Observatory equipment
I have imaged with various rigs over the years but have have owned my current telescope and mount setup since circa 2007.
My mount is an Astro-Physics AP1200 GTO upgraded to CP4. AP equipment needs little introduction, but suffice it to say that this mount is simply the finest thing I own. It has a huge payload capacity and a very small periodic error. I recently carried out its first re-grease and gear re-mesh - the periodic error is a very smooth 3 arc sec peak-to-peak which is better than it was when new, so I suppose it’s now well run-in! The mount is solid and bullet-proof, and has always worked flawlessly with no real issues.
My telescope is a Takahashi TOA130 - arguably one of the finest 5” apochromatic refractors there is. It has a highly-corrected, air-spaced triplet objective lens up front giving a focal length of 1000 mm at f7.6. When used with the 67 field flattener, the scope produces a whopping 90mm illuminated image circle and is fully corrected across a full-frame sensor. A Feathertouch 3515 focuser replaces the the stock Takahashi focuser which was prone to flexure and had a narrower clear aperture. The scope is beautiful to use for visual astronomy but is also capable of producing exceptional images. I’m a big fan of the largely artefact-free images that apochromats produce.
On the imaging end of things, my current camera is a ZWO ASI6200MM Pro monochrome full-frame (35mm format) CMOS instrument with a Sony back-illuminated IMX455, 62-megapixel sensor with 3.76 um pixels. This is attached to a 7 position filter wheel containing Chroma LRGB and 3nm narrow-band filters. The Takahashi 67 flattener then sits at the correct back distance using a PreciseParts adaptor which is then connected to my Optec Leo low-profile focuser. Rotation is carried out by hand using the locking ring of the Feathertouch focuser.
The wide image circle from the flattener plus the large clear aperture yield only minor vignetting and a very good flat field. Luckily, this system is quite orthogonal and only small adjustments have been necessary to adjust for camera tilt - stars tend to be sharp into the corners of the full frame. The image scale is around 0.77 arc sec/pixel - right in the sweet spot for image sampling given the combination of camera pixel size, focal length and local seeing conditions. Occasionally I hook up my ZWO camera to my old Nikon 180mm ED-AIs camera lens, which gives very under-sampled images, but is good for capturing wide-field views of very large objects (e.g., the LMC, or the Rho Ophiuchus Complex). On other occasions, I piggback my regular Nikon Z6 camera with 50mm Sigma Art f1.4 lens on top of the rig to produce images like THIS.
Other accessories include a Pegasus Astro Ultimate Powerbox V3 sitting atop the scope which controls the dew heaters, supplies power to everything at the scope and acts as a USB hub. The Pegasus has allowed me to simplify the wiring and eliminate the morass of cables hanging off the back end of the telescope - I have only one power and one USB cable running up to the mount, so balancing and cable snags are much less of an issue. The Pegasus is connected to a Morefine M6 mini PC which is situated on the pier - this runs NINA for camera control and image capture, PHD2 for guiding and the Astro-Physics ASCOM utility for mount control. I then connect to the Morefine wirelessly via the WiFi LAN using Remote Desktop. Images are saved directly to a SanDisk Extreme Pro 1TB portable SSD which is also connected to the Morefine mini PC. Power for everything comes from a bank of 12V batteries via a voltage regulator giving 13.4V. The batteries are kept charged by two solar panels on the roof connected to a Morningstar charge controller, so it would be true to say that all my images are made using glorious Wairarapa sunshine!