Sunday, May 13, 2018

Heart Nebula (IC 1805)

I took the data for this image October 2016 (!!!) It's a mosaic of 4 images and I always had problems stitching them together. Especially the OIII data which had very different noise levels in the 4 panels. But I finally figured out a way to minimize the effect! As always an awesome tutorial from Light Vortex Astronomy helped me!

(click here for a full-resolution view)

The Heart Nebula is at a distance of 7,500 light years from earth in the Perseus arm of our galaxy. It spans 200 lightyears! The nebula is ionized by the relatively young stars at the center of the nebula (their open star cluster is known as Melotte 15). The nebula is 150 arcminutes in size (the moon is 30 arcminutes!) in the constellation Casiopeia.
It was discovered by William Herschel on November 3rd 1787 (he first discovered the brightest part in the lower left - NGC 896).

Being a mosaic there is SO much interesting detail here:

1. The bright NGC 896

2. The open star cluster Melotte 15 at the core


3. Beautiful dust pillars (created by the energetic light from the young, hot stars at the center)

Each of the four panels has and integration time of 10 hours (10xHa, 20xOIII, 40xSII - each 10 minutes). I think this is the longest integration time I ever had.

Saturday, May 12, 2018

Mosaic with different background levels

Taking the images for my mosaic of the Heart Nebula took a long time (several weeks). And as a result the background levels of the different panels were quite different (mostly because of the moon). This was most noticeable in the OIII channel:

Here is mosaic of them without modification:

The first advice that I found was to remove backgrounds as much as possible using ABE or DBE. That made it better, but the differences were still very noticeable.

On one thread in the Pixinsight forum, somebody recommended to use LinearFit to equalize the levels - but that did not work at all for me:

The histogram got completely squished...

On another thread, somebody mentioned AutoHistogram:

The usage is fairly straight forward: select the image that you want to use as a reference image (preferably the image with the largest range) and click on "Set As Active Image". This reads out the median pixel value of the selected image to be used for the adjustment.

Then you just apply this process to all the other images:

Doing this to all images and combining them with GradientMergeMosaic results in:
Yei! That looks much better! I had to play with the Feather Radius to avoid a pinched star, but apart from that it was now straight forward.

Saturday, February 10, 2018

Delta T and UTC Data is expired. consider updating.

After several weeks of bad weather and travelling, I could finally take out my scope again. When I started ModelCreator for the 10Micron mount, I saw this message:

Searched around. Couldn't find anything. Asked on the 10Micron forum and got a quick answer - yei! Turns out this is something to be update every now and then.

First challenge: where to get the updater software from. Looked around. Turns out, it comes with the firmware updates! So, I downloaded the latest firmware update from the 10Micron forum site. When starting this, it installed and started the firmware updater where I could select to update the UTC / Earth rotation data:

Then, after clicking on "Edit" it tells me where to download the necessary files from:

http://maia.usno.navy.mil/ser7/tai-utc.dat and
http://maia.usno.navy.mil/ser7/finals.data

To import them, you have to select the second(!) file and it will ask you for the first. Once they are imported, click "Next >" on the screen above and data is sent to the mount. yei!

... I can think of at least 10 ways to make this easier with relatively little effort ...

Thursday, January 4, 2018

Debugging my FLI camera

My FLI ML16070 showed some issues: from time to time, it seems as if the shutter didn't open or opened slow or such. And then a few days ago, the camera completely failed (didn't turn on at all anymore).

I sent it to FLI and received the following comments:

"It appears as though somehow insects had managed to get in there and caused quite a problem! Honest, we've never seen this either!"

"I checked with Greg and the only thing he can think of is that something (one of them) got stuck in shutter just enough to make room for more"

... so, there you have it: debugging is still a thing!

Saturday, December 2, 2017

Wrong mount detected in firmware

... and after all these days, I just realized that my firmware / keypad thinks that my mount is a GM 2000HPS (not 1000)!!! I looked into the keypad settings but didn't find any place to set this - I also looked if there is a way to reset the firmware to factory defaults - but that also doesn't seem to be possible.

Upon further investigation, the wrong mount is also displayed in the ASCOM driver and the MGBox software.

At this point, I contacted Tolga (from Tolga Astro where I bought my mount) and asked for help.

Update December 4th:
The support from 10Micron contacted me and asked to send in a log file from their mount logger app (I love it if companies have good logging software that you can run and they can use for further diagnosis). They also wanted to see a photo of the control box of the mount:



... this one also says GM1000!!! :-(

10Micron sent me a "Mount Remote" app that I can use to connect to the mount and they can use it to diagnose it from the distance. Very cool. Installation was almost straight forward. Initially the vcruntime140.dll was missing, but I could download and install this from Microsoft. Now, I'm waiting for 10Micron to connect and hopefully find out what's wrong.

