Plain glass filter

[Robin]

I have been trying to buy a 1.25 plain glass filter to use as a dust cover for my DMK camera but they are all out of stock in the uk. Is there any other filter I could use which would not effect my imaging, I have a box full to choose from

[Allcart]

I keep an IR/UV filter on mine Robin. I don't know if there is a better choice, but that is all I have.

[brianb11213]

I keep an IR/UV filter on mine Robin. I don't know if there is a better choice, but that is all I have.
Should be OK for hydrogen alpha but a UV/IR blocker will kill CaK (not quite opaque but needs a major increase in exposure or gain).

Robin, I have a spare 1.25" plain glass "filter", drop me a PM if you need it.

[Robin]

Hi Brian
Many thanks, I don't think you can PM on Solarchat, I may be wrong
Robin

[solarchat]

ya, I didnt install a PM mechanism because if its important enough to tell one person on the forum, its probably of interest to everyone.. You can always email.

[brianb11213]

ya, I didnt install a PM mechanism because if its important enough to tell one person on the forum, its probably of interest to everyone.. You can always email.
Well I don't think publishing snail mail addresses, telephone numbers or email addresses on an open forum is particularly sensible. I have the same username on Cloudy Nights forum which does have a PM service.

[solarchat]

its only in your profile if you choose to put it there.
every private message I ever received on CN was someone talking trash about someone else or the moderators telling me my image was too large, lol. Ill be happy to put a PM service on here but I just dont see the need for one. When I had the private chat feature on, everyone complained about it so I took it down.

[RobBower]

Robin I use Astronomik MC filters. They are multi coated for no reflection. I have them on my dmk51 and dmk 21 i get no nasty reflection, no ir block.... Etc. they are from Germany, but I order mine from OPT only 40 bucks and highly recommended!

[Robin]

Thanks Rob, I can get them in the uk, do they have a thread to attach additional filters, focal reducers etc?

[RobBower]

Yes they are threaded to accept stacking of filters! They do not cause.....or should I say...Have not.... Introduced and reflections or altered the image from what I can tell. And maybe its just me, but the multicoated glass for reduced reflection seemed to help with Newton Ring when I use my powermates.... An added bonus in my opinion! They are a great buy!

[MjrTom]

Been meaning to do the same myself, it's easier to clean a filter than the little optical window of a DMK31.

Are luminance filters also UV/IR filters by another name or are they plain glass?
My LRGB filter set are the Baader ones.

Mark

[MjrTom]

Scrub that last question...
The luminance is a UV/IR filter which sharply cuts off either end of the spectrum outside of the RGB spectrum.
Would a Baader clear filter meet your needs?

http://www.firstlightoptics.com/rgb-fil ... r-set.html

Pretty cheap as well.

Mark

[brianb11213]

The luminance is a UV/IR filter which sharply cuts off either end of the spectrum outside of the RGB spectrum.
Yeah, typically the passband is 420 - 680 nm which means good transmission of Ha but very poor transmission of CaK.

In the UK, Modern Astronomy lists Astronomik clear glass filters, £31 for 1.25", £58 for 2". These are good quality multicoated filters which definitely pass all visible light and enough of the UV and IR to make e.g. the Astrodon UVenus and Astronimik Planet Pro 807 useable.

BTW I've posted my spare clear glass "filter" to Robin. Sorry I don't have any more to give away!

[Robin]

Thanks Brian, all now sorted