Tuesday, March 29, 2016

#29 - Tuesday, March 29th, 2016 - Bad Behavior

I moved to a new spot at the state park – that dirt parking lot out front of the gate on the road to the observatory.  The trees are kind of high, but it’s much more secluded than my previous spot, and I’m more comfortable being back there alone.  It’s also closer to the compost toilet, which I finally found a few trips back (which was open during the winter!). 
It was in the lower 40s, but the trees shielded me from the wind.  Putting the telescope together by myself took a lot longer than I had anticipated, so I didn’t start getting images until almost 10 PM.  I came up with a clever idea to keep the battery from getting cold – I wrapped the 8-inch dew heater around it, and covered it in a fleece blanket, and turned up the heat.  The alignment process worked well and worked the first time, for once.  Its initial guesses at the two alignment stars and the first calibration star were terrible, but it cleaned up pretty well by the third calibration star.  I used Sirius for the all-star polar alignment.
I started with one more go at the Orion Nebula, although it’s in the western sky now, toward the city, where there’s lots of skyglow from the city lights.  There were also some high clouds I could only see in long-exposure images.  So my Orion photos came out terrible.  After about 35 of those, I slewed to the Cigar Galaxy, M82.  It wasn’t showing up in my photos though, even after fishing around for a bit, so on a hunch I tested whether it was still aligned – I had it slew to Polaris.  It was most definitely not.  So, without power-cycling, I re-added the alignment and calibration stars, and it stuck.  I found M82 with no problem.  So I started that set going, and went and read in the car.  I forgot to check what time it crossed the meridian – I only got about 20 images before it did, and another 20 had massive star trails since the scope had stopped moving.  So I had it slew to M82 again – and again, it was way super off.  So I power-cycled and re-aligned (I didn’t have to re-polar-align, since I hadn’t moved it), but it wasn’t working; it was way off on goto.  By this point, it was about 11:45 PM, close to quitting time.  So I gave up and packed up. 

The battery was nice and warm, so I think we can rule out the battery being cold as a cause for it getting lost.  It sounded again rather terrible when it was slewing, more in declination than right ascension, though.  This is in part caused by the fact that I balance the telescope with the camera attached, and I align using the star diagonal and 25mm eyepiece, so it’s not balanced when I’m doing that, but it sounded worse than it did earlier in the evening when I was aligning the first time.  It really sounds like it’s not getting enough juice, but I don’t think that that’s the problem, unless the battery is crapping out on me.  My next suspicion is that the grease in the gears gets too viscous when it’s cold, so it’s working against that as well.  So I’ll have to wait until a warmer night to go again, I think.

On the bright side, the 20-or-so pictures I got of M82 yielded 18 decent ones (I’m pretty liberal with how much star asymmetry I allow at this point, since I haven’t yet had a good night with a lot of pictures to choose from).  Even with only 18x30 sec images, it came out pretty well!

M82 Cigar Galaxy, Nikon D3100 on C11, f/6.3 focal reducer
18x30s, ISO-3200, no flat [I just made the background really dark in post-processing to hid the vignetting]

Saturday, March 19, 2016

#28 - Saturday, March 19th, 2016 - Some mount issues

The sky cleared up rather nicely not long after sunset, and the moon was bright but the sky was transparent enough that the parts of the sky opposite the moon were still relatively dark. I aligned using Sirius and Capella, then added Pollux and Mizar as calibration stars (Mizar because I was going to image M81 and M82, which are in the northern sky). Then I did the polar alignment using Sirius [using Celestron's All-Star Polar Alignment routine], and then went to re-add the alignment and calibration stars. I re-did Sirius and Capella, and then went to do Pollux, and it was waaaaaay off, like it was pointing northish rather than southish. I told it to go find Sirius, and it was in the trees below and to the east of it. It was also sounding like it was super-struggling with moving, more than usual (there is some struggle because I balance it with the camera attached but align it with the 25mm eyepiece, so it’s not balanced during alignment. I’m told this is okay, and just to do a Calibrate Goto after I reattach the camera). I power-cycled it, checked the time and date, power-cycled it again, changed the time (it had gotten off by a few seconds, which is usual), checked cables, everything I could think of. I tried aligning it with its super-wrong guesses anyway, but it was still way off after adding the two alignment stars. And it also moved on its own once while I was finding Sirius in the finderscope. So we packed up and left. Agh I was so looking forward to getting great images of M81 and M82, the conditions were pretty good! Even the wind had died down. I did some research today, and it looks like it might be as simple as a power issue. I looked at the specs for the power tank, and its minimum operating temperature is only 32 degrees. That’s about what it got down to last night, if not a little below that. I also suspect I might need to add some grease to the gears, but one thing at a time. Next time, I’ll put the battery in the car to keep it warm, and see if that helps.

