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12" Newt.

RobinW

By RobinW
in Imaging - Deep Sky

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RobinW

RobinW

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I got myself a 12" F4 GSO newt and a 3" ASA corrector.

I had to replace the spider and sec holder in the GSO to get it stable.

Here's a quicky from the only clear night since the new secondary arrived from astrosystems.

8x150sec Lum bin x1 and 5x50sec RGB bin x2.

GSO 12" Newt, Atik 11000, OAG/QHYL5 II

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x6gas

x6gas

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Slighly reassuring to know that the weather has been bad in Oz too... coz it absolutely stinks in the UK!

Nice images. It makes me wonder if I am doing the right thing in letting my imaging newt go... but I just don't use it...

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laser_jock99

laser_jock99

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I got myself a 12" F4 GSO newt and a 3" ASA corrector.

I had to replace the spider and sec holder in the GSO to get it stable.

Here's a quicky from the only clear night since the new secondary arrived from astrosystems.

8x150sec Lum bin x1 and 5x50sec RGB bin x2.

GSO 12" Newt, Atik 11000, OAG/QHYL5 II

Nice setup (fairly similar to mine (excepting the Atik 11000!!) is the 3" ASA correcter also the reducing version? That would be a nice fast rig indeed.

I'm intrigued about your troubles with the spider and secondary holder- what problems did you have? Is this something I need to look out for too?

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RobinW

RobinW

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I found that putting the tube on the mount pointing west so it was level and setting the laser to hit the middle of the primary, if I rotated the scope to east and level, the dot had moved out of the primary spotting circle by about 3mm. This ended up being the spider moving in/out of the tube a bit. The holes for the spider bolts where a little too big and it wouldn't tighten up enough. It really needs a 4" mirror anyway so I changed to an astrosystems setup and can simply change to one of their 4" secondaries when I can afford it. I'll get a longer bar for the tube as well eventually to rain in the tube flex a bit. When I try the laser test now, the dot still moves but it stays inside the spotting circle so it's a lot better. I also bent and cut a piece of galvanised sheeting which I put between the focuser and tube to strengthen the tube. James has a pretty good webpage on the scope > http://deepspaceplace.com/at12in.php

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laser_jock99

laser_jock99

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I found that putting the tube on the mount pointing west so it was level and setting the laser to hit the middle of the primary, if I rotated the scope to east and level, the dot had moved out of the primary spotting circle by about 3mm. This ended up being the spider moving in/out of the tube a bit. The holes for the spider bolts where a little too big and it wouldn't tighten up enough. It really needs a 4" mirror anyway so I changed to an astrosystems setup and can simply change to one of their 4" secondaries when I can afford it. I'll get a longer bar for the tube as well eventually to rain in the tube flex a bit. When I try the laser test now, the dot still moves but it stays inside the spotting circle so it's a lot better. I also bent and cut a piece of galvanised sheeting which I put between the focuser and tube to strengthen the tube. James has a pretty good webpage on the scope > http://deepspaceplace.com/at12in.php

Thanks for the information on the spider- not something I'd noticed but I'll see if I can repeat the 'shift' later. The tube re-inforcing mod around the focuser had already occured to me, something I'll get round to if it ever became an issue (still using 'lightweight' DSLR's at the moment). Certainly a beefier dovetail plate will lessen any tube flexure. I'm having a 25mm thick x 500mm long Losmandy plate milled out to give extra support.

The current dovetail I'm using is 350mm- there is substantial 'top bar' fitted too which adds rigidity.

Dscf6720_1024_zpsbac071e2.jpg

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RobinW

RobinW

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What back focus distance you use with ASA corrector? Do you use GSO 3" focuser to mount it corrector?

It's really close to 58mm which is what the 3 KORRW corrector should be.

I needed that corrector to get the big corrected FOV (50mm) for the big sensor.

I was lucky enough to get one 2nd hand. An expired astromart add came up in google before they cancelled my membership.

I haven't changed the focuser yet but I did modify it by adding extra grub screws to stop it rocking.

Also the 10:1 knob on this GSO can't lift the 3 Kg camera assembly but I do have a robofocus I could fit to it.

There hasn't been enough clear sky to really test it out :(

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RobinW

RobinW

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Thanks for the information on the spider- not something I'd noticed but I'll see if I can repeat the 'shift' later. The tube re-inforcing mod around the focuser had already occured to me, something I'll get round to if it ever became an issue (still using 'lightweight' DSLR's at the moment). Certainly a beefier dovetail plate will lessen any tube flexure. I'm having a 25mm thick x 500mm long Losmandy plate milled out to give extra support.

The current dovetail I'm using is 350mm- there is substantial 'top bar' fitted too which adds rigidity.

I haven't seen anyone else had spider problems either, I'm just lucky I guess :)

http://admaccessorie...s_Universal.htm have some really long bars but I don't want to add anymore weight to it just yet ..

Here's a pic of the galv sheeting I added. Most people seem to end up with flex around the focuser.

post-15847-0-28666300-1364262325_thumb.j

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RobinW

RobinW

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Cheers guys, I just wish the weather would play the game so I can run it a bit more. Someone told me we've had 35days of rain in the last 50. It's clear tonight but that moon ....

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laser_jock99

laser_jock99

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I haven't seen anyone else had spider problems either, I'm just lucky I guess :)

http://admaccessorie...s_Universal.htm have some really long bars but I don't want to add anymore weight to it just yet ..

Here's a pic of the galv sheeting I added. Most people seem to end up with flex around the focuser.

Thanks for the focuser reinforcement mod picture. I was thinking about using a slightly larger sheet, but concealed inside the tube. Food for thought.

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