Custom made webcam adaptor?

[AstroTux]

Just a quick question, does anybody know where I could get a custom made webcam adaptor from? I've trawled through back posts on this site but could not find anything of use.

My problem is that I have recently acquired a 0.5 focal reducer for one of my SPC900s. When I tried it I quickly found out that I did not have sufficient inward focus travel on my 'scope. Further tests revealed that the required inward focus travel was about 1 cm.

The current webcam nosepiece has a flange that stops it from being moved further into the focuser, so I thought about removing this but then realised that the camera body would prevent further inward movement. As I've already modded a couple of these webcams taking the camera to bits is a very attractive proposition. If I remove the current enclosure and remount the boards in another box there will be far more room to play with in front.

This is where the problem with the nosepiece comes in. Even if I remove the flange, the design of the adaptor means that the locking screws in my focuser would have nothing to grip when the camera is moved inwards, hence the reason for asking if anyone knows where I could get an adaptor made to my specifications. It needs to have a body that comes further back towards the CCD chip than those designed to be used with an intact camera. Another possibilty would be to have a collar made to extend the 1.25" part of my current adaptor backwards.

If anybody has any other ideas I would be pleased to hear them.

BTW, I do not want to start moving the primary mirror up the 'scope as I'm near the farthest limit with some of my eyepieces already.

[woodbob123]

If you have a model engineering club or society near give them a try.

[ronb]

Have a word with Steve at FLO. See theCustome-made Astronomy Adapters post in Sponsor Announcements on this site.

[The Sailor]

Don't know if I am reading this right but have you tried a diaognal:

Jim

[JamesF]

If you want something that screws into the M12 thread of the board lens mount I think you may need someone to turn something up for you out of aluminium or delrin or something along those lines.

An alternative might be to fit the boards into a new box as close as possible to the front face, saw the back off a normal nosepiece and then glue the remainder to the face of the box. Still could be quite tight though.

James

[Steep]

I've an spc880 and a 900 and in trying to get them to work in my Coronado PST I've done as JamesF suggests above, I've had to remove them from the original casing and fit them into flusher mounting rectangular abs boxes. Careful drilling to make a hole in the box just big enough to ensure a tight fit round the outside of the threaded collar over the camera sensor (so that the collar protrudes a few mil from the box) makes sure it's still light tight where it needs to be and the nose piece is still aligned with the sensor even if the camera electronics isn't perfectly flush inside the box. I've also had to shave off the collar you mention and cut the nose piece down by about half. This works for me as it gets the sensor much closer to the focal point of the scope but you would not then be able to attach the reducer assuming it is meant to screw onto the end of the nose piece?

[The Sailor]

Sorry, I understand the problem now, I have done the same, new box and a cutdown, this is the first box I used, later one was half the size:

Moon filter used a s a dustcap

Jim

[JamesF]

I've also had to shave off the collar you mention and cut the nose piece down by about half. This works for me as it gets the sensor much closer to the focal point of the scope but you would not then be able to attach the reducer assuming it is meant to screw onto the end of the nose piece?

I assumed it does, which is why I suggested gluing that bit of the original nose piece to the box. What I'm not sure about though is how it will work. It's often the case that reducers need to be a fixed distance from the sensor and that may need a fair bit of fiddling about.

James

[AstroTux]

Many thanks to you all for the swift replies. I've taken the liberty of taking a couple of photos and then gimping them together to give a better idea of the problem. As they say "a picture speaks a thousand words":-

The top image is of the standard SPC900 and the bottom is it uncased. As can be seen the distance available for inward focus is over 1.5cm, but the adaptor would put a stop to that. Even if the flange is removed the locking screws on my focuser would have nothing to grip!!! Maybe a 1.25" collar to fit between the back of the adaptor ( minus the flange ) and the new webcam casing would be the way to go?

If you have a model engineering club or society near give them a try.

Unfortunately I don't, but I know a man with a lathe and he has said he will try. Unfortunately he is unsure as to whether he can cut the 1.125" x 42 tpi thread to attach the filter/focal reducer....

Have a word with Steve at FLO.

Great idea. I didn't know they could do such things, but as a backup plan to my man with the lathe this sounds good.

It's often the case that reducers need to be a fixed distance from the sensor and that may need a fair bit of fiddling about.

Many thanks for this, James. As this is a 'variable' 1.25" focal reducer from Bernard at Modern Astronomy do you know if this still holds?

Doing a bit more research it appears that FLO advertise two webcam adaptors, one for 'thick case' ( SPC900 ) and the other for 'thin case' ( Toucam ) webcams. Does anyone know if the thin case adaptor will fit the M12 thread on an SPC900, and if so will it benefit me in any way?

Once again, many thanks for all your help and any other bright ideas you may have would be greatly appreciated,

Alan

[JamesF]

I believe the difference in the two different nosepieces is the length of the threaded section.

Another approach I guess might be to cut through the nosepiece flush with the back of the 1.25" section, leaving you with a 1.25" piece with a hole in the centre and a stepped section with a thread on the end. Cut the second piece close to the end of the unthreaded section to leave a threaded section with a flange on it. Glue that flange back to the 1.25" piece (so you've effectively eliminated the narrower smooth section in the middle of the nosepiece). It might still be necessary to trim off the flange on the 1.25" section.

