Comparison of a Skywatcher Evostar 120/1000 with a Skywatcher Maksutov 127/1500 using a PST40 modification Stage 1

Since I only have a small balcony for my hobby, I'm always looking for small and effective solutions.

So today I compared the two telescopes mentioned above.

They both have the following components in common:

1. Baader DERF 110 mm as an energy-protection filter in front of the lens:

I added two motors to this PST40, one for the etalon and one for the focusing knob. I printed the gear on the etalon using TPU, and I also improvised the etalon's timing belt. The electronics are based on the myFocuserPro2, with one board for each motor, since Indi apparently only supports one motor per board.

I'm happy to provide the print files as STL files. These include the one shown above and a version with just the focusing motor (but not the motor for the etalon). Just let me know at karsten@teleskop-spezialisten.de

(I'm also currently working on a solution with the ZWO-EAF. The PST's stage 2 mod will follow later.)

To make it easier to compare the two telescopes, they were mounted together on a mount.

Yes, the balcony is really narrow. On the trolley is my intermediate adapter for attaching the Evostar 120's DERF to the MAK127. The Evostar 120 has an outer diameter of 143 mm at the dew shield, while the MAK127 has 145 mm. So, I quickly printed an adapter out of PETG with carbon fiber (10 hours 57 minutes).

Here's the version: Mak normal, Evostar 120 with H-alpha.

Fun fact: The Evostar 120 had to be shortened to achieve sufficient backfocus, while the MAK127's focus travel is more than sufficient.

The small Askar FM180 was only mounted for testing purposes; it's intended for another, future project.

The camera used is the ZWO ASI178 MM, which unfortunately produces a grid pattern with H-Alpha. This should be able to be corrected using flat-frame computation. I'll do that later.

Here are the initial results: the photos were adjusted using a histogram only, so the raw properties are visible, including no flat frames. The images were stacked. Due to its 1500 mm focal length, the MAK127 is darker than the Evostar120 at 1000 mm.


These were just the first, rough tests, more will follow.