Daytime Moon with H-a filter

[Luke]

I took this daytime shot of the moon in the morning and experimented by using a Baader H-alpha 7nm filter that I normally use for narrowband imaging of DSO's. Ironically, I normally use the H-a filter to keep the moonlight out of images!

I had to slow the frame rate from 26FPS to about 13FPS to get a bright enough image. I stacked about 800 frames.

Equinox 120 / Grasshopper 3 (ICX687) / Baader 7nm H-alpha filter

[cfpendock]

That has worked incredibly well!

Chris

[Radman40]

Very impressive. I would never have thought. What gave you the idea?

[Luke]

Thanks, Chris and Radman.

Radman, I got the idea after seeing Pat's (Todd8137) post here, where he used a ProPlanet IR filter on some moon shots that I really loved:

LUNAR 26 August 2013

I then read up on filters a bit and how red and IR wavelengths are less affected by the seeing. I ordered the ProPlanet (thanks, Pat!), but before it arrived, I had a chance to image the moon. So I wondered if the H-a filter would be better than no filter, being in the red wavelengths and being very good at cutting out "stray" moonlight. The quality of the graph in Autostakkert was really high, I was surprised.

I don't have much experience with CCDs, but my new camera seems very sensitive, so I wondered if it might be able to cope with such an aggressive filter.

[Luke]

I forgot the airplane transit!

Probably not the sleek jet fighter I hoped it was but something a bit slower that looks fast due to the long exposure time?

[geoff_k]

Both images are very nice indeed. Any idea what the plane actually was?

Geoff

[todd8137]

Great image looks like the filter worked well i have a ,Astronomik IR Pro (742nm) filter - the baader one is a 640mn i think but you got a nice image with your filter

Pat

[Luke]

Thanks, Geoff and Pat.

Geoff, I tried removing blur from the plane to see what it was, but no joy. We sometimes get airplanes on their way to shows passing over, so my fingers are crossed I'l nab something exotic at some point (any Vulcan dive bombers still flying?). We had a couple of WW2 fighters overhead yesterday doing loops, I'd settle for one of those

Pat, I'm hoping to compare the IR Pro with the H-a filter. I guess the winner should be the IR Pro, but I don't know how the really narrow pass of the H-a filter affects play?

[michael.h.f.wilkinson]

Nice images indeed. The narrow pass band of the H-a will reduce any chromatic aberration, but it passes less light that the IR, I would guess. Furthermore, moonlight in H-alpha is not particularly strong, because of the strong H-alpha absorption line in the solar spectrum. The IR filter passes light for which the Equinox has not specifically been corrected, I assume. The passband might still be narrow enough to avoid any significant CA.

[Stargazer33]

Very nice image. Lovely and sharp even at maximum size.

[Radman40]

Love the aircraft image. Looks like something from Star Wars on its way to Nabu.

[Superdavo]

Wow! That's a really sharp image!

David

[wxsatuser]

Both images are very nice indeed. Any idea what the plane actually was?

Geoff

Could be a Tornado.