Replacing the Rusted BF30 Filter

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Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Tue May 08, 2018 7:59 pm

I'm looking at replacing my rusted straight through BF30 filter with a durable ITF Beloptik filter. I understand that I will also need a UV/IRcutKG3 filter as well since the double stacked Coronado (external) SM90's use a front red ERF filter.

Can somebody direct me where I can find the layout of the blocking filter, a simple diagram will do showing their positions. Is the ITF filter and UV/IRcutKG3 filter sandwiched together? If so, will the filters fit in the cavity left from the rusted BF30 filter? What is the orientation of the ITF filter? I would presume that the UV/IRcutKG3 filter is placed before the ITF filter? Is it an easy straight forward conversion in changing the filter?

Sorry about the large number of question but your advise would be appreciated.

George
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Tue May 08, 2018 8:57 pm

This sounds interesting for me in a near future, but on the other side I have been getting all my new BF30 free of charge refunded by MEADE eg. former Coronado as when I bought them they came with Lifetime warranty.
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Re: Replacing the Rusted BF30 Filter

Post by christian viladrich » Thu May 10, 2018 11:33 am

Hi,
The Beloptik ITF includes the UV/IRcut and KG3.
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Thu May 10, 2018 7:20 pm

Thank you Christian.

George
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Thu May 10, 2018 7:36 pm

GeorgeIonas wrote:
Thu May 10, 2018 7:20 pm
Thank you Christian.

George
Yesterday I did send an e-mail to Beloptik asking for BF30 filters. So far no answer.

Rainer
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Fri May 11, 2018 12:04 am

Hi Rainer,

Oliver at Beloptik said that Friday is a public holiday.

George
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Re: Replacing the Rusted BF30 Filter

Post by Merlin66 » Fri May 11, 2018 12:26 am

George,
We’ve had success using the Baader 35nm Ha CCD filter as a replacement for the ITF.
Just remove the old ITF, and screw the Baader onto the front of the body.
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Fri May 11, 2018 5:20 am

Thank you for the information Ken.

George
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Fri May 11, 2018 1:14 pm

GeorgeIonas wrote:
Fri May 11, 2018 12:04 am
Hi Rainer,

Oliver at Beloptik said that Friday is a public holiday.

George
Hi,

I got an answer from Oliver. He quoted me Euro € 280.00 (sans VAT) + shipping.

He asked me if the BF30 has 34 mm diameter. Anybody knows or I would have to open one of mine in order to measure it.

I am keen to order 3 so I do not have to worry about the ongoing back and forth to USA of my BF30

Rainer
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Fri May 11, 2018 1:24 pm

Merlin66 wrote:
Fri May 11, 2018 12:26 am
George,
We’ve had success using the Baader 35nm Ha CCD filter as a replacement for the ITF.
Just remove the old ITF, and screw the Baader onto the front of the body.
Hi Ken,

Interesting and thanks. Looking at my BF30 the elements are tilted and just screwing in a filter would mean the surface is not tilted. ¿ no Problems with reflections ?

Rainer
Last edited by rsfoto on Fri May 11, 2018 11:47 pm, edited 1 time in total.
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Re: Replacing the Rusted BF30 Filter

Post by Merlin66 » Fri May 11, 2018 10:37 pm

Rainer,
No, no problems.
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Fri May 11, 2018 11:47 pm

Merlin66 wrote:
Fri May 11, 2018 10:37 pm
Rainer,
No, no problems.
Thank you
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Sun May 13, 2018 10:15 am

Hi Rainer,
I had an email from Oliver Smie from Beloptic suggesting that I would only require the UV/IRcutKG3 filter as an ITF replacement with diameter of 34mm for my double stacked Coronado SM90 Etalons.

What I don't understand is why I only require the UV/IRcutKG3 filter and not their replacement ITF ?

George
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Fri May 18, 2018 5:43 pm

GeorgeIonas wrote:
Sun May 13, 2018 10:15 am
Hi Rainer,
I had an email from Oliver Smie from Beloptic suggesting that I would only require the UV/IRcutKG3 filter as an ITF replacement with diameter of 34mm for my double stacked Coronado SM90 Etalons.

What I don't understand is why I only require the UV/IRcutKG3 filter and not their replacement ITF ?

George
Yes that he said to me too. I talked by phone with him about it.

Because a BF30 has 2 elements in there. If you unscrew the rusted element you will see a second filter a bit deeper in the 2" housing.
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Fri May 18, 2018 5:46 pm

Merlin66 wrote:
Fri May 11, 2018 12:26 am
George,
We’ve had success using the Baader 35nm Ha CCD filter as a replacement for the ITF.
Just remove the old ITF, and screw the Baader onto the front of the body.
Hi Ken,

I found a 12nm 2" Ha filter from Astronomik in my unused filter collection. I guess I can use that one too as ERF in front of the ITF at the fron of the BF30?

I take out the rusted part and screw this filter into the 2" nosepiece.

Thanks Rainer
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Re: Replacing the Rusted BF30 Filter

Post by Bob Yoesle » Fri May 18, 2018 6:24 pm

I went with the BelOptik UV/IR KG3 as my BF30 ITF replacement, and couldn't be happier:

viewtopic.php?f=9&t=14783

Oliver can turn it down to 34 mm in diameter as he did for me so it is a drop-in replacement. As long as you have another RG630 element in the filter stew,such as the etalon ERF, you'll have good to even better results than the OEM ITF.
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Fri May 18, 2018 11:05 pm

Hi Bob,

I read your post "A filter journey" which explains all that I need to know - excellent post !

