18 replies to this topic

[bullmav]

Hello folks,

I received my ff107 a few weeks ago and finally had an hour of roughly clear skies to do a test
I made a quick test shot with guiding of m42 to test the scope and also saw weird spikes.
Is this the a pinch optics issue? See a pictures below
 

https://www.cloudyni...339_138476.jpeg

 

https://www.cloudyni...339_233225.jpeg

 

 

 
Test shot is a single frame of 300seconds with a ZWO 2600mc and guidingscope and cam (zwo 290) on a EQ6R-PRO mount) roughly 0 degrees temp. outside.
I use the same camera with my Askar FRA400 and have no problems at all.@bullmav
 
Anyone any ideas?

Edited by bullmav, 06 January 2025 - 03:05 PM.

[Cliff Hipsher]

I am not on X so I can't get to the pictures.  Try posting them here.

[John Miele]

Hi,

 

Not sure if you saw my recent post here...

 

https://www.cloudyni...pinched-optics/

 

I am also seeing strange star shapes with my new FF107.They look similar but not identical to yours. I plan to try heater strips on the tube to see if that fixes it. My image was also taken on a cold night. 

 

FWIW, I contacted ZWO tech support today and received a reply within a few hours. They recommend to also check that the tube rings were not snugged down too tightly. I will check into that as well.

 

cs...John

Edited by John Miele, 06 January 2025 - 03:25 PM.

[bullmav]

Hello John,

 

I did saw your post. Wierd stuff going on I would say.I also contacted ZWO today. Having terrible clear skies up here for weeks. Not a single star to catch also for the upcominng days so testing is a no go for now.

I will also try to loosen the tube rings and use my two new dew heat straps next time.

 

Wil report my rep[ly from zwo and outcome of test in this forum.

 

Regards

[John Miele]

It looks like I will get a clear and cold night tomorrow. My heater strips are supposed to arrive today. I will let you know how it goes!

 

cs...John

[bullmav]

Update:

 

I received the feedback from ZWO to check the tube rings. Make sure that they are not "over tightened".

I will do so and provide feedback to ZWO and post an update here @ the forum.

[bullmav]

John, are you using filters? Like a light pollution filter? If so in what way? Are you using a filter wheel or a filter drawer?

I did a test this evening and still had the same spikes with loose tubes and dew straps attached. Target was again m42 which was low near earth. Around 30” in the sky. At some point I tried Mars as a test and again had the spikes. Mars was more towards the 45 to 60” in the sky. Tried everything till the point that I removed my lightpolution filter and tried M42 again. At this point higher in the sky. Result, round stars… now i put the filter back in my zwo filter drawer and made a test shot and all was fine found round star… so how could this be the case because besides the fact that I removed the filter had it in a warm place and entered it back at some point nothing changed. Beside the fact that at this time Orion was higher in the sky and was pointing less towards a light polluted sky (street lights). Could streetlights be the bad guy in this case?? Could a filter be the bad guy… lacking time due to clouds I had to stop and was unable to test further. I hope to have some more clear skies in the upcoming days to test the configuration again and try to pinpoint the issue.

I”ll attaches photo’s asap.

 

Picture of spikes (after loosening tubes and adding dewband)

Edited by bullmav, 08 January 2025 - 11:21 AM.

[John Miele]

I was using no filter, no reducer, nothing but the scope and my camera.

 

Looking at your star image again, it appears you may have something a little different going on than what my image shows. I think I am clearly in the realm of pinched optics. Your stars had more of  well defined bright diffraction looking spikes. It is a mystery to me. Tomorrow, I finally get a clear sky and can try the heater strips.

 

cs...John

Edited by John Miele, 07 January 2025 - 06:34 PM.

[John Miele]

Hi Bullmav,

 

Any news on your fix?

 

You did not leave a bhatinov mask on by any chance? Your 2nd image looks very much like a bhatinov focus pattern.

