A question for RASA owners

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For you RASA, are you using a OSC or mono and filter sliders?
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ScottF avatar

Hi,

I recently purchased an 11” RASA and I’m using a 2600mm with filter sliders. I typically use one NB filter per night, take flats in the morning, then swap the filter for the next NB filter. For strictly NB imaging it seems ok, but I find it a lot of trouble to do RGB stars. I’m curious about swapping the camera for a OSC camera and using dual narrowband filters for NB and a LP filter so I can capture RGB stars in one go. What is everyone using, and reasoning?

thank you

Scott

Engaging
Nicolas Molina avatar

Hi Scott.

I have a RASA 8, but it’s basically the same problem. I started with the 2600 mm, but I changed it to the 2600 mc pro because of what you mentioned. My choice was the IDAS NBZ. I would not recommend typical 3nm dual-band filters; they are not preshifted to use on fast telescopes.

CS

Nicolás

churmey avatar

If the RASA is your dedicated instrument, my advice is to keep things simple, and get the same camera in both mono and OSC. In my case, I will image with the mono for Lum or Narrowband, then simply switch cameras when doing color. I never switch during a session….In other words, I’ll image 1 full night in Lum, or several nights, until I complete Lum. Then I’ll switch and image OSC a full night or until I complete RGB and so on…. I have used this system with both the 183m/mc and now use the 2600m/mc.

Helpful
ScottF avatar

churmey · Oct 27, 2025 at 03:21 PM

If the RASA is your dedicated instrument, my advice is to keep things simple, and get the same camera in both mono and OSC. In my case, I will image with the mono for Lum or Narrowband, then simply switch cameras when doing color. I never switch during a session….In other words, I’ll image 1 full night in Lum, or several nights, until I complete Lum. Then I’ll switch and image OSC a full night or until I complete RGB and so on…. I have used this system with both the 183m/mc and now use the 2600m/mc.

So you are fixing tilt after each switch? I’ve only done it once so far, but it was a fairly time consuming, onerous experience. lol

ScottF avatar

churmey · Oct 27, 2025 at 03:21 PM

If the RASA is your dedicated instrument, my advice is to keep things simple, and get the same camera in both mono and OSC. In my case, I will image with the mono for Lum or Narrowband, then simply switch cameras when doing color. I never switch during a session….In other words, I’ll image 1 full night in Lum, or several nights, until I complete Lum. Then I’ll switch and image OSC a full night or until I complete RGB and so on…. I have used this system with both the 183m/mc and now use the 2600m/mc.

So you are fixing tilt after each switch? I’ve only done it once so far, but it was a fairly time consuming, onerous experience. lol

Nicolas Molina avatar

I agree. Tilt adjustment is something I don’t want to do very often.

Well Written
churmey avatar

ScottF · Oct 27, 2025 at 03:31 PM

churmey · Oct 27, 2025 at 03:21 PM

If the RASA is your dedicated instrument, my advice is to keep things simple, and get the same camera in both mono and OSC. In my case, I will image with the mono for Lum or Narrowband, then simply switch cameras when doing color. I never switch during a session….In other words, I’ll image 1 full night in Lum, or several nights, until I complete Lum. Then I’ll switch and image OSC a full night or until I complete RGB and so on…. I have used this system with both the 183m/mc and now use the 2600m/mc.

So you are fixing tilt after each switch? I’ve only done it once so far, but it was a fairly time consuming, onerous experience. lol

I suppose I’m just lucky, but my flat field falls within my personal tolerance. There is some, it’s minimal but it’s not to the degree that I have to spend time on it especially after final edit. If it was outside of my tolerance, I certainly would move to a different method.