It might even be possible to trim off some of the length of the threaded section and cut down the height of the board mount to get even more room to play with.

James

[JamesF]

Many thanks for this, James. As this is a 'variable' 1.25" focal reducer from Bernard at Modern Astronomy do you know if this still holds?

Not a clue, I'm afraid. The blurb about the reducer suggests that the reduction factor will change, so perhaps you'd be ok.

James

[AstroTux]

Another approach I guess might be to cut through the nosepiece flush with the back of the 1.25" section, leaving you with a 1.25" piece with a hole in the centre and a stepped section with a thread on the end. Cut the second piece close to the end of the unthreaded section to leave a threaded section with a flange on it. Glue that flange back to the 1.25" piece (so you've effectively eliminated the narrower smooth section in the middle of the nosepiece). It might still be necessary to trim off the flange on the 1.25" section.

Thanks James. I never even thought of that ( Dooohhhh!!!! ). The only issue I can see is that it would bring the reducer closer to the chip, but maybe that's not too important with this one.

Alan

[AstroTux]

Not a clue, I'm afraid.

Yup, I think "try it" is probably the way to go here. If it doesn't work then I'll have to get someone to turn me a new adaptor.

Thanks,

Alan

[JamesF]

Actually, that makes me wonder...

I wonder if it would achieve focus if you could just make the nosepiece longer? If you, say, put a UHC or LP filter into the nosepiece, and the reducer into that? Or even two filters? Obviously not a desirable long-term solution, but for the purposes of extperimentation...

James

[The Sailor]

Not required

Jim

[AstroTux]

I wonder if it would achieve focus if you could just make the nosepiece longer? If you, say, put a UHC or LP filter into the nosepiece, and the reducer into that? Or even two filters? Obviously not a desirable long-term solution, but for the purposes of extperimentation...

This is how I found the 'possible' solution in the first place. I orignally placed the reducer straight onto the front on my IR filter ( and dust excluder!! ) and could not achieve any kind of focus. When I swapped the two over ( CCD, then reducer, then IR filter ) I started to get focus but on relatively nearby objects such as a flagpole 400 yards away. This is what made me think that I should try to get the chip further into the 'scope but with the same distance between reducer and CCD.

However, thinking about it, if the reducer is further away the reduction factor should be less but the focal point should be further from the primary mirror. I think I'll try what you suggest in daylight - more experimenting leads to more success ( and makes SWMBO think I'm doing something and should not be disturbed ) ............ :grin:

Thanks,

Alan

[AstroTux]

I have the SPC and a few other webcams and on all my OTAs I can only get focus with a diagonal even when I put a reducer on cam, am not quite sure of the problem as all mine work.

Many thanks Jim, but unfortunately I don't have a diagonal to play with.

With my limited knowledge of optics I'm struggling to see how one could help, but could it be that all your OTAs have low profile focusers fitted? My OTA has a rather large and 'clunky' focuser that I would love to replace but my 'shoestring astronomy' approach won't let me do this :grin: .

Alan

[The Sailor]

Sorry Alan I deleted my last reply as I asumed I was not in the converstaion, I myself have next to zero regards how the lot works except that it was just my trying out different parts that I got to focus on the webcams. I would not like to see you cut up parts when maybe a secondhand diagonal would be worth trying and if it works then go for a better one. So far a number of people who have had problems with this have achieved focus with the diagonal so I am putting that forward as an answer, if you could borrow one before you cut than great. All my webcams/OTAs are different, you can see what I have in my sig and I have no problem with focus, just hope that helps.

Jim

[JamesF]

I can't see how a diagonal would help, to be honest. I think it could only lengthen the optical path and what's required as far as I can see is to make it shorter.

James

[AstroTux]

I would not like to see you cut up parts when maybe a secondhand diagonal would be worth trying and if it works then go for a better one. So far a number of people who have had problems with this have achieved focus with the diagonal so I am putting that forward as an answer, if you could borrow one before you cut than great. All my webcams/OTAs are different, you can see what I have in my sig and I have no problem with focus, just hope that helps.

No probs. Thanks Jim.

[The Sailor]

Understand you James, but what I can't understand is I have that webcam and using filters/reducers I have not had a problem, we live and learn

Jim

[JamesF]

'fracs, Maks and SCTs often have sufficient focuser travel that it's possible to get to the position you need without bother. By comparison, newts often have quite limited focuser travel. Depending on the combination of OTA and focuser it's quite likely that some will manage to reach focus and others won't. It's probably got more to do with how the designer thought the scope was going to be used and what parts they had to put it together from than anything else.

James

[JamesF]

Here's your solution:

http://stargazerslounge.com/topic/174822-3d-printed-spc900-case/

James

[JamesF]

You'd need one with a thread on the 1.25" bit though, I guess.

James

[AstroTux]

Here's your solution:

http://stargazerslou...ed-spc900-case/

You'd need one with a thread on the 1.25" bit though, I guess.

Nice idea James. My mate with the lathe wants to try and build a 3D printer so maybe I could get him to build this as a trial piece............. :grin:

Oh dear, just remembered I've got to build the electronics to control the motors for him, Ah well...... maybe when I've finished playing with the webcam. Am going to do more experiments with different reducer positions tomorrow and will let you know how I get on,

Alan