Totally unscientific LP filter comparison

[Dave_D]

was bored, so i pointed my tablet out the curtains and held the filters over the lens...

1st pic is with no filter

2nd pic with a cheapo unbranded  1.25" filter

3rd pic with IDAS D1

the IDAS makes the moon blue 

[ronin]

Makes sense from the transmission curves.

5300-5500 is blocked,

5700-5900 is blocked,

6100-6300 is blocked.

They are basically bits of green/yellow, yellow/orange and  orange/red removed.

So you have a predominance of blue.

A narrow bit of blue gets blocked, about 4250-4400 also.