LP filter for Guide camera?

[Marios]

Hi Guys

Im using an Orion Star shoot auto guider with an ST80, I noticed it has threads for 1.25 filters. I'm curios to know if anyone has tried using a LP filter to improve the quality of stars available to PHD in urban LP areas?

I was thinking of using a mild filter like Baader Moon and Skyglow or Atsronomics UHC-E filter.???

[cometcatcher]

Doubt it would work. All LP filters dim stars, especially yellow ones.

[OzStarGazer]

Wouldn't it be nice if they invented a filter that darkens the sky and makes stars brighter? Unfortunately Kevin is right though. :(

[Marios]

Thanks for your thoughts, I guess a conventional LP filter wont work.
Perhaps a UV filter might help with those saturated stars.?

[cometcatcher]

What exactly is happening? Are you getting fat bloated stars? It could be UV and IR. If so a UV / IR blocker will help. Or is the bloat caused by CA from the ST80? If that is the case then a Baader semi-apo filter may help, or using an ED refractor for the guidescope.

[Marios]

Hi Cometcatcher

The brighter stars through the ST80 appear to be Saturated/Haloed.
I'm not sure if its just average optics or UV/IR distorting the image. I have read on LP threads the UV/IR if not filtered can cause this effect.

I am going to take your suggestion and give the Baader APO filter a go, claims to improve contrast while filtering UV/IR.
http://www.ozscopes.com.au/baader-planetarium-semi-apo-filter.html/