Ghost of Jupiter

Jon (Jonathan) · #1 31-03-2013, 10:42 AM

I thought I'd take advantage of the fact that my setup (10" f/10 SCT, 2540mm focal length, DSLR with very small pixels) lends itself best to small-scale imaging, and have a crack at a planetary. This is a stack of 10 180s subs, using a 2x Barlow with an UHC filter into the bargain.

Stacking was a problem; there were no background stars for Maxim DL or DSS to get a handle on. I eventually stacked them by hand in Photoshop, but I'm not sure how accurate I was.

carlstronomy (Carl) · #2 31-03-2013, 02:04 PM

Jon, it appears you are out of focus. Not sure if the 60d you have has live view but what you have in that image is exactly what I get when I have not reached focus.
The blue would be from the filter I would try it with no extra's to start with as once you have used AutoStakkert to stack the image you can put it into registax to do some colour trimming and wavelet adjustments.
You just need to get that focus closer and you will have no issues, AutoStakkert does not require stars it is designed for planetarty and is what you need (its free). DSS is for deep space not planetary so it wont work, I have not used Maxim DL so can give no advice. Hope this helps somewhat and keep up the good work you will get there.

Carl

Jon (Jonathan) · #3 31-03-2013, 02:14 PM

Hi Carl,

Yes, the focus could well be an issue - I focused as well as I could on a nearby bright star but there was no way the nebula was going to come up on the liveview screen or the live view on Backyard EOS, which was what I was using. I suspect some of the lack of detail was from my manual stacking.

I'm puzzled by your comment about the colour, though. The Ghost, like many planetary nebs, is known for its bright blue, which came through the UHC filter just fine.

carlstronomy (Carl) · #4 31-03-2013, 02:21 PM

Probably just my lack of knowledge of what you meant by ghost....

I am still learning myself. Now I see it is called NGC3242 as your post stated you were having a go at planetary and you were having issues stacking I assumed (incorrectly) the ghosting was a problem you had. Now I have learned there is a nebula called the Ghost of Jupiter. You learn something new everyday.

Carl

Quote:

Originally Posted by Jon

I'm puzzled by your comment about the colour, though. The Ghost, like many planetary nebs, is known for its bright blue, which came through the UHC filter just fine.

rogerg (Roger) · #5 31-03-2013, 05:18 PM

Not a bad effort ... good amount of exposure time! and better result than I expected from a DSLR.

Good plan to think about what objects match your gear, rather than fighting against your gear working with it

I'm not sure what you did with the central star though! vapourise it?

I'd expect it to easily stand out but somehow you've wiped it out

Perhaps focus, but the object is so diffuse anyhow it's hard to say what your focus is like, other than the missing central star.

How do you focus your DSLR on your scope at that FL? Must be tricky for fainter objects like this.

Jon (Jonathan) · #6 31-03-2013, 05:45 PM

Quote:

Originally Posted by rogerg

How do you focus your DSLR on your scope at that FL? Must be tricky for fainter objects like this.

Cheers Roger. I focus on a brighter star as near as possible to the target, then creep the scope across back to the target. Hopefully nothing shifts ...

Jon (Jonathan) · #7 31-03-2013, 06:01 PM

Quote:

Originally Posted by rogerg

I'm not sure what you did with the central star though! vapourise it?

I'd expect it to easily stand out but somehow you've wiped it out

Perhaps focus, but the object is so diffuse anyhow it's hard to say what your focus is like, other than the missing central star.

I think it's the filter. Not sure what the UHC filter actually does, and I know it's intended for visual use not photographic. Here's a sub, unprocessed - the central star is gone too. So it wasn't something that happened in processing.

rogerg (Roger) · #8 31-03-2013, 06:07 PM

Quote:

Originally Posted by Jon

I think it's the filter. Not sure what the UHC filter actually does, and I know it's intended for visual use not photographic. Here's a sub, unprocessed - the central star is gone too. So it wasn't something that happened in processing.

Ahh yes, it would be the filter. That effect is probably making it look more out of focus than it actually is, from my experience of using such filters. But I don't use filters much.

Jon (Jonathan) · #9 31-03-2013, 06:26 PM

I like this nebula. I'll have another crack without the filter.