Front end replacement ERF for new "blue" PST??

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Re: Front end replacement ERF for new "blue" PST??

Post by Merlin66 »

I'm following up with them as we speak....let's see what happens.


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Hi All,
I just got this note from Maier Photonics about shipping the filter over seas

"If they contact me I can reply with email and attach a paypal invoice. It can be processed by credit card from there. I’ve done that before with Russian customers."

So it sounds like there should be no problems in selling the filters outside the USA.

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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Ok, email sent. I'll report back on what they say...


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Great news, they are happy to ship to me in the UK :)


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Great news, they are happy to ship to me in the UK :)

That is great news. I'm looking forward to what you think of the filter. It's Sunny here in Delaware, USA so I'm going out to use my PST with the new filter to see what is happening on the Sun.

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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Yes, i'm going to get one ordered and replace the rusting ITF in my BF10 - this isn't the original one, it's a replacement from a spare PST I had that has since rusted.

I going to send the original ITF to walter and hopefully he can measure the transmission against the Maier ITF, be interesting to see the difference.

Thanks for all your hard work with this Dave :)


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Re: Front end replacement ERF for new "blue" PST??

Post by Merlin66 »

Chris at Maier has also confirmed shipping to Oz.
He's also prepared to manufacture the ITF in larger sizes (to fit Coronado/ Lunt blocking filters!!??)


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

I've just ordered one. $6.55 for USPS First Class Mail International Parcel, or they do the uber quick, signed for and insured USPS service for ~$42. I just went for the cheaper option.

I can feel a review coming on soon :)


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Re: Front end replacement ERF for new "blue" PST??

Post by Merlin66 »

Mark, I've done likewise...it will be interesting to compare with the Baader 35nm Ha filter.
I need some feedback on preferred sizes for possible ITF replacements (Coronado/ Lunt). I'll measure the BF10/BF15 (and a BF30) ones I have here...what about other sizes/ variations.


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Hi All,
I worked with Chris Maier before. He made custom filters for a coronagraph I designed and I hosted a class were we built 20 of them in a weekend. Chris does great work and I very pleased with the replacement ITF he made for my PST. I'm sure if there is a market of larger units he'll add them to his product line.
I'm not happy that Meade quoted me a price of between $150 to $350 to replace me that only last 3 years and also told me that it take a number of weeks to complete the repair. On top of that I had the ship my PST to them. The filter just unscrews and takes maybe 10 minutes to change if you take your time.
Looking forward to the review by others. I hope that the words spreads that these filters are available from Maier so others can repair their PST and again enjoy observing the Sun with them. I have no connection with Maier Photonic except being a happy customer.

Happy Holidays,
- Dave


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

This is great for the world of PST repairs. It's a shame that Meade are so slow, slovenly and expensive with their service for the PST. I'm sure Chris will do well from this. He should come and join us on the forum.

I will certainly and quite happily put together a tutorial video showing how to change the ITF over.


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Dave, Ken and Mark

great News I read here. I'm more then willing to compare them with my UV/VIS gear


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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

Hello Folks,

I was able to try one of the new Maier Photonics ITF filters yesterday. The good news is that it is the correct size and does allow for Ha views but its throughput makes it very dim when compared to a Coronado ITF. I placed it in a BF5 and paired it with an SM40 on an 80mm f5 refractor. I also used a TV Binovue with 25mm EPs. It was immediately noticeable that the view was too dim. I swapped the BF5 for a stock Coronado BF15 and it was like going from a double stacked PST to the single SM40. To be sure that it wasn't just the BF5 blocking filter I replaced the Maier with the partially rusted ITF from my PST and it too was much brighter than the Maier. In a non double stacked PST this ITF is most likely okay but it would be, IMHO, useless if you double stack. I'm going to email Maier and see if he can make an ITF replacement with better light transmission.

Clear Skies,

Steve


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Steve,
The Maiers ITF was designed for a PST and not the BF5. diagonal. The transmission characterist of the BF-5 diagonal when matched with the SM-40 Etalon are different, and this why the image is dim. When I used the filter in my PST the image is bright and much brighter then my rusted ITF. As specs show the Maier ITF passes 70% of the H-alpha wavelength which I believe is higher then the original Meade ITF. There is a difference in how the PST works vs the SM40 with the BF series diagonals. For one the Etalon in the SM-40 already has a red long pass filter built in and the ITF in the BF series does not, while the ITF in the PST is combination of the both the red long pass filter and ITF. So if the Maiers filter is used with a SM-40 Etalon, the image would be much dimmer because now one has two long pass filters in the light path.
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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

Hi Dave,

I'm concerned that when double stacked this is going to be too dim. It was extremely dim with the SM40. The rusted PST ITF in the BF5 was performing similarly to a brand new BF15.

