Accident with my rig over the weekend - is this damaged ?

[irtuk]

Hey all.

Over the weekend I had to travel up North and whilst I was away my scope cover broke free of its restraints in high winds and left my rig exposed to the elements for a couple of days.

Electronically its fine, I have dried everything out and reassembled it inside and N.I.N.A can see and connect to everything, the mini-pc is fine and all the cameras seem to be OK.

The concern I have is with the scope itself, obviously when it came inside I got a significant amount of condensation developing on the lens unit, I have wiped this down and left it to dry out overnight. 

The scope is a Skywatcher Esprit 80ED Pro and now I have removed the focusing module and the hood so I can see just the lens element it seems to be very "foggy". I have never stripped it down before so I have not seen this component in its "pre-incident" state so I don't have anything to compare to. I don't want to do anything to it, for example clean it with some sort of cleaning agent, until I know whether this is as expected, whether this is something to do with the lens coatings.

I will add some images in a sec, started writing this on my work laptop and I can only add images from my personal machine!

 

here we go. this to my untutored eye does not look like a clean and happy component... that said this is looking directly through it at a light bulb with a DSLR flash, so it would never get that much light through in normal usage, I dont know, I think probably it needs to go for a professional clean, 

 

 

 

This is the component, I can break this down a bit more and remove the tube foot section leaving only the lens unit. this would give much better access to the lens and would let me clean it with a DSLR sensor cleaning kit or some other recommended kit.

 

 

Edited November 28, 2022 by irtuk

[teoria_del_big_bang]

That's not a good homecoming.
I certainly am not knowledgeable enough to give any advice  on the scope but there is the option of taking it to somewhere they can test / clean (if needed). For me I would take it to RVO which is not too far away for me but maybe somewhere similar closer to yourself.

Steve

[Carbon Brush]

If you want to clean any glass, Baader fluid and their cloth (sold by FLO and others) is the way to go.

If you are only dealing with accessible glass, there are no problems. It is easy.
In other words the front of the objective, and reaching in to the back of the objective.

If you need to separate lens elements because of deposits or fogging, that is a bit more to think on.
I haven't had this particular scope in pieces so can't advise the intricacies.

HTH, David.

 

[scotty38]

If it got in then it should be able to come out.....

If it was mine I'd be tempted to leave it in warm airing cupboard, or even fire up the dew straps, and give it a couple of days of gentle drying out and then see what you're left with.

[Adam J]

1 hour ago, irtuk said:

Hey all.

Over the weekend I had to travel up North and whilst I was away my scope cover broke free of its restraints in high winds and left my rig exposed to the elements for a couple of days.

Electronically its fine, I have dried everything out and reassembled it inside and N.I.N.A can see and connect to everything, the mini-pc is fine and all the cameras seem to be OK.

The concern I have is with the scope itself, obviously when it came inside I got a significant amount of condensation developing on the lens unit, I have wiped this down and left it to dry out overnight. 

The scope is a Skywatcher Esprit 80ED Pro and now I have removed the focusing module and the hood so I can see just the lens element it seems to be very "foggy". I have never stripped it down before so I have not seen this component in its "pre-incident" state so I don't have anything to compare to. I don't want to do anything to it, for example clean it with some sort of cleaning agent, until I know whether this is as expected, whether this is something to do with the lens coatings.

I will add some images in a sec, started writing this on my work laptop and I can only add images from my personal machine!

 

here we go. this to my untutored eye does not look like a clean and happy component... that said this is looking directly through it at a light bulb with a DSLR flash, so it would never get that much light through in normal usage, I dont know, I think probably it needs to go for a professional clean, 

 

 

 

This is the component, I can break this down a bit more and remove the tube foot section leaving only the lens unit. this would give much better access to the lens and would let me clean it with a DSLR sensor cleaning kit or some other recommended kit.

 

 

Get a zip lock plastic bag and a large amount of desiccant place the cell in the bag with the desiccant. Put it in a warm place and leave it for at least a week then take a look. But I would also be tempted to get a UVC light and expose the cell to it for 30mins or so before doing this to kill anything off that may want to start growing. 

DO NOT take the lens elements out of the cell you will not get them centred correctly again without an interferometer. You would need to send the cell off to a specialist to have this done and it would not be cheap. Just give it time and let it dry. 

Adam 

Edited November 28, 2022 by Adam J

[catburglar]

I’m with @scotty38- keep it somewhere nice and warm for a couple of days and see how it is then. If there’s no improvement I’d take it to a professional rather than have a go myself…

[ollypenrice]

Let's assume you've dried the front of the objective, which you can do with a hair dryer. Do you then see signs of moisture on the inside? This may be on the innermost service of the cell, in which case you could direct the hair drier into the inside of the tube.

There might also be moisture on the internal surfaces of the lenses, those not exposed at front or rear. As suggested, steady, protracted warmth should drive that out and dessicants would help. The UVC light also sounds like a good idea.

