Serious Flat Frame issues - ASI1600MM-C - What am I doing wr

cfosterstars

I am having serious issues with the ZWO narrow band filters creating artifacts in my images. this is a post I did in cloudy nights on the subject and I am about to post a lot more data. I have now tried the filters in both orientations and wasted a lot of dark nights collecting data that is useless. Both orientations of the filters have issues. I do not see similar issues with the LRGB filters. These are 36mm filters and I know that this is NOT vignetting. You just dont see any issues with the LRGB that should show the same problems if it was vignetting. If it is NOT the orientation of the filter with respect to the camera and telescope, then what could be causing this?? I am about to give up and bit the bullet for Astrodons, but that is hugely expensive. I would like to make your filter work.

https://www.cloudynights.com/topic/594808-serious-flat-frame-issues-asi1600mm-c-what-am-i-doing-wrong-here/?hl=%2Bserious+%2Bissues+%2Bflats#entry8168217

Sam@ZWO

we think this is because there is some light linkage from the side of the filter

you can exchange the order you connect the filter wheel

kaos

I too am having this issue with concentric rings in my images around the corners of the image. Flats will not correct the lights as they are hard circles that show up in both the lights and flats. I am using the 1.25" LRGB filters. The issue is worse with the Lum filter than with the RGB filters. I tried taking out the lum filter and taking a flat and it shows a nice flat field as it should look. You can view a copy of one of my flats on the previous poster's link to Cloudynights on page two of that thread. There seems to be a reflection issue with the ZWO filters themselves. Please advise. Thanks. Kaos

kaos

I made reference to the wrong thread in my post. The right thread on page two is here: https://www.cloudynights.com/topic/596112-whats-with-the-concentric-rings-in-my-flats/page-2

Kaos

kaos

Okay...I ran the problem down to the ZWO filters being the cause of the ring issue.

See this thread for results of my test ZWO filters against the Meade RGB filters toward the bottom of page 1.

https://www.cloudynights.com/topic/600525-flats-issues-with-zwo-filters-and-un-correctable-ring-artifacts/

I believe the problem is either in the coating of your filters or the curvature (I am leaning toward the coating).

Kaos

cfosterstars

This post has a comprehensive analysis of the issue. Flipping the filter orientation does not work. This is due to leakage around the filters:

https://www.cloudynights.com/topic/600525-flats-issues-with-zwo-filters-and-un-correctable-ring-artifacts/

The fix out in the threads is to use a ring mask around the edge of the filters. I think the ZWO needs to fix this issue by making a mask for the filters and supply them to customers who have purchased these products.

kaos

I agree with the prior post. I purchased these filters because they were suppose to be a great match to the 1600MM C. However, because the filters are not coated to the edge and the edges are not coated to block reflections, I feel like I was sold a bill of goods. The ZWO filters are pretty useless. You guys should offer replacements of correctly coated 1.25 filters. A mask might work for larger filters, but the 1.25" filters do not have that option. Going forward, you guys need to correct this manufacturing defect on ALL of your filters so that they are fully coated and the edges are blackened. The tests for both the mounted and unmounted filters prove there is a real problem with these filters.

Kaos

Sam@ZWO

we think only 36mm filter would have such problem as the light may leak from the edge

we make some mask to come with the 36mm EFW to solve this problem now

but 1.25" filters should be OK as there is filter mount

kaos

The 1.25 filters ARE NOT okay. I have posted flats in the thread referred to above (posted by Kaos). The flats CLEARLY show the ringing artifices in the ZWO 1.25 filters because they are improperly coated. I get horrible rings in my lights & flats with the ZWO 1.25 filters. I removed the ZWO filters and replaced them with Meade LRGB filters and the flats look normal with no ringing artifacts! That should tell you that the ZWO filters are the cause of the problem.

My ZWO filters are not coated to the edge and neither are the edges darkened. This creates horrible reflections. Mr. Sam, please try addressing the issue with the 1.25 filters instead of ignoring it. I will be happy to provide you copies of the test flats. You can see them if you will simply go to the Cloudynights thread referred to.