Steve


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »


Steve,
Your rusted ITF from your PST must be different then what is being used now in them. It is possible that it is ITF from BF diagonal ? All the ITFs I have seen that have come out of a PST are combination of two filter systems. The ITF layer is used to block IR, these layer is deposited on red filter glass which is Schott RG630. The ITF layer blocks very little light at 656nm so almost all of transmission at this wavelength is mostly determined by the Schott RG630 glass, which over 70%. That is very high.
In the BF series diagonals the ITF layer I believe it is placed on clear glass. The red Schott filter has been moved to the front element in the SM-40 Etalon. So in both a PST and the Solar Max system that is using a BF series diagonal, there is only one piece of the Schott RG630 red filter glass. If you use the Maier’s filter in place of the original ITF in the BF diagonal you now have two piece and that dims the image. If each piece transmits 70% the two together drop it to 50%.
Here is a picture showing my original rusted PST ITF on the left and the Maier filter on the right. As you can see the Maier filter is transmitting more light. The Maiers filter was designed for a PST and not a Solar Max system so there must be difference in the two system’s ITF which are causing the dimming your seeing.


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

You're spot on Dave, here is a pic of my rusted ITF from my BF10.







As you can see, it is on clear glass rather than RG630. I have put a ITF from a PST in place of the above, and have to say haven't had any problems with it on either my Coronado DS40 or my many PST mods...


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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

Hi Dave,

My PST is USA made circa 2006. The only difference that I can see between the three Coronado ITFs that I own are the two from the BF diagonals are edge blackened and the PST is not. I'm going to install the Maier in my PST and test it and I'm keeping an open mind. I to evenly illuminate the three ITFs but it's clear that the PST ITF is the brightest of the trio.

Steve


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Wow, what a little repository of information we're getting here. Good work chaps! :)


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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

After seeing Dave's, Mark's, and my own PST and BF ITFs I think that they are all essentially the same and Coronado uses or (used) whatever ITF filters that they had on hand at the time of production. I tried my PST with just a piece of KG3 and no ERF of any kind and I still got very nice Ha views at the EP. I do think it's MUCH WISER to use at least a red filter before the KG3 for IR safety but it isn't necessary to achieve Ha views. A Baader UV/IR plus a 610 LP at the objective end with the KG3 in the BF assembly has given me the best Ha views from my PST by a significant margin.


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Steve,
Your picture clearly show that both your BF-15 and rusted PST ITFs are using clear glass as the substrate just like Mark's BF-10 ITF. So that is the difference of why the Maier's filter is causing the dimming when used in the Solar Max system. Mystery solved ! This is first I have seen a PST ITF being made on a clear substrate. I'm wondering if the 5mm blocking filter used your PST makes up for the absents of the red filter ?
I just had email exchange with Chris Maier and he can also make the ITF on a clear substrate. He just needs to know the transmission specs.

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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Inspired, I took the PST ITF out of my BF10 (are you following this :P ) and compared it to the rusted ITF from the BF10...






As you can see, the ITF that was originally from the PST has a black ring around it's periphery that is labelled, and would certainly appear to be RG630 rather than clear...


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

I just had email exchange with Chris Maier and he can also make the ITF on a clear substrate. He just needs to know the transmission specs.

:woohoo: As much as possible @ 656nm - the nearer 100% the better :)

:thanx:


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

By the way the "edge blackening" shown on the filters is the epoxy seal that stops the filter from "Rusting". If it is not there then the life of the filter is GREATLY reduced. I wouldn't be surprised if the filter didn't last a year. That is real poor of Meade to let a filter be installed that they know is going to fail very quickly.

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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

Not to go too off-topic but I received on the 13th of December an SM II 90mm scope from Meade that not only had a chipped objective but was so dirty both inside and out that it appeared as though it was assembled outdoors in a windy desert. Meade is not putting quality first, IMHO.




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Re: Front end replacement ERF for new "blue" PST??

Post by SMS »

Hi Dave,

All three of my Coronado blocking filters show deep red when you shine a flashlight through them.

Steve


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Hi Steve,
The edges of all your filters, were there is no coating are clear so that shows the coatings were applied to a clear substrate and not the RG630 glass. The red color could be from a number of sources. It could be a coating that was applied on purpose, it could be from the ITF coatings or it could be from the "rusting" of the original coatings and the ITF material turn red when it degrades. Having the coating put down on clear glass vs RG630 glass indicates to me that there will be difference in the percentage of how much the the filter transmitt. So I think it safe to say that there are differences between the ITF made to be used in a PST vs a Solar Max BF diagonals and that the Maiers filter is not a drop for replacement for the Solar Max units. We know that the optical configuration of the Solar Max system is different, in terms of were each type of filter is located in the optical path vs PST.
All I can say is that the Maiers filters I have tried have worked very well in my PST and I bet they will also work well in any other PST and that has rusted ITFs that were made using the red RG630 glass.

