GPCAM and ST80

[sooty]

Hi All. I'm really struggling to get my Altair Astro GPCAM (colour) version,to focus with the ST80.

Have tried with and without the supplied 45* diagonal. Do i need extension tubes,do you think?

 

Regards,

Mitt.

[RayD]

4 minutes ago, sooty said:

Hi All. I'm really struggling to get my Altair Astro GPCAM (colour) version,to focus with the ST80.

Have tried with and without the supplied 45* diagonal. Do i need extension tubes,do you think?

 

Regards,

Mitt.

I had to use extension tubes on my 60mm Altair, so I suspect so.  If you can run a capture session using SharpCap or similar, and can see the image, just hold the cameral behind the scope and move it outwards by hand to see if it comes to focus.  It doesn't need to hold it as you are just seeing if you need extensions, but it will identify whether you need them or not.

[happy-kat]

To use a camera with my ST80 I don't use a diagonal but I do have a 2 inch extension tube

[MattJenko]

You need what seems like a ridiculously long extension for these.

[sooty]

Thanks for the replies all.

Doesn't look like i will be guiding any time soon then.

Was rather hoping to try my PA with Alignmaster.

Regards,

Mitt.

 

[MattJenko]

Extensions are cheap and readily available, don't let that put you off guiding. Getting guiding working was one of the single best things I did in terms of astrophotography.

[MattJenko]

Here are 2 ST80s with 2 different sized extensions, showing the various amount of backfocus needed as the extensions are different sizes, all ready to guide 2 different rigs. The 2 cameras are an Atik 16ic, and an ASI120M, which is similar to the GPCAM.

 

[sooty]

Thanks for that.So,something like this?

http://www.rothervalleyoptics.co.uk/antares-125-extension-tube-2-long.html

 

Mitt.

[cjdawson]

2 hours ago, sooty said:

Thanks for that.So,something like this?

http://www.rothervalleyoptics.co.uk/antares-125-extension-tube-2-long.html

 

Mitt.

One of those should work.   I'm using one at the moment with my Starlight express Superstar.

For mounting my camera I'm going for a different option.  Rather than plugging the camera into a 1.25" tube, my camera has a "C mount".

I've got one of these, which my Superstar will screw onto.

http://www.rothervalleyoptics.co.uk/rother-valley-optics-c-mount-t-thread-adaptor.html

 

I'm not currently using it as I need to about 4" of extension tube. And as I'm using  T-Thread, that means I need T-thread to T-thread extensions.

I could get away with using 2" of extension tube, and racking the focuser out.  But... I'd prefer to do the 4" of extension tube and have the focuser racked almost all the way in.

The purpose for racking in as much as possible is so that most of the focus tube is inside the telescope, and therefore mechanically supported.    By having everything screwed together with threaded connections, and the focusserr supported should give my setup the most mechanical stability and minimize possible flexure issues.   It's most likely overkill, but only hurts the wallet once whilst getting all setup.

[Bagnaj97]

FLO sell a guiding kit with the ST80 and Touptek camera, this is the extension tube they include - https://www.firstlightoptics.com/adapters/flo-80mm-125-focus-extension-tube.html. Your GPCAM is a rebranded Touptek, so it's basically the same setup and that extension should do the trick.

[sooty]

Success at last.Have managed to get the ED80 and ST80 to focus on the Moon,and marked the focus tube for future reference.I then got some of M45 in the eyepiece with the ED80,GPCAM in the ST80,where it will 'live' for the foreseeable future.I then started Sharpcap but couldn't see any stars.I'd read somewhere,that stars should show,without having to alter the focus??.I presume it must be something to do with the settings,but didn't know where to start!.I then opened up PHD Guiding but nothing showing there either.Any advice regards settings for either,will be greatly appreciated. 

 

Regards,

Mitt.

[tomato]

I have a GPCAM mono on a 60 mm Altair guide scope and with a 3 to 4 sec exposure in PHD2 and in focus,  I'll have stars on screen no matter where I point it in a clear sky.

So I think you may still not be at focus on your guide camera.