Kaos

cfosterstars

when will you be able to send me a set of 7 of these masks? Right now, I basically dont have any ability to take good data. Also there is at least one user out there with 31mm filters that also has reported having this problem.

pointofview_365

Thank you Sam, I'll take 7 of those myself(36mm). I appreciate you taking the time to hear our complaints and making a reasonable solution. They look better than the ones I made.

Sam@ZWO

cfosterstars wrote:
when will you be able to send me a set of 7 of these masks? Right now, I basically dont have any ability to take good data. Also there is at least one user out there with 31mm filters that also has reported having this problem.

please email us and we can send it to you through air mail

we are going to provide this to our dealer too

so your guys can get it from our dealer

kaos

Sam...I drafted an email dealing with the 1.25" filter reflection issue and sent it to Highpointscientific. They should forward the email to you. I had a description of the reflection issue with the 1.25" filters and copies of the comparison flats with the ZWO filters versus my Meade LRGB filters. I would really like to get to the bottom of this issue and find out what is causing the reflective issue with the ZWO filters. Rings appear in the 1.25" filters and no rings in the Meade filters. Please address that issue in the Highpoint email their tech support sent you. They said they agree that there is am issue with my ZWO filters based upon my tests. Thanks

Kaos

cfosterstars

Sam,

I sent you an e-mail to directly send me the masks. I purchased direct from ZWO.

thank for your support.

Chris Foster

Sam@ZWO

Kaos wrote:
Sam...I drafted an email dealing with the 1.25" filter reflection issue and sent it to Highpointscientific. They should forward the email to you. I had a description of the reflection issue with the 1.25" filters and copies of the comparison flats with the ZWO filters versus my Meade LRGB filters. I would really like to get to the bottom of this issue and find out what is causing the reflective issue with the ZWO filters. Rings appear in the 1.25" filters and no rings in the Meade filters. Please address that issue in the Highpoint email their tech support sent you. They said they agree that there is am issue with my ZWO filters based upon my tests. Thanks

Kaos

we tested our 1.25" filter but did not find such issue

can you change your optic and test again?

Sam@ZWO

cfosterstars wrote:
Sam,

I sent you an e-mail to directly send me the masks. I purchased direct from ZWO.

thank for your support.

Chris Foster

no problem

kaos

Sam wrote:
Kaos wrote:Sam...I drafted an email dealing with the 1.25" filter reflection issue and sent it to Highpointscientific. They should forward the email to you. I had a description of the reflection issue with the 1.25" filters and copies of the comparison flats with the ZWO filters versus my Meade LRGB filters. I would really like to get to the bottom of this issue and find out what is causing the reflective issue with the ZWO filters. Rings appear in the 1.25" filters and no rings in the Meade filters. Please address that issue in the Highpoint email their tech support sent you. They said they agree that there is am issue with my ZWO filters based upon my tests. Thanks

Kaos

we tested our 1.25" filter but did not find such issue

can you change your optic and test again?

Okay, I tested the ZWO filter on my LXD75 SN8 telescope. I sent you an email with the comparison flats.

Thanks for responding.

Kaos

davebl

I have the same problem with the 31mm filters. Are you making masks for them as well? If so, how do I get some.

Dave

pointofview_365

Sam, just so you know the new mask sent have issues. They're to big and the sides of the mask overlap the mask mounted next to each other. We've already tested this type of mask were the sides overlap, which still allow light to leak underneath. The good thing with your mask is them being made from a pastic type material. This adds rigidity, if we cut the overlap out they may accomplish the goal and lay flat against the wheel. The 3 tabs for the screw mount is perfect but reducing the outside diameter to fit within the filter area, in my case 36mm, would prove most beneficial easest

szg

Please see my experiment.

I use 31mm set purchased direct from your online store on October 2017.

Could you please make filter mask to help 31mm users too?