Sunday, August 7, 2016

#54 - Sunday, August 7, 2016

I left the C11 set up, and then just powered it back up and checked alignment.  It looked good.  I was helping Miqaela a bunch though, and didn’t really get started imaging for a while.  I couldn’t get the guide camera to give me good signal – it was noisy as hell, and at the focal point I couldn’t see any stars still – so I shut it off and just did my normal unguided imaging.  First, I imaged the Sagittarius Star Cloud through the C11.  You can see a cluster in it, but none of the nebulosity.  Perhaps I need a larger FOV to see it.  It’s mostly just a massive star field, but I like it because there are so many stars.
M24 Sagittarius Star Cloud, Nikon D3100 on my C11, f/6.3 focal reducer
11x30s, ISO-3200
I’m also happy that you can see the many different colors of stars.  Such diversity.
There were patchy clouds moving around the sky, and time was passing quickly, so I slewed over to the challenge object – the Veil Nebula.  One of the things I definitely needed a faster focal ratio and larger FOV to do properly.  The Orion ST-80 did the trick!  This is the Eastern Veil Nebula.
Eastern Veil Nebula, Nikon D3100 on my Orion ST-80
16x60s, ISO-3200, no flat

For this one, since I still don’t have a functioning intervalometer, I timed them myself using the remote shutter and the stopwatch on my phone.  It was tedious.  I had to time the darks too, so I only took ten.  It’s looking like I’m going to have to get a different DSLR body, one that can be controlled by the computer.  This will let me not only be able to automate long exposures in bulb mode, but also do Live View on the computer, record video directly, and use a plate solver like Astrotortilla to center my images and, eventually, an autofocuser.  So lots of benefit.  Still just a temporary measure until I can save up for a high-quality astro camera.  But that’s further down the road; I’m still doing well with the DSLR. I just need to have more patience and take more light frames so that I can beat down the noise.  Sure, I’ve figured out how to get rid of background light using GIMP or Photoshop, but the graininess in my images is all from read noise, shot noise, and thermal noise, which can be beaten down by having a lot more light frames.  We’ll get there.  I’m also buying a QHY5 guide camera from another club member, which I can also use for planetary.  Will says I can use it for DSOs too potentially, especially if I shoot black and white instead of using filters.  

No comments:

Post a Comment