The Flame and HorseHead

mch3898 · Post by **mch3898** » Fri Feb 18, 2011 1:05 pm

Last night's sky was good. Despite it being full moon ("Chap Goh Mei" by the Lunar Calendar) and thanks to HA filter, managed to capture the Flame and Horse Head Nebulae.

But there seemed to be a skewed halo around Alnitak. Any reason for it? Hope my scope's not out of collimation. It's a refractor and may not be so easy to collimate.

Flame Nebula and HorseHead

orly_andico · Post by **orly_andico** » Fri Feb 18, 2011 1:31 pm

hi Christopher

i also see that halo around bright stars on my refractor when using the DSLR. so unless my refractor is also miscollimated...!

i notice that it disappears when you shift the focus just a tiny bit. if so then it would be an airy disk... which means my refractor is miscollimated. :-P

Post by **rcj** » Fri Feb 18, 2011 4:43 pm

have encountered this asymmetric halos before, and my guess is: depending on the light input into the tube and how the bafflings are constructed and positioned, as well as the internal reflections caused by the intermediate filter pathway, u get these halos. i have gotten a couple of such isolated halos before especially on very bright stars within the imaged FOV, but they can be slowly removed by software. What HA filter are you using? Very nice and crisp image btw!

orly_andico · Post by **orly_andico** » Fri Feb 18, 2011 4:52 pm

how many exposures, duration, and camera?

mch3898 · Post by **mch3898** » Fri Feb 18, 2011 5:36 pm

Thanks all for looking.

I did 10 subs of 500s each, imaged with Meade DSI Pro III through HA filter (Orion Narrowband HA). Just placed an order for the Orion OIII and SII to complete the parfocal set. Very tempted to do false color.

Mount is the Orion Atlas and guided with PHD through the Kwik guider.

Did processing with Nebulosity and noise filtering with Noiseware.

Glad to know that my scope's not miscollimated.

mch3898 · Post by **mch3898** » Fri Feb 18, 2011 5:41 pm

Sorry. Forget to add. The scope is a WO Megrez 90 with Flattener II.

cataclysm · Post by **cataclysm** » Fri Feb 18, 2011 8:56 pm

Very Nice and contrasty. Yes narrowband filters is the best way to fend off light pollution, even the natural one like Moonlight. [smilie=admire2.gif]

eMinity · Post by **eMinity** » Fri Feb 18, 2011 11:03 pm

nicely taken. i was wondering if i could take a picture like this with my 5" MCT?

Clifford60 · Post by **Clifford60** » Fri Feb 18, 2011 11:28 pm

Very nice including the others in your Flickr account

wucheeyiun · Post by **wucheeyiun** » Sat Feb 19, 2011 4:52 pm

It is very nice

i like the clarity