Coronado BF30 rusted and repair

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rsfoto
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Coronado BF30 rusted and repair

Post by rsfoto »

¡WARNING! ¡NOT FOR VISUAL USE!

Hi,

The BF30 which I am using since long time got rusty many years ago and Iread here that instead of an ITF a H-alpha filter could be used. I had a 2" spare one, took it our of the mounting and glued it wih silicone at the front.

Now I found out the unmounted 2" filter fits into the 2" filter housing so I decided to print two washers and sandwich the H-Alpha filter inbetween. One washer has a bit of flocked paper so the H-alpha filter does not crack when tightening the ring.

BF_Ha_2.jpg
BF_Ha_2.jpg (105.18 KiB) Viewed 712 times
BF_Ha_1.jpg
BF_Ha_1.jpg (251.15 KiB) Viewed 712 times
BF_Ha_3.jpg
BF_Ha_3.jpg (216.18 KiB) Viewed 712 times
As I have two more I offered a friend if he wanted to try one and saw it was rusted too so I decided to use a 1.25 H-alpha filter instead of the rusted ITF and below the solution. I printed an adapter in the outer size of the ITF and inside a M28.5x0.6 thread.

BF_Ha_4.jpg
BF_Ha_4.jpg (199.36 KiB) Viewed 712 times
Last edited by rsfoto on Tue Jun 25, 2024 9:02 pm, edited 3 times in total.


regards Rainer

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San Luis Potosi Mexico

North 22° West 101°
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Re: Coronado BF30 rusted and repair

Post by marktownley »

Nice mod thanks Rainer


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Re: Coronado BF30 rusted and repair

Post by Bob Yoesle »

Hi Rainer,

Just an important safety note for visual use that most of the newer H alpha filters by themselves are probably NOT a replacement for the ITF. The ITF is blocked from the deep UV to ~ 5000 nm to OD5.

Most dielectric filter coatings are only blocked out to ~1200 nm. It most certainly is not blocked out to > 3000 nm of the solar irradiance profile. For this you'd have to add a KG3 filter.

It would need to have OD5 blocking in the 300-790 nm range. Unless it is on a RG610 or RG630 substrate (like the ITF and older nighttime H alpha filters), it likely it is no more than OD4 in this range.

Bob


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Re: Coronado BF30 rusted and repair

Post by rsfoto »

Bob Yoesle wrote: Thu Apr 25, 2024 12:25 pm Hi Rainer,

Just an important safety note for visual use that most of the newer H alpha filters by themselves are probably NOT a replacement for the ITF. The ITF is blocked from the deep UV to ~ 5000 nm to OD5.

Most dielectric filter coatings are only blocked out to ~1200 nm. It most certainly is not blocked out to > 3000 nm of the solar irradiance profile. For this you'd have to add a KG3 filter.

It would need to have OD5 blocking in the 300-790 nm range. Unless it is on a RG610 or RG630 substrate (like the ITF and older nighttime H alpha filters), it likely it is no more than OD4 in this range.

Bob
Thanks Bob and yes I know that but I do NOT do any visual observing. Only imaging.

I just mofified my original posting and added a WARNING notice to it


regards Rainer

Observatorio Real de 14
San Luis Potosi Mexico

North 22° West 101°
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