2" thread/M48 thread

this is the main message area for anything solar :)
Post Reply
gabrieli
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2410
Joined: Thu May 24, 2012 12:12 am
Location: Woodbridge, Ontario, Canada
Been thanked: 1735 times
Contact:

2" thread/M48 thread

Post by gabrieli »

In some current work, I'm attaching a 2 inch focal reducer to a 2 inch extension tube with a good fit. Then I attach the 2 inch extension tube to an M48(2") to T2 adapter. Finally, I attach a T2 to 1.25 inch eyepiece holder (see image). Although the M48 thread is described as being 2", the fit is not perfect and the threads seem to cross after about 1.5 turns. The attachment is secure since it's not carrying significant weight but I find the same situation trying to connect other M48(2") devices to "true" 2 inch threads. I've had some difficulty finding a "true" 2" to T2 adapter.

Does anyone have any source for a "true" 2" to T2 adapter without the "M48" in its name?

Lou
DSC00041.JPG
DSC00041.JPG (1.71 MiB) Viewed 1152 times


christian viladrich
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2150
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Has thanked: 1 time
Been thanked: 2713 times
Contact:

Re: 2" thread/M48 thread

Post by christian viladrich »

Maybe, have a look at Telescope Service, they have a lot of adapters. I have not checked whether they have that one.
Best regards
Christian


Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10248 times
Contact:

Re: 2" thread/M48 thread

Post by marktownley »

I've found this sort of thing before too. Telescope service is excellent for things. Does the reducer thread onto the m48/t2 adaptor properly?


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
AndiesHandyHandies
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1444
Joined: Fri Mar 30, 2018 6:46 am
Location: Derbyshire UK
Has thanked: 3295 times
Been thanked: 1887 times

Re: 2" thread/M48 thread

Post by AndiesHandyHandies »

Hi

Baader use a different thread on their 2" extension tubes to Revelation ones.

Revelation M48 to T2 seem OK to me.

I am thinking of using T2 instead for a DS as it seems to be more 'standard'.

Andrew.


gabrieli
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2410
Joined: Thu May 24, 2012 12:12 am
Location: Woodbridge, Ontario, Canada
Been thanked: 1735 times
Contact:

Re: 2" thread/M48 thread

Post by gabrieli »

Hi, Mark

The 2" reducer fits the 2" extension tube perfectly but doesn't fit the M48/T2 adapter. That tells me that the 2" extension tube threads and the reducer threads are a perfect match. However, when I try to attach the reducer to the M48 threads on the m48/T2 adapter, the threads will seize after 1.5 turns. There is an obvious difference in M48 threads and what I call a "true" 2" thread.

In the post above, Andrew mentions Revelation extension tubes. Although extension tube threads are not an issue. Its the M48 threads that cause the problem. I'll look into that and see if there is a Revelation adapter that fixes the issue.

Lou


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10248 times
Contact:

Re: 2" thread/M48 thread

Post by marktownley »

Your other way then Lou would be to ditch the 2" extension tube and get a 2" T2 extension, put it between the ep holder and the m48/T2 adaptor.


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
AndiesHandyHandies
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1444
Joined: Fri Mar 30, 2018 6:46 am
Location: Derbyshire UK
Has thanked: 3295 times
Been thanked: 1887 times

Re: 2" thread/M48 thread

Post by AndiesHandyHandies »

Hi

I have been trying to mount the PST Etalon in a 2" focusser, with the Collimator lens in a 1.25" barlow nosepiece suspended inside and a 2" extension on the front for a possible 2" ERF or just an extra baffle for the Sun cone. Photos to come.

The Revelation 2" extension threads onto a Guan Sheng ED Barlow nosepiece and Kood 48mm to 43mm step down ring threads.
And their M48 to 42T2 threads into their extension ring properly.

They are a different thread to the Baader extension rings and filters.

The Kood 48mm to 43mm step down adapter threads onto the Revelation and Baader extension rings so tolerance designed in?

The front PST to 48mm adapter I bought does not match the Revelation extension tubes or Baader threads on their extension tubes or filters. A bit annoying.

Andrew.


AndiesHandyHandies
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1444
Joined: Fri Mar 30, 2018 6:46 am
Location: Derbyshire UK
Has thanked: 3295 times
Been thanked: 1887 times

Re: 2" thread/M48 thread

Post by AndiesHandyHandies »

Hi

More playing about the Revelation extension tube does screw into the AOK Swiss PST front adapter, the Black2 paint making it tight.

Andrew.


Post Reply