Moon in H alpha

[Geochron (Jon)]

Here is a quick 'experiment' from last night. The moon was looking great but the scope was rigged for Deep Sky imaging.....sigh. So here is the moon in H alpha, using an ASI2600MM running flat out at a blistering 4 frames per second, lol

This is the best 5% of 400 frames using a C11 XLT with Starizona LF reducer/corrector. Stacking in Autostakkert 3, finished off using Camera Raw in Photoshop.

https://astrob.in/gvqbve/0/

[graham.hobart (Graham stevens)]

nice shot!

[Dave882 (David)]

That’s turned out really well mate. Imaging in Ha will (if you can get enough signal due to the narrow band pass) give a nice stable view. Similar to using a red or IR PASS filter. The good thing about the moon is you aren’t limited as to how long your capture can go for so 4fps while a little frustrating can still ge the job done. Good stuff!

[Peter Ward]

Originally Posted by Dave882

That’s turned out really well mate. Imaging in Ha will (if you can get enough signal due to the narrow band pass) give a nice stable view. Similar to using a red or IR PASS filter. The good thing about the moon is you aren’t limited as to how long your capture can go for so 4fps while a little frustrating can still ge the job done. Good stuff!

Nice crisp lunar image. Curiously many have captured the moon through H-alpha over the years as, due the moon's brightness, they are a good ND-like filter.

As mentioned above IR-Pass filters give slightly better results. All good fun

[bkm2304 (Richard Brown)]

Superb, Jon.

Richard

[Geochron (Jon)]

thanks everyone

While I'm here could I ask any seasoned lunar imagers whether they capture in 8 or 16 bit as this seems to be a matter of some debate online.

Most (I think) people suggest that you can't tell the difference so may as well go with 8 bit and the resulting higher frame rate....but I have also seen suggestions that the higher dynamic range of 16 bit can be helpful to avoid blown out highlights.

What do you do?

[Dave882 (David)]

Hi Jon,
It's an interesting question and one I've pondered myself... I can understand that there is a theoretical benefit for imaging in 12/16bit - but on the few occasions I've tried at the higher bit depth I didn't notice any appreciable difference. That's not to say there isn't any difference, it's just that there certainly wasn't anything to my eye that would make this a priority.

To prevent blown highlights, I set my gain / capture frames with a very careful eye on the histogram. As a rule, I never want to go above 50%. For a wider (full moon) image, I drop it even more as there are often some crater rims or other bright features that are like to blow out. After stacking in AS!4 and wavelets in RS6, I save as a 16Bit Tiff file just in case I want to play with the histogram a in PS. If you use the histogram as your guide you won't blow highlights, irrespective of what bit depth you're shooting at.

Regarding frame rate - if you're imaging the full moon and using the whole sensor, reality is the frame rate will be slow. That's not a problem since very fine detail is not a priority. If you want too do long fl close-ups you will use a much smaller ROI and take advantage of much faster frame rates and look to capitalise on those moments of exceptional seeing so you can extract every bit of detail. Just my 2c...

[Geochron (Jon)]

thanks David,

That's very useful info. I'll try an 8bit comparison next time I have the opportunity.

Looks like I am also running my histogram a tad high (around 60-70%) and also I was not aware that there was a new version of Autostackert out - obviously been a while since I tried any lunar imaging!

thanks again, Jon