Another ASI 178MM Question

[rray6]

Hello All,
I've been off my solar game for a while (a personal solar minimum) but have been slowly starting to get back into it. I was checking my camera situation and realized that my old ZWO ASI 174MM was weather-damaged due to a leaky roof. I want to replace it with the same or something better if there is such a thing. I've been looking at the ASI 178MM and would like some feedback from anyone who has used it. I realize that there are other topics skirting around this issue but I wanted to specifically ask about the 178. My main solar scopes are the Lunt LS80THA DSII (FR: 7, FL: 560 mm) and Wm Optics 132mm f/7 (FL: 925 mm) for white light and CaK.

Hope everyone is weathering the pandemic safely.

-Robert

[EGRAY_OBSERVATORY]

Hi Robert,
https://astronomy.tools/calculators/field_of_view/ will show you the best camera to use with whatever scope and set-up you use..

I have two ASI 178Mm cams in use for Ha and Cak and no known problems to date. USB-3 capable, but will run on USB-2...

Cheers
Terry

[rray6]

Terry,
Thanks so much. I knew of this Astronomy Tools Calculator but never used it much. After plugging in my scope data, I think I could get some good use from the ASI 178 for several of my scopes depending on my barlow use. In any case, I think it will be a good addition to my cameras. And that calculator will be very useful for camera selection for all my imaging projects. Thanks again!!!

[ammonthenephite]

I generally like my 178mm, but I'm one of those that when using it for solar h-alpha I get fixed pattern noise from the sensor that limits how much sharpening I can do on small details. For this reason I'll soon be looking for a different camera to replace it, though I have no idea which one to get, lol.

[Merlin66]

Hmmmm.
I've just ordered an ASI 178MM for my small(er) SHG.
I hadn't heard of any fixed pattern noise issues.
Do you have any sample images???

[rray6]

Yes, I would like to see some samples of fixed pattern noise, too.

-Robert

[Merlin66]

I found the extensive thread on CN Re FPN with the ASI 178. It seems to be the same problem I experienced with an ASI 183MM. I returned it to ZWO and replaced with a ASI 1600MM.
https://www.cloudynights.com/topic/7004 ... a-imaging/
(Google ASI 178MM FPN and click the images tab for examples)

[rray6]

Well, you have given me a lot to think about. Who said solar imaging was easy?

[marktownley]

Hi Robert.

The 178 is suited for prime focus imaging with the setups you list, however, as others have said there can be a fixed pattern noise issue. For close up views a 174 chipped camera would be better.

Mark

[krakatoa1883]

Nothing to be worried with, the FPN can be easily removed by taking a flat, actually any H alpha image would benefit from this irrespective of the camera used. Never seen the FPN on full disc images taken with my 178, though.

[rray6]

Could it be that part of the problem (FPN) with the 178 is due to rolling vs global shutter?

-Robert

[Merlin66]

IMHO, I think it is due to the very small pixels and us trying to use it at 1x1 binning.
Doesn’t seem to be related to the shutter.