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)
I've got filter set h-alpha,h-beta,sII,oIII for full frame ccd, when will arrive the filter size 1.25" for h-alpha 3.5nm?
Question by: Nazario Montuori on Apr 30, 2017 11:39:00 PM | 1 Answer(s)
The H-alpha 3.5nm filter in 1.25" size will become available in approx. four months. Thanks for your patience
Answer by: Baader Web Team (Admin) on May 2, 2017 8:24:00 AM
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
Do all Baader narrowband filter both UV and IR as well? I am thinking of using them with a Full Spectrum DSLR. Thanks.
Question by: Jon on Nov 1, 2016 11:59:00 PM | 1 Answer(s)
All Baader Planetarium narrowbandfilters are blocking UV and IR, they are made for use with fully unblocked monochrome cameras.
Answer by: Baader Web Team (Admin) on Nov 2, 2016 3:43:00 PM
I understand your 3.5nm Ha filter in 1.25" size will become available later this year. When will you produce 3.5nm filters of the same size in SII and OIII? Thank you.
Question by: Peter on Jul 3, 2017 10:44:35 PM | 1 Answer(s)
We are working on these filters, too, and hope to have them ready by the end of the year - but we can't promise it.
Answer by: Baader Web Team (Admin) on Jul 5, 2017 12:34:00 PM
Can you share actual transmission characteristics? Does this filter allows NII wavelength to pass?
Question by: Thomas on Aug 16, 2020 10:15:00 PM | 1 Answer(s)
This filter is fully blocked from 390 to 1150 nm. It will not pass N II.
Answer by: Baader Web Team (Admin) on Aug 18, 2020 12:34:00 PM
Can this filter be used as an internal energy rejection filter for H-alpha solar observation on 140mm and 60mm refractors? The ERF would be placed in front of the diagonal mirror, and the etalon behind the diagonal.
What is the filter's throughput beyond 1000nm?
Question by: Desiderius on Jul 1, 2020 11:40:00 PM | 1 Answer(s)
We do NOT recommend this! No filter near focus can replace a front end blocker - as 100% of solar energy hit the filter close in front of the focus position. Front end energy blocking is mandatory for H-alpha work - but not so for white light work.
Why - because in white light you could use a Herschel Wedge Prism to throw away 95.4 % of ALL entering energy - before it even reaches the first neutral density filter or dielectric continuum filter.
This is not possible on H-alpha - you need 100% of the H-alpha wavelength, but preferably zero of anything else. so - in theory - you can do this as you describe - but the filter at that heating point can break on you any second.
Also - all photographic narrowband filters ought to be fully blocked OD 4.0 from 390 nm to 1150 nm - as this is the sensitivity range of almost all CCD/CMOS-chips (most filter suppliers though do not show their blocking efficacy above 700 nm....).
So the 3.5nm H-alpha-filter is surely blocked to 1150 nm - but our front end D-ERF-filters are blocked to 1450 nm - exactly to provide perfect solar safety. Above 1400 nm most optics do not pass IR anyhow.
Answer by: Baader Web Team (Admin) on Jul 2, 2020 7:47:00 AM
Are you developing a 36mm unmounted version of this filter?
Question by: Paul Tribe on Nov 30, 2017 2:43:00 PM | 1 Answer(s)
Currently there is no production of 36mm running but this may happen in future. Unfortunately we cannot predict when.
Answer by: Baader Web Team (Admin) on Nov 30, 2017 3:29:00 PM
What bandwidth is recommended for H-alpha imaging at f/15?
Question by: Stephen on Sep 13, 2020 2:57:00 AM | 1 Answer(s)
We recommend 7nm so that exposure times will be acceptable
Answer by: Baader Web Team (Admin) on Sep 14, 2020 11:58:00 AM
Are all Baader narrowband filters parfocal? I mean could I use extreme narrowband filters like the Baader 3.5nm with normal narrowbands like the OIII 8.5nm and expect them to be parfocal?
Thanks in advance for your time and help!
Question by: ILIAS GALANIS on Feb 5, 2019 9:50:00 PM | 1 Answer(s)
Filters *with the same diameter* are parfocal, so you can combine the filters you have mentioned.
Answer by: Baader Web Team (Admin) on Feb 6, 2019 10:58:00 AM
Do you have any plans to make a 1.25" of this filter?
Question by: Elias Galanis on Jan 24, 2018 3:18:00 PM | 1 Answer(s)
We are working on a 1.25" version, but we can't give you a delivery date yet - we don't know when it will be ready.
Answer by: Baader Web Team (Admin) on Jan 31, 2018 3:25:00 PM