9 replies to this topic

[jstir]

Hi all. Thanks for reading. I recently got a used (but 2024 model) Tak TOA130 NS, with the 645 flattener.

 

My imaging train is TOA130/Moonlight Nightcrawler/Spacers/645/Adapter/Askar Back Focus adjustment/QHY OAG/QHY CFW/QHY 600

 

I have used it for a few days now, and generally things look ok. While I can slightly tune the back focus for flattener, the biggest issue I have so far is I see spikes around the bright stars.  Attached is an example (screenshot from NINA).

 

Here is a link to a couple raw subs (https://drive.google...KzX?usp=sharing). You can see this occurs throughout the image on brighter stars.

 

Is this from the collimations screws on the triplet a bit too tight? I just don't see where else on the imaging train this would occur and with such symmetry (so not OAG protruding - which it isnt).

 

Any insight would be appreciated and especially if someone has see this on their TOA 130..

 

Thanks!

Jeff

 

Attached Thumbnails

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[ngc7319_20]

Thats a bit different from other cases I've seen of lens pinch, collimation screws, etc.  Usually there are 3 or 4 sets of spikes.  The spikes you have are more uniformly distributed around the image, and theres like 11 of them.  Hmmm....

 

Some other diagnostics would be to get some star images far outside (and inside) focus  See what the aperture shape looks like.  See if any irregularies, blockages, glass striae, etc.   Warm optics in cold air can also make spikes, but they dance around and move.

 

Can also mask off the outer 5mm of the aperture and see if it magically disappears.  Just get a cardboard with a 120mm hole and put it in front of the scope.  Good luck!

 

Edited by ngc7319_20, 23 March 2025 - 12:23 AM.

[T1R2]

Take off all the photo stuff and look through an EP without the reducer several mags...what do you see?  Also did you give plenty of time for that big triplet lens to acclimate to try to rule out thermal reasons?

[jstir]

Thanks. Yes I need to remove the imaging equipment and test as you suggested. But regardless there is an issue. And I see this all night. This particular image was taken 3 hours after dark. The scope lives in an observatory. So I don’t think it’s an equilibrium temperature issue. (Doesn’t mean is not a thermal issue).

[Drothgeb]

First, I would contact the person you bought the scope from, and see if it had the issues then. Did you ask for star images before you bought it? 

 

It could be the screws or spacers, or it could be something completely different. The mask is the easiest thing to try, so I would try that first. Just be aware that the inside edge of the mask has to be really smooth, or it will cause spikes. If the issues goes away with the mask, it’s the screws or spacers. If it doesn’t go away, look somewhere else.

[thebonz]

The TOA has 6 sets of collimation screws and it looks like you have 12 spikes. If it is a lens issue it could be a real mess

[scoale]

Yes, I've experienced this.

 

What temps are you observing at?  Does degree of spiking change with temperature?

 

Reach out to Darrin @ TNA.  He can share instructions on how to loosen the retaining ring and lens cell.  If that doesn't solve, it will have to go back to TNA.

 

 

[Erik Bakker]

Yes, I've experienced this.

 

What temps are you observing at?  Does degree of spiking change with temperature?

 

Reach out to Darrin @ TNA.  He can share instructions on how to loosen the retaining ring and lens cell.  If that doesn't solve, it will have to go back to TNA.

TNA or TNR, i.e. Texas Nautical Repair?

[scoale]

TNA or TNR, i.e. Texas Nautical Repair?

Good question.  

 

Land, Sea & Sky

Takahashi America

713-529-3551

[jstir]

Thanks all. I was contacted privately my another individual who had the ECmXACT same issue. He sent it to Tak America for collimation. He just got it back and now it seems to be perfect. I contacted them on the phone and they said it could be collimation and lens spacing issue. I will be sending it to them later this week.