I need a favor from the owners of the Explore Scientific First Light 152mm Maksutov-Cassegrain Telescope:
If you have a camera, of any type, can you take a single photo of the night sky.
No reducer or anything else, with enough stars to plate-solve on https://nova.astrometry.net/, or other plat-solve routine.
Respond with:
1. The Pixel scale, in arc-second/pixel, from the plate solve
2. What camera you used, or its pixel size, if known.
I am asking for this because I just purchased one, and my copy has a focal length of approximately 2480mm to 2490mm focal length (~f/16.3)
It is specified to be 1900mm focal length, f/12.5
So I am wondering, is this just my telescope? Or a specific "lot" of telescopes? Or are they all like this, and ES is showing incorrect specifications?
Last night I used the collimation pull-screws, (with the push-screws backed off all the way) to bring the mirror as far aft as it would go, and started collimation from there, trying to keep the mirror as aft as possible.
1. I started with prime-focus using one Explore Scientific 37.5mm spacer. The focuser position ended up at around 30mm.
2. I then used the Astro-Physics CCDT67 tele-compressor, with 89.5mm back-focus from the flange, no additional spacers. The focuser position ended up around 27mm.
Results:
1. 2388 mm focal length (f/15.7)
2. 1592 mm focal length (f/10.5) Note, this is a reduction of 0.667
So that is the closest I can get it to its specified focal length of 1900mm, f/12.5, only using the collimation screws.
It is still significantly off.
Any help is appreciated!
Steve
