Rust on either Lunt or Coronado

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
Post Reply
RKBerta
The Sun?
The Sun?
Posts: 4
Joined: Wed Nov 07, 2018 7:08 pm

Rust on either Lunt or Coronado

Post by RKBerta » Wed Nov 14, 2018 3:29 am

I have a 60mm Coronado Ha filter and both a BF15 and BF30 blocking filter also Coronado. It is used on a TV 85 APO refractor. I did have Meade replace the BF 15 filter because of rust but the BF30 is holding up thus far. All equipment was US produced before Coronado moved facility to Mexico.

I am contemplating upgrading to either a Lunt 100 or 152 with double stacking. Is rust also an issue on some Lunts or have either Coronado or Lunt solved it?

Also....since it seems moisture is a cause of the rust....guess getting between the two elements, I have been using a moisture absorbing device in the case to suck up any moisture. Have others found that to be useful or not?

User avatar
Merlin66
Librarian
Librarian
Posts: 3167
Joined: Tue Dec 13, 2011 1:23 pm
Location: St Leonards, Australia
Contact:

Re: Rust on either Lunt or Coronado

Post by Merlin66 » Wed Nov 14, 2018 9:59 am

Failure of the ITF filter in both the Lunt and Coronado is still a common occurrence.
I know know if it really helps but I do store my BF in sealed containers with Silica Gel.......
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

4average
The Sun?
The Sun?
Posts: 1
Joined: Wed Oct 10, 2018 7:50 pm

Re: Rust on either Lunt or Coronado

Post by 4average » Wed Nov 14, 2018 6:10 pm

https://www.cloudynights.com/topic/4330 ... ?p=5592771

Lunt no longer uses ITF in its blocking

User avatar
Merlin66
Librarian
Librarian
Posts: 3167
Joined: Tue Dec 13, 2011 1:23 pm
Location: St Leonards, Australia
Contact:

Re: Rust on either Lunt or Coronado

Post by Merlin66 » Wed Nov 14, 2018 10:47 pm

I agree, but the Lunt replacement BG element is also subject to failures....
B1200_failure_iis.jpg
B1200_failure_iis.jpg (163.58 KiB) Viewed 329 times
Lunt-blocking-filter-problem_12-09-25_12r.jpg
Lunt-blocking-filter-problem_12-09-25_12r.jpg (195.12 KiB) Viewed 329 times
IMG_9852_lunt b1200.jpg
IMG_9852_lunt b1200.jpg (102.82 KiB) Viewed 329 times
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

RKBerta
The Sun?
The Sun?
Posts: 4
Joined: Wed Nov 07, 2018 7:08 pm

Re: Rust on either Lunt or Coronado

Post by RKBerta » Sun Nov 18, 2018 7:56 pm

Thanks all for feedback. Sad that this evidently is still an issue after all these years with both C and L products. Hopefully using a desiccant pack in my case will help. Luckily where I live humidity isn't a big issue like it was where I lived before.

mdwmark
Ohhhhhh My!
Ohhhhhh My!
Posts: 127
Joined: Tue Mar 04, 2014 6:13 pm

Re: Rust on either Lunt or Coronado

Post by mdwmark » Mon Nov 19, 2018 1:21 am

That's not a humidity problem on the images. Humidity usually fails from the outside in. This is something different.
Mark W.

User avatar
Bob Yoesle
Im an EXPERT!
Im an EXPERT!
Posts: 473
Joined: Thu Mar 08, 2012 7:24 pm

Post by Bob Yoesle » Mon Nov 19, 2018 3:16 pm

As shown in Ken's pics, and as in the above Cloudy Nights link, the Lunt issue now appears to be "glass disease:"

https://en.wikipedia.org/wiki/Glass_disease

See the Stage 1 and Sage 2 descriptions.

It is known the Lunt uses BG glass (verses an ITF), which is a simple soda lime glass. It seems the KG glasses are susceptible to UV exposure deterioration, and perhaps this UV exposure is some sort of accelerator for glass disease, especially the concentrated exposure near focus. The solution would seem to be coatings to protect the surface from both moisture and UV penetration. I note that Oliver uses a UV/IR blocking coating on his KG3 BelOptik glass filters...

Lunt seems to be well aware of the issue and will send you a new BG element for free as a replacement if the problem develops.

During the winter and in high humidity months I store my blocking filters in a sealed food storage vacuum bag with a desiccant, and have employed UV/IR blocking filters and DERF's ahead of every ITF. So far no problems with ITF failure after 10 years. Prior to using these methods I had 2 failures within two years. It would be interesting to see if these methods would have an effect on the standard BG filter used by Lunt.
Last edited by Bob Yoesle on Mon Nov 19, 2018 5:35 pm, edited 1 time in total.
Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders

User avatar
Christopher
Ohhhhhh My!
Ohhhhhh My!
Posts: 96
Joined: Tue Sep 26, 2017 2:07 am
Location: Cincinnati, OH USA

Re: Rust on either Lunt or Coronado

Post by Christopher » Fri Nov 23, 2018 3:30 am

The wonder fluid is great stuff. I’ve been using it for years. I can’t attest to it being a cure for the aforementioned glass disease one way or the other. But I use it to clean all my optics. It does claim to protect from fungus etc. I get it from Alpine Astro here in the states.
Christopher

"Our imagination is stretched to the utmost, not, as in fiction, to imagine things which are not really there, but just to comprehend those things which 'are' there.". -Feynman

Zeiss APQ 130, MiniBorg 45ED, Lunt 100THa

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests