Newtonian problem with spikes

Astroneck:
Hello. If you see my last image of M101(link below) you can see spikes in the small stars. This spikes are diferent (I Think) that the  typical spider spikes of all newtonians in big stars. 

https://www.astrobin.com/4m79f2/B/?nc=user

I don't know what cause this rare spikes. If you zoom in, you can see this problem in all my astroimages with dslr and now with my new qhy294mpro. 

I image some small deep sky objects with a televue powermate 2x2" combine with mpccIII... And I don't see it, the small stars looks better.

Maybe the mpccIII coma corrector is the problem? optolong Lpro filter? Bad Collimation?

Can somebody help me?

Thanks. Clear skies!

And sorry for my English ;)

Having looked at your image I think your problem is bad collimation (it's way out). So your extra spikes comes from that, comatic PSF right through the center.

I am having the same issue with my photon 200 F4 - my research is pointing at the focuser tube sticking into the telescope and causing diffraction and the clips on the primary mirror.  I have just had a set of aperture rings made will post the results of that soon when the clouds go

If your German is good  Tommy Nawratil's collimation primer has been really useful for me

https://teleskop-austria.at/information/pdf/FN25010c_Photonewton_Justage_Primer.pdf

Julian Mochayedi:
In general the Baader isn't too great.

 Yep, but in its defense it is more effective on the F5.  Agree with the 4 lens CC, but with everything at F4 it is fussy about spacing!

Hello. Thanks to all for your answers.

I modified two things on my telescope and I found the solution.
The focuser not was the principal problem, but It obstructed the primary mirror when the camera was in focus.
The solution for me was to romove a 35mm focuser extender. After I adjusted the screws of the primary mirror to put it some millimeters inside the tube…
I can focus the camera without the extender. Maybe change the focuser is better solution, but for the moment, this can solve the problem.

The principal problem was the collimation. Now, after five or six years that I took my first astrophotography with a dslr and a newtonian, I know what is
the offset of the secondary mirror in this telescopes… (something essential for  take good images, you will agree with me)
I my case with a 200mm f4 newtonian, I found in an internet forum that the offset is 4,5 mm.
¿Is a good distance for my telescope?
Last night I recollimate the TS Photon 200F4. To offset the secundary mirror I used a ruler above it, and to get the telescope collimated I used a laser collimator. I remove the focuser extender too…
Then I started to imaging… And in all my lights finally the stars looks better, are round stars whithout this rare spikes

In adittion, now I have a aperture ring, but I have not install it yet. I expect this improve my images too.

Yes, and my camera backfocus are not correct, I can see. I bougth a M48 rings kit to fix this problem.
I have read that the good backfocus for the mpccIII is 55mm, but without the T2 ring is 57,5mm. ¿Is it correct?
¿Someone knows whats the correct backfocus for my configuration?

Between the camera and the mpccIII I have an Altair filter changer… for RGB filters. I use the optolong Lpro on the mpcc for all the lights, Lpro afects to the RGB lights. ¿Is this a good idea?
And Another question I have is if the filters affect the backfocus ¿?

Too many questions may be asked. but if anyone can help me, thank you very much!!!

Joaquín.
Clearskies!!!

Hey my friend had your exact setup and had the same problem
after a long search and trail and error, we realized that the coating on the edge of primary is not so good. you can either use an aperture ring or just simply cover the edge of your primary for 5 mm or so with a non reflective duct tape

unfortunately I had bad correction with TSGPU and the TS ONTC f4 6" at 1 mm difference ...
despite calculating several times the distance with adapters (it felt I was not able to sum numbers...) to exactly 55mm from the sensor, I had coma...
At the end (useful also for @Astroneck) the filters were extending the optical path by 1mm (by a general thumb rule of half of the filter thickness).
Newtonian f4 are over sensible to everything by my short experience... sometimes I really think I should have stick to the f5 ... nowadays CMOS sensors can very easily recover the difference among a fast f4 and a "less fast" f5...
The f5 can hold winter temperature changes of 6-7 degrees before to need a refocus, the f4 barely 3...

I am pretty specific that this refers to Baader's MPCII/III (I have the former). In my tests that was the tolerance (+/- 1 mm). The filter only increase the focus position moving it outward. If the position of the filter is, as it should if it is a permanent installation, ahead of the corrector then nothing happens. If you have filter wheel or a filter holder in between corrector and sensor then obviously the filter optical thickness needs to be accounted for.  If we assume that the typical refractive index of the substrate is around 1.6 then given that thin lens formula for the focus displacement being:

displacement = filter thickness * (n -1)/n, with n the refractive index (centred on whatever wavelength it is you require, say green)

 which gives .375 mm per mm of filter thickness. For a 2mm thick filter (2") this yields .75mm optical thickness which falls within the tolerance.