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

Focusers, Filters, Barlows etc..

Moderators: Sam, Sean.Wang

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

Postby cfosterstars » Tue Nov 28, 2017 7:11 pm

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/5948 ... try8168217
cfosterstars
 
Posts: 8
Joined: Fri Sep 29, 2017 5:30 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Sam » Fri Dec 01, 2017 11:03 am

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
ZWO Founder
Location:lon=120.6 lat=31.3
SuZhou China
User avatar
Sam
 
Posts: 2546
Joined: Thu Feb 21, 2013 2:51 am

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Kaos » Fri Dec 01, 2017 10:32 pm

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
 
Posts: 12
Joined: Sun Mar 05, 2017 10:03 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Kaos » Sat Dec 02, 2017 4:59 am

I made reference to the wrong thread in my post. The right thread on page two is here: https://www.cloudynights.com/topic/5961 ... ats/page-2

Kaos
Kaos
 
Posts: 12
Joined: Sun Mar 05, 2017 10:03 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Kaos » Sat Dec 02, 2017 10:57 pm

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/6005 ... artifacts/

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

Kaos
Kaos
 
Posts: 12
Joined: Sun Mar 05, 2017 10:03 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby cfosterstars » Sun Dec 03, 2017 3:33 am

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/6005 ... 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.
cfosterstars
 
Posts: 8
Joined: Fri Sep 29, 2017 5:30 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Kaos » Sun Dec 03, 2017 5:12 am

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
Kaos
 
Posts: 12
Joined: Sun Mar 05, 2017 10:03 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Sam » Mon Dec 04, 2017 8:11 am

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
Attachments
QQ图片20171204162059.jpg
ZWO Founder
Location:lon=120.6 lat=31.3
SuZhou China
User avatar
Sam
 
Posts: 2546
Joined: Thu Feb 21, 2013 2:51 am

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby Kaos » Mon Dec 04, 2017 2:47 pm

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
Kaos
 
Posts: 12
Joined: Sun Mar 05, 2017 10:03 pm

Re: Serious Flat Frame issues - ASI1600MM-C - What am I doin

Postby cfosterstars » Mon Dec 04, 2017 10:31 pm

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.
cfosterstars
 
Posts: 8
Joined: Fri Sep 29, 2017 5:30 pm

Next

Return to Accessories

Who is online

Users browsing this forum: No registered users and 1 guest
cron