ZWO ASI174MM Pixel size too large for PST??

[SuperG]

Are the pixels too large on the ASI174MM for a PST and solar imaging?

[Merlin66]

Basically yes....
I have an ASI 174MM I use for solar imaging but find I need an effective focal length >1000mm for it to work "well" for me.
I recently purchased the ASI 183, with much smaller pixels for use on the ED80 (600mm focal length) but this was returned to ZWO due to "technical issues when imaging extreme narrowband" - ie Ha solar!
They replaced it with an ASI 1600MM which also has smaller pixels than the ASI 174 and I'm testing it at the moment......

[Atmos]

Why was the 183 not suitable for solar out of interest?

[04Stefan07]

I had great results with my QHY5L-II and PST when I used to image through that scope.

[Merlin66]

Colin,
I was having "crawling ants" type results with Ha solar - when I checked on the ZWO forum others were experiencing problems imaging with the ASI 183MM in Ha.
ZWO acknowledged there was a "technical issue" with this camera when working in Ha and agreed to a return for credit.

[SuperG]

I was seriously considering the 183 but more so the 174 because of price. Thanks a heap for the info on the 183MM.

Now, who knows whats a good one. The 1600MM is priced too high at ~$1400. I may probably end up sticking with the 120MM and stitch frames to get a full disk.

[Merlin66]

Not sure but the ASI 178MM may be an option????

[SuperG]

That's a super suggestion. I actually went back through my email and I had asked a certain telescope shop about the 178 and they said people normally use the ASI174. Regardless, stargazerslounge has a couple of ASI178MM Solar threads. I think this will be a go'er for me.

This will be a back-order item so it will be a couple of weeks before I can show the results. In the mean-time , if you have some ASI1600 results that you can share that would be great.

[AstroJunk]

I have an 120MM and a 174MM, both work very well in Ha. The 120 is probably a tad small in chip size but it would give a full disk view (just).

The 174 is a very nice camera, but those pixels are a bit large. I use it at 711mm which gives it a nice full disk view, but even then the resolution is not that good. The 183 would be a great camera for me - shame it doesn't seem to work for Ha.

Using http://www.skyatnightmagazine.com/astronomy-field-view-calculator the 178MM looks ideal for your focal length, but I have no experience with it personally.

[Atmos]

I've use a ASI120MM-S with a Lunt 80 and it gives a near full disk view but it certainly doesn't have much in the way of resolution.
I have been thinking of moving to a QHY183M for normal imaging over the QHY163M I've got and had considered it for some solar as well with the smaller pixels.

As the ASI120 and ASI1600 have the same pixel size it is going to increase FOV but not resolution.

[SuperG]

So I gave the ASI178MM a short test drive this afternoon. I'm interested that when I stacked all of the videos, various parts of the top of the disk yielded a striped pattern.Intrying to process out the stripes you can see the coloured image has splotches.

The videos looked ok if a little over saturated at the top. But I think this is promising. I just need to get better at tuning the etalon to stop the bright spots on the disk. The coloured image is obviously too hard in terms of sharpening.

EDIT: I've put another image in for sharpening in Autostakkert. The strange banding doesn't seem to be present but I don't think the Autostakkert wavelet processing is as agressive. Anyway, The ASI178MM does seem to be a good solar cam and the pixel size looks good to me.