Charting DSSR Autoguider History

 Tutorials, Uncategorized  Comments Off on Charting DSSR Autoguider History
Jun 202015

SmarTrak is DSSR’s helper that steps in to guide your scope when the guide taget is lost due to cloud or other obstructions. I seem to have broken it in DSSR5 and I have added some logging features to help me fix it. These can also give you an insight into how DSSR is controlling your scope.

When DSSR loses the guide target it logs the guiding history like so:

08:22:17.838 Target lost – SmartTracking
08:22:17.839 SmartTrak totalTms:4638563 ppmsH:-0.01001258 intH:-49937.2 pH:-500.0 ppmsV:-0.03671094 intV:-13619.9 pV:-500.0
08:22:17.839 ,0001,6834,0,0
08:22:17.839 ,0002,7170,51,305
08:22:17.839 ,0003,7668,103,508
08:22:17.839 ,0004,8266,155,711
08:22:17.839 ,0005,8662,-310,-1322
08:22:17.839 ,0006,65300,-310,-1220….. etc for all stored guide history points.

Each red line contains the log time, point index, time in milliseconds since the last guide pulse and the pulse times in milliseconds for the RA and declination axes. You can copy and paste these points into a spreadsheet and chart the guide pulses in each axis against time. Below is the RA chart for one of my sessions.

Click for full image

Click for full image

This shows the plus or minus RA guide pulses have a recurring period of about 10 minutes. I don’t use periodic error correction on my HEQ5 Pro but this chart shows that I probably should. When I play back my session videos I can clearly see the target moving back and forward in RA around a mean position during SmartTraking.

SmartTrak applies the mean pulse (-50ms red dotted line) but you can see that the polynomial trend line runs from -20ms at 78 minutes ago to -70ms when SmartTrak kicked in at right on the chart. This suggests that I need to cut my number of history points down to cover say just 2 cycles or 20 minutes. This will give a better mean pulse time for SmartTrak to use.

The fact that the mean line is not at 0ms suggests that my mount still has an alignment error. You can see a similar alignment error in the declination chart below.

Click for full image

Click for full image

This shows that all the guide pulses are negative and there seems to be a much shorter periodic error. The mean pulse is -175ms but the polynomial trend is at -150ms when SmarTrak kicks in at right. Again this suggests that fewer history points are needed to give a more accurate mean value.

The above charts have been very useful to help me see what DSSR is doing during autoguiding and I hope to have SmartTrak fully operational soon.

You can try this out for yourself by changing your screenshot interval to 5 seconds, turning on logging, checking the SmartTrak box and then guiding for an hour say. Then raise the minimum guide similarity to 999 to force SmartTrak to kick in and leave it running until the target leaves the field of view. Make a session video as per Appendix E of the manual and scrub it back and forward in VirtualDub to see how SmartTrak is faring.

You can then use a spreadsheet to construct the charts above. I used the free LibreOffice Calc spreadsheet for mine.

 Posted by at 6:51 pm

Earth Overlay Size in DVS

 Solar HA, Tutorials  Comments Off on Earth Overlay Size in DVS
Jun 202015

The graphic below shows how to calculate the size of the scale Earth to use as an overlay in DVS animations.

Click on image for full size.

Click on image for full size.

 Posted by at 11:36 am

Testing of DSSR5 Scanner Mark II

 News, Solar HA  Comments Off on Testing of DSSR5 Scanner Mark II
Jun 092015

I have just been testing DSSR5’s rewritten scan feature. This effectively triples the area covered by your imaging chip and also completely eliminates Newton’s rings. Here is how it works on a PST – DMK21 – PowerMate 2.5x setup.

Scan 20150609085207 text

Click for full size scanned result.

It also allows you to take full disk images of the Sun with a PST and DMK21 at prime like below.

Scan 20150609100546 text

Click for full size scanned result.

DSSR5 is currently only available to members of my user group but will be released publicly soon.

The scanner uses the same file format as DSSR captures so that DVS can automatically add the date and time like the 1123×673 pixel scan below.

