Solar with barlow

[deadsimple (Ash)]

An attempt at higher magnification with a small aperture, with better processing than previous sessions. The clouds rolled in by the time I realised I should have centred the sunspots better, so oh well.

• LS60THa/PT/BT1200
• ASI174mm
• Televue 3x barlow
• Stack: best 20% of 90 secs @ ~100fps, 1.5x drizzle
• Gain: 292
• Exposure: 1ms
• Software: Firecapture + Autostakkert!2 + AstraImage
• Post-processing (in order):
  • Wavelet: small details @ 100
  • Remove focus blur: kernel_size=2.4, HQ method, VH sharp
  • Histogram stretch/shift
  • Small histogram bump for dim pixels (bring out some prominence)
  • Crop, downsample by ~1.5x, flip vertically

I had significant trouble with focuser/draw-tube slippage with the weight of the barlow added, so the focus was not perfect. I can't figure out how to resolve this, as there's only a screw to play with - and that only locks the focuser.

[5ash (Philip)]

Nice image . you should be able to tighten the focuser by tweaking the Allan key screw which is near the locking screw.
Regards philip
Ps are there 3 faint horizontal bands across the image?

[Merlin66 (Ken)]

I also use an ASI 174 for Solar, but find I also need a tilter to remove those newton rings......

[deadsimple (Ash)]

Originally Posted by 5ash

you should be able to tighten the focuser by tweaking the Allan key screw which is near the locking screw.

I didn't even realise those were screws. All good now, thanks!

Ps are there 3 faint horizontal bands across the image?

You're right. I didn't see them until I stood away from the screen / shrunk the image.

[Prickly]

Wow.This is an extraordinarily good image. Very smooth and detailed. Great work. Thanks for adding the processing summary.

Cheers
David