Image Amplification beats Resampling for planetary imaging

[Robert_T]

Hi All, during last nights Mars imaging run I decided to do a comparison between images from two avis taken back to back. Identical settings and processing with the only difference being the use of 2.5x powermate giving around F30 on the F12 Mewlon for one avi and a low quality 3x barlow plus ~50cm ext tube giving around F45-50 for the second avi on the same instrument. The idea was to resample up (1.5x Mitchell in Reg3) the 2.5x powermate shot to match the F45 image scale shot (without resampling) and compare relative detail between them.

Check the difference in detail between the resampled shot at left and the higher image amplified shot at right !!! Probably not news to many of you, but looks like image amplification at the scope beats resampling hands down - even if using lower quality barlow/tubes to get the scale.

Thoughts, comments welcome.

[asimov]

Yeah I hate resampling in registax, does'nt give pleasing results very often for me. I'm finding out now my extension tube I'm using is giving too much image scale for the 6" refractor...May have to drop back a fraction.

[Dennis]

Great experiment and comparison Rob - thanks for sharing the results.

Cheers

Dennis

[LT_Ng]

I only do re-sampling in Registax if the image scale is small and stable images are recorded.

Moreover, for this shrinking Mars, I would suggest you shoot it with Powermate 2.5x rather than the low cost 3x barlow.

LT

[Robert_T]

I would have thought the same LT, but the experimental results (albeit a very smallsample size) below graphically demonstrate that, when seeing permits, that the greater image amplification of the cheap 3x barlow and ext tube actually gives better detail than the 2.5x powermate all else being equal.

cheers,