2" Filter Thread Pitch?

[silentrunning]

Anyone know the thrread pitch of standard 2" filters in particular Baader 2" filters?

Thanks in advance.

[fozzybear]

16 minutes ago, silentrunning said:

Anyone know the thrread pitch of standard 2" filters in particular Baader 2" filters?

Thanks in advance.

Baader Planetarium of Germany use a slightly different thread pitch (which they do not specify, but which is a little less than 0.75mm) for their M48-threaded products. This was selected based on their measurements of hundreds of other M48 threaded accessories on the market, and which they believed would therefore increase the chances of their products being compatible with the largest number of non-Baader items.

[silentrunning]

12 minutes ago, fozzybear said:

Baader Planetarium of Germany use a slightly different thread pitch (which they do not specify, but which is a little less than 0.75mm) for their M48-threaded products. This was selected based on their measurements of hundreds of other M48 threaded accessories on the market, and which they believed would therefore increase the chances of their products being compatible with the largest number of non-Baader items.

Struff! What a can of worms astronomy gear is! Thanks.

[fozzybear]

17 minutes ago, silentrunning said:

Struff! What a can of worms astronomy gear is! Thanks.

Found this on their website

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

[silentrunning]

4 minutes ago, fozzybear said:

Found this on their website

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

Thanks fozzy bear that clears things up!

What a strange stance for Baader to take. I understand their reasoning for producing something that presumably fits as many non-standard bits of kit as possible but not telling us what they pitched for in the the end is crazy- sorry for the pun!

[Merlin66]

Unfortunately this is the situation. I've had bad experiences in the past with T thread adaptors. Yeah, all M42 x 0.75 threads.......but don't fit each other.

I do agree that Baader's strategy seems to work. Never any issues with their threaded gear.