Let's talk filters

[johninderby]

3 minutes ago, Stardaze said:

I've bought an Astronomik 2" O-III secondhand which has just arrived. What's the best practice for cleaning a filter? I've blown some dust off but it could do with a clean really. 

This works great on filters.

https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/baader-optical-wonder-set-cleaning-fluid-and-cloth.html

[John]

+ 1 for @johninderby's recommendation. That's what I use on my eyepieces and filters along with a hurricane blower for the initial dust removal.

 

[Stardaze]

5 minutes ago, johninderby said:

This works great on filters.

https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/baader-optical-wonder-set-cleaning-fluid-and-cloth.html

I was going to add some of this to my next FLO order.

Wondered whether the same method as cleaning mirrors would do a better job? Still have plenty of deionised water left.

Ive bought some lens brite this morning from spec savers as mentioned in another thread?

Edited June 20, 2020 by Stardaze

[johninderby]

You don’t want to pour water over a mounted filter. Much better to use the proper stuff. Spray a little bit onto the cloth then clean the filter. Never spray directly onto the filter.

Edited June 20, 2020 by johninderby

[fireballxl5]

another +1 for the Baader Optical Wonder Fluid, great stuff!

[RT65CB-SWL]

And another +1 for Baader Optical Wonder fluid and cloth.

Other useful optical cleaning products I use and purchases are:

• 2x pair of cotton gloves
• a camel hair brush
• a hurricane/rocket blower; (do not use an aerosol blower)
• medical/surgical cotton wool
• cotton wool buds/Q-tips, (for e/p's and filters)
• optical/medical cleaning tissue

Edited June 21, 2020 by Philip R

[John]

3 hours ago, johninderby said:

You don’t want to pour water over a mounted filter. Much better to use the proper stuff. Spray a little bit onto the cloth then clean the filter. Never spray directly onto the filter.

As above. Keep the ionised water for mirrors.

[Stardaze]

I’ve given it a clean with what I have but you still get a slight smear that you tend to with coated optics. Certainly my UV filters on my camera lenses also exhibit this if you really look following a clean with all fluids I’ve used. I’ll get some baader fluid in the week and see if that completely removes this. 
I suffer with a bit of OCD with keeping my camera lenses pristine but the general consensus is to not frequently clean EP’s, I’ll have to sit on my hands. Even being very careful out in the field, small marks do happen. That must be normal when swapping EP’s frequently? I kept them all in their box last night and had them laid out with caps going back on each time? Frustrating.

[Don Pensack]

Some pure cotton balls and some high grade isopropyl alcohol will work.

No additives to the alcohol--just IPA and water, 70-90% grade.

No additives in the cotton balls either.

You will need a clean microfiber cloth--preferably the ones that feel like silk--but unused.

In a pinch, use a clean cotton Q-Tip or two in place of the microfiber cloth.

Warning: do not use a lens pen or lens cleaning paper.  These will scratch the surface.

 

1) blow off as much dust as possible.

2) get a cotton ball wet with alcohol and gently make a pass across the filter until you are certain the whole surface has gotten wiped with alcohol.

3) Quickly grab a 2nd cotton ball and gently wipe up the alcohol still on the filter.

4) Now that the filter has nothing on it, gently wipe the filter surface with the microfiber cloth, using your finger behind the cloth to get into the corners.

This is where a Q-Tip might work as well, but be careful.  Some swabs have polyester tips (a no-go) and some have lanolin added (another no-go).

Under a bright light, look for residual stains,  and see if the swab or cloth simply wipes them away.  If not, you might have to repeat the whole process.

I have used those little tear-packs containing a small piece of cloth soaked in alcohol when I had nothing else, and they worked fine as well.

5) If it looks clean and free of stains or spots, you're done.

 

Thee are many lens-cleaning fluids out there.  I've used ROR when a stain was really bad, like smeared pollen.

 

The surface is not as hard or durable as the coatings on an eyepiece, so be careful not to rub two dry surfaces together, though once the filter is clean, a silk-like microfiber cloth

will not likely scratch at all.  None of the cleaning methods outlined will work on a pre-2000 Lumicon filter.  These were not designed to be cleaned, so if you clean one, expect scratches.

Ditto for filters from the long-gone company Sirius Optics.

 

If you can avoid getting your fingers on the filter, the cleaning procedure need not be a regular thing--only when the filter seems to get a haze on it, or otherwise looks very much like it needs cleaning.