Scan_20150611 101552 DVS

 Posted by at 6:12 pm

Preview of DSSR5’s Solar Scan Feature

 Solar HA  Comments Off on Preview of DSSR5’s Solar Scan Feature
Apr 172015

DSSR5 has a new scanning feature which enables cameras with small chips to produce images of the entire sun. I tried it with my DMK21 (1/4″ CCD) at prime focus on my PST which looks like this during capture.

Raw video frame

Raw video frame

I then used the new scan function to automatically record a 5 minute video of the Sun while DSSR steered the scope to cover the entire solar surface. Registax then did its magic to produce this full disk image below.

Full solar disk produced by Registax

Full solar disk produced by Registax 20150417 @ 09:30UT

This is a lot easier than mosaics and it looks like the method smooths out the PST hot spots as well. (It’s also a lot cheaper than a 1/2″ chip camera:-)

A very big thanks to Sylvain Weiller for suggesting this feature and helping me bring it to fruition.

Below are some recent scans – all taken with a 1/4″ DMK at prime focus on a PST.

201504181233 scan

Scan 20150418 @12:33UT


 Posted by at 2:14 pm

Review of Pipo X7 Win8.1 nanoPC

 News  Comments Off on Review of Pipo X7 Win8.1 nanoPC
Mar 282015

My old XP desktop in my garden observatory finally started chugging so I checked out the price of an upgrade to a newer version of Windows. Doing so, I found this little beauty which is a quad core PC with Win8.1 for a few dollars more than Win8.1 on its own.


Setup was a doddle and the stock SSD had 21GB free after updating Windows. I then installed ASCOM, DSSR, DVS, DFM, DSR, AstroKam, TIS driver, TeamViewer, Cartes du Ciel, AviStack, StarTools, Krita, Sony Vegas, Microsoft ICE, LibreOffice, VirtualDub, 7Zip, DeepSkyStacker, AdBlockPlus, Canon DPP and Utilities, AS2Cull, EQMOD, EQDIRECT and SPC900 drivers. This left the SSD with 14GB free.

It starts from cold in 20 seconds and is very nippy because all programmes are on the SSD. Power consumption is 8W with no camera and 11W with my DMK21 attached. I can afford to leave it running 24/7 which will cost me around $12 a year. There is no fan so it is totally silent which makes it great as a media player. The aluminium case doesn’t even get warm to the touch.

It is roughly 40% as powerful as my 8-core AMD 3.1GHz, 8GB, 64bit W7 desktop PC, based on these comparison processing times:

DeepSkyStacker image stack: Pipo = 34Min, AMD = 15min.

AviStack batch video processing run: Pipo = 36min, AMD = 13min.

However, the Pipo wins hands down on a bang per buck and bang per watt basis.

It runs my HEQ5 Pro and DMK21 under DSSR with no problems which is why I bought it. It can autoguide all day long while constantly capturing video clips with no dropped frames. One thing to note is that you need to be wary of how much power your devices suck from the USB ports. I have to run my DMK21 camera from a front port and a portable HDD capture disk from a rear port. A powered USB hub should solve this problem.

I added an un-powered 4 port USB hub which lets me add a mouse, keyboard and DSLR together with my EQMOD cable, DMK21 camera and 500GB capture disk.

Here is one of the its first capture and processing tests. Intermittent clouds makes for a jerky video with stacking artifacts but I think it performed to spec.

[vimeo 123507654]


I can see the Pipo being a lot of use in astronomy. You could strap it to your scope tripod with a battery pack (or solar cell) and control it via TeamViewer. Or, have a bunch of them running in a cupboard as a video and imaging processing farm.

Would I buy it again? I already have, and #2 is my new media PC. Netflix, YouTube, iPlayer, etc all play 1080p video without a hitch. The great thing is I can also do video or image processing on it overnight.

ps I have heard rumors than Win10 will be offered as a free upgrade to Win7 and Win8. This would make the Pipo even more of a bargain.


