1 reply to this topic

[akmal89]

Hi experts,

 

Mean not to make some fuss and looking forward as a learning curve for me and others.

 

Since I made a dumb mistake by rubbing my Alpy 600 grism with cotton bud, I tried to have clarification from expert here.

 

Attached hereby the spectrum profile that being captured (pointing to day sky) of before and after rubbing.

 

From my less experience eye, seem no different between it or is there any way to verify that the grism really defected. (Actually, I am not care much on it since just purchased the new Alpy 600 core)

 

Link attach of the recorded video and calibrated DAT data.

 

Thanks and look forward for your opinion !

 

Link===> https://drive.google...c7G?usp=sharing

[robin_astro]

The effect of damage to the grating is typically increased scattered light that should not be in the spectrum and decreased efficiency which would not immediately be apparent in a test like this. Small amounts of damage may indeed go unnoticed and I have gratings in use that have scratches or fingerprints on them and still perform ok. If you attempt to clean a grating though you are always more likely to do more damage than leaving it alone.  

 

You also mentioned that the collimator lens fell out when you dismantled the core module. Note this is not symmetric and must be installed the correct way round and held in place with the spring which must have also come out at the time. 

 

Cheers

Robin