Mine seem to go a few years between cleanings other than merely blowing off the dust.

If you are a smoker, you may need to do it a lot more often.

 

Edited June 20, 2020 by Don Pensack

[Stardaze]

14 minutes ago, Don Pensack said:

Some pure cotton balls and some high grade isopropyl alcohol will work.

No additives to the alcohol--just IPA and water, 70-90% grade.

No additives in the cotton balls either.

You will need a clean microfiber cloth--preferably the ones that feel like silk--but unused.

In a pinch, use a clean cotton Q-Tip or two in place of the microfiber cloth.

Warning: do not use a lens pen or lens cleaning paper.  These will scratch the surface.

 

1) blow off as much dust as possible.

2) get a cotton ball wet with alcohol and gently make a pass across the filter until you are certain the whole surface has gotten wiped with alcohol.

3) Quickly grab a 2nd cotton ball and gently wipe up the alcohol still on the filter.

4) Now that the filter has nothing on it, gently wipe the filter surface with the microfiber cloth, using your finger behind the cloth to get into the corners.

This is where a Q-Tip might work as well, but be careful.  Some swabs have polyester tips (a no-go) and some have lanolin added (another no-go).

Under a bright light, look for residual stains,  and see if the swab or cloth simply wipes them away.  If not, you might have to repeat the whole process.

I have used those little tear-packs containing a small piece of cloth soaked in alcohol when I had nothing else, and they worked fine as well.

5) If it looks clean and free of stains or spots, you're done.

 

Thee are many lens-cleaning fluids out there.  I've used ROR when a stain was really bad, like smeared pollen.

 

The surface is not as hard or durable as the coatings on an eyepiece, so be careful not to rub two dry surfaces together, though once the filter is clean, a silk-like microfiber cloth

will not likely scratch at all.  None of the cleaning methods outlined will work on a pre-2000 Lumicon filter.  These were not designed to be cleaned, so if you clean one, expect scratches.

Ditto for filters from the long-gone company Sirius Optics.

 

If you can avoid getting your fingers on the filter, the cleaning procedure need not be a regular thing--only when the filter seems to get a haze on it, or otherwise looks very much like it needs cleaning.

Mine seem to go a few years between cleanings other than merely blowing off the dust.

If you are a smoker, you may need to do it a lot more often.

 

Thanks Don. I have some isopropanol but it’s several years old now. Probably needs replacing? Just to be sure, is that a 70-90%
of alcohol, the rest being water?

[Don Pensack]

1 minute ago, Stardaze said:

Thanks Don. I have some isopropanol but it’s several years old now. Probably needs replacing? Just to be sure, is that a 70-90%
of alcohol, the rest being water?

Yes, water is typically the other ingredient, so 70% means 30% water.  70% may be better than 90% for avoiding residual stains, since it evaporates slower.

 

[John]

I wonder what the original owner of the filter has been doing with it

Mine stay in their cases for the majority of their lives - the most I've had on them has been a few specs of dust.

[Stardaze]

18 minutes ago, John said:

I wonder what the original owner of the filter has been doing with it

Mine stay in their cases for the majority of their lives - the most I've had on them has been a few specs of dust.

I'm just a bit particular with keeping lenses clean, always have been with my photography. It wasn't filthy by any means, just had a small smudge and dust.

Managed to find a new cloth and so have used @Don Pensack's method and it's now pristine, just like new. Whilst I pinched the better half's pure cotton pads, they weren't great, kept leaving threads of cotton in the edge. Took some time and a few careful repeated passes to clear them away. That's probably a better method to clean EP's too, though I'll need a better supply of cotton and a pack of disposable cloths. 

[John]

1 minute ago, Stardaze said:

I'm just a bit particular with keeping lenses clean, always have been with my photography...

Same here. Everything capped or in it's case when it's not being used.

 

[Stardaze]

5 minutes ago, John said:

Same here. Everything capped or in it's case when it's not being used.

 

I’ve seen some photographers in my time with filthy front elements. I can’t pay all that money to not look after them. 
 

Very basic question John, but what’s your process? I have a little portable table which I rested my case on. When I remove an EP I put the caps back on and put it back, leaving the lid open though. Or do you take out what you’ll use and have them lined up on a table? That sounds such a ridiculous question 🙄

[John]

My observing site is just a few paces from my dining room so the eyepiece case / cases and other stuff go on the table and I step outside to the scope with what I want to use. It works well for me because I can pop in to warm up / have a brew, consult the star atlas, change eyepieces etc, and then pop out again for the next targets.

