Unable to focus Cinema HD Mod - ETX 80

[Savo83]

Hi,

I've tried and tried to get focus with my webcam mod on my PC but I just can't get it right.  I've even tried to remove it from the housing and pop it straight into the barrel but everything seems just a tad out of focus.

Anyone have any tips?  I'm using the default Cinema HD software for the moment and I've switched the auto zoom etc off but it just won't get sharp enough.

Do you think it's software related? Also, is there anything I can buy to increase the focus range available?

Any help would be greatly appreciated as it's extremely frustrating.

No difference if I use it through the diagonal or with a barlow.

Thanks 

[Savo83]

http://instagram.com/p/fsEMTPsC72/

http://instagram.com/p/fcz2I6MC5Q/

Here are two examples if that helps..

[ronin]

What is the "webcam mod" you mention?

Exactly what are you doing, or trying to do - where is the webcam in the optical chain?

[Savo83]

Sorry, I mean that I've modded the webcam as per these instructions: http://ghonis2.ho8.com/lifecam/lifecam1.html

[Mr TamiyaCowboy]

black parts in the second image could be dust bunnys, soon as the sensor is uncovered it collects dust.

if you can you may want to try and shift the camera unit inside the body forwards say no more than 5mm 

that will bring the sensor closer to the focal plane.you will nodoubt find focus.

its just a game of shifting the unit inside barrel back or forth and testing , also an IR bocking filter fitted will help to.

it will bring back the color and cut out the telescope focusing IR wavelength

[Savo83]

I've tried removing it from the housing but still no joy, i.e. it was placed directly onto the lens.  I'm just wondering if I can adjust it through software such as Registax so I might need to give it a go. 

[Savo83]

Yeah, it's definitely dust.  I might try using some filters I got with my Celestron kit as it's extremely bright.

Thanks

[Mr TamiyaCowboy]

yes the pink color is from both IR and visual light wavelengths trying to be focused. so a IR blocking filter

will stop a huge amount of that. 

moon and likes i found very bright, i found it toned down better using a moon filter ( the gray filter one, it blocks a few % of the light and makes less bright )

i also found adding filters changes the focus, you could find camera struggles to get focus again when filter installed, but when removed focus is perfect again.

its a pain but tweeking here and there can help

[JamesF]

I'm confused about a couple of things here...

For the Gary Honis mod you remove the camera lens (the entire zoom unit) completely, yet you talk about setting the zoom control.

You say "it was placed directly onto the lens".  What's "it" in this instance, and which lens?

James

[Savo83]

Hi,  I've removed the lens that's in the guide - the autozoom feature is for the software which I've had disabled and enabled but with no change.

I was referring to the fact I placed the webcam directly into the eye piece holder (out of it's casing) so it was as close to the mirror as possible.

[JamesF]

Ah, right, I see.

I reckon that if you put an eyepiece in and get it in focus, then you want to have the camera sensor in the same position in the focus tube as the field stop was in the eyepiece.  I'm not certain about that as I've never thought about it that way before, but if the field stop is sharp and in focus and the image is in focus then the field stop must presumably be at the focal plane, so that's where you need the camera sensor to be if it is to be in focus.

If you move the camera up and down the focus tube you should be able to see the image getting closer or further away from focus, which may give you a better idea of where you need to be.

And if you can't move the camera inwards far enough, try adding a barlow if you have one.  They will often move the focus point outwards far enough that a camera will reach focus.

What sort of scope is it that you're using?

James

[Savo83]

I'm using an ETX-80.  I've tried using a barlow but it still wouldn't make any difference.  I'm beginning to think it is in focus and it's possible to do with the software settings I'm using.  I have a 6mm lens so I'll try and focus that as I've been told the camera is in the same kind of range.  I was just curious to see if anyone has used this with a similar scope and if there was an easy fix that I'm missing. 

[Savo83]

Not a lens, a 6mm eyepiece... doh! 

[Savo83]

Also, just to add, the unit is housed in a Billetparts adapter - http://www.billetparts.co.uk/catalog/lifecam-adapter-p-122.html

How the heck do you edit a post?! 

[JamesF]

Doh! Should have read the subject line

The 6mm eyepiece is a complete piece of misdirection.  Ignore it.

Imagine the telescope as projecting an image of what arrives at the objective lens on an imaginary "screen" somewhere near the top of the eyepiece tube.  That's where the image is in focus.  To get an eyepiece in focus you need the focal point of the eyepiece to be at that position as well.  To get a camera in focus you need the camera sensor to be in the same place.

Generally the focuser moves the eyepiece or camera in and out to achieve this.  I'm not entirely sure how the ETX-90 focuser works.

It may be that the image looks bad because the brightness is turned up too high.  It's worth turning that down a bit I think.  It may also be worth looking at the gamma and exposure settings.  I can't recall exactly what's available with this camera at the moment.

James

[JamesF]

How the heck do you edit a post?! 

Disabled until you reach 50 posts I think, thanks to abuses past...

James

[Savo83]

I'm going to give that a go if I get a clear patch of sky.  Thanks very much for your help, hopefully the brightness will do the trick.

I'll let you know how I get on.  Think I might try it through SharpCap as that looks to have much more options. 

[JamesF]

SharpCap would be a good choice.  I don't know what state v2 is in at the moment.  It might be best to stick with the latest v1.5 release.

James

[Savo83]

Thanks for all your help James.

[Savo83]

Just thought I'd let you know that I was able to get focus today! This was on trees very owe so should be working great at night now. Uninstalled the Microsoft drivers and I'm now using 720p@30fps through sharpcap. I also had a play around with Registax so I'm really looking forward to clear skies to awe you all with my highly light polluted images

Thanks everyone for your help!