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New ride - AP900GTO

Posted: Sat Feb 24, 2024 5:18 am
by CharLakeAstro
For a few years, I have been looking to upgrade to a heavier mount. Patience is a virtue, and this Astro-Physics 900GTO came available... within 1 hour from my home. It was an estate sale, and the sellers contracted a knowledgeable person to help them liquidate some high-end astro equipment. I stayed task focused on the mount, and while I did drool a bit at several rare Astro-Physics refractors, my wallet reminded me that it was only the mount I was looking to buy.

On inspection, the mount has barely been used. Some testing and verification, a bit of back-forth and we reached an agreement. The mount 900GTO, (2) counterweights, AP Portable Pier, Hand controller. I brought it home and set it up in my workshop, on the AP 54" pier. The 1.875" counterweight shaft is massive, a counterweight in it's own.
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The mount needed some maintenance due to it sitting, namely, removal of the old grease and re-greasing, un-sticking of one pinion gear as part of the re-greasing, a new lithium cell in the Hand Control, and replacement of the hand controller cable due to the outer jacket deteriorating. Lastly, the CP-2 controller was upgraded to a CP-3 with the V2 chip. The mount is now restored to full functionality, and compatible with APCC software.

The original top plate is designed for use with refractor rings. Off that came, now replaced with a new DOVELM162 from Astro-Physics, allowing more versatility. First up was my Celestron Ultima C8 OTA on an ADM plate (OTA was originally on my Ultima2000... way back in 2001)
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Next, some balance tests with my Orion ED-80 riding on the C8 OTA. The mount is rated up to 65lb payload, and it doesn't seem to know the scopes are there. This is a fun upgrade... way overmounted, which was my original hope when seeking to upgrade.
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Then, an ADM Side-by-Side was installed, along with my William Optics GT71ii imaging rig mounted.
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Next, following the Balancing, I was able to do a Side-by-side test with two refractors, the Orion ED-80 (DDG focuser) and the WOGT71 together.
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I use (2) ZWO cameras (ASI183MM-Pro and ASI294MM-Pro) and (2) filter-wheels, with (3) EAFs. The new mount will allow more versatility with quick swap-outs of scopes already near focus. At some point, I may try simultaneous imaging with the two refractors, but for 2024, my plan is to image one at a time. The SCT will be imaging alone, with OAG guiding.

For this year, it will be brought in and out when imaging, but In the longer term, this mount will be installed in my observatory. First light should be in April. Looking forward to this ride.

Re: New ride - AP900GTO

Posted: Sat Feb 24, 2024 9:19 am
by Graeme1858
Looks like you found an excellent buy. Patience is certainly a virtue!

We look forward to seeing your images.

Graeme

Re: New ride - AP900GTO

Posted: Sat Feb 24, 2024 9:24 am
by Lady Fraktor
A nice looking mount, I hope you get a lot of use from it.

Re: New ride - AP900GTO

Posted: Sat Feb 24, 2024 3:00 pm
by messier 111
fine setup , thx .