[bullmav]

Hi John,

I’m very confused. After removing the filter I had clear round stars. So I thought the problem was the filter. Putting back the filter gave me still round stars. So I’m very confused right now. Could be the fact that m42 was close near some streetlights that caused the spikes. No mask attached. I don’t have one. I’m using EAF’s to focus. Still no clear skies to retry my setup. Hopefully by the end of this week we are getting some clear skies again. I’ll report after I did another test.

Edited by bullmav, 12 January 2025 - 11:43 AM.

[John Miele]

Maybe it was very cold the first night and warmer on the other nights? Not really sure what caused it, but it sounds like you are in good shape now. Sadly, my sample still has issues...

[bullmav]

Maybe it was very cold the first night and warmer on the other nights? Not really sure what caused it, but it sounds like you are in good shape now. Sadly, my sample still has issues...

That was not the case because the same night, in de beginning, I still had the spikes. So i need another clear night to figure out the problem I have. 

BTW, I also have a FRA400 with no problems at all so the cam is not the problem.

 

I'll update this post as soon as I have more info. 

 

I attached 3 dewheaters just to make sure the ff107 is "warm". I'll check if this is the "solution".

[bullmav]

Hi John, how are you doing.

I saw you returned your FF107?

 

I contacted ZWO today also, i had a good open night yesterday (cold, aroun -8 degrees celsius) and again had star spikes. Even with 3 dew heatstraps attached.

I hope they will provide me with a new one also.

 

 

Did you have to pay for the shipment to china?

 

regards Maikel

[John Miele]

My replacement scope is on the way. I don’t have the expected arrival date yet. They sent me a prepaid label to return the first one. But I only had to ship it to New York. Not china. They must have a US support center

[bullmav]

Hi John,

 

Thank you! I'm realy out in the blue. Yesterday started with an image session. Still spikes. in that same night switched targets and was able to image M42 10x 300sec without spikes... om totaly confused now.

 

I'll just wait on the reply from ZWO to check what they have to say.

[civis]

My new FF107 appears to have rather severe spherical aberrations, as per star test - in-focus nice symmetrical airy rings, out of focus fuzzy mess, barely any rings visible. Does it make sense to try exchange it? How high are my chances to get a good one?

[Cliff Halliwell]

Hello folks,

I received my ff107 a few weeks ago and finally had an hour of roughly clear skies to do a test
I made a quick test shot with guiding of m42 to test the scope and also saw weird spikes.
Is this the a pinch optics issue? See a pictures below
 

https://www.cloudyni...339_138476.jpeg

 

https://www.cloudyni...339_233225.jpeg

 

 

 
Test shot is a single frame of 300seconds with a ZWO 2600mc and guidingscope and cam (zwo 290) on a EQ6R-PRO mount) roughly 0 degrees temp. outside.
I use the same camera with my Askar FRA400 and have no problems at all.@bullmav
 
Anyone any ideas?

I had pinched optics on my 107PHQ, which persisted despite additional heaters.  They manifested as somewhat triangular stars but no spikes, and across the full field.  Yours are quite asymmetric, on the right of your image.  My dealer and ZWO arranged to replace it.  The new OTA was fine.  You might use some of the available software to look at field flatness.  That might confirm that something is off-plane.

[bullmav]

Finally found the problem. I had two type of spikes.
One are solved with 3 dew heaters and the other problem (i was very stupid) was that a small tree branch was in the image creating a strange spike (like bathinov), I now use the gear without any problems at all.

Good luck and clear nights folks

Edited by bullmav, 06 April 2025 - 12:25 AM.

[John Miele]

Great news Bullmav!

 

As you know, my first FF107 was riddled with spikes coming off my stars even with dew heaters. But my replacement unit is nearly perfect. I have only had the chance to use it a few times but I could not ask for better star shapes all over the field. Exactly what I wanted with the image scale right at 1 arc-sec/pixel. I am pleased with mine.

 

cs...John