Should I buy a CMOS camera?

[Thefatkitty]

Hi all, hope you're good

I've been taking pictures of the Sun and Moon for what seems to be an eternity with a Canon DSLR. It seems I do more Solar lately; clear nights are few and far between.

I take about 100 or so shots of the Sun as it floats by on my second-hand EOS 550D(T2i) camera's viewfinder. I use my C80-HD mostly, a second-hand mid 90's f/11.4 achro. The scope, mount and camera totalled $300 cash, and the Solar Continuum and UV/IR cut filters and the Baader 5.0 film was another $350 total. Only $650 to shoot the Sun and Moon; not too bad really

This is it mounted on the non-motorized CG4 it came with.

However, it does do a good job in it's current state. This is the Sun taken with that setup on Jan 14th of this year:

I also have a laptop; an Acer Aspire Vero, 15.6" FHD IPS, Intel Core i5-1155G7, 12GB DDR4, 512GB SSD, Intel Iris Xe, Win 11 model (copied that right from the site description). I'm hoping that would be enough to run this type of camera.

As well, I'm toying with (OK, probably getting) an HA scope as well. I realise Hydrogen-Alpha is color...


So here's my questions. I was looking at a ZWO ASI290 Mono Camera; it would set me back just under $400CDN with tax/shipping. All I would need for the Sun in white light and the Moon. But, if I throw the HA scope into the mix, would I be better off with a color camera or is there a filter I could use for colour? It's just more expensive so I would have to save some pennies, but no big deal.

Also, would I need a motorised mount (even just one for RA)? Or could I just use my floating-by-and-shoot method?



I realise most of you folks use these cameras for deep-sky, but I would like the input regardless. Certain models to stay away from or the like? I gather ZWO is a good brand as well.


I really appreciate any input given; thanks in advance!

All the best,

[Solsearcher]

For CCD or CMOS a mono camera is better for Ha solar . The reason is easy to understand , the Ha scope will only allow the red line or wavelength to be visible . On a color CMOS array only the red pixels will be active and contribute to the image , about 1/3 of the chip array The green and blue dedicated plxels will not contribute to the image . A mono camera will bring more detail because all pixels will be contributing to the image .

[seigell]

A mono CMOS will do rather well for Lunar Imaging, especially given the rest of your current equipment. The ZWO 290MM isn't a bad place to start - economical but decently capable.

Realize that it will be a world of difference from the T2i - even if you were doing Video Capture and Stacking.
1) Field of View will be DRASTICALLY Different - no more Full Disc Images without a significant Focal Reducer. The CMOS Sensor is just that much smaller.
2) Image Capture will be quite different - even if you were using Video Capture on the T2i. If simply snapping 100+ still images and stacking from the T2i, the Frames-per-Second on the 290MM will be blazingly faster. The T2i actually has a unique for a DSLR 640x380 1:1 Video Capture Mode that shoots the Center of the Frame at upwards of 40fps, but the 290MM can readily top 125-150fps (all at 1:1 pixel ratio). Image Capture Software will be different too, whether you use FireCap or SharpCap or BYE/APT already.
3) Image Processing will be different - you will really need to learn Video-Stacking software such as AutoStakkert3! or RegiStax6. And after Stacking, the process to generate a Real Color image will require Color Mapping Features that weren't necessary for the Full-Color T2i.

But, transitioning to a CMOS Planetary Camera is the most logical next step for you - unless you are ready to Go Big (budget over $1000) and replace everything but (maybe including) your Scope.
For DSO Imaging, an EQ Motorized Mount is a MUST.
It is also an appropriate Next Step - even just an RA Drive - whether you stay with the T2i or add the 290MM. The RA Drive would allow you to shoot Still Images up to 30-60sec.

Good Luck.

[SkyHiker]

The resolution of your scope that has an objective diameter D=80 mm and a focal length of f=900 mm has an angular resolution of lambda/D=1.3". At the sensor this becomes f*lambda/D=5.6 mu. This is a typical size of a DSLR pixel. So yes, the Bayering will reduce its resolution by a factor 2 and you can do better with a mono camera. At the same time you want the pixel size not to be smaller than 5.6 mu because that would just lead to more noise (at least, with DSLRs, not sure about astro cams). If you take images without a motor, the sky moves at 15 degrees per hour or 15" per second. So, to get the maximum resolution of 1.3", if your exposure time were 1.3"/15"=0.085 second or so, the maximum resolution image circle would be smeared out by a factor 2 so your exposure time would have to be less than, say, 0.01 second to get close to the maximum resolution. Your image seems to be just a single shot; isn't the normal way to take video and stack the images? In that case the frequency would have to be at least 100 Hz based on the last number. I would suggest that you get a motorized mount if you want to get around this limitation.

[Gordon]

I have been using a ZWO ASI174-mm-c for my solar work for quite a few years, it was the camera that Lowjiber suggested to me.

With that said, the "cooled" version has been discontinued and they only offer the non-cooled version (ASI174-mm.) The pricing is comparable to what you are looking at.

I capture using video (about 500 frames) and process from that. As solsearcher suggested, capturing in mono and adding color later is the best method.

[rpineau]

You might also want to have a look at these : https://player-one-astronomy.com/solar-camera/

[JayTee]

After a little bit of research, I would also recommend the ZWO ASI174mm mini with a 0.5 reducer. I think this is your most economical approach.

Cheers,