Thursday, August 18, 2016

#55 - Thursday, August 18, 2016 - Sidewalk Astronomy

My original plan was to image Saturn with the QHY5 camera, but just as I was setting up, a girl who lived in a nearby apartment walked by and asked what I was doing. I invited her to hang out for a few minutes while I got the telescope set up and aligned.  Thankfully, the C8 is so easy to put together and align.  I invited three other curious passers-by to check it out as well, and they went back and grabbed some of their friends.  It was awesome!  There were clouds overhead, but thin enough to still view through.  This limited how high I could push the magnification though.  So first I had them look through the 8mm eyepiece, and then the 17mm, which offered a sharper view but smaller.  Titan was visible, however, in both views.  I was very happy to share Saturn with all these people, and they were thoroughly impressed with both Saturn and my setup (and my credentials), but clouds came over and didn’t clear, so I didn’t get to image Saturn after all.  Oh, well.  Next time!

The girl hung out for a bit longer than the others, and we looked at Mars too.  It was very bright but also appeared to not be “full,” although that may have been the eyepiece I was using – the 17mm has some weird internal reflections that muck things up.  It was bright enough that I had a hard time making out surface features, but my eyes were also still dilated from my eye appointment earlier that day, so anything bright had a weird chromatic aberration shadow and was just saturated in my eye.   But yeah, still an enjoyable evening!

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.  

Saturday, August 6, 2016

#53 - Saturday, August 6, 2016 - At Last, Guiding (Almost)

I set up my C11 plenty early, and then started alignment once it got dark to see a few stars.  I looked at the moon and Jupiter before it got dark, since Jupiter sets pretty early these days.  However, it started doing the thing again, where the shielded cable is shorted and the servos start overdriving.  So I taped the cables to the mount so that they definitely wouldn’t move.  It worked for the rest of the night.  *sigh* like WTF Celestron, who in the hell uses the shielding of a cable as another pin.  And allowing a short to overdrive the servos!  At least ground it out, for goodness sake.
Once I got the cables taped down to the mount, alignment went smoothly, and getting the guidescope and camera set up went smoothly as well.  I was able to focus the guide camera, and then I changed the calibration step size back to a normal value, and calibration went smoothly.  Then I started imaging!  M16, the Eagle Nebula, was my first target.  I took a 90-second image.  It almost worked…but the stars were elongated.  Will showed me how to pull up the guide graph, and sure enough, the RA axis looked like crap.  He says he hasn’t been able to get his working right either, and that one solution is to make sure the balance is slightly toward the east in RA to counteract backlash.  I moved the counterweights up a bit to accomplish this, but it didn’t seem to help.  I can’t check how the balance is though because I don’t want to loosen the clutches and lose my alignment.  So that’s something I’ll have to do next time, I guess.  A more perfect polar alignment also helps.  I also saw online to make sure you have the backlash compensation turned off.  I don’t think I’ve had it turned on on this mount, but I’m not sure. 

Since my guided images weren’t looking very good because of the elongation, I decided just to do what I normally do – 30-second images.  I still got some awesome results last night.  Tracking wasn’t stellar – I lost quite a few due to drift – but things turned out anyway.  First was the Eagle Nebula, M16.  You can see the Pillars of Creation!!
M16 Eagle Nebula, Nikon D3100 on my C11, f/6.3 focal reducer
18x30s, ISO-3200
Despite the fact that I only got 18 usable images, it still looks awesome.  I’m going to collect more data tonight, hopefully.

Next, I tried the Helix Nebula, but I couldn’t see anything.  I didn’t try for long and instead moved on to the Swan Nebula, M17, while I was in the vicinity.  I’m not getting much more detail than the images I got last year on the C8, surprisingly.  I brightened it up a bit in Photoshop just to see, and I think I like the effect, actually.
M17 Omega/Swan Nebula, Nikon D3100 on my C11, f/6.3 focal reducer
20x30s, ISO-3200
It is a lot less grainy, however.  And still only with 20 usable images.  This one is smaller angularly because we’re seeing it edge-on, or so I read on Wikipedia.  Interesting.
Next I tried the Crescent Nebula.  I’ve tried it before without success, but this time I could just make out something in the image on my tablet.  I stacked them, and sure enough, there it was!  Well, the edge of it, at least.  I’ll have to get guiding going first I think before I can get more detail on the rest of it.
Crescent Nebula, Nikon D3100 on my C11, f/6.3 focal reducer
29x30s, ISO-3200
I need more data on this one too.
Then I decided I wanted to take a shot at imaging through the guide scope.  So I attached the DSLR to it, got it focused, and imaged the Andromeda Galaxy.  WOW did it come out awesome!!!  Probably now my second favorite image after the Orion Nebula.  Can’t wait to get more data on it – I lost a lot of frames due to clouds.
M31 Andromeda Galaxy, Nikon D3100 on my Orion ST-80
15x30s, ISO-1600
[I would just like to take a moment here to point out that I got this rather nice image of M31 using 30-second exposures on a $100 telescope with an entry-level DSLR.  You can do astrophotography too!]

You get M32 as well!  Due to the large FOV, drift from the mount is virtually non-existent.  I could probably do longer exposures and not see any drift.  However, since it’s got a focal ratio of like f/5, it’ll also collect a lot of background light.  Which I can more or less tamp down with stacking and Photoshop.  More experimentation is required.  But yeah, I got this image with only 15 frames!
I also imaged the Pleiades, and you can just make out some nebulosity.
M45 Pleiades Cluster, Nikon D3100 on my Orion ST-80
23x30s, ISO-1600

Imaging through the guide scope is a whole new adventure!  Fast focal ratio and large FOV.  It’s going to be AWESOME for the Orion and Horsehead nebulae together come winter.  And I’m using the 8-inch dew heater wrapped twice around it, and it works great.  I’m going to try other large nebulae soon, as well as galaxy clusters.