New PST ITF?

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New PST ITF?

Post by JB80 »

Hey all,

I took a look at my ITF/blueglass for the PST today and can see that it is possibly looking a bit degraded which I have suspected as I'm getting a bit/lot of haziness to my images. I'm not sure to be honest but there is a darker spot in the middle with a lighter ring around the outside, I have a pic and it doesn't show all but you can see what I mean. There is also some speckled dots on the inside with I'm not sure what they could be but they may be cleanable, they aren't visible in the picture though. It's probably mold.

The PST is 4 years old and was brought new but who knows how long it was sitting in stock somewhere and I would say it has had pretty heavy use in the last couple of years..
as.jpg
as.jpg (93.64 KiB) Viewed 9589 times
I'm guessing from the looks of it I need a replacement?

Any way I have seen here that the Maier filter is a suitable replacement and I have seen other filters mentioned, beloptik for instance and some baader ones but really I don't know what is my best option.

So my questions are, will I need a replacement?
What are my options for a replacement?
And are there any EU suppliers that I'm likely to find that can get one to me by the 20th?

I'm just looking for a new one for the standard PST eyepiece holder as shown and it will either be used in a stage 1 mod or as the standard PST itself.
I use it mainly for imaging but occasionally I like to have a gander as well.

Any ideas or can someone point me in the right direction please?


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Re: New PST ITF?

Post by swisswalter »

Hi Jarrod

for the fast solution you are asking, I could only offer you a whole black body of a PST without the etalon though, for little money


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Re: New PST ITF?

Post by JB80 »

Hi Walter,

That would certainly be an option, I wouldn't need the entire black box but I could consider it.

If I take visual out of the equation can I use something like a Baader 7 or 35nm or something else perhaps?


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Re: New PST ITF?

Post by Merlin66 »

Jarrod,
The Maier replacement seems to work well.
I'd continue to use what you have until you get a replacement.
Ken
(The Baader filters work better in the BF diagonal ITF replacement due to the 1.25" filter size)


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Re: New PST ITF?

Post by JB80 »

Hi Ken,

Looking at the pic would you say my ITF is on the way out and it could do with replacing?
I think it would explain the hazy/blurred edges to my images, at least I hope it's that anyway. It's by no means the end of the world so I can live with it for a while.
I may contact Maier and see what they can do, is there an EU dealer?


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Re: New PST ITF?

Post by Merlin66 »

Jarrod,
Yes, it looks like it's beginning to go....
I'm not aware of any other distributor - just direct supply from Maier.


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Re: New PST ITF?

Post by JB80 »

Well I'll fire off an email today and see what they say.
Hopefully they can send it via UPS for me.


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Re: New PST ITF?

Post by Sungazer »

Hi All, I can assure you that the Maier ITF filter is a direct replacement for the PST original, and in my opinion improves the image from the old one. I replaced mine last year. You can order direct from Maier Photonics and pay using Paypal. The cost is about £57 delivered,just depends on the exchange rate on the day.
Hope this helps, John.


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Re: New PST ITF?

Post by JB80 »

Hi John, thanks for the recommendation.
It looks to be the way to go, how long did it take to send it and I presume it was taxed by customs?
That wont be an issue but I guess it needs to be considered.

Not really supposed to be spending anymore money as we just paid a deposit on a house but I will make an exception for this, it's at a really fair price so I can get away with it. :)


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Re: New PST ITF?

Post by marktownley »

Yes, a new ITF is needed. The Maier option works fine, I have one.


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Re: New PST ITF?

Post by JB80 »

Cheers Mark, do you suppose this could be the culprit to the lack of detail on the edges of my images?


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Re: New PST ITF?

Post by marktownley »

Can you post an image as example...


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Re: New PST ITF?

Post by JB80 »

These show it fairly well, I haven't added a flat to it but that doesn't remove the lack of detail any way.
Not the greatest images but they are straight from AS!2.
You can notice quite a bit on the left hand side, I generally just crop it out.
142050_g4_ap510.jpg
142050_g4_ap510.jpg (52.32 KiB) Viewed 9532 times
Also on the right hand side of the images too.
140735_g4_ap445.jpg
140735_g4_ap445.jpg (52.9 KiB) Viewed 9532 times


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Re: New PST ITF?

Post by marktownley »

i think it is just the sweet spot. Are you using a barlow lens with the camera?


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Re: New PST ITF?

Post by JB80 »

Nope no barlow, it's rarely worth putting one on.
It just seems to me that I'm noticing it more and more lately. My sweet spot has always been in an odd and annoying position, in one of the corners. Bottom right visually. It could be though.


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Re: New PST ITF?

Post by marktownley »

I would recommend using a barlow, that is what is causing the uneven illumination and variance in detail across the field. If the sweet spot is not dead centre then this means something is not square some where along the optical axis.


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Re: New PST ITF?

Post by Sungazer »

Hi Jarrod, The ITF only took about 6 days to come via airmail,to England. As to customs they did not bother. I think you are allowed to bring in items for personal use up to £50 Maier Photonics are very nice people to deal with. All the best with your purchase, and fitting,make sure the silvery side of the filter faces the Sun, to avoid over heating the blocking filter. Kind regards, John.