Happy New Years !
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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi chaps

great new informations. Thank you very much for the insight


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

I thought it was appropriate to include the plot of the transmission of a BF15 ITF from http://www.sonnen-filter.de/






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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

Hi Mark,
Thanks for posting the plots. What I find interesting is that these plots show that the total transmission at 656nm is 45% for a Coronado ITF, while the Maier filter is 70%. So in theory if all else was same the Maiers filter should provide a brighter image.

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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Indeed. I shall definitely be giving mine a good try and comparison when it it arrives (and the sun is a bit higher in the sky!). However like Steve says, and just looking at the variance in the pictures just us 3 have posted in this thread I suspect there's a variety of ones out there in circulation...


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Re: Front end replacement ERF for new "blue" PST??

Post by DSobserver »

so here is my contribution :

rusted ITF from BF15 VS ITF from PST Meade




What is interesting if you compare this BF15 ITF to the SMS's one is that mine is from Schott RG630 and edge are not black treated :



Last picture is I think mentioning a different batch production compare to the one from Mark



comparing both ITF, I've the feeling that the PST one is thinner and both side silver treated (the one from BF15 is only one side treated....strange)

At the end everything looks possible, but don't understand the main ITF differences between BF and PST...


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Re: Front end replacement ERF for new "blue" PST??

Post by Merlin66 »

Mark,
I think those transmission curves are already in the Library, you may want to check and add the Maier curve as well.....


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Here are the Maier curves...






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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

What might be really good as 'additional' info to complement all this is if anyone could take some pictures like those above of the ITF from a Lunt blocking filter. I would do this but I don't have a Lunt blocker...


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Mark

I'll give it a go the next days and run a plot on it


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Good stuff! Thanks Walter! :)


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Chaps

missing the disc on the sky I went into my lab.


Here we go:

start disassembling (note the fine handy tool ;-) used)





blocking filter and ITF





ITF edge on





Diagonal mirror





the plots









The ITF seems to be a double coated clear glass, the blocking filter is a stack of two glasses one deep red (okulare side) and golden coated (objective side).

The mirror on the diagonal is very special, it seems to have the same coating as the objective side of the blocking filter


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

Well that is an interesting plot Walter. I knew you would make good use of that lens spanner ;)

Lots more transmission with the Coronado blocker than the Lunt at 656nm, no wonder Lunt say you can use a Lunt blocker on a Coronado but can't use a Coronado blocker on a Lunt...


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

That Lunt ITF looks suspiciously like Schott BG glass to me

http://www.schott.com/advanced_optics/e ... ng=english

I wonder which variety?


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Mark


thank you very much for the comments. The lens spanner is just a wonderful tool, I guess you should get one too next birth day ;-)

Difficult to say about the BG glass ware. They cut the plot at 300 nm, makes it difficult to choose the right variety if it is from them. I'm not yet convinced


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

I'm sure i read somewhere Lunt are using the newer BG glass in their blockers http://www.schott.com/advanced_optics/e ... ng=english I will have to search around for it.

The mirror looks like it's coated in some way too....


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Mark

thanks for the plots. So the ITF seems not to be of the BG6 type. All surpressing transmission well before 300 nm.

Yes the mirror has a special coating. Should I scrape it off and run an FTIR on it ;-)


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

So the ITF seems not to be of the BG6 type. All surpressing transmission well before 300 nm.

Yes, all the BGs seem to fall short of 300nm :unsure:


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Re: Front end replacement ERF for new "blue" PST??

Post by swisswalter »

Hi Mark

Comes time, comes solution. We just have to watch out and be aware ;-)


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Re: Front end replacement ERF for new "blue" PST??

Post by DSobserver »

I've 1 question : why this solution would be better than the one from Beloptik that is already existing?


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Re: Front end replacement ERF for new "blue" PST??

Post by marktownley »

I've 1 question : why this solution would be better than the one from Beloptik that is already existing?

Which is the Beloptik solution?


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Re: Front end replacement ERF for new "blue" PST??

Post by DSobserver »

UV/IR cut on KG3 + night time Ha filter!

Did I miss something????


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Re: Front end replacement ERF for new "blue" PST??

Post by DavidG »

I've 1 question : why this solution would be better than the one from Beloptik that is already existing?
If you referring to a PST, those are not a direct drop in replacement for the original ITF and the cost is higher.

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Re: Front end replacement ERF for new "blue" PST??

Post by Merlin66 »

Yes,
That was the original solution!
But as Dave says - not a 'drop in' replacement (at the eyepiece)and more $$$$


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