Hmm.. think it's time the old 'frac had a clean..?

[ChrisLX200]

Not sure, maybe I can leave it another year - I can still see light coming through it ;-)  On the other hand it might explain the slight drop off in sharpness I've been getting...

ChrisH

[Uplooker]

Go on, give it a clean, ya know ya want to

[Dave Lloyd]

Looks like it has it's own built in starfield.

[nightfisher]

Looks like it has it's own built in starfield.

Just what i was thinking, a close up of M13

[laudropb]

Your frac certainly has coated lenses

[ChrisLX200]

Job done, a lens brush, Baader fluid, and about 20 lens cleaning tissues later...

ChrisH

[ollypenrice]

I never hesitate with refractors. Coatings on glass are hard. In fact they can be harmed by corrosive chemicals both man made and natural so regular cleans are routine for me. However, I'm far more circumspect with aluminium coatings on mirrors. In this situation I'm the original minimalist.

Olly

[Alien 13]

I certainly would never even hesitate cleaning a frac or lens and as Olly said there are lots of things out there that like to eat glass and coatings.

I do worry though that it took so long using fluids to clean the lens my own experience is that you will allways be struggling with smears when using any liquids when a lens pen removes all with a single swipe (provided you blow the dust off first).

Alan

[timwetherell]

I tend to use methanol/ethanol (just regular methylated spirits from the supermarket) for the first wipe then breath fogging for the final wipe. Sounds scary but human breath (not spit) is actually mostly  just clean steam and it dissolves the water soluble compounds the alcohol misses and that tend to cause streaks. I think that so long as you remove the loose dust with a blower or brush first, most sensible gentle cleaning methods are unlikely to harm a lens surface

[ChrisLX200]

Of course my post was a bit tongue-in-cheek, I can't believe I was imaging with it in that state and I'm amazed it worked at all. You quite literally could hardly see through it! The thing is, I never look at the objective end because the scope is carried out and mounted with the lens cap on, then I have to reach up high to remove it. Putting it away again is just the reverse (there's never any dew to worry about because of the heater). Yet this scope was producing FWHM stars ~2.4 even in that condition, weird. In the two years I've owned it (since new) it still has never had an eyepiece in it so I would not have noticed a deterioration of the view through it.

ChrisH

[mikeDnight]

I tend to use methanol/ethanol (just regular methylated spirits from the supermarket) for the first wipe then breath fogging for the final wipe. Sounds scary but human breath (not spit) is actually mostly  just clean steam and it dissolves the water soluble compounds the alcohol misses and that tend to cause streaks. I think that so long as you remove the loose dust with a blower or brush first, most sensible gentle cleaning methods are unlikely to harm a lens surface

I used to use alcohol based lens cleaning fluid to clean my Tak FS refractors. However, in the instruction booklet that came with my FC100D, it states that alcohol based cleaning fluid must not be used as it will harm the coatings. Just thought I'd mention this as I know a number of SGL members use these scopes. It may also be that other manufacturers may use similar coatings, and so avoiding the use of alcohol may be the wisest thing to do.

Mike

[nightfisher]

I tend to use methanol/ethanol (just regular methylated spirits from the supermarket) for the first wipe then breath fogging for the final wipe. Sounds scary but human breath (not spit) is actually mostly  just clean steam and it dissolves the water soluble compounds the alcohol misses and that tend to cause streaks. I think that so long as you remove the loose dust with a blower or brush first, most sensible gentle cleaning methods are unlikely to harm a lens surface

Over the years i have found that mentholated spirit seems to work best, used very sparingly along with a few gentle "huffs" of breath 

[knobby]

Over the years i have found that mentholated spirit seems to work best, used very sparingly along with a few gentle "huffs" of breath

Smells nice too [emoji3]

[ChrisLX200]

Alcohol really should not bother today's coatings, they're tougher than the glass underneath them. A lens from the 60's or 70's would be a different matter. I don't know what is in Baader Wonder Fluid but I suspect it's IPA or something, there needs to be some sort of solvent to get the sticky bits off.

ChrisH

[knobby]

Smells nice too [emoji3]

As its been 42 minutes since my post I should clarify that I was joking as the post said 'mentholated' spirit as opposed to metholated

[StuartJPP]

I tend to use methanol/ethanol (just regular methylated spirits from the supermarket) for the first wipe then breath fogging for the final wipe. Sounds scary but human breath (not spit) is actually mostly  just clean steam and it dissolves the water soluble compounds the alcohol misses and that tend to cause streaks. I think that so long as you remove the loose dust with a blower or brush first, most sensible gentle cleaning methods are unlikely to harm a lens surface

I have seen pro lens rental companies cleaning lenses with spit (as a last resort after IPA and then breath)...it will remove certain stubborn stains that won't budge with either alcohol based cleaners or water based cleaners. Of course you need to then clean the spit off properly afterwards.

Although small blemishes won't affect the image, as others have said, they can damage the coatings and cause more harm long term.