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Re: New PST ITF?

Post by JB80 »

marktownley wrote:I would recommend using a barlow, that is what is causing the uneven illumination and variance in detail across the field. If the sweet spot is not dead centre then this means something is not square some where along the optical axis.
A barlow doesn't seem to work to well with me, it might just be the barlow is rubbish but I don't get pleasant results using it. I might try unscrewing the lens from it though, that may work better.
Sungazer wrote:Hi Jarrod, The ITF only took about 6 days to come via airmail,to England. As to customs they did not bother. I think you are allowed to bring in items for personal use up to £50 Maier Photonics are very nice people to deal with. All the best with your purchase, and fitting,make sure the silvery side of the filter faces the Sun, to avoid over heating the blocking filter. Kind regards, John.
That's not bad, 6 days. I'm waiting on a response and see what happens. Spain doesn't have any allowances for things from outside the EU. It is luck of the draw here, sometimes they ask for customs fees and other times they don't. Hopefully a small envelope will get through.
Good tip re the silvery side too. Thanks.


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Re: New PST ITF?

Post by JB80 »

OK update, I ordered from Maier last night, had an issue with the pay form although I was warned this may happen but Chris was on hand at the time to put the order through anyway. In total it came to 75 euros which is alright.
Anyone know if USPS international first class is signed for?


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Re: New PST ITF?

Post by Merlin66 »

Yes,
Normally signed for at receipt.


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Re: New PST ITF?

Post by Bob Yoesle »

Unless you add additional IR blocking in front of the replaced ITF, such as the 2" Baader Red CCD filter or the IR/UV blocking filter over the objective, you will likely encounter future failure of the ITF.

OR you could use the Beloptik KG3 ( http://beloptik.de/en/left/if-uv-ir-cut ... ng-filter/ ) with a suitable 2" RG630 or RG 610 in front of the objective, such as the Baader 35 nm H alpha filter. This combination should not be so easily susceptible to deterioration as an ITF is.


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Re: New PST ITF?

Post by swisswalter »

Hi Jarrod

hope that filter will arrive at time


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Re: New PST ITF?

Post by JB80 »

swisswalter wrote:Hi Jarrod

hope that filter will arrive at time
Merlin66 wrote:Yes,
Normally signed for at receipt.
Thanks Ken and Walter, it was dispatched yesterday so I have hope it will make it. And if it is signed for then it should come to my door as they stopped delivering regular post here and picking it up would be a pain.
Bob Yoesle wrote:Unless you add additional IR blocking in front of the replaced ITF, such as the 2" Baader Red CCD filter or the IR/UV blocking filter over the objective, you will likely encounter future failure of the ITF.

OR you could use the Beloptik KG3 ( http://beloptik.de/en/left/if-uv-ir-cut ... ng-filter/ ) with a suitable 2" RG630 or RG 610 in front of the objective, such as the Baader 35 nm H alpha filter. This combination should not be so easily susceptible to deterioration as an ITF is.
Hi Bob,

Thanks for the information, I have bit the bullet already but will file this away for future reference. Thankfully it's not a big hit to the wallet and if I can get another 3-5 years from it it's probably money well spent. Never no I might upgrade before then. :D


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Re: New PST ITF?

Post by solarchatted »

has anyone a good second - hand ITF for sale?
Just thought about it.


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Re: New PST ITF?

Post by solarchatted »

I know this is an old thread.

I do need to replace the ITF from a second hand PST I managed to get.

I have a few questions for the experts here, please.

1. I believe it is probably worth getting the ITF from Maier [out of stock] - not just for the price, but because it does not have the second protective glass 'glued'. Would the glue be a problem?

2. where exactly should I fit the 2" Baader Red CCD filter?
Is there an image to understand it? Glued on?

Please be nice, I am a newbie on Solar.

Thanks in advance
M


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Re: New PST ITF?

Post by marktownley »



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Re: New PST ITF?

Post by solarchatted »

I had a look at that already and also been reading 'a lot' about these 'trap' filters - trap in the sense Astronomy sellers 'cartel' try always to push you buying more than you really need.

That above was my input in general with filters and prices and - do I really need that? Type of thing!

About this filter, maybe just taking it out and get a Baader 35nm RED CCD and fit it on the front as some people do - also Merlin66 mentioned it.

It will be even better being on the front safe-guarding the whole optics and re-usable if one buys a Quark and fit it before the Diagonal [if used]!

I am getting quite a culture here now!


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Re: New PST ITF?

Post by Bob Yoesle »

Hi M,

I would not be too disregarding and suspicious - I doubt there are astronomy "cartels" trying to push more than you need when it comes to solar filters and safety. Indeed, my experience has been that the filter makers and suppliers have at times overestimated the blocking ability of their filters, and additional filtering is needed for filter longevity and/or safety.

