with some of the smaller scopes. Instead of the usual three clips around the edge of the mirror, the actual glass is more conical and is fixed centrally at the back into the cell. Do you still need to remove the whole cell from the OTA tube or is it possible too remove the mirror by undoing the central fixing and lifting it out via the OTA tube? 

Any advice welcome. You may just say "Don't!"

Kerry 

[Beulah]

I think if I was going to wash my 400p, I'd wash the mirror in its cell (not going to give it a wash for a long time..).  If your bath is large enough and you have plenty of towels, it's doable - I suspect taking the mirror from its cell might make it more unstable if you needed to let go of it to reach for something else. At least it's free standing in its cell...

[kerrylewis]

That's a good suggestion Beulah. I am rather nervous about the undertaking and to leave the mirror in the cell assembly would mean less to go wrong. Thanks

Kerry 

[Beulah]

No problem, please let us know how you get on - good luck. They're heavy blighters!

[kerrylewis]

Finally plucked up the courage - it's in the bath!

[Mike73]

Your mirror will appreciate its bath Kerry.

I like to keep my primary as clean as possible but now I've moved to a OOUK scope its a little tricky much like Skywatchers.

[kerrylewis]

It did Mike - looks very good now. All done and back into the OTA - phew!

[jetstream]

Once the technique is figured out washing the mirror is a good idea IMHO. The big difference noted is the scatter that comes from a dirty mirror and the impact it has on planetary/lunar and in particular star splitting. Nice job.

[Beulah]

Good job.

Looks like my mirror will *just* about fit in my bath!!    When the time comes I'll have to wash mine on the draining board...

[kerrylewis]

Part way through!

Beulah - I'm glad that I followed your advice and left the mirror in its cell - I might have tried to remove it otherwise. There really is no need given the way that the mirror is fixed leaving its full surface exposed. The frame also gives you something to grip and helps give support during process. Thanks again!

Kerry 

[NGC 1502]

Well done Kerry, can be scary at first, but nowhere near as bad as it seems.

I really like the conical centrally secured mirrors, simpler and better.

Here's another company that does it the same way - http://www.rfroyce.com/conical/

Regards, Ed.

[bomberbaz]

Just noticed this as I am about to clean my mirror. Kerry, what did you clean it with as in water type, temperature, detergent and how did you dry it.

tia

Steve

[Dave In Vermont]

I just put on my Chemist-Hat, Steve. You can use regular tap-water - at ambient temperature - for the initial wash. But make certain you use distilled water for the final stage. And to all folks reading this: Spring water is not the same thing, so drink your Perrier - don't rinse your mirror with it. Distilled - preferably triple-distilled - water contains no minerals in it. Spring water may. So do read the label, or ask your local chemist/pharmacist where they keep it if you can't find it on the shelf. I always keep a jug of distilled around. You never know when you'll have a need for it.

Have fun,

Dave

[kerrylewis]

Just noticed this as I am about to clean my mirror. Kerry, what did you clean it with as in water type, temperature, detergent and how did you dry it.

tia

Steve

Hello Steve

As Dave says, I used ordinary tap water for the initial cleans with a dash of Fairy Liquid at lukewarm temperature. The final rinse was with Deionised water (we used to call it distilled water) which I got from Asda! For drying I just left it to dry naturally helped in the beginning with the corner of a paper towel to soak up big blobs. I wasn't happy with the the first run which left some watermarked area but the second rinse was better

Hope that helps

Kerry 

[bomberbaz]

have you a link to a step by step guide Dave, and where does one obtain distilled water?

Steve

[bomberbaz]

Kerry I think our posts crossed in the web space

[Dave In Vermont]

I get my distilled from a drug-store, which are called 'Chemists' over in Europa. Large chain-stores have everything under the Sun here - including distilled H2O - so I'd call one and inquire. Some large supermarkets (grocer's) carry it as well. There are tons of 'step by-step' guides out there, Steve. Rather like collimation. I don't have one handy. Try a search for: Cleaning telescope primary mirror.

Hope this helps -

Dave

[kerrylewis]

https://www.youtube.com/watch?v=-fDO_rf7xBg

This is  the guide I followed 

[Uplooker]

Visit any aquatics shop with a clean receptical and ask for Reverse Osmosis (RO) water. You should be able to get 4 or 5 litres for £1 or less. Wash your mirror as above and then use the RO water to rinse. Leave mirror at a slight angle to allow the water to drain off. As Kerry says use the corner of kitchen towel to absorb some of the bigger droplets - et voila

Sent from my Fone

[bomberbaz]

Thanks guys. Looks like I know what I am doing this weekend