Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Reflectors

Pages: 1 | 2 | (show all)
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Did I damage my primary mirror??
      #6488099 - 04/25/14 03:01 PM

Ok, so I just bought my first scope about a month and a half ago, a used Zhumell Z10 It is great shape and looks well taken care of. It had a good bit of dust on the primary mirror and a couple smudges on the secondary so after watching several youtube videos and reading many articles and post on here I decided to pull em out and clean em. I used tap water and a tiny bit of dishwashing liquid to let it soak for about 15 min, rinsed with tap water and wiped very softly with my fingers and then cotton balls changing balls after ever swipe from the center to the outside edge. I did a final rinse with a gallon of distilled water and leaned it up against the wall to dry. Now for the issue. When I inspected it after drying, the mirror appears to have a goldish or copper colored dust on it, but there is not actually any dust on the mirror. You really can't see it when you look at it straight on, but when you look at it from an angle with the mirror out or shine down the tube you can see it. I have used the scope once since the cleaning and the views look good, but I don't really have anything to compare to. BTW, I did everything the same way with the secondary and it looks perfect. If this issue doesn't ring any bells to anyone, I will take some pictures and post them.

Post Extras: Print Post   Remind Me!   Notify Moderator  
The Planetman
professor emeritus
*****

Reged: 01/27/06

Loc: Western KY
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6488114 - 04/25/14 03:08 PM

No, you didn't damage them. The coatings are fairly durable.
Question though....
Did you collimate it after reassembly?


Post Extras: Print Post   Remind Me!   Notify Moderator  
sixela
Postmaster
*****

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Did I damage my primary mirror?? new [Re: The Planetman]
      #6488167 - 04/25/14 03:24 PM

We'd like to have pictures, yes.
Usually, it's just some residue picked up by the distilled water before it finally dried (which is why I tend to use a hair dryer to minimise the time it takes for the water to evaporate.

But it could also have been something starting to degrade the coatings (where do you store your scope? Not in a garage with a car that happens to have a running engine just next to it, I hope, nor very close to a sea with lots of salt ions in the air...)


Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? new [Re: The Planetman]
      #6488168 - 04/25/14 03:25 PM

Hey The Planetman, Dawson Springs isn't too far away from me.
I did collimate, with an Autosystems laser. I'm still figuring all the collimating stuff out and I think I'm in the "ballpark". Not that I really know how to star test, but it looks good going by the pictures and videos of star test I have seen. I'm getting a collimating cap and have a Tublug on the way. The laser is just slightly out of collimation and I'm working on a jig to fix that. So to sum all this up, I think my collimation is probably passable but certainly not perfect.


Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? new [Re: sixela]
      #6488219 - 04/25/14 03:44 PM

If I can figure out how to post pictures, I just took some and will get them on here.
I just pulled it back out to take a closer look at it. It looks similar to when you focus in on a quartz counter top except really small of course, it appears to have tiny gold flake in it. Now I need to clarify a bit, under a normal overhead light fixture looking at it with the mirror in your hands, it looks perfect. No water spots, scratches or anything. when I use my high powered LED light and look at it closely that is when I can see a gold cast in the mirror. I can also see it looking down the tube with a low powered red light at night. I am probably overreacting about this, at least I hope so.


Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6488238 - 04/25/14 03:50 PM

Oh, I forgot to answer some of your questions. I kept it in the house for a while, but everything was sweating really bad when I brought it in at the end of the night. The previous owner said he kept it in the house and the outside of the scope seems to confirm this. Now I am keeping it in a storage building, It's dry, no vehicles or chemicals in there and I don't live close to the ocean. The humidity can get high here, but I've only had it for 1 1/2 months now.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Billytk
Pooh-Bah


Reged: 04/22/12

Loc: Lake Mary, Fl.
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6488319 - 04/25/14 04:39 PM

Your mirror is fine, it's the coatings they put on the mirror. Keep your scope in an unheated garage if possible. Get a shower cap to cover the mirror end and cover the scope with something. this will reduce cool down times. when you bring the scope in for the night, keep the tube horizontal so that any dew that may form will run off the mirror.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6488822 - 04/25/14 09:29 PM

I've had this same result with tanish coloring remaining on my mirror when I used acetone and generic cotton pads for a final rinse. Don't use pharmacy store cotton. It can leave a colored residue with certain liquids. Use certified optical paper or wipes. Re-clean the mirror and the coloring will disappear.

