What's the actual size of your 2" filters in "mm" with and without frame/ring? What step down adapter is suggested from a 52 mm to "-- mm"?
Question by: Waqas Ahmad on Oct 10, 2016 7:54:00 PM | 1 Answer(s)
What are the threads and pitch of your 1.25" and 2" filters?
Question by: Anders G. on Sep 20, 2017 12:55:00 PM | 1 Answer(s)
Our 1.25" filters have a M28.5 male (and M28.5 front female) thread / our 2" filters have a M48 male (and M48 front female) thread
Both thread sizes come with our proprietary pitch - which is not the same for the female and male threads.
This is our own proprietary "emergency solution" for uniting a world were manufacturers all over the world copy from each other - to the point that there are almost a dozen different pitches in use for male and female threads. Traditionally US-companies used to do a UNF-based pitch and the rest of the world went for metric threads - but these do vary from 0.5 to 0.75.
For this reason it does not make sense to publish our non standard pitch because our pitch is made to cope with all existing metric and US-pitch standards - and as said - our solution has evolved from sheer necessity. It is a mixture of a queer pitch and under-/over-dimensioning . We will not want to declare this as a standard and get bashed up for it. It works for us and is a result of 20 years adaptation to fit our filters onto all crazy threads we have seen. And inspite of this - every now and then there comes another "dragonboat-eyepiece" were even our filters may not fit...
Answer by: Baader Web Team (Admin) on Sep 22, 2017 1:43:00 PM
I have bougth an used filter #2458380, but on the body filter, in the original Baader label, is written "H-Alpha 45nm Passfilter 2" wIR-cut.
Since in your catalog the #2458380 is 35nm filter, my question is: there where an old version with same P/N but different band?
Thanks a lot in advance for your help.
Question by: massimo nardoni on Oct 13, 2016 5:19:00 PM | 1 Answer(s)
Yes it is true - the older filters had 45 nm bandpass.
Answer by: Baader Web Team (Admin) on Oct 14, 2016 8:32:00 AM
Does the filter block IR radiation right down to 2400nm. Solar radiation extends that far. KG3 heat absorbing glasses protect down to 2400nm. On your UV IR blocking filter you say it is better than KG3 so that implies that goes down to 2400nm.
Question by: Andrew Huskinson on Nov 9, 2017 2:22:00 PM | 1 Answer(s)
Our H-alpha filters are developed with the usage of CCD imaging in mind. The most used camera chips are sensitive to light with a wavelength up to 1150 nm. Therefore blocking the light on such stretched region, would have resulted in an unnecessary cost increase.
We do not use KG- glass because it does not allow 100% transmitance on the visible spectrum. In this respect, our filters acheive a better result than KG glass.
Answer by: Baader Web Team (Admin) on Nov 10, 2017 8:32:00 AM
Hi, Astrograph use these filters as internal ERFs in solar telescopes, tested in refractors up to 152mm. I have been using a 1.25" version in a Vixen 110mm VMC with no issues. I am considering using a 2" in a 180mm Mak. Is there a specification for the watts per square cm on the filter and a specification for the maximum working temperature? I calculate there would be 26W incident on the filter spread across it, with 1.3W transmitted. Andrew.
Question by: Andrew Huskinson on May 18, 2019 12:11:00 PM | 1 Answer(s)
We are NOT RECOMMENDING these filters for solar observation or photography at all! If somebody does this, its on his own risk, it may lead to permanent damage of the eye or the camera/telescope setup. We are warning and recommend not to use these filters as an internal ERF - they are not designed for this use. We have no values for working temperature a.s.o.
Answer by: Baader Web Team (Admin) on May 20, 2019 12:44:00 PM
Hi, can I use this H-alpha 35nm filter with your solar film to get images of the chromosphere, prominences, filaments etc on the Sun? I would be imaging with a dslr. Thanks.
Question by: Simon Johnson on May 6, 2019 5:13:00 PM | 1 Answer(s)
WARNING! This filter is only for Deep Sky imaging! Experiments on the sun are not recommended, this would be dangerous for your your eye! A proper Halpha solar filter for taking photos of prominences and filaments needs to be below 1nm (around 0,8-0,3nm).The 35nm filter is much too open for this and way too bright. Adding an Astrosolar film in front of the telescope will reduce all wavelength, Halpha too, so that you don´t see anything.
Answer by: Baader Web Team (Admin) on May 7, 2019 9:28:00 AM
What is the thickness of the 1.25" H-alpha filter cell including the depth of the thread? Thank you.
Question by: Tim Haymes on Mar 19, 2017 11:14:00 PM | 1 Answer(s)
The height of the cell that contains the filter glass is 6 mm. The filter thickness is 2 mm - with a retaining ring thickness of 1 mm.
Please calculate that there are roughly 2.5 mm of thread space remaining in the cell. However - we do not recommend to mount two filters straight into the same cell. This might cause very strong retro reflections.
Answer by: Baader Web Team (Admin) on Mar 20, 2017 8:39:00 AM