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Spikes are not centered

Reflectors Artifacts Coma Help Needed Troubleshooting
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Rainer Ehlert avatar
Rainer Ehlert avatar

Hi,

A friend has an aged Celestron C8 and he has trouble with the star shape eg. the spikes are not centered

What could be the cause ?

Thanks Rainer

📷 image.pngimage.png

andrea tasselli avatar
andrea tasselli avatar
There should be no spikes for a C8 but otherwise collimation needs to be sorted by the look of the stars in the image.
Rainer Ehlert avatar
Rainer Ehlert avatar

andrea tasselli · Jan 7, 2026, 04:56 PM

There should be no spikes for a C8 but otherwise collimation needs to be sorted by the look of the stars in the image.

Thanks. 👍️

Rainer Ehlert avatar
Rainer Ehlert avatar

Now I remember that he installed a DIY heater inside the telescope near jsut in the corner between tube and meniscus holding ring.

I had the telescope here and saw some wires of this badly constructed heater protruding into the light path.

I just told him to get rid of it and install it on the outside of the tube. His scope is in a roof observatory surrounded by 4 walls and I do not understand why he has trouble with dew.

I also have a 4 wall observatory and my Mewlon never gets a dew problem.

🥶