Quote:

Ok, so I just bought my first scope about a month and a half ago, a used Zhumell Z10 It is great shape and looks well taken care of. It had a good bit of dust on the primary mirror and a couple smudges on the secondary so after watching several youtube videos and reading many articles and post on here I decided to pull em out and clean em. I used tap water and a tiny bit of dishwashing liquid to let it soak for about 15 min, rinsed with tap water and wiped very softly with my fingers and then cotton balls changing balls after ever swipe from the center to the outside edge. I did a final rinse with a gallon of distilled water and leaned it up against the wall to dry. Now for the issue. When I inspected it after drying, the mirror appears to have a goldish or copper colored dust on it, but there is not actually any dust on the mirror. You really can't see it when you look at it straight on, but when you look at it from an angle with the mirror out or shine down the tube you can see it. I have used the scope once since the cleaning and the views look good, but I don't really have anything to compare to. BTW, I did everything the same way with the secondary and it looks perfect. If this issue doesn't ring any bells to anyone, I will take some pictures and post them.




Edited by Peter Natscher (04/25/14 10:34 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
okieav8rAdministrator
I'd rather be flying!
*****

Reged: 03/01/09

Loc: Oklahoma!
Re: Did I damage my primary mirror?? new [Re: Peter Natscher]
      #6488885 - 04/25/14 10:14 PM

Quote:

I've had this same result with tanish coloring remaining on my mirror when I used acetone and generic cotton pads for a final rinse. Don't use pharmacy store cotton. It can leave a colored residue with certain liquids. Use certified optical paper or wipes. Re-lean the mirror and the coloring will disappear.





If you're using cotton, make sure it is medical grade cotton--which is pure, sterile cotton, and nothing more. It isn't capable of discoloring a mirror. It's never caused any cleaning issues for me.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Bill Weir
Carpal Tunnel
*****

Reged: 06/01/04

Loc: Metchosin (Victoria), Canada
Re: Did I damage my primary mirror?? new [Re: okieav8r]
      #6489026 - 04/25/14 11:51 PM

Don't even use abrasives like cotton at all. Wet soapy fingers are good enough.

Bill


Post Extras: Print Post   Remind Me!   Notify Moderator  
TCW
Pooh-Bah


Reged: 11/05/13

Loc: The North 40
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6489057 - 04/26/14 12:29 AM

Don't know about the dust issue but the following may help a bit.

If you carefully rinse the mirror at an angle almost all the water will run off. Next keep the mirror at an angle and use compressed air from a can and gently blow the remaining water drops off. Don't use much or you will freeze the water drops to the mirror as the air coming from the can can be very cold due to expansion.


Post Extras: Print Post   Remind Me!   Notify Moderator  
John Fitzgerald
In Focus
*****

Reged: 01/04/04

Loc: AR
Re: Did I damage my primary mirror?? new [Re: TCW]
      #6489490 - 04/26/14 10:13 AM

Don't look at the mirror in the dark with a flashlight. A newly cleaned mirror will look horrible.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Binojunky
Carpal Tunnel
*****

Reged: 12/25/10

Re: Did I damage my primary mirror?? new [Re: Bill Weir]
      #6489562 - 04/26/14 10:42 AM

Quote:

Don't even use abrasives like cotton at all. Wet soapy fingers are good enough.

