Visual Back Thread Size for Saxon 203mm Mak

[Wookie (Ryan)]

Good morning all,

I was wondering if anyone knows the thread size for the visual back of a Saxon 203mm mak.
It has a threaded 2" diagonal that I was hoping to replace with a crayford focuser.
It is roughly the same size as a Celestron SCT thread (C11) but seems less coarse.
Any info would be great.
I have emailed Saxon in hope that they have this information but I thought I'd ask you knowledgeable people in the meantime.

Ryan

[mental4astro (Alexander)]

Hi Ryan,

You may like to ask Dave as he also has the 8" Saxon Mak:

http://www.iceinspace.com.au/forum/member.php?u=19165

Alex.

[doppler (Rick)]

Hi Ryan, you might need one of these?
https://agenaastro.com/blue-fireball...telescope.html
Rick

[Wookie (Ryan)]

Thank you both for your extremely quick replies.

Thanks Alex, I have messaged Dave to see if he can shed some light.
I also received your PM and will speak to you asap after work.

Thanks for the link Rick, I'll enquire with them.

[Aussie_Dave]

Hi Ryan.

Going by what you've explained you may have a slightly different back end to mine. Mine has a simple single speed Crayford style 2" rotatable focuser and my 2" diagonal slips into the focuser 2" draw tube. As far as I know this is the focuser from factory. Maybe you have a newer or older series or maybe a previous owner has modified yours? Your primary mirror should be fixed and you shouldn't get any mirror shift.

By the sounds of it, it's probably just the thread size if your C11 visual back sort of starts to screw on. If you know the thread type of your C11 then you're half way home.

Unfortunately I know nothing about tech specs for telescopes, I just use them

[Wookie (Ryan)]

Hi Dave,

Definitely a different series to yours.
I appreciate you taking the time to upload photos and info.
Your setup is essentially what I'm looking to accomplish.

Some more information from the archives can be viewed here notably the reply from Saxon in regards to secondary size, coatings etc.
http://www.iceinspace.com.au/forum/s...ead.php?t=3530

Mine looks the same series as the one Tony had for sale:
http://www.iceinspace.com.au/forum/s...ad.php?t=66926

[Wookie (Ryan)]

I obtained a reply from Saxon - shown below
It seems that your blue version is the one they are referring to.
I guess they sourced a white version too but I doubt they have any records any more....we'll see (I've sent them photos of mine).

"Hi Ryan,

Our 203mm Mak came with a 2” crayford focuser with 118mm travel with no mirror shift. A visual back is not required for our 203mm MAK.

Information and details of the discontinued model can be found from the following link: Here
(http://www.saxonoptics.com/products/...roductid=10901)

Hope this helps.

Best regards,

Kenny

saxon
Splendour Trading Australia Company

[Wookie (Ryan)]

Saxon replied to my email saying they do not have any information on my version.

If anybody in SA has a Mak (Skywatcher 150 or 180 etc) who would be willing to let me test their visual back accessories/fit my diagonal on theirs - Please let me know.

[FlashDrive (Poppy)]

I have 1 of these here ... !!

I have no idea if it will suit you ...but check this link.

https://agenaastro.com/baader-sct-ad...star4-c90.html

This adapter is one part of Baader's item # 2958500. It has a female 1.375"x24TPI (almost 35mm) thread on one side to attach to your telescope. The other side has a standard male SCT thread (2"x24TPI). With this item you can attach standard SCT threaded accessories meant for larger SCT scopes to your telescope (before doing so, however, make sure that you have sufficient clearance from the telescope's focuser knob so that it does not interfere with your added SCT accessory).

This adapter also incorporates an internal 1.25" female filter thread which allows you to install any 1.25" filter inside the adapter. This allows you to direct couple any accessory and still be able to incorporate photo or visual filters in the optical path. Or install a clear UV/IR cut filter to completely seal your telescope from dust and the elements.

Just trying to help...... Col.

[Wookie (Ryan)]

Thank you so much for your post Col,

This female thread will be too small - I think this would suit a smaller Mak.

I'll need to measure my thread diameter and pitch but it will be more in the order of a M44.5 x 1.0 or larger.

I'll see what adapters I have floating around...never know your luck right?!

[Aussie_Dave]

yep Ryan, very interesting. It looks like a C8 back with yours actually moving the primary mirror.

I have found very little info online about these Saxon Mak's apart from a couple at astronomy forums and a couple of old classified ads when they were being sold.

My series is also referred to as Saxon m20325 (m for Maksutov, 203 for diameter and 25 for the first part of the focal length), also referred to as Saxon 20325.

They are still being sold in New Zealand going by this website. About a year ago it was listed as out of stock but they may still have a couple left. I don't think these Mak's were popular sellers.
https://www.kiwibinoculars.co.nz/sho...ov-cassegrain/

The only other link I have for my dark blue tube is in Chinese with the only reference being the second last image on the page of the tube being screen printed with the Saxon brand name.
http://translate.google.com/translat...sl=zh-CN&tl=en

Good luck to anyone trying to find any more info. I have tried many times over the years that I've owned mine and haven't come up with much.