Here's a slide from my powerpoint presentation on solar filters related to safety:

Slide 49.jpg
Slide 49.jpg (435.11 KiB) Viewed 4138 times

Note that the Sun has considerable output in the IR. Most of the typical filters for blocking IR only block IR A - there is little IR blocking beyond 1400 nm, even though the Sun can put out significant IR to IR B and even beyond. The amount of IR reaching your eye is completely dependent on aperture (total irradiance of 1.05 mW per mm^2), and the telescopes f ratio, which concentrates this output to the focus and can multiply its intensity greatly - for example, a magnifying glass collects only ~ 5 W, but this concentrated near focus, as occurs near your eye with a telescope, is enough to ignite paper and burn wood.

Magnifying glass.jpg
Magnifying glass.jpg (108.45 KiB) Viewed 4138 times

IR A will penetrate the eye all the way to the retina, IR B will penetrate to the lens (causing cataracts and corneal keratitis long-term), and IR C will affect only the cornea. So I would recommend IR blocking out to IR B (2500 nm +), and for this (in lue of an ITF) the BelOptik ITF replacement filter or the UV/IR on KG3 in conjunction with the red 35 nm H alpha filter would be ideal.

It's your eye(s) so do as you want, and know that opthamologist and eye surgeons will always appreciate the business if you choose poorly... but as with most things a little prevention is worth a bunch of cure.


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Re: New PST ITF?

Post by solarchatted »

Thank you very much for the info - appreciated.


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Will try and do it justice when I can with the help of various filters, Baader 1.25" Solar Continuum 10nm is one.
SW 72ED Pro - fixed 'stock faulty' focuser ... 'I think' !
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Re: New PST ITF?

Post by solarchatted »

Just got the replacement ITF from Maier.

Which way should be fit? Just to be sure - I guess the Maier O-ring goes over the marked edge of the new ITF, but which way is the SUN side?
Another guess: since the O-ring 'seems' to go on 'one' side only - as above, that must be the side where the screwed on filter ring goes, but is it?

Not sure


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Will try and do it justice when I can with the help of various filters, Baader 1.25" Solar Continuum 10nm is one.
SW 72ED Pro - fixed 'stock faulty' focuser ... 'I think' !
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Re: New PST ITF?

Post by solarchatted »

Ha ha ha ha ha ...
Finally done it - with the O-ring too!

The locking ring thread is NOT perfectly manufactured straight - it is slightly angled!

I have taken filter + O-ring out, cleaned the threads using thin tweezers and then tried it without anything and found out the thread was not straight from factory.

I also pressed the O-ring a bit using flat part of tweezers - thrown it in and managed to catch thread using middle + annular fingers + finger nails ... just to catch it then managed to tighten it without forcing it by holding it and turn the whole structure.

What a difference this filter is - it is also has clearer coating.

I might have to reduce Exposure time or gain or both.

Looking forward for next time I manage to match when The Sun is out and I am at home !


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Sometime I use Explorer Scientific AR152/988 + Used once only... Altair 2" Solar Wedge (very good indeed)
Will try and do it justice when I can with the help of various filters, Baader 1.25" Solar Continuum 10nm is one.
SW 72ED Pro - fixed 'stock faulty' focuser ... 'I think' !
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Re: New PST ITF?

Post by Merlin66 »

The angled thread is to give a slight tilt to the ITF filter.....


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Re: New PST ITF?

Post by Live_Steam_Mad »

>I have a few questions for the experts here, please.

>1. I believe it is probably worth getting the ITF from Maier [out of stock] - not just for the price, but because it does not have the second protective glass 'glued'. Would the glue be a problem?

>2. where exactly should I fit the 2" Baader Red CCD filter?
Is there an image to understand it? Glued on?

>Please be nice, I am a newbie on Solar.

>Thanks in advance
>M

Hi, if you have an old style PST with front ERF as merely a coating on the objective lens, then there is no way that I know of, of replacing the ITF filter, because there is no ITF filter to replace. These old style PST's had a light blue metallic looking "opaque" coating on the objective lens or gold colored coating on the objective lens.

If you have a later style PST with dark blue coated, clear objective lens, then you can replace the ITF with the Beloptik or Maier replacement ITF filter.

I never heard of the use of any 2" Baader red CCD filter with a PST.

I don't know what you mean by "second protective glass" or the reference to "glue". The eyepiece end of the later style PST has 2 filters, one is the 5mm Blocking Filter that you see when you look down the barrel where the eyepiece goes, the second filter is the ITF filter and is in a separate barrel UNDER the one with the 5mm Blocking Filter.

You have to remove the second barrel (and first one of course also by default as a result) by unscrewing it from the black body of the PST. They seem to have thread lock on the threads and generally need a strong strap wrench and a heat gun to get it off. Our local club has repaired 3 PST's in this way that all had oxidised and useless ITF filters.

The ITF filter is for blocking the Infra Red and takes a large heat load, apparently. Expansion and contraction makes the filter edges fail at the seal on the original Meade made filters.

Best Regards,
Alistair G.
Last edited by Live_Steam_Mad on Sat Mar 23, 2019 6:50 am, edited 1 time in total.


Live_Steam_Mad
The Sun?
The Sun?
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Location: St.Helens, England, UK

Re: New PST ITF?

Post by Live_Steam_Mad »

Whoops there was a page 2 that I didn't read before replying... must be too early in the morning and I didn't notice page 2...

Best Regards
AG


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