Solar Imaging Without Tracking?

[Paul73]

Possibly a really stupid question..... 

Given that solar images are generally made by selectively stacking many short exposure images, is it possible to get good results without a tracking mount?

If it is. What would be a good camara to stick in the back of a 100mm f10 PST stage 1 mod? It is parked atop a SkyT II on a very solid ash tripod.

Paul

[xtreemchaos]

yes. asi120mm or mc, qhy5ii, theres many more cams but there the ones I use. charl.

[Paul73]

Thanks Charl. You seem to get some decent results!

The two cameras seem well priced. Pros/cons? Colour or mono?

Paul

 

[Stu]

You would only need mono for Ha Paul, you can add the colour afterwards but it's basically a very narrow frequency band, so is only one colour.

Here endeth my knowledge  

[Zakalwe]

Have a look through this thread. it has answers and more to similar questions:

 

[xtreemchaos]

I agree mono is best, but I use a colour because 1. I didn't have a mono cam to start with, 2. there cheaper , 3 after using both types I find the colour you can turn the red channel up when seeing isn't so good and grab more detail than my mono under the conditions. but remember I'm strange . charl.

[Lowjiber]

I'll second everyone's recommendation of the ASI120MM.  Make sure to get the "-S" model, as it's USB 3.0 and can deliver faster data.

Monochrome is the only way to go in my opinion for solar work.  A mono cam uses all of the pixels, whereas the color cam of the same size only uses the red channel... only one-fourth of the pixels.

Clear Skies

[Paul73]

Thanks guys. I’ll try the ZWO ASI120MM. For an extra £30, I may as well get the USB 3!?

Our old laptop died. So my wife (the technical brains of the team) replaced it with a quad core gourmet version. I was properly unhappy about the outlay. Was thinking £350 ish. She spent a lot more. So I’m due a present just to highlight that her profligacy does have real consequences.

Paul

[David Smith]

There was a time when all my solar images were taken with no tracking involved so it can be done and successfully at that. Good luck.

[Pete Presland]

I have done a few manually tracked images as well over the years, mostly when my battery has gone flat. You can let the area drift through the field of view and still get a decent image.

[Paul73]

???????????

Thanks for the advice guys.

Paul

[Zakalwe]

On 28/01/2018 at 12:31, xtreemchaos said:

I agree mono is best, but I use a colour because 1. I didn't have a mono cam to start with, 2. there cheaper , 3 after using both types I find the colour you can turn the red channel up when seeing isn't so good and grab more detail than my mono under the conditions.

I cannot see how that is possible @xtreemchaos, as the light coming into the camera is the same frequency. Yes, if using a telescope to image the moon you can use a red filter to cut out the blue frequencies (these are most disturbed by the seeing) to help "cut through" the seeing, but on a hydrogen-alpha scope the scope itself strips out all of these frequencies before the light hits the camera.

It's, AFAIK, impossible for a colour sensor to get more detail than a mono sensor* as the green and blue pixels will be doing nothing other than adding read noise into the final image. Even if you separated the channels and only used the R channel then the mono would still win hands down as it is collecting data across all pixels, whereas the colour sensor is only collecting data in one of four pixels.

 

 

*Naturally assuming that the sensor are the same type, just one is mono the other colour. If your mono camera is using a completely different sensor to your colour then all bets are off.

[xtreemchaos]

6 minutes ago, Zakalwe said:

I cannot see how that is possible

try it, it will not hurt. as I said I agree mono is best charl.

 

 

[Lowjiber]

Paul, regards your new ASI120MM-S, we have a saying in the US... "That dog will hunt."

[Zakalwe]

59 minutes ago, xtreemchaos said:

try it, it will not hurt. as I said I agree mono is best charl.

Oh I know it won't hurt. But I can't see how "turning the red channel up"* would ever deliver more detail than a mono camera with the same sensor in the same conditions.

 

 

*I presume that you mean increasing the gain?

[xtreemchaos]

I didn't say it would, its down to how you image, I'm just sticking up for the colour cam and how can get great results from one if you know whats the best settings and in no way saying its better than a asi120mm mono, my mono cam at the time was a qhyv5.

[Highburymark]

On 29/01/2018 at 06:14, Pete Presland said:

I have done a few manually tracked images as well over the years, mostly when my battery has gone flat. You can let the area drift through the field of view and still get a decent image.

Bit of a blast from the past this thread, but wonder if Pete or anyone else could explain how you manually track the Sun when imaging - with standard solar refractor on manual alt-az mount with slow motion controls?

[Pete Presland]

Most important thing for me was to get myself orientated, in terms of which direction the Sun was going to drift in. Most of the manual adjustment is going to be done in R/A assuming your are reasonably polar aligned. 

I simply used to align on the A/R, wait to see which direction the drift was going to be and then hit record.  Adjusted manually is not as smooth as using the motors, but sometimes i had little choice. From memory this was mostly at work, or in the winter when the Sun was low and i was in the countryside.