Atik 314L+ spacing?

[Astroblagger]

Hello im trying to get the spacing of my reducer to Atik 314L+ correct there are afew things im not sure about though,what is the distance to the chip with the threaded part added? you cant measure it as there is a glass cover over the chip? as in the photo, also do you take the reducer measurement as being to the glass part or just to the threaded part? to get the correct distance?

[Oddsocks]

The distance from the ccd surface to the front (red) face of the camera body is 13.5mm.

Here is a link to the ATIK dimensional diagram for future reference:

http://www.atik-cameras.com/external/Website/Drawings/314lplusmech.pdf

Some reducer manufacturers quote backfocus distance from the glass and some from the flat part of the threaded flange, what is the make and model reducer that you are using?

[Astroblagger]

its the SW120/80 0.85 reducer.

[Astroblagger]

At the moment with all the bits connected to the ccd end ie filterwheel,  iv got a distance of 40.5 from the chip to the end of the filterwheel, on the sw 0.85 reducer end iv got a M48 to T2 adapter which adds 1mm to the optical length, now does that distance mean to the glass or the screwed connection to reducer? i think the distance has to be 55mm in total from chip to reducer, correct me if im wrong? so thats 55mm -41.5mm  so thats leaves an extension adapter  tube of 13.5 is this correct??

Also who supplies adapters suitable for this job??

[Oddsocks]

Usual lack of any meaningful Skywatcher specification on their web site!

The 55mm is measured from the flat flange at the body end of the m48 thread.

I use one of these Baader variable 12-to-16mm T2 extensions with my camera, doesn't flex and locks solidly.

http://www.365astronomy.com/variable-locking-t2-extension-12-16mm-optical-length-p-484.html

William

[Astroblagger]

ok thanks for the info, that looks the biz, do they do m42 male to female ones as thats what i require? do you know any other companies that make adapters?

[Astroblagger]

so i take it that is 55mm at point A?

[Oddsocks]

Baader don't make variable 48mm spacers only 48mm to T2 adaptors.

This company make bespoke parts, might be worth a call or e-mail, otherwise wait until November, I'm buying a lathe and milling attachment, might take a while before I learn how to use it though 

http://stargazerslounge.com/topic/192594-billetpartscouk/?hl=%2Bbespoke

William.

[Oddsocks]

Thats right, point "A" to the chip should be 55mm.

William

[Spikey]

I'm at least 5mm out spacing wise on my 16HR (same chip) with the SW FF/FR and I always seem to get decent corner stars. Maybe it's not 'as' critical on the smaller chips. 

[Uranium235]

This is where a digital caliper is worth its weight in gold. Get one, and it will solve any questions over the spacing.

Dont waste money on a variable spacer, just get a mixed set, get it close (must be a few mm under to start) - then make up the distance using plastic spacers (0.5mm thick). Using the spacers will prevent cold welding as well. 

Additionally, you may want to consider a spacing of 56mm - with the extra mm added due to the filter and CCD window extending the light path slightly. As Simon commented, there may not be a need to be so precise with your chip size.

[Astroblagger]

so this is what i have so far 40.5mm + 7.5mm = 48mm  so

55mm -48mm=7mm spacer required is this correct? also i need an M42 to M42 male to female spacer where could i pick one up? or something similar i have access to a lathe.