Johanvk

On 02/04/2021 at 17:33, Budgie1 said:

I had this with my ASI294MC Pro but I could process it out with PixInsight using the DynamicBackgroundExtraction tool. Then, when playing with the settings in DSS I found a setting which removed most of the green cast.

In DSS, go to the Settings Menu > Stacking Settings > Light tab > click where it says "RGB Channels Background Calibration" and you get a drop-down menu, click on "RGB Channels Background Calibration" if there isn't a tick next to it and then click on "Options". In the Background Options window I have the Calibration Method set to "Rational" and the RGB Channels Background Calibration set to "Minimum".

Click OK to save the setting changes and run the stack again and most of the green cast should have been removed.

I'm still collecting images to see what happens. For now: but it seems that this setting of parameters for DSS removes te green coloring. If this is so then the probleem is in the processing not recording of images. I want to be sure, and also to understand what happens, so will spend more time on this.

Last year I started to use a ZWO533mc colour camera, but I do not get the colours right at all.
Up to now I used (ZWO183) b/w  camera's with LRGBHa filters, and also (modified) Canon colour camera's. Up to the Corona closure of my observing site, I used a C14/Hyperstar telescope, but now for the time being smaller backyard refractors. Images are stored in FITS format. Stacking was done with DSS, APP, and Nebulosity.
The images are horribly greenisch beyond repair. There must be a reason for this and I tried what I could think of. Debayer? I am more an observer than an image processor, still I feel stupid I cannot trace a cure. Can someone show me a way out?
The attached picture is a simple stack, without any calibration, but shows my problem.
Johan.

Thanks!

Thank you. It is informative and systematic, and it lead to other relevant sources.

I moved from color (Canon) DSLR camera's to more advanced ZWO black and white camera's with color filters. Now I have to handle gain and offset instead of ISO. In theory I think I understand very well what it's about, and took notice of the literature. In practice at the telescope I have to rely on trial and error with test exposures.  Can someone point a (reference to a) cookbook-like procedure to me, which lead to the optimal setting of gain and offset?
Johan, Netherlands. [C14/Hyperstar, with a ZWO-183, and with a lot of light pollution.]

On 05/06/2019 at 18:33, mftoet said:

The Lacerta MGEN can guide in RA only. I’ve been using one for about 7 years now and I’m very content with it. In fact, I love it! It also controls the camera (Canon and Nikon DSLRs, not sure about other brands) as a remote shutter and it supports dithering which is essential for reducing noise patterns when using a DSLR.

Stay away from the Synguider and LVI smartguider. I don’t have first hand experience with these standalone autoguider, but I’ve heard a lot of people struggling in order to get theme to work.

There’s a new interesting player on the market developed by a Dutch team of astrophotographers: the StarAid. Check staraid.ai for info. It is quite an expensive unit though and it doesn’t support camera control and dithering yet. 

If you plan to use the StarAdventurer for wide field imaging only (lenses with a focal length of 85 mm max) you probably don’t have to (auto)guide. Just take extra time for proper polar alignment. 

I tested the StarAid. An interesting development, but be aware it's in the beta-test phase. Ask quantitive specs and proof before buying. It's not cheap.

I'm since a few months experimenting with an Hyperstar on (an orange) C14 with a Losmandy mount. So far it looks promising. The reason to go for an F2 system is that we already have good greater F-ratio telescopes on site. Also an OAG was almost impossible to use, because finding suitable guiding stars was a (wasteful) time consuming, and frustrating, job. A more expensive guider camera was not in the budget.

The speed is indeed amazing, which is important considering the small amount of clear nights here. Autoguiding is done with a guiderscope, but I want to see if that is really needed at all, with such a short focal length, and such short exposure times of subs. The chip of a DSLR can be covered rather well (using flats etc.). The reported problems with the very small focussing range were not encountered - just turn the knob. A limitation is posed by the pixel size of 1.3". I'm not sure what the effect of tha limitation is on the sort of photometry I want do do. So far I did not test (narrow band) imaging through filters. On any bigger telescope these become exponentially more expensive... Testing is still going on.

For a (more modern) Edge I would certainly consider an Hyperstar, especially because the F2-F10 set-up can be switched so easy.