Re: TPoint vs. APPM -- Translation Possible?

Ray Gralak

Hi Marty,

Since you mention TPoint, does that mean you have SkyX?

If so, have you tried plate-solving any of your images with SkyX's image link? If needed, there is a much deeper stellar database available:


-----Original Message-----
From: [] On Behalf Of mjb87 via
Sent: Wednesday, November 3, 2021 5:32 AM
Subject: Re: [ap-gto] TPoint vs. APPM -- Translation Possible?

I've tried four cameras, all coupled to a focal reducer. I've tried binning from 1x1 to 3x3.

Sensor data (microns and arcminutes):
Sensor 1: Pixel = 5.9 and FOV = 1.4x0.9; unbinned image scale = 0.40 (Mono)
Sensor 2: Pixel = 3.8 and FOV = 3.5x2.6; unbinned image scale = 0.26 (OSC)
Sensor 3: Pixel = 3.8 and FOV = 4.7x3.1; unbinned image scale = 0.26 (OSC)
Sensor 4: Pixel = 2.4 and FOV = 2.3x1.6; unbinned image scale = 0.16 (OSC)

I am targeting scale at about 0.9 to 2.1 and binning appropriately.

However, my seeing isn't great and I'm probably at 1.5 arcsec FWHM. I can easily manually align a star (e.g.,
using TPoint) and I can do lucky imaging but I'm having a problem with platesolving.

Again -- my primary concern is pointing, not unquided tracking, so the dual-axis tracking is a "nice to have" for
this installation. I'm mainly interested in pointing accuracy.

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