B1200 Lunt blocking filter degradation

[rat156]

Hi All,

Of particular interest to those of you who have a B1200 BF from Lunt.

I took my solar scope out yesterday to align my mount as I have made some modifications to the pier. The PMX rough alignment just needs one known point, so I decided to use the sun. On looking through the Lunt 60Ha I noticed that the view was quite fuzzy, not out of focus, but like looking through cloud. I looked up at the sun and saw that, indeed, the sun was behind sone high level cloud, didn't think much more of it. Until the sun cleared the cloud and I had another look, still a rubbish view.

I opened up the B1200 and saw this. I have contacted Lunt to find out what the options are, a new BF is about $850. There is a known faulty batch of these filters, so if you have one check it.

Cheers
Stuart

[h0ughy]

yep look here - http://www.iceinspace.com.au/forum/showthread.php?t=91015&highlight=lunt - BTW Bintel have replacement filters

[Paddy]

This happened to my BF 600 horribly close to the eclipse. Lunt are very good about replacing them for free, but I found it useful to talk to Faye at Lunt by phone (skype - cheap). Local stockists had nothing at the time.

I couldn't be happier with their response. I did end up upgrading to a BD1200 anyway which gave much better views.

[rat156]

Thanks Houghy, I'll be ringing them tomorrow.

Cheers
Stuart

[Poita]

My B600 was the same, had to send it back to Lunt and they had it recoated and sent back to me.

[Merlin66]

Stuart,
It's not just a faulty batch.
The "mini-erf" filter element in both the Coronado and the Lunt Ha scopes seem to suffer from premature failure. No satisfactory reason has been given, but when using and/ or aquiring an Ha scope it's worth checking out.
The actual narrow band blocking filter element (between the mini-erf and the eyepiece) seems to be far more resilient and I have no record of failures.

[MikeyB]

I wish I hadn't looked - my B1200 has got the filter-rot too. :(

How do I detach the diagonal mounting barrel from the body of the diagonal, as has been done in the linked pics? Do I use brute-force twisting to (presumably) break the Loctite seal or is their a gentler, correct way?

[Rob P]

I had the same problem a couple of months back.

I'd purchased my Lunt though Bintel. Sent off a couple of phtoto's and received a speedy response from Malcolm (if I remember correctly) advising me to send it down for replacement.

All completed with in a week (including the postage time, which for tropical Qld is a bloody miracle), no headaches involved at all and, so far, no re-occurrence of the problem.

[rat156]

Both ends of the diagonal unscrew, so you can get at the filter.

If you are the original purchaser, then Bintel will replace the filter for free. If, however, you are not the original purchaser ( as I am, bought the scope off IIS, a couple of years ago) then they will want to charge $110 for the service.

Take some photos, send them to Lunt, with the serial number of the scope and they'll send you the new filter. It's a simple matter to install.

Cheers
Stuart

[MikeyB]

Thanks, Stuart. Your purchase situation is the same as mine and that's exactly the info I need: much appreciated.

[Merlin66]

The breakdown of the "mini-erf" section of the Blocking filter assembly is not unsafe...it just has a significant effect on the loss of contrast and definition.

[tempestwizz]

More Kudos for Lunt.
I checked my owned B1200 which was parto of a LS60T I bought of an IISer some four or five years ago. Had never removed the diagonal from thedrawtube and inspected previously.
Noting mine also was/is degraded, I took photos of Serial number, the B1200 and a few different angles on the faulty filter and emailed Lunt.
Overnight I received a response asking for my mailing address to which they advised they will send a replacement filter.
Can't complain about that!