MN190 Collimation: Possibly Worse.

[wimvb]

I've been playing with WinLens to learn more about the Maksutov design, but summer vacation put a temporary halt to that. I will probably continue with it in the autumn. Atm I'm trying to get a ssd drive to work with my Raspberry Pi. Your suspicion that SW may have used the wrong offset is interesting. I'd think they would have corrected such a fabrication miss by now. The 190MN isn't exactly a new design. But imo, SW should release their in house alignment procedures. It would make life a lot easier for all MN users. I don't think such procedures would contain any trade secrets.

[coenie777]

21 hours ago, wimvb said:

I've been playing with WinLens to learn more about the Maksutov design, but summer vacation put a temporary halt to that. I will probably continue with it in the autumn. Atm I'm trying to get a ssd drive to work with my Raspberry Pi. Your suspicion that SW may have used the wrong offset is interesting. I'd think they would have corrected such a fabrication miss by now. The 190MN isn't exactly a new design. But imo, SW should release their in house alignment procedures. It would make life a lot easier for all MN users. I don't think such procedures would contain any trade secrets.

You are right, one would expect them to have corrected any mistakes in the later DS models at least From your signature it would appear that you own one of these. Mine is an earlier version. One interesting thing I have noticed is if you look at advertising images of the MN190 on various sites, there is definitely not a set and fixed position for the focuser bolts on the slide. This tells me that there is possibly some unique setup for each scope that is derived from maybe setting the specific secondary at a specified point. As the focuser is then moved to complete the setup, it ends up in different positions. There seems to be either a screw in the center of the slide gap, or close to the meniscus side of the slide. On my current setup I ended up very close to the upper end of the slide.

I agree that SW would make the world much easier for a lot of us if they released their procedure. I once made contact with SW US and requested assistance. Their answer was that the secondary position is very critical and should best be done on a bench.

Good luck with getting your ssd to work on the Pi.

[wimvb]

3 hours ago, coenie777 said:

Mine is an earlier version

The one with the smaller diagonal? I've read that SW made a design change in the MN, upgrading the secondary to a larger diameter. The larger mirror made the telescope better suited for AP, at the expense of slightly lower contrast. (This changes the offset with only 0.1 mm.)

3 hours ago, coenie777 said:

Good luck with getting your ssd to work on the Pi.

I reconfigured the Pi so that it will boot from the SD card, and use the SSD for root file system (including all software). Trying to get it to boot from SSD wasn't as easy as every online tutorial made me think. Not all SSD adapters are fully compatible (my SSD is a cheap internal model with a casing and SATA - USB adapter). But instead of 29 GB storage for images, I now have 220 GB, plus higher speed, and longer lasting. (SD cards aren't meant to be used as system drives.)

[coenie777]

18 hours ago, wimvb said:

The one with the smaller diagonal? I've read that SW made a design change in the MN, upgrading the secondary to a larger diameter. The larger mirror made the telescope better suited for AP, at the expense of slightly lower contrast. (This changes the offset with only 0.1 mm.)

I reconfigured the Pi so that it will boot from the SD card, and use the SSD for root file system (including all software). Trying to get it to boot from SSD wasn't as easy as every online tutorial made me think. Not all SSD adapters are fully compatible (my SSD is a cheap internal model with a casing and SATA - USB adapter). But instead of 29 GB storage for images, I now have 220 GB, plus higher speed, and longer lasting. (SD cards aren't meant to be used as system drives.)

No, it is the 64mm secondary version. The DS version seems to be a cosmetic upgrade from mine. I think the 52mm secondary version had the single speed focuser as well. The dual speed focuser was used for all 64mm models.

That storage multiple should come in very handy for your future MN190 images. I will keep an eye open on Astrobin.