Filter for Kowa TSN883 (1 Viewer)

[Brett Richards]

Having recently purchased the Kowa TSN883 telescope I sent off for a 95mm clear filter, the only size mentioned on Kowa's web-site for this 'scope. On receiving it I was disappointed to see that it screwed into the end of the sun hood instead of into the end of the 'scope body as I had expected. There are threads on the end of the 'scope body and I have been told that these will take an 88mm filter. Can anyone verify this?

Brett Richards

 

[Sc0tty]

I've also got an 883 and considered getting a filter but I'm put off because it fits on the sun hood. This has been mentioned before on BF:
https://www.birdforum.net/showthread.php?t=159606
https://www.birdforum.net/showthread.php?t=105075

If you are handy you could always make a new lens hood out of some plastic tubing.

As for getting a filter to fit the scope body, I can't answer that. One thing is for sure is that it will need to be slim otherwise it will stop the hood sliding out.

 

[Binastro]

I would think that a filter for a good Kowa scope would have to be high quality not to affect performance at high magnification.
Also it seems more sense to have it nearer the objective to avoid ghost images.

For astro scopes with optical windows, which can cost more than a main mirror, tilting at 1 degree is useful to avoid ghost images.

 

[Brett Richards]

I've also got an 883 and considered getting a filter but I'm put off because it fits on the sun hood. This has been mentioned before on BF:
https://www.birdforum.net/showthread.php?t=159606
https://www.birdforum.net/showthread.php?t=105075

If you are handy you could always make a new lens hood out of some plastic tubing.

As for getting a filter to fit the scope body, I can't answer that. One thing is for sure is that it will need to be slim otherwise it will stop the hood sliding out.

Thanks Richard

I sent an email to Kowa enquiring about this and got the following reply

"Hello Mr Richards,

Thank you very much for your recent service enquiry.

You are correct, the thread fits the hood only.
The inner thread that you see is for assembly purposes only, you will notice that there are special tool marks that precludes the use or fitting of a filter.

The only place that you can fit the filter therefore is the shade, the filter is properly multi-coated and has hydrophobic coating (our Kowa proprietary KR coating) that repels water and other liquids.
This also cleverly protects the front optics and the shade from potential damage from the ingress of salt spray and/or sand.
If the filter was in the position you hoped, it wouldn’t have this extra further protective effect.

I hope this answers your question.

Yours with best regards,"

At least this answers my query, but I still think it would be better on the end of the 'scope body. I will have to make some sort of extension from a pop bottle or something as you suggested.

Brett

 

[SteveClifton]

Thanks Richard

I sent an email to Kowa enquiring about this and got the following reply

"Hello Mr Richards,

Thank you very much for your recent service enquiry.

You are correct, the thread fits the hood only.
The inner thread that you see is for assembly purposes only, you will notice that there are special tool marks that precludes the use or fitting of a filter.

The only place that you can fit the filter therefore is the shade, the filter is properly multi-coated and has hydrophobic coating (our Kowa proprietary KR coating) that repels water and other liquids.
This also cleverly protects the front optics and the shade from potential damage from the ingress of salt spray and/or sand.
If the filter was in the position you hoped, it wouldn’t have this extra further protective effect.

I hope this answers your question.

Yours with best regards,"

At least this answers my query, but I still think it would be better on the end of the 'scope body. I will have to make some sort of extension from a pop bottle or something as you suggested.

Brett

Brett, assuming your filter also has a 95mm thread on the front, you could also consider something like this (a bit more classy than a pop bottle!)

https://www.amazon.co.uk/DSstyles-Mirror-Reflex-camera-Filter/dp/B01MFGA3MX/ref=sr_1_1?ie=UTF8&qid=1527876266&sr=8-1&keywords=95mm+metal+lense+hood

 

[Brett Richards]

Brett, assuming your filter also has a 95mm thread on the front, you could also consider something like this (a bit more classy than a pop bottle!)

https://www.amazon.co.uk/DSstyles-Mirror-Reflex-camera-Filter/dp/B01MFGA3MX/ref=sr_1_1?ie=UTF8&qid=1527876266&sr=8-1&keywords=95mm+metal+lense+hood

Thanks Steve, good suggestion.

Brett

 

[dogbreath]

I have bought a used Hassleblad filter for my 883. Got it from a camera shop - much cheaper than a Kowa new one. I reckon a good used filter from a medium format camera such as a Hassleblad should be ok. If Hassleblad was good enough for NASA to send on the Appollo moon missions, it is probably good enough for me. Still doesn't resolve the hood dilema though.

 

[Binastro]

Hi dogbreath.
Hasselblad filters may be B and W or Zeiss and should be good.
The Russian filters from the 1000mm f/10 MTO are also good, although may be a little thick. Maybe 105mm.

Even Kowa's own filters may not be true astro quality optical windows, although good enough for the maximum normal magnification of the Kowa.

The optical window of my 317mm aperture windowed Dall Kirkham cost more than the main mirror to make.
I could use it at any magnification up to 750x and beyond.

Personally I never used or use filters on cameras, except polarising ones when needed.

 

[Grando]

I think filters are useful on a scope, particularly when seawatching. I have one on my Kowa 823 and I don't really notice any difference at the 32x I usually have the scope on...

 

[dogbreath]

When I was looking I saw 95mm filters from makes I had never heard of. I also saw a number of filters from medium format camera manufacturers (including Bronica and Hassleblad). On the basis that you are likely to get what you pay for in optics, I avoided the £10 filters.

I am old enough to have used film cameras and processed my own B&W film. Filters were useful in those days and I remain of the view that a good optical quality filter has a place particularly a sacrificial place when seawatching. I would much rather clean or replace a filter than the front element of my scope.

 

[Stephen Mark]

I have had a B+W multi-coated nano filter on my 884 for years and since I mover to North Carolina most of my scope use is at the beach. Definitely prefer getting fine wind blown sand off a filter rather than the front element. Even with my 1.6 extender I don't notice any difference with or without the filter.
Steve