SamuraiOZ

Yes, I'm using exactly same newtonian SkyWatcher Quattro 200/800 F4.

OK, I see. The issue caused by the incompatibility of Baader CC and my telescope.

I will consider purchasing SkyWatcher CC for F4.

Anyway, thank you guys for a lot of reply and suggestions!

Hi, thanks for the suggestion. Does spacing mean the optical axis alignment?

Yes, it is another issue on my telescope. Since my F4 Newtonian has offset, I can not use laser collimating tool. I'm wondering how I can align it.

Coma corrector! Yes, I'm using MPCC-MARK III with the filters.

Is there any idea to reduce reflection from coma corrector such as anti-reflection coating or something?

Hi, thanks for the quick comment.

I'm using ZWO's 7nm Ha filter:

https://astronomy-imaging-camera.com/product/zwo-new-narrowband-1-25-filter

This donuts ring appears not only on this filter but also any filter such as L, R, G, B, and Oiii.

So I'm doubting this caused by reflector telescope's optics.

Hi all,

As shown in the attached picture, I'm annoyed by the donuts ring around the bright star.
It was stacked and enhanced from 20 shots of 300sec exposure with h-alpha filter on 200/800 F4 reflector telescope.
Before stacking, each shot is subtracted by dark frame and divided by (flat - dark) frame.
Flat frame is taken at the neighboring sky with translucent cover using exactly same telescope settings.

Has anyone had the similar experience using reflector telescope?
I appreciate if someone can share the technique to avoid this donuts ring or remove it in the post-processing.

Hi all,

I'm trying to connect SkyWatcher Synscan to my MacBook Air via wifi adapter using EQMac v2.0.0 beta3.
According to the release note of EQMac v2.0.0 beta1, it supports wifi as well as serial connection. However, I couldn't find any document for wifi connection.
What I'm trying to do is..

1. Establish Wifi connection to "SynScan_WiFi_####"
2. Configure following connection in EQMac's Preference
    Connection Type: TCP/IP
    IP Address: 192.168.4.1
    Port: 11880
3. Close Preference setting

However, EQMac console is still gray out..
Appreciate if anyone share how to configure EQMac for wifi or alternative application/tool to connect Synscan to Mac via wifi.