Olly

[irtuk]

Cheers all. I have the cell isolated now, but I have not taken the cell itself apart so the lens elements are all as they were. I have the dew band on and it does appear to be working, I am less than pleased to note however that the massive fingerprint is on the inside of the lens cell and is not one of mine!

 

Anyone know where you can buy desiccant, or even what a domestic desiccant might be?

[Prador]

Lots of different options on Amazon. Bulk or individual sachets are available. Most of them can be reactivated for more long-term use.

[Carbon Brush]

2 hours ago, Adam J said:

get a UVC light and expose the cell to it for 30mins or so before doing this to kill anything off that may want to start growing. 

That is an excellent idea. Thanks.

[Tomatobro]

53 minutes ago, irtuk said:

where you can buy desiccant

Flo has some in its accessories

[ollypenrice]

1 hour ago, irtuk said:

Cheers all. I have the cell isolated now, but I have not taken the cell itself apart so the lens elements are all as they were. I have the dew band on and it does appear to be working, I am less than pleased to note however that the massive fingerprint is on the inside of the lens cell and is not one of mine!

 

Anyone know where you can buy desiccant, or even what a domestic desiccant might be?

A fingerprint will have precisely zero impact on your imaging.

Yes, I know it's annoying to see one, though! 

Olly

[davidc135]

FWIW, the miniature sachets I bought absorbed a max 33% by weight of moisture in 12 hours if left uncovered and indoors, but could be refreshed by 2hrs at max 60degees C.

David

[irtuk]

Turns out there is a small bag of desiccant in each and every covid test strip we have (and we have a couple of boxes full!) 

Seems like I left my UVC lamp in my other jeans, but the ziploc and desiccant is working a treat, I can see the fogging clearing up nicely and in time I might be able to forget about the fingerprint 

 

[irtuk]

Morning everyone. 

Just thought I would post a quick update to let you know the plastic bag and desiccant plan has worked an absolute treat, the lens assembly is crystal clear again and I have reassembled the scope.

Thanks so much to this wonderful community for all the suggestions (and warnings! because I was tempted to crack that optical assembly open!)

Ed

[Clarkey]

On 28/11/2022 at 10:30, Adam J said:

But I would also be tempted to get a UVC light and expose the cell to it for 30mins

To save anyone some money who might be thinking of the UVC idea. I might be wrong, but to my knowledge UVC will not pass through glass. (This is why you do not get sunburn sitting in the car). Anything within a glass lens cell will not be affected.

FWIW, if you manage to get the atmosphere dry enough using a desiccant, this will probably finish off most things that are likely to grow in the lens cell.

[Adam J]

39 minutes ago, Clarkey said:

To save anyone some money who might be thinking of the UVC idea. I might be wrong, but to my knowledge UVC will not pass through glass. (This is why you do not get sunburn sitting in the car). Anything within a glass lens cell will not be affected.

FWIW, if you manage to get the atmosphere dry enough using a desiccant, this will probably finish off most things that are likely to grow in the lens cell.

Most fungus starts on the outer surface of the glass and then moves inwards towards the moisture, thats because spores will only land on the outside lens surface and around the seal. Killing them at that point will prevent them from growing between the lens elements. Growth never starts out from inside the lens cell for that reason. 

After that it depends on the type of glass / crystal being used in the telescope. For example florite is good down to 100nm and many types of flint glass used in telescopes will go down to 200nm. So its worth remembering that the glasses used in our optics are not the typical types used in  a car window. 

We had a similar post about mid wave IR transmission recently and fluorite is able to transmit at close to 10um but the flint glass wont. 

Adam 

 

Edited December 1, 2022 by Adam J

[Clarkey]

2 hours ago, Adam J said:

Most fungus starts on the outer surface of the glass and then moves inwards towards the moisture, thats because spores will only land on the outside lens surface and around the seal. Killing them at that point will prevent them from growing between the lens elements. Growth never starts out from inside the lens cell for that reason. 

Yes, agreed. However, there are fungal spores everywhere so surface removal is a bit of a thankless task.

With regards to the UV, yes, fluorite glass does allow some transmission into the UV shorter wavelengths. I believe the Esprit uses BK7 glass as the non-ED elements. This has very poor transmission below 300nm. Yes, it does depend on thickness - thicker glass moves the wavelengths, and the exact glass properties will vary. In general, for biological disinfection 254nm is the target wavelength to damage DNA / RNA. At this wavelength the transmission is near zero. Given that many fungal spores are very resistant to UV the benefit of a UV light will be negligible.

[LDW1]

If the moisture could get in there it can get out over time. Just take the diagonal out and leave in a dry room with a small heater. I doubt if there will be any rust as everything inside should be either ss, aluminum or a bit of plastic.

[LDW1]

To get fungi starting it will have had to be damp / moist / cool for quite a while, IMO !

[LDW1]

If you open up the diagonal end and hold the tip of a shop vac type vac very close to the opening you will be surprised how much moisture it can pull out, do that a half dozen times over a day while in a warm area. I do that for inside dust in a scope whenever necessary which is not too often.

Edited December 2, 2022 by LDW1