DIY Motorized Focuser for FSQ 106ED Telescope

The goal of this project was for the automated focusing system to have great holding torque (80Ncm) for heavy image trains (4-5kg) and very fine steps to accommodate the super tight FSQ106 critical focus zone.

The formula to calculate the critical focus zone on a telescope is :
CFZ = Focal Ratio * Focal Ratio * 2.2
For the FSQ106ED we have : CFZ = 5 * 5 * 2.2 = 55microns
So to be able to have perfect focus achieved we need every step on the motor to be 55microns or less for even better resolution.

The motor used on this build is geared and has a reduction of 250:3 which gives us 4000 steps per revolution.

One full revolution on the focuser coarse knob (where we are coupling our motor) makes the focuser move 29.8mm.
Now we have all the data we can do the maths 😛
(29.8mm * 1000) / 4000 = 7.45 microns per step.

The actual resolution achieved with this build is 7.45 microns per motor step!

Astrophotography – Moon Mosaic Part II

Date : 26/04/2020
Telescope: Vixen VC200L
Camera: ZWO ASI120MM-S

6 part mosaic comprised of 800 frames for each panel.
Stacked on registax and then assembled in Pixinsight.

The Moon today is in a Waxing Crescent Phase. A Waxing Crescent is the first Phase after the New Moon and is a great time to see the features of the moon’s surface. During this phase, the Moon can be seen in the western sky after the sun dips below the horizon at sunset. The moon is close to the sun in the sky and mostly dark except for the right edge of the moon which becomes brighter as the days get closer to the next phase which is the First Quarter with a 50% illumination.

New astronomy website!

Astronomy is a really broad subject. Same goes for astrophotography and all the weird gimmicks of this hobby.

Because for the most part of the year, I went full berserk mode into both and have gathered allot of images, data, procedures and various tutorials, which would kind of hijack this personal blog I decided to move astronomy and astrophotography into its own separate – special website 🙂

So if you are into any of those things or maybe like “nice”  images of the cosmos, do visit the website :


NGC6910 Gamma Cygni and nebulosity

HaRGB version of the beautiful Gamma Cygni and surrounding nebulosity region.

NGC 6910 is a Y-shaped cluster oriented northwest southeast. The two brightest stars are of magnitude 7.NGC 6910 is a small cluster, only 10′ in diameter

NGC6910 Gamma cygni by Marios Tsalkidis

The southernmost star is SAO 49563 (or V2118 Cygni), a variable star of spectral type B1.5Ia. Gamma Cygni, not far off the galactic plane is subject to a great deal of interstellar extinction and reddening from interstellar dust. The dust selectively absorbs and scatters blue light (roughly 1/wavelength), so when you look at a star through dust it will appear redder than it really is (basically the same reason the sun is reddened at sunset). The intrinsic B-V color of a B1.5Ia super giant is -0.2. The observed color is 0.83, about the color of a K0 dwarf or a G5 giant, so the star appears yellowish to the eye. Notice the yellow stars in the cluster, caused by interstellar dust, and the bluish-white stars in the vincinity of NGC 6910.

Technical details
Sky-Watcher 80ED Pro Black Diamond
SBIG 8300M
HEQ5 Pro
Skywatcher .85x Focal Reducer & Corrector
PixInsight,  Main Sequence Software SequenceGeneratorPro
Accessories: Starlight Xpress Starlight Xpress FW 5*2”
Resolution: 1676×1266
Dates: June 13, 2015

Baader 7nm Ha 2”: 10×300″ -5C bin 2×2
Baader Blue 2″: 10×120″ -5C bin 2×2
Baader Green 2″: 10×120″ -5C bin 2×2
Baader Red 2″: 10×120″ -5C bin 2×2

Integration: 1.8 hours
Darks: ~50
Flats: ~10
Bias: ~300
Avg. Moon age: 25.75 days
Avg. Moon phase: 15.29%
Bortle Dark-Sky Scale: 2.00
Temperature: 17.50

Annotated version :

NGC6910 Gamma cygni Annotated by Marios Tsalkidis