Which filter - Semi-APO or Contrast Booster

[Knighty2112]

Hi all. Leaning towards getting either a Baader Semi-APO filter, or their Contrast Booster 1.25"  filter. Both roughly similar prices, but wondered which of the two are best; the Contrast Booster gets good reviews, but the APO filter is more neutral when reducing the CA in refractors so leaning towards that more, but just wondered what other members thoughts are on this if you own one or the other. 

Cheers,

Gus  

[rwilkey]

Hi Gus, in my opinion the Semi-APO filter will serve your purposes better for reducing CA, I used to have one and it is quite good, but got rid of it when I bought an ED refractor.

[Knighty2112]

13 minutes ago, rwilkey said:

Hi Gus, in my opinion the Semi-APO filter will serve your purposes better for reducing CA, I used to have one and it is quite good, but got rid of it when I bought an ED refractor.

Thanks Robin. Plan to use the filter on the first three 'fracs listed in my signature. Don't need it for my ED 80mm obviously, as the CA in that is almost none existent.  

Edited January 8, 2017 by Knighty2112

[John]

This review of the contast booster, semi-apo and fringe killer might be of interest:

https://www.baader-planetarium.uk.com/en/pdf/baader_contrast_filters_US_ATT_review_0414.pdf

If it was me I'd probably go for the one that give the most natual looking views / tints even if some residual CA was still present. I suspect personal preferences might vary on this though.

[Knighty2112]

46 minutes ago, John said:

This review of the contast booster, semi-apo and fringe killer might be of interest:

https://www.baader-planetarium.uk.com/en/pdf/baader_contrast_filters_US_ATT_review_0414.pdf

If it was me I'd probably go for the one that give the most natual looking views / tints even if some residual CA was still present. I suspect personal preferences might vary on this though.

Thanks John. I read that review already. The reviewer does state that the semi-APO filter is more neutral than the contrast Booster, but it could be like you say dependant on who views through them. Still leaning towards the semi-APO filter so more than likely go with this one.  

[Paz]

I haven't compared those filters personally but I got the semi apo after reading about them. I use it in the ST120 and ST80 for medium to high magnification of bright targets. I find it tidies things up very well. At low magnifications I find that stopping down the aperture and not having any filter works fine for me.

[Knighty2112]

53 minutes ago, Paz said:

I haven't compared those filters personally but I got the semi apo after reading about them. I use it in the ST120 and ST80 for medium to high magnification of bright targets. I find it tidies things up very well. At low magnifications I find that stopping down the aperture and not having any filter works fine for me.

Thanks!  

[Astro_Dad]

Old thread but as new here I found this to be very useful in deciding upon a sensible CA filter for my Startravel 102. I’d considered the contrast booster but switched to the SA as the more neutral view appeals more than purity of fringe elimination. Arriving in the next few days. 
 

AD

[Carl Au]

On 08/01/2017 at 14:32, rwilkey said:

Hi Gus, in my opinion the Semi-APO filter will serve your purposes better for reducing CA, I used to have one and it is quite good, but got rid of it when I bought an ED refractor.

I concur 

[Adam J]

On 08/01/2017 at 13:56, Knighty2112 said:

Hi all. Leaning towards getting either a Baader Semi-APO filter, or their Contrast Booster 1.25"  filter. Both roughly similar prices, but wondered which of the two are best; the Contrast Booster gets good reviews, but the APO filter is more neutral when reducing the CA in refractors so leaning towards that more, but just wondered what other members thoughts are on this if you own one or the other. 

Cheers,

Gus  

For what scope?

For visual or imaging?

Have you caractroised how bad the CA is?

Adam

[Louis D]

55 minutes ago, Adam J said:

For what scope?

For visual or imaging?

Have you caractroised how bad the CA is?

Adam

Old thread resurrected.  OP is long gone from this thread.

[AtlantaAstro]

On 29/01/2021 at 06:48, Astro_Dad said:

Old thread but as new here I found this to be very useful in deciding upon a sensible CA filter for my Startravel 102. I’d considered the contrast booster but switched to the SA as the more neutral view appeals more than purity of fringe elimination. Arriving in the next few days. 
 

AD

What did you think of your Semi-Apo?

[EntropyTango]

I use the contrast booster and find it works well on the planets and Moon

I haven't tried the semi apo, so its a one sided opinion

[Astro_Dad]

Sorry late response here! - have been testing the SA filter mainly on the moon and have been very satisfied with results. Compared to no filter, purple fringe is very well contained and the image looks sharper to my eye - if a little more towards the yellow. Based on my observations on a full and the recent crescent moon I’d certainly recommend. It is now permanently attached to my zoom eyepiece when on the Startravel! 
 

Clear Skies,

AD