Side note, the collimation seemed fine for the northern sky this time. I’ll just have to keep an eye on that and check for it every time.

Thursday, March 17, 2016

#27 - Thursday, March 17, 2016 - Collimation Nation

ClearDarkSky promised no clouds, but clouds there were, about 50% until 10:30 PM.  The moon was waxing gibbous and very bright, so none of my Orion photos really turned out.  I also imaged Bode’s Galaxy, M81, for a while, but then when I had to re-slew to it after it crossed the  meridian, I realized that the image wasn’t in focus, so I re-focused it on a nearby star and went back to it.  Goto wasn’t being particularly cooperative (I think I forgot to have the telescope find the switch position before I polar aligned it), so it got me close, but not right on, M81.  So I looked around for a bit, saw some stars that I remembered seeing in the viewfinder that are nearby, and started imaging.  A much different-looking (and brighter) object appeared on the screen.  Come to find out, it was M82, M81’s companion, the Cigar Galaxy.  It appeared brighter, even though it is technically lower in magnitude than Bode’s Galaxy.  So I decided to image that. 

However, when I went to process the next day, I realized that it wasn’t focus that was the problem, but collimation.  On the last trip, I realized that the collimation I did previously didn’t hold – I figured the collimation left the secondary a little loose, so it was moving because of gravity depending on where the telescope was pointed.  So Anton and I re-collimated using Sirius, and only tightened the screws, rather than loosening any of them.  We achieved excellent collimation.  But, when I look at the northern sky now, it is no longer collimated.  I’m wondering if it’s still loose.  But I’ll try collimating to that part of the sky, only tightening the screws, on the next trip, and see if that helps. 

So, long story short, none of my images came out, and I was up till 2 AM the night before I had to be awake at 5 AM for a poster symposium all for naught.  I did snag a few pictures of the moon, though.
Moon, Nikon D3100 on my C11, f/6.3 focal reducer
Single frame, ISO-400, 1/320s

Wednesday, March 9, 2016

#26 - Tuesday, March 9, 2016 - Finally, some images on the new telescope and mount!

We set up this time on the road [it was a side road that I was sure no one would drive down in the middle of the night, since this was at the state park.] That made the leveling much easier, since it wasn’t sinking. I aligned the mount to Polaris, did a two-star align with two calibration stars, did the polar alignment procedure on the hand controller with Procyon, and then replaced the two alignment stars (I hadn’t figured out how to replace the calibration stars yet – I figured it out later in the night). The first two alignment star guesses were pretty far off, but it ended up working out anyway. I turned it to the Orion Nebula, and it was within the eyepiece, as was Jupiter, so the alignment seemed to be working. I tried a 30-second image of Orion – no drift! I tried a minute, and there was a little, but then again, I didn’t re-do the calibration stars. So I imaged the Orion Nebula with 30-second images, and the Whirlpool Galaxy too. What a difference the focal reducer and skyglow filter make in what I can see in an image! So on my fourth trip, I finally got this new telescope to work. And it seems very promising for imaging! They’re stacking now, but it’s 3 AM, and I need to go to bed.

[Next morning...]

They came out fantastic!!

M42 Orion Nebula, Nikon D3100 on my new C11

f/6.3 focal reducer, Orion Skyglow filter
44x30s, ISO-3200 & 1600 combined, no flats

M51 Whirlpool Galaxy, Nikon D3100 on my C11

f/6.3 focal reducer, Orion Skyglow filter
70x30s, no flat (had to use Super-pixel mode and 2x drizzle because the stars were a little stretched)

I had to not use the flats – since the telescope as at a different angle depending on where it’s pointing, and I rotate the camera so that it’s upright, flats taken in one position are not the same as flats taken in another. I’ll have to think about what to do about that.