This is probably a rather unusual approach - I expect most people are observing further away from the house than I do. I'm not a very hardy astronomer I'm afraid - I don't like getting too cold !

Keeping the eyepieces and filters above the outside temperature works well for keeping them from misting up though.

 

[Stu]

4 hours ago, Stardaze said:

I’ll get some baader fluid in the week and see if that completely removes this. 

Make sure the cloth is new, or at least clean and that should help prevent the smears.

[Stardaze]

13 minutes ago, John said:

My observing site is just a few paces from my dining room so the eyepiece case / cases and other stuff go on the table and I step outside to the scope with what I want to use. It works well for me because I can pop in to warm up / have a brew, consult the star atlas, change eyepieces etc, and then pop out again for the next targets.

This is probably a rather unusual approach - I expect most people are observing further away from the house than I do. I'm not a very hardy astronomer I'm afraid - I don't like getting too cold !

Keeping the eyepieces and filters above the outside temperature works well for keeping them from misting up though.

 

For north and west facing views I can more or less do the same, but for southern viewing I need to venture further  into the garden and essentially I'm above the house. At home, 2 hours is probably the norm, especially in the cold as I'm like you in that respect.  Was thinking that dew control would be more necessary when I venture out and later in the year.

[Don Pensack]

1 hour ago, Stardaze said:

I'm just a bit particular with keeping lenses clean, always have been with my photography. It wasn't filthy by any means, just had a small smudge and dust.

Managed to find a new cloth and so have used @Don Pensack's method and it's now pristine, just like new. Whilst I pinched the better half's pure cotton pads, they weren't great, kept leaving threads of cotton in the edge. Took some time and a few careful repeated passes to clear them away. That's probably a better method to clean EP's too, though I'll need a better supply of cotton and a pack of disposable cloths. 

For eyepieces, simply use Q-tips instead.  Coatings are much harder, but stains more likely to be organic (oils, spittle, etc.), so a typical lens cleaning fluid works a tad better than pure IPA.

[Stardaze]

5 minutes ago, Don Pensack said:

For eyepieces, simply use Q-tips instead.  Coatings are much harder, but stains more likely to be organic (oils, spittle, etc.), so a typical lens cleaning fluid works a tad better than pure IPA.

Q-tips (cotton buds - assume there's nothing special to the brand? Guessing just more widespread in the States?) would work nicely into the edge. I'm glad you mentioned to not use a lens pen because for camera lens filters, I do use one and had pondered that. Luckily I hesitated. Thanks for the advice again Don.

[Don Pensack]

I should more properly have said, "cotton swabs".  The problem with a lens pen is it's only clean on the first use.

Cotton swabs are cheap to throw away.  Lens pens are not.

[RobertI]

Informative thread. 🙂 I have a question and hope it’s ok to put it here rather than starting a new thread. 

I am looking to get an OIII filter, primarily for the Veil, but also any other nebs which may benefit from OIII. I had settled on the Astronomik OIII. I’m now wondering if the Astronomik UHC might be a better bet, not quite so good on Veil but possibly a better all rounder. I’d be using it with a C8 (+0.63 reducer), 150PL and possibly 130P. The lowest power eyepiece I have a present is the Hyperion 21mm. 

What do folks think - Astronomik OIII or Astronomik UHC? 

Thanks. 👍

Edited June 22, 2020 by RobertI

[MarkAR]

4 minutes ago, RobertI said:

I am looking to get an OIII filter, primarily for the Veil, but also any other nebs which may benefit from OIII. I had settled on the Astronomik OIII. I’m now wondering if the Astronomik UHC might be a better bet, not quite so good on Veil but possibly a better all rounder.

If you want to shoot narrowband on nebula then the Oiii is what you want. Do you have an Astronomic Ha to match with the Oiii ?

[John]

1 minute ago, MarkAR said:

If you want to shoot narrowband on nebula then the Oiii is what you want. Do you have an Astronomic Ha to match with the Oiii ?

I think Rob is primarily a visual astronomer.

 

[RobertI]

1 minute ago, MarkAR said:

If you want to shoot narrowband on nebula then the Oiii is what you want. Do you have an Astronomic Ha to match with the Oiii ?

I should have mentioned, this is for visual! Apologies.