Banding and color blotches with asi185mc and F3.3 Focal Reducer

fivel

Hello to all.

I have been enjoying two of your cameras, the 1600mc-c and the 185mc.

I have had no previous issues with either, except as mentioned in the subject line.

The 185 works well for planetary videos and for guiding.

I connected it to the Meade (Chinese version) F3.3 focal reducer (FR) but the camera gets severe horizontal color bands and other background color blotches. For the spacing I have a combination of 30mm and 15mm. The focus is sharp, with nice round stars, but along with the above issues, I also get concentric rings around the DSO (such as the Andromeda Galaxy). I never had these problems using this camera for planetary videos, even when connected to an eyepiece projection adapter. I also borrowed the same FR from a friend and I get the same issues.

Is there a history of the Meade FR causing these issues?

Fivel

katherine.tsai

Hi Fivel，

Sorry I did not encounter this before, could you upload some pictures to show us the problem, fits file would be better.

katherine.tsai

Hi Fivel，

Sorry I did not encounter this before, could you upload some pictures to show us the problem, fits file would be better.

fivel

Hello Katherine, thank you for your reply.

Sorry that I got back to you so late, but I had more testing to do.

The good news is that after re-seating the lenses in my focal reducer, the banding and blotches improved. I also lowered the gain level which also helped. Now I just need to get a better focus, to see how the stars look. These Meade F3.3 reducers make getting good focus a lot more challenging.

I will let you know how the combination of the asi185mc and the focal reducer works out.

Fivel

katherine.tsai

Hi Fivel,

Thank you for your update.

fivel

Katherine, I did some tests last night and had these issues, that were probably caused by the reducer.

1. With 43mm of spacing (from the reducer to the camera flange) I could not get a good focus. It was at the CCW extreme of my 8" SCT and still needed more back focus.

2. I was getting some reflections around the stars and some mild coma. I also got some color blotches, but it was a very bright moon last night. That could have caused some of the reflections and blotches.

Fivel

fivel

Katherne, I thought you may want to see the latest image using the asi185mc and the Meade F3.3 focal reducer.

I attached that image.

On a different topic. I was looking at cooling this camera and saw the fan kit. Is there an adapter to allow me to directly connect a 12v power supply to the fan. I want to use the same connector that the camera uses.

Fivel

M31-13 Nov 2019_Siril-stacked-BAck-Ext-Neutr-Stretch.jpg

katherine.tsai

Hi Fivel,

Thanks for your info.

Sorry to tell you the fan kit is used to replaced the fan in the cooled camera. We do not supply such a adapter.