ZWO ASI183MC

[2STAR]

On 23/07/2019 at 11:07, Adam J said:

You will end up with a pixel scale of <0.5 arcseconds per pixel. Along with the weight of a 200/1000 (don't go with the F4 for galaxies) you will be struggling to guide to the required accuracy without an extremely capable mount / probably in a obsy. Also you will be struggling to get sufficiently good seeing (atmospheric conditions) to enable you to resolve objects down to <0.5 arcseconds per pixel unless you are imaging from an elevated location.

Thats not to say you cant do it though, its actually potentially a very good galaxy combination, your just setting yourself up for a challenge. The 183 is useful as a pure galaxy imaging at between 750mm and 1000mm focal lengths and for wide field nebula imaging at focal lengths <400mm.  I would seriously consider the 183m though as opposed to the OSC if you want to image galaxies in any light pollution at all as using filters with an OSC will result in horrible colour balance.

Adam  

Adam, you refer to the use of any filters with OSC  resulting in 'horrible Colour' balance,  can you please enlighten on that assumption, as it contradicts what I have read and researched elsewhere, eg:  The Optolong L-enhance duo band filter which I have  read numerous articles on its recommendation for use in Bortle 6 + skies, in particular with the ZWO range of ASI OSC.

regards

Eric

[Adam J]

59 minutes ago, 2STAR said:

Adam, you refer to the use of any filters with OSC  resulting in 'horrible Colour' balance,  can you please enlighten on that assumption, as it contradicts what I have read and researched elsewhere, eg:  The Optolong L-enhance duo band filter which I have  read numerous articles on its recommendation for use in Bortle 6 + skies, in particular with the ZWO range of ASI OSC.

regards

Eric

In my experience lots of the yellows are lost in any LP filter when imaging galaxies. That would go in hand with the filter absorption curve. I can only speak about DSLR from personal experiance, but there is nothing fundamentally different from a DSLR to a dedicated OSC in terms of RGB color balance.

Adam

Edited February 1, 2020 by Adam J

[2STAR]

19 hours ago, Adam J said:

In my experience lots of the yellows are lost in any LP filter when imaging galaxies. That would go in hand with the filter absorption curve. I can only speak about DSLR from personal experiance, but there is nothing fundamentally different from a DSLR to a dedicated OSC in terms of RGB color balance.

Adam

Thanks for your reply

eric

[2STAR]

Has a small pixel size to bear in mind

[rickwayne]

This may be pretty orthogonal to your original request, since:

• I have the cooled version
• I have the mono version
• I'm running at 336mm focal length
• I'm strictly a DSO guy

OK? Caveats noted. I deliberately chose the tiny-pixeled 183 because my DSLR had whacking great pixels and I wanted as distinct an alternative as I could feasibly obtain. So now I've got a wide-field, low-noise, OSC camera, and a narrower-field, fine-image-scale one. YMMV, and almost certainly does.

Know that the IMX183 sensors are notorious for amp glow. It calibrates out, yes, but it does add complexity -- if you use darks at a slightly wrong temperature, or forget which way bias or dark-flat frames go, you'll be left with a very visible pattern on your image after stretching. This is an argument for ponying up the extra cash for a cooled camera, so that all your frames are at precisely the same temperature and dark current can be correctly subtracted from everything.

For what it's worth, here are a couple of narrowband and an RGB image shot with the 183. Focus and guiding were both a lot better on the Heart than on the other two.