Oliver has sent me the replacement UV/IRcutKG3 filter for the DS SM90s. My other option was to use a Baader 35nm Ha filter as suggested by Ken.

I just don't know why Meade do not use this conversion on there BF filters, it would stop the filters continually going back for repair.

George
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Re: Replacing the Rusted BF30 Filter

Post by Merlin66 » Sat May 19, 2018 1:26 am

Rainer,
My experience is with the Baader filter, but the Astronomik should work OK.
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Re: Replacing the Rusted BF30 Filter

Post by TheSkyBurner » Sat May 19, 2018 1:52 am

KG3 glass absorbes moisture over time and suffers from environmental damage over time as well, so it is also not a long term solution unfortunately. It is also only od2 blocking I believe and this is why the blocking filter has multiple elements and must work in junction to the ERF filter.. The only permanent solution is a hard coated filter with od6 blocking from 300 to 1500nm, and this does not exist at the moment. (but it could if buyers were interested!)

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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Sat May 19, 2018 5:25 pm

GeorgeIonas wrote:
Fri May 18, 2018 11:05 pm
Hi Bob,

I read your post "A filter journey" which explains all that I need to know - excellent post !

Oliver has sent me the replacement UV/IRcutKG3 filter for the DS SM90s. My other option was to use a Baader 35nm Ha filter as suggested by Ken.

I just don't know why Meade do not use this conversion on there BF filters, it would stop the filters continually going back for repair.

George
Hi George,

Did you order the 2" filter ? If yes I think I have bad news. I found a 2" Ha 12nm bandwidth filter from Astronomik Gerd Neumann and tried to thread it into the from part of the 2" nose piece of my BF30 and it does NOT fit :shock: and I tried it on 3 three different BF30 I have here and NO luck.

The 2" filters do not thread into the front part of the 2" nose piece of the BF30, at least 3 three of mine.

Rainer
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Sat May 19, 2018 7:48 pm

Hi,

OK after finding out the 2" standadrd filters do not thread onto the nose piece what I did with my US $ 280.00 Ha 12nm filter was to take out the glass and glue it onto the front part of the original threaded holder.

Below 2 images with original rust and new 12nm Ha filter.

The focusing point moved and I gained speed in my camera eg the exposure time went down by about 20-25% :seesaw

Below two images which look for me absolutely the same. ;)

So now I will see how long lasts the 12nm Ha filter there.

2018-05-19_12-09-00_pp-1f_500.jpg
2018-05-19_12-09-00_pp-1f_500.jpg (602.87 KiB) Viewed 1084 times
2018-05-19_12-30-16_pp-1f_500.jpg
2018-05-19_12-30-16_pp-1f_500.jpg (560.83 KiB) Viewed 1084 times
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Re: Replacing the Rusted BF30 Filter

Post by Merlin66 » Sat May 19, 2018 9:29 pm

TheSkyBurner <Name>?
The safety requirements for extended VISUAL solar exposure is ND5 across the full spectrum. This does not obviously apply to imaging situations.

There's a copy of the ICNIRP Review in the Solar Chat Reference Library.

Rainer,
Hmmm, sorry to hear the Astronomik didn't fit.....but the final outcome looks satisfactory.
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Re: Replacing the Rusted BF30 Filter

Post by GeorgeIonas » Sun May 20, 2018 12:07 am

Hi Rainer,

I went with the UV/IRcutKG3 filter cut down to 34mm so it would be a easy "drop in" replacement into the BF30.

Sorry to hear that the 12nm Ha filter did not thread into the BF30. An alternative would be to screw the filter into a short extension tube in front to the BF30.

On another note it is good to hear that you can reduce your exposure times, this helps to beat poor seeing.

George
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Re: Replacing the Rusted BF30 Filter

Post by mdwmark » Sun May 20, 2018 2:55 am

You got me worried here. When you start replacing part without knowing the design.
If you look at the blocker filter. It will be between .6nm-1nm HW. I'm petty sure its a standard coating. Well put it at 656.3nm +/-.3nm. Just the bandpass will turn back on at about 700nm on the red side and 480m on the blue side. If they designed it to be blocked to 1000nm. Then the KG3 or KG5 will block the long side just fine.But if it's not block that far in the red, then the ITF is what is required. The KG glass is still transmitting at 700nm. For the short side the RG630
can handle that. So if they have a ITF in the stack there probably a reason. If you can replace it for less then $300 then that is still a good deal. If made right they should last 5-8 years.
There was a comment about using a hard coated blocker. You still have the problem of the IR pass the 1500nm . There is still a lot of IR light making it way through. Once you get out to 2400nm the amount of IR making it pass the atmosphere is very low. You shouldn't have to worry about anything that far out. Besides the ITF and the KG are still working at 3000nm.
PS: I have been using hard coated blockers for two years on the TEC models . Also I do not use KG glass because of the problems that were stated earlier.
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Re: Replacing the Rusted BF30 Filter

Post by rsfoto » Sun May 20, 2018 3:17 am

Merlin66 wrote:
Sat May 19, 2018 9:29 pm
TheSkyBurner <Name>?
The safety requirements for extended VISUAL solar exposure is ND5 across the full spectrum. This does not obviously apply to imaging situations.

There's a copy of the ICNIRP Review in the Solar Chat Reference Library.

Rainer,
Hmmm, sorry to hear the Astronomik didn't fit.....but the final outcome looks satisfactory.
Hi Ken,

You do not need to be sorry.

Not the Astronomik and not any other standard 2" filter did fit.

Rainer
Last edited by rsfoto on Sun May 20, 2018 3:21 am, edited 1 time in total.
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