 Posted by at 8:19 pm

More DSSR EzyTrak Jupiter

 Planets  Comments Off on More DSSR EzyTrak Jupiter
Mar 222015

More EzyTrak testing on Jupiter with my NexStar 4SE/DMK21/PowerMate 2.5x combo.

[vimeo 122306917]
 Posted by at 10:06 am

Solar Eruption 14th March 2015

 Solar HA  Comments Off on Solar Eruption 14th March 2015
Mar 152015

It was a gorgeous, clear sunny Spring day in the Scottish highlands yesterday and I captured this time-lapse. Lots of crackling and a nice eruption about 2/3rds in.

[vimeo 122228068]

This was capured using DSSR’s new EzyTrak guider which is in development. The full 5 hours DSSR session can be seen below speeded up 600x.

[vimeo 122190081]
 Posted by at 10:51 am

First Test of EzyTrak

 News  Comments Off on First Test of EzyTrak
Mar 112015

DSSR’s autoguide module seems to cause most problems for new users so I am now revamping it to make it a foolproof guider. The new guider is called EzyTrak and is currently only available to my user group but will be released soon with DSSR5. Below is the result of a trial run on Jupiter (animated in DVS).

[vimeo 121874966]
 Posted by at 10:58 am

My Garden Observatory

 News, Tutorials  Comments Off on My Garden Observatory
Feb 282015

Here are some pics of my second observatory which is an HEQ5 Pro mounted on a small table outside my garage. The control cables run into the office in the garage corner and are stored coiled in the empty gas meter cabinet on the wall. The hardest part of making this was drilling a 55mm hole thru the wall for the cables. It only takes a minute to remove the cover bag, install the scope and connect the wires. The mount is on the south-east corner of the garage so it can cover the whole sky except the north-west quadrant. Perfect for solar, lunar and planetary work.

DSC04521 DSC04524

 Posted by at 8:45 pm

DSSR Eclipse Notes

 Tutorials  Comments Off on DSSR Eclipse Notes
Feb 282015

The next eclipse of the Sun will occur on March 20th this year and here are some tips on how to use DSSR to guide your scope during it. First, here is a white light simulation of what the eclipse will look like from Inverness, Scotland. Note that this was created in CdC and is an alt-az view, which is why the Sun is rotating and the Moon follows a curved track.

General Tips

If your camera is in auto exposure mode the sky brightness will vary during the eclipse which is maybe what you want. I intend to use a fixed manual exposure which I think will look better in the time-lapse animation.

Do a dry run on the Sun before the 20th.

Use new or recharged batteries and have spares ready.

Use a remote release cable or intervalometer as a backup to DSLR usb capture.

Use DSSR’s recticle to centre the Sun before you start guiding.

White Light

I have tried to get DSSR to do a virtual guide on this animation but it breaks down near the point of maximum cover. What I suggest for WL is that you guide for as long as you can on a sunspot and then stop guiding. Then, right-click on the 6 or 12 o’clock position to begin monitoring. Stop monitoring and then right-click on the picture in the guider window to show the monitor box in the main video window. Then use your HC buttons to keep the monitor position lined up with the red box. You can start guiding again when a surface feature reappears (remember to click in the guider picture to hide the monitor box).

H-Alpha Light

You might be luckier in h-alpha if there is a prominence or surface feature in the uncovered portion of the Sun. DSSR should be able to guide right thru the eclipse on it. If there is no feature then follow the procedure for white light above.

Poor Man’s Guider

I don’t have a full disk video camera so I can’t use DSSR for the eclipse. My plan is to use a Canon 1100D DSLR connected to a NexStar 4SE and use Canon’s utility app to capture a full-disk WL still every 5 seconds. My guider will be a sheet of cling film over my monitor on which I will draw the dotted outline of the Sun in the Canon preview window. I can use this with the HC buttons to keep the Sun aligned.

Construct Time-Lapse Animation

Coming soon – how to use DSV to create a time-lapse animation with your results.

 Posted by at 12:10 pm