Antila Triband RGB Ultra Filter and ASI294MC PRO Flats

casej

I have been unable to take reliable flats with this combination following the ZWO recommendations of 5 seconds with a 24000 adu. I have tried a dozen different combinations in addition to the recommended one, and the red circular artifacts that are produced by this sensor remain. The Antila Triband filter is new and works well with my ASI183MC PRO, and the flats generated with the recommended settings for the ASI294 MC PRO work well with my Optolong filters. The filter is designed to produce a balanced RGB image with OSC in light polluted sky.

Tech@ZWO

casej
Could you attach some images here? if there are some fit files will appreciate it.

casej

The Master Flats are larger than the software will allow me to upload. I can send them an alternative way if it would help. I have the one master flat that worked but I have not been able to replicate as well as several failed attempts. The histogram of these flats suggests that there is a stronger red channel than either the blue or green in the flats that did not work, while the one that did work has a more balanced red channel that is similar to the green and blue channels. I will upload screen shots that should help to illustrate the problem. Thanks for any help you can provide.

Tech@ZWO

casej Thanks, it is the characteristics of the ASI294 camera, and can be calibrated via flat.(Don't use iPad to take flat, usually recommend sky flat.
How did you take flats?

casej

I use a variable LED tracing pad with a couple of neutral density filters to cut down the lowest light intensity. To use an iPad I turn off the auto option in display settings, set the intensity level low and turn on guided access once I load a pure white page. The LED pad is much easier. I have been able to calibrate with the ASI294MC PRO successfully using both the OPTOLONG L-Extreme and the L-PRO filters, as well as the Antila Duo Narrowband filter. The new Antila Triband RGB filter is the one with which I am having a problem.

Bonzer2u

I use an ipad running the whiteboard app for my flats as well, no issue thus far.
I thought you mentioned a 5 sec exposure? I always shoot my flats for no more than 1.5 sec, typically closer to 1 sec by turning up the brightness accordingly until I get a midpoint histogram I'm looking for. Sounds like your too dim.
Perhaps you can give this a try.

casej

ZWO recommends a 5 second 24000 ADU for the ASI294mc pro. I use much shorter exposures for the ASI183mc pro, using the auto flat function in the ASAIR. I have been experimenting with a variety of alternatives with this new filter and the 294. I will give your suggestion a try. Thanks.

Bonzer2u

Of course they know their products best but you might find this works better with this particular filter? Certainly worth a try if you have the time. It also would be worth posting your issue on CN forum as many 294mc-p users are available for timely feedback.

casej

Good suggestion. I did post a positive thread on the filter on CN and mention the calibration issue - it may also be worth a separate posting. Thanks.