Update December 5th:
The engineers at 10Micron analyzed my mount and determined that at some point a configuration file was corrupted during shutdown. Which isn't a problem as they get restored automatically. Only that the program restored the wrong configuration file (for a 2000HPS mount). So, now everything should work again. Yei!!!

Incomplete Slews with the 10MIcron mount

When using the 10Micron mount, I noticed that slews seem to be very inaccurate (with or without a model or alignment). Upon further analysis, it turns out that all slews are incomplete.

E.g. starting the mount from it's park position (RA 1h20min, DEC 89° 32') to Neptune (RA 22h 53min, DEC -8° 6')


RADEC
Park1h 20min89° 32'
1. Slew23h 42min25° 54'

2. Slew23h 11min3° 55'

3. Slew23h 1min-3° 34'

4. Slew22h 57min-6° 11'

5. Slew22h 54min-7° 37'

...
Neptune22h 53min-8° 6'

I.e. the mount gets closer (each time about 66%) but never reaches. Initially I thought that this would be some timeout issue, but then the mount would slew the same amount each time. But that's not the case. This happens when using the keypad, the virtual keypad, software (TSX or SGPro) or through the API (e.g. from ModelCreator). It also happens both with the 12V power supply and the 110V power supply.

No idea what this is - and I also asked on the 10Micron forum.

---

Update: It turned out to be caused by the other problem that I had (that the control box thought my mount is a GM 2000HPS). Once that was fixed, this issue was gone. Yei!

New Mount: 10Micron GM1000 - First time out

With everything in place, I could finally take the mount out for the first time!!!

First, I wanted to try out the rough polar alignment with the green laser pointer on the scope. But either the laser is broken or WAY too weak, but I could not see a beam at all :-( So, scrap that idea.

Now, rough polar alignment turned out to be tricky. The 10Micron mount uses simple star alignments for polar alignment (3 stars for a rough alignment, a full model for exact polar alignment). But when the mount is not even nearly polar aligned these are difficult through a camera as the I can't use "Closed Loop Slew" in TSX or plate solving as the it is WAY too far off.

So, as I want to use the mount unguided anyway, I decided to remove my good, old Borg scope + Lodestar guider and replace it with a simple red dot finder:

Another nice side-effect of this is that there WAY less weight on the scope now. I could move my counterweights significantly up - maybe I can even get rid of the smaller one completely!!!

With a rough polar alignment, I tried various of the 10Micron functions:

1. Balance check
I really like that they put this into the functionality of the keypad. The mount moves the scope into specific positions and measures on both sides if any creates more or less friction. Measuring in RA was quick and showed that I was only 0.01% off (everything below 0.04% is considered enough for good, stable imaging).
For the DEC measurement, the tripod became an issue. As the mount is pointed almost straight to the side and moves the scope all the way from one side to the other, my filter wheel collided with the tripod and stopped the whole procedure:

This is another reason why I like the AP Eagle pier (the other one being that it has better possibilities to fix all the boxes).

The good news is that there is a dialog box asking for confirmation before slewing to the other point. At that moment, I can slew the scope further upwards and then it passes. But I should really try to get an adapter from the Eagle pier to the 10Micron mount. For now, I'll probably move the filter wheel around and point it upwards.

2. Orthogonality (cone error)
From the various alignment points, the mount calculates the orthoganility error. In my case it was 0!!!

3. Polar alignment
Now, the polar alignment was fairly easy. Select it in the keypad and do the usual azimuth/altitude adjustment to center the star.
While doing the alignment, I noticed two things:
  • to adjust the mount in Azimuth, the four screws that fix the mount to the tripod have to be loosened. And of course, I have to remember to fix them again afterwards.
  • the Altitude know has a significant amount of backlash (see above). It's not getting too much in the way of adjusting the mount, but it is weird that it is SOOOO much. Asked in the 10Micron forum about this.
But now, my mount is polar aligned.

4. Tracking precision
Without guiding, I measured the precision of the mount as-is (i.e. no model or such): << 1" !!! That's a pretty awesome precision!!!

5. Configuring in SGPro
The main difference in SGPro configuration was to switch from PHD2 guiding to "Direct Mount Guider". This basically doesn't do any guiding, but still does Meridian Flips and Dithering.
The other thing I wanted to configure is to not track too close to the Meridian to avoid that the filter wheel collides with the tripod. I measured that filter wheel collides roughly, when the scope is 5' away from the zenith. In SGPro, I can use negative values in the Meridian Flip settings dialog to indicate this:

... and then it got too late to really try it out ...