It's been a good two years since I posted here. I'm ashamed to  admit I forgot I created the blog. That's not to say I have abandoned the DSI-II. For some reason I no longer remember I stopped posting. Time to give it a renewed try. For the near future posts will catch up on past activities.

Meade no longer produces the DSI-II. There was a DSI-III which has been discontinued along with the full DSI line. In fact I was "lucky" to grab mine for a substantial discount as Meade was closing out the IIs. I put lucky in quotes because the DSI-II is a mixed blessing. It was cheap $290. It does work as you can see from the earlier images.

With its automatic dark frame subtraction it is easy to use. On the other hand the product is really poorly documented and the software interface is poorly designed. Meade left it to an enthusiast to create a video tutorial that is not done under the dark but none the less is more informative than the included documentation. The documentation does little to explain how to use the various settings or what many of them mean. This has been a recent pattern with Meade. The documentation for its Autostar

Whoever coded the software interface did not account for varying screen resolution. Thus the user must futz around with screen resolution settings on a high resolution laptop just to get a usable screen. The lack of temperature regulation is another source of frustration on nights when temperatures constantly change. One is forced to keep generating new sets of dark frames as the device cools along with the night air. A few users have modded their DSI-II with Peltier cooling. I'm not yet brave enough to try that.

Under a full moon

June 16 was just one day past full moon. Between 10 and 11PM the moon was still low to the southeast which offered a test for using the DSI-2 under fairly adverse conditions. Randolph, MA where I live is already very light polluted with poorly shielded sodium vapor lights. Adding to the challenge, the  local elementary school in whose parking lot I do my local observing has both broadband mercury vapor along with sodium vapor lighting.

Messier 3 just past full moon

After setting up the scope it took longer than usual to iterative align the 127ED because I forgot about the problems posed by using Arcturus or Spica as alignment stars. I need to recompile a list of compatible alignment stars which which differ between 3 and 9 hr away from Polaris in R.A.


I chose M3, which rides high in the sky this time of night to image. The globular cluster was obvious at 1s exposures in focus mode. After  creating a fresh set of darks for the night and merging with my old set of darks I acquired two sets of exposures at 2.8 and 4.0s. The 4.0s set were averaged to produce the final image after some histogram, brightness and contrast tweaking.

A few nights in Maryland Part 2

Below is my first DSI-2 image of a galaxy Messier 51. M51 is near the end of the handle of the Big Dipper. As luck would have it a member of the Meade DSI Yahoo discussion group, Bill Rouse announced there is a new supernova or exploding star in M51 also supplying a link to before and after images. I didn't get a chance to image the galaxy until June 8th. Again I did not keep good exposure records. The red arrow in the post processed image points to the exploding star. Exposure was unguided which helps explains the oval shapes of the stars.

A few nights in Maryland Part 1

M3

I was in Frederick, MD for a week with the scope which afforded me couple of opportunities for  a little more DSI-2 imaging. The moon was between a young crescent and first quarter. I like to keep different night sessions separate by creating a date named folder.

It dawned on me to bundle dark frames in a single archive and copy it to the new folder for each night of imaging. This improves the odds of the Envisage software finding a compatible set of dark frames for the current session. Dark frames are coded for temperature and Envisage complains for more dark frames  if the temperature changes significantly.

M13

Only one night offered half decent transparency. On the first night with any transparency 6/6/11 I managed  bag four  globular clusters i.e., M3, M5, M13 and M53. Because, I'm still in the familiarization mode my record keeping for these was poor. The images appear to the below.

In my next DSO imaging round I will try imaging without the mirror diagonal on the hope it will improve the roundness of the stars. The DSI-2 also offers  options to sharpening during imaging. However, according to Meade you give up some sensitivity

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  M5

M53

Periodic Error Correction.

Sunday night I thought I would attempt to train the drive for periodic error correction or PEC.  It took longer than usual to get the drive aligned tonight. I suspect because I dumbly sync-ed Polaris after each drive Azimuth/Altitude(tilt) adjustment. It was unusually humid and transparency was mediocre. As one might expect clouds moved  in ending the night.

It dawned on me that I should simply clear any PEC data that might be polluting the drive and causing it to correct for non-existent errors. Tonight I bring the scope upstairs and retrain the RA/DEC axes. This is different from PEC training. If I get a break on the sky I'll try imaging one easy DSO. There are few visible from my tree obstructed terrace between 9-12 midnight. This weather is really sucking right now.

First Real Night Out

I caught a break in this almost two week cloudy, showery, foggy spring weather pattern and managed to get the telescope over to the local Donovan elementary school on Friday night. While clear there was high cirrostratus and transparency was poor. I decided to try my hand at M3 and M13. Both are near the zenith between 10 and midnight.

Last winter the Meade 1697 computer drive system needed a repair and I opted to have it upgraded to an AutoStar I. I have mixed feelings about the Autostar. The good news is that alignment and tracking appear to have improved. I rarely have to spend as much time as in the past getting the GEM aligned with Polaris. On the other hand Autostar's usability and documentation is abysmal compared to Meade's original #497 controller. The menu system has become deeper and adds extra annoying steps.

That rant said Friday's results were a mediocre start. Using Arcturus I got rough focus. I then moved over to M3. I fine focused on the globular cluster using 1s preview exposures. In color mode the image had a very orange cast which I hope has to do with all the sodium vapor light pollution scattering off the high clouds and smog. I decided to image in B/W.

To my disappointment I was only able to use 2 to 4 sec exposures because of the severe periodic error. I guess my next night out will be devoted to learning how to and tuning PEC.

The focal end of the scope was getting dangerously close to a tripod leg during my M3 imaging session. Rather than chasing M3 to the other side of the GEM I moved to M13 which was now near the zenith. Again with M13 tweaked into focus I tried imaging the globular in B/W and color. Again the color images featured an orange cast and washout of the brightest stars. I'm not sure if this is a consequence of imaging in JPEG. I'll try using FitsInt, Fits or Fits3D

Barely a first night out

It's been 12 days since I received the DSI-II. The weather has been cloudy with showers with zero clear nights until last night. I wasn't convince the clear sky would hold so I only set up the scope on the terrace. For local observing I usually take the scope to a local elementary school parking lot/play ground. Trees block most of the view from the terrace. However one DSO the Sombrero galaxy was available.at 10PM. I detest daylight saving time.

Scope aligned I used Spica to get a rough focus. From Spica I jumped over to M104. A group of stars in the field to the left of M104 served as a fine focus. To my delightful surprise I could just make out the core of the Sombrero in 1 sec exposure preview mode. This is about as far as I got. I made the mistake of setting dark frames to 5 per average. By the time I got to imaging the Sombero it was moving behind one of those inconvenient trees.

Tonight it's back to crappy, overcast New England spring weather.