Bill




Hope you keep your nails nice and short? DA


Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? *DELETED* new [Re: Binojunky]
      #6489609 - 04/26/14 11:00 AM

Post deleted by staticclover

Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6489622 - 04/26/14 11:05 AM


I posted some photos of the primary on Google+, give this a try:Mirror pictures


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6490029 - 04/26/14 02:36 PM

Quote:


I posted some photos of the primary on Google+, give this a try:Mirror pictures



OK, the mirror in the pictures is, hopefully, filthy.
The bluish tint is the result, probably, of a MgFl2 overcoating (not a bad thing).
A goldish color could be indicative of tarnish in the aluminum coating, or it could be indicative of extra dielectric coating layers added to the mirror. If the color is only visible at an angle, but disappears when you look straight on, it's probably not tarnish. As aluminum tarnishes, it tends to appear grayer or hazier, anyway.
But, IF the mirror in the pictures has been freshly washed, then the mirror probably needs recoating. A freshly-coated mirror, if you look at a very bright light through the back of the mirror, will have a small handful of pinholes in the coating. I hold it up to the sun to see this, but a bright studio light will work.
As the coating ages, the number of pinholes increases. When the coating is really old and on its last legs, it looks like the mirror has measles, kind of like the pictures.
I'm hoping your pix were pre-cleaning.


Post Extras: Print Post   Remind Me!   Notify Moderator  
DocFinance
sage
*****

Reged: 01/14/14

Loc: Clear Lake, Texas
Re: Did I damage my primary mirror?? new [Re: Starman1]
      #6490054 - 04/26/14 02:46 PM

Never seen that kind of thing before. Yowza.

Post Extras: Print Post   Remind Me!   Notify Moderator  
staticclover
member


Reged: 02/12/14

Loc: Clinton, KY
Re: Did I damage my primary mirror?? new [Re: Starman1]
      #6490177 - 04/26/14 03:43 PM

This was a post cleaning picture. When I look at it in the sun or under bright overhead lights, it looks absolutely perfect. When I look down the tube at it at night with a red light, it appears to have some fine "dust" on it, but looks much better than before the cleaning. The light I was using to take the picture is a high powered 3 LED hunting light I use to do work around the farm after dark. This thing puts out a really strong white light. When you have it on in the rain, the reflection from the rain drops look like Christmas lights and animal's eyes can be seen from a loooong way off. So this light really shows the flaws in anything. I'm not sure if every primary would look this way under this type of light or if it's just mine. If I ever get the chance, I will try it on another mirror. Does the secondary mirror have the same coatings as the primary? The secondary mirror has none of the look that the primary does and I did the same cleaning process on it. The scope is only about a year old and the previous owner said he has never cleaned it and kept it in the house and it looked well taken care of when I picked it up. I don't believe this was a bad deal or anything, he sold this to get astrophotography set-up. If the mirror was already like this before I cleaned it, you wouldn't have been able to tell with the dust on it. It wasn't super dirty, but I just couldn't leave it alone.

Post Extras: Print Post   Remind Me!   Notify Moderator  
azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6490196 - 04/26/14 03:54 PM

You know what - get it recoated.

A ten inch mirror is not expensive to get recoated and you'll like your options the folks out there have to offer on different degrees of reflectivity.

Another thing - and I know Ill draw scorn for this but I'm careful about it and have NEVER introduced a sleek ever. After the typical soapy water thing, I rinse with tap water, then alchohol I leave it on its side to dry .

Ahhh that very pale blue haze at that low angle when studying the mirror. And, a residue spot here and there.

I've resigned to the notion these will NEVER come off chemically ever.

But, I didn't give up...

I open up a fresh box of Kleenex - take several in a loose bundle - MAKING ABSOLUTELY SURE MY FINGERS DON'T TOUCH the part that will contact the mirrors surface.

I give a dry rub a couple times and the haze is gone as are the water spots. And I mean virgin clean.

I give the tissues a fair shake before the dry buff.

There you go. Try it. If its still there - send that baby out and for probably $150 you'll have dandy new coatings better than it ever had and that includes the secondary.

Pete


Post Extras: Print Post   Remind Me!   Notify Moderator  
sickfish
super member


Reged: 01/13/09

Loc: Watertown Ma.
Re: Did I damage my primary mirror?? new [Re: staticclover]
      #6490201 - 04/26/14 03:57 PM

I have had my dob for 4 years and have not cleaned the mirror once based on what i have read here. I always thought a little dust is fine and just blowing it off and it should be ok. How old is this scope? Is this just age of the mirror?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
10 registered and 15 anonymous users are browsing this forum.

Moderator:  ausastronomer, Phillip Creed, JayinUT, okieav8r 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1191

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics