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Reflector owners  

20 members have voted

  1. 1. How often do you clean your primary mirror

    • Never
    • Once a year
    • Every 2-3 years
    • Often
      0


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I've seen so much about this topic, but never a poll? Whilst I know many leave them well alone until things look desperate, there must be some that also like to regularly take things apart and spruce them up. There's many variables, such as frequency of use and how the optics are stored, but mine seems to have gotten very dusty in a short period of time. I'm not itching to do it, far from it, but interested to hear you experienced folks actual frequency. 

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Never cleaned my RC6 mirror (I've had it around 5 years) but it rarely gets used and is pretty well wrapped. Never cleaned my Heritage 130P mirror (had it around 3 years) but it does get used more often and is more prone to dust and would probably benefit from a light wash to remove dust and grime - which I may attempt soon. Of course the mirror of my 20 year old SCT has never been touched and is as pristine as the day I bought it! :) 

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so far, having bought used I've cleaned all of mine soon after purchase or when I've overhauled/refurbished the scope. You could argue that all were performing fine before so could have been left, but if I'm taking it apart it makes sense to do the cleaning at assembly time. Other than that I'd go with as and when needed.

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Only when absolutely necessary. You could do more harm than good to the mirror fettling. The odd bit of dust or a very light covering is not going to effect the views, but incorrect cleaning or accident when cleaning can effect the coating/mirror. So only when absolutely necessary IMO 

 

 

 

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I've had my Dob just over 3 years now and have washed the mirror twice in that time.

Living on unmade dirt roads up in the hills east of Melbourne the dust in the drier warmer months has to be seen to be believed every time a car goes past, like a dust fog.

It is extremely fine and just gets into every nook and cranny imaginable. I keep the scope with dust caps always on in its own little wooden house outside with a well sealed door but the dust still gets in somehow.

I probably wouldn't bother if we were on sealed roads which would cut down the dust problem considerably, I'm not too precious about keeping it spotless at all.

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55 minutes ago, johninderby said:

Think you need another option in the poll. Only clean when needed.

I have no set period between cleanings. Maybe every couple of years. 🤔

And that's a great answer John, it is however determining exactly when it's needed. How do you 'know'? 

My problem is that I am a little anal with keeping things clean, I'll admit that. And so it's tricky to sit on your hands, but I am going to, as I don't see any issues with the viewing at the moment. I take it that once the screws are removed the whole assembly just drops out? 

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With a solid tube newt you can probably get away with longer intervals between cleaning - depending on how frequently it is used, the conditions you observe from and how/where the scope is stored. I tend to wash the primary every couple of years and typically before the galaxy season begins.

Without question, my current scope (an ES 12” Ultralight II dob) has been the one that I have found most challenging to keep clean(ish). The mirror was washed 12 months ago and it looks rather dusty at the moment. I use an air blower before each session to remove what I can. The mirror box has a large opening on each side which allows you to lift it up with ease (a positive), but they are also perfect for letting in dust between sessions (not so good). I resort to covering everything with a large towel in an attempt to keep the dust at bay.  In contrast, my old Meade Lightbridge 12”, which had a plastic cover for the primary, is looking cleaner than my ultralight... after selling it some 8 years ago (I use that scope occasionally with its new owner). Ironically, the owner has never cleaned the mirror either!

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25 minutes ago, Stardaze said:

And that's a great answer John, it is however determining exactly when it's needed. How do you 'know'? 

My problem is that I am a little anal with keeping things clean, I'll admit that. And so it's tricky to sit on your hands, but I am going to, as I don't see any issues with the viewing at the moment. I take it that once the screws are removed the whole assembly just drops out? 

Before it gets to this state? 😁🙀🙀🙀

And no it’s not my mirror. 😁

A9C0D45C-082A-45CA-9A6A-B4DCB19B6C59.jpeg

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5 hours ago, Rob_UK_SE said:

With a solid tube newt you can probably get away with longer intervals between cleaning - depending on how frequently it is used, the conditions you observe from and how/where the scope is stored. I tend to wash the primary every couple of years and typically before the galaxy season begins.

Without question, my current scope (an ES 12” Ultralight II dob) has been the one that I have found most challenging to keep clean(ish). The mirror was washed 12 months ago and it looks rather dusty at the moment. I use an air blower before each session to remove what I can. The mirror box has a large opening on each side which allows you to lift it up with ease (a positive), but they are also perfect for letting in dust between sessions (not so good). I resort to covering everything with a large towel in an attempt to keep the dust at bay.  In contrast, my old Meade Lightbridge 12”, which had a plastic cover for the primary, is looking cleaner than my ultralight... after selling it some 8 years ago (I use that scope occasionally with its new owner). Ironically, the owner has never cleaned the mirror either!

I have wondered whether a truss dob is easier to blow off dust a little easier. Mines not that bad on further inspection, seemed worse first thing when I moved it back from the shed to inside. 

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3 minutes ago, Stardaze said:

I have wondered whether a truss dob is easier to blow off dust a little easier. Mines not that bad on further inspection, seemed worse first thing when I moved it back from the shed to inside. 

If it’s not too bad then I would recommend holding off until it really does need a clean. 

A truss dob is indeed easier for using an air blower, but you do have to be much more careful / aware of the mirror as it is quite exposed to the elements -especially when you are assembling it. As we live quite close to the coast, I am ever so slightly paranoid by the seagulls that frequently pass overhead. For one thing, I don’t want the centre dot on the primary mirror to promote target practice! 

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15 minutes ago, Rob_UK_SE said:

If it’s not too bad then I would recommend holding off until it really does need a clean. 

A truss dob is indeed easier for using an air blower, but you do have to be much more careful / aware of the mirror as it is quite exposed to the elements -especially when you are assembling it. As we live quite close to the coast, I am ever so slightly paranoid by the seagulls that frequently pass overhead. For one thing, I don’t want the centre dot on the primary mirror to promote target practice! 

I'm in no rush 😀 Mine's generally kept inside the house with a shower cap on the bottom too, so pretty sealed up. It's going to have plenty of nights in the shed though during the winter after viewing, when the temp changes. I'm always mindful when I leave it out to cool of birds etc so leave it on the horizontal, just in case. Next mod might be a fan, going to look into making something up.

Edited by Stardaze
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Depends whats on it- organic material and dew can cause etching of the coatings. My 7 yr old dob has a small spot being etched from this despite cleaning. Tree pollen, bugs whatever should be cleaned off. 

Because of my conditions here I clean often, on advice from the mirror maker

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I've had my 12" Dob for about 7 years and my 6" Newt for about 5 years, both have been kept in the summer house, neither have been cleaned as both mirrors still look fine in fact the 6" still looks like new. The 12" mirror dews up during the winter months but the 6" has never dewed up, this probably explains why the 6" still looks like new.

Avtar

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1 hour ago, jetstream said:

Depends whats on it- organic material and dew can cause etching of the coatings. My 7 yr old dob has a small spot being etched from this despite cleaning. Tree pollen, bugs whatever should be cleaned off. 

Because of my conditions here I clean often, on advice from the mirror maker

Is dew a constant problem for you? Only the once here but bought the dew kit in readiness for the winter.

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2 hours ago, Stardaze said:

Is dew a constant problem for you? Only the once here but bought the dew kit in readiness for the winter.

If you bring your scope inside from the cold it can dew up- I leave my dobs in an unheated sea can with a small bulb on in the winter near the primaries. Refractors can have fits from the cold so I use an insulated case to bring them in which prevents dew.

I live in an area of extreme climate in northern ontario though so maybe your circumstances are different.

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13 hours ago, jetstream said:

If you bring your scope inside from the cold it can dew up- I leave my dobs in an unheated sea can with a small bulb on in the winter near the primaries. Refractors can have fits from the cold so I use an insulated case to bring them in which prevents dew.

I live in an area of extreme climate in northern ontario though so maybe your circumstances are different.

I guess I wish I had those problems Gerry 😀 

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I've not selected as they've been cleaned within the past year having either been recently acquired or overhauled. I'd say that I would do them as needed with no fixed schedule but no option for that 🙂 

So far I've not had dew issues but stored in the conservatory they see very little temp change when moved outside or back inside. I usually leave the conservatory door open when out back with the scope which stabilises the temps tho I do that more for convenience really.

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