Getting more light through my Rumak180 safely

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AndiesHandyHandies
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Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

I have recently added a CLP to reduce the various filter reflections but with a reduction in brightness.

Using a Baader 35nm as a ERF.

Using a Bekoptic UV-IR KG3 for long IR reduction. Rod says a KG1 on its own dims the image.

Then a Omega 1.5A as a blocker and the PST Etalon.

And a CLP after the PST etalon but before the moved back re-imaging lens.

Would a dichoric red do in place of the 35nm which can pass more red. Bob uses a Baader Red.

Do I need to worry about the long IR for amatuer visual solar observing?

Does an eyepiece reduce the long IR?

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

Long IR safety.

Most UV-IR filters show blocking out to 1100nm, restriction tester? Baader show switching on after.

CAF2 blocks long IR

https://www.google.com/search?q=bk7+gla ... ux4Vfr6wEM

And on AliExpress I can but a 25mm 1mm CAF2 optical window.

https://www.aliexpress.com/item/3283671 ... lsrc=aw.ds

Would this in a Celestron/SW plastic Moon Filter on the eyepiece give sufficient long IR protection, if its needed.
Use a red CCD dichoric filter up front as a ERF. More transmission at H-Alpha than a Baader 35nm. I assume the dichoric will protect out to 1100nm.

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by george9 »

For naked eye eclipse viewing, you don't need to worry about long IR, but in a telescope I worry that the long IR could be amplified, and so yes I keep it safe. The CaF2 you reference I think blocks 10,000nm and up, so very long IR and not useful. You need 1000-3000nm. I use the KG3 and yes I give up the 30-40% at H-alpha as a consequence. I also wonder what other filter might do better. A thinner KG3 might be sufficient in long IR but pass more H-alpha.

George


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi George,

Did not clock the larger scale, Thanks.

Merlin I think says short exposure to the long IR over 1100nm is OK.

A filter for our particular requirements would be great.

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

Would this be safe with a red dichoric which blocks out to 1100nm?

https://www.newport.com/p/10SWF-1100-B# ... 5526612343

Better than a KG3 for transmission?

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

BK7 blocks over 2700nm so need a filter blocking out to there as eyepiece glass should block.

https://www.google.com/search?q=bk7+tra ... OzClE8orMM

Asked Newport about transmission switching on again at longer wavelengths.

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

One problem is different peoples transmission graphs for the same thing are different.

Shott KG3

https://www.sydor.com/wp-content/upload ... Filter.pdf

Shows OD4 at 1200nm but switches on a bit after that. But as supplied now with solar scopes and offered by Beloptik as part of a ITF replacement enough dimmimg to be safe I presume for longer IR.

BK7 used in my Rumak 180 Corrector, any prism diagonal or eyepeice lens in general dips down at 2700nm but then switches on a bit after. If you could get a Red Baader CCD type dichoric filter but blocking out to 2700nm then that might be safe along with a BK7 component, thick prism ideal. Dichoric would have much better transmission at H-alpha tham KG3 is the advantage.

Need to try some test with my cheap thermometer.

I know the Beloptik KG3 reduces the temperature added at the eyepiece end.

Seperately:

Not tested to see if eyepiece does the same as a test, but a bit of thermometer waving on 127mm 4.2x Quark Chromo did seem to show a reduced temperature when a 40mm Celestron Plossl was added, which is reasonable if blocking some longer IR.

Has anyone seen transmission graphs for Quarks? Or any replacement Andover blocking filters or ERFs?

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

One image with a promising longer IR was from a filter design consultancy and just a simulation.

Newport said no optical filter supplier will show graphs over 1500nm.

Also their KG3 is not warranted over 1100nm.

Adding the KG3 to my bino-viewer PST setup today reduced the remote thermometer reading by 6C so it does absorb extra energy.

Unless there is some new development I am stuck with what I have.

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by mdwmark »

OK , DON'T BE FOOLED THAT FOR VISUAL YOU ONLY NEED TO BE BLOCKED TO 1100NM.
KG3 AND KG5 ARE YOU BEST CHOICES. iF YOU DON'T WANT TO USE A ITF. ALL THREE WILL TRANSMIT ABOUT THE SAME AT HA. IF YOUR PRE-BLOCKING IS TO AT LEAST TO 900NM THE KG GLASS WILL BE SAFE TO THE FAR IR. THE ONLY PROBLEM WITH KG GLASS IS THAT IT ABSORBS WATER. SO YOU MAY HAVE TO CHANGE IT OVER TIME.
NOW TO BE HONEST I TESTED A FILTER ON THE SUN THAT WAS BLOCKED TO ONLY 800NM. I ONLY LOOKED THROUGH FOR LESS THEN A MINUTE. AFTERWORDS I COULD NOT FOCUS ANYTHING WITH THAT EYE. AFTER ABOUT AN HOUR EVERYTHING WAS FINE. I CONCERTED MYSELF LUCKY. SO MAKE SURE THAT IT IS FULLY BLOCKED IN THE IR BEFORE YOU USE IT VISUALLY!!!
Mark W.


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

Well the KG3 seems to be the only long IR option.

Would going to a Baader Red CCD filter for my ERF result in brighter H-alpha but does the wider bandwidth than a 35nm result in more scatter or heating issues?

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by marktownley »

I really dont think there will be a huge difference Andrew


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

Had a session with the PST mod on the Rumak 180 today and the bino-viewers.

Took out the slide in baffle Rodastro made for me. And luckily found a 1.25" Svbonny UV-IR filter just jams in the front. Slight vignetting from the design size of the baffle to give 8mm illuminated spot to match sweet spot.

Tried without Baader 35nm but Bobs 1.5A filter has a blue green leak as I forgot. Tried a cheap Meade dichoric before but that had a green leak.

The front of the PST mod nosepiece with the pushed forward collimator lens felt cool.

Next time try two red filters I have.

Moved the Beloptik KG3 after the PST as less energy on it there so safer from damage.

I could see the proms on Gong OK. And some surface mottles.

Cheers. Andrew.


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Re: Getting more light through my Rumak180 safely

Post by marktownley »

Be careful with all these blue green leaks, they won't be good for eyesight!


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Re: Getting more light through my Rumak180 safely

Post by AndiesHandyHandies »

Hi

I appreciate that.

The Baader definitely stops them.

Double UV filters.

See if a red glass filter stops and brighter red?

A cheap Meade red dichoric had a green leak so no good.

Cheers. Andrew.


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