I’ve had a longer term project running for a while to image Abell 31. As this object is in Cancer it’s now too late in the year to accumulate further sub-frames so I’m going to have to make do with what I have. Altogether though, this now amounts to about 20 hours so I’ll have to knuckle down and process a final result. In the meantime, I’ve been messing with some brighter objects and this is one, NGC 4244 in Canes Venatici. A nice sized, edge on spiral galaxy. Image is comprised of 20 ten minute sub-frames.
Having pollarded a willow in the garden and removed an Alder I now have a much clearer view across the southern horizon and for objects above Sirius I don’t have to worry about obstructions. Having also replace the Observatory Netbook with a dual core Atom embedded PC board this was a convenient test target to ensure that all was working as it should be.
This is 200 minutes of exposure in 10 minute sub frames, processed in Pixinsight.
Bob Samuel had also imaged this object with Ha, SII and OIII filters using his ED80 and combined them with my colour data for this result:
Another New Moon and another dark, dusty nebula; this time in Taurus. Barnard 15 is listed in the catalog with this note: “Large, irregular, with brighter condensation (B 10) in SE part“.
I was lucky enough to get 6 hours worth of images on the first night and I followed this up with another 3 a couple of days later. Individual sub-frames are the usual 10 minutes and both stacking and processing are done exclusively in Pixinsight.
I haven’t posted here for a while now. I post most initial looks at data sets on the Breckland Facebook page so this is the place to visit for the most up to date information. However, I will endeavour to keep this page reasonably current.
Last Saturday evening was crisp and clear with a waning moon. As I have an interest in dark dusty things I selected Barnard 15 as the target. Outside of the main plane of the Milky Way, this dark nebula is very black and sharply defined against a background of uniformly bright stars. Also in the frame are Barnard 16 & 17 along with much fainter dust clouds.
The lack of stars in front of B15 indicate that it’s pretty close to us. These clouds are dark due to the presence of sub-micrometre dust particles coated in frozen nitrogen and carbon monoxide. Also present is molecular hydrogen, atomic helium and C18O along with a cocktail of exotic molecules.
This is an update of the image I posted on Facebook with a more aggressive noise reduction process early in processing. Consequently, I’ve been able to stretch the contrast more to emphasise the fainter dust structures and apply a stronger colour saturation to the stars.
37 individual exposures of 10 minutes each were gathered before the moon rose for a total of a little over 6 hours.
After getting back to using my Astrotrac at the club’s Haw Wood star party I decided I’d like to do some more of the same at Kelling. There was an ulterior motive as well; since building and setting up the observatory there’s rather more work involved in stripping it all down to take into the field.
Once committed to the Astrotrac the choice of lens was made. The Canon 75-300 zoom works really well at shorter focal lengths and is ideally suited to unguided imaging with the Astrotrac. The camera was my QHY9 which had to be removed from it’s permanent home on the back of the Tak.
Once the sun set on Friday evening the sky cleared quite nicely, rather hazy with a lot of moisture but better than a lot of the skies we’ve had this year. As my pitch was completely over-hung with trees I negotiated with a neighbour for a corner of theirs. Once setup, Cygnus was close to the zenith so I started there aiming the red-dot finder between Deneb and Sadr taking some short exposures and then re-framing. Once done, I set a sequence of 5 minute exposures and left the Astrotrac to do it’s thing for the remainder of it’s 2 hour tracking time.
Once that had completed I moved the setup along the Milky Way towards Lacerta aiming for the dark nebula B168. The procedure was repeated and then, finally I moved to Auriga. By this time two things were apparent; 1) The skies were closing down and 2), after a week at work I was ready for bed so I cut this session short and headed for the van. Packing up with the Astrotrac consists simply of splitting it into parts small enough to fit in the van and stowing them in the cab in front of the seats.
Approximately 20,000 years ago a star in Cygnus ended it’s life in a violent explosion. The shockwave from the blast started travelling outwards and what we’re left is the remnant SNR 065.2+05.7. The intervening time has the remnant spanning about 70 parsec and subsequently it’s very faint.
This is my second attempt at one of the brighter filaments of this structure, Sharpless 2/91 and comprises 6 hours of 10 minute exposures. It’s reproduced here at 80% of the original image size.
The skies didn’t clear until 4am on Sunday during the weekend of the Breckland autumn star party at Haw Wood Farm. By then the winter constellations were rising and this posts subject makes an early appearance this year.
I’d gone equipped with the Astrotrac and Canon 75-300mm zoom lens. Using this with the QHY9 camera requires a Geoptik adapter between the two. As the focus adjustment on this lens is so sensitive I’d previously purchased a set of fine focus rings that clamp to the lens and provide a fine adjustment as well as locking the focus once achieved.
Before the sky got too light I acquired 11x 5 minute frames of the belt region of Orion along with some dawn sky flats. Processed in Pixinsight.
I attempted this object last year using the Zenithstar 70mm and resolved to make another attempt with more exposure and a darker sky. This year I’ve assembled a lot more exposure time (8 hours in 10 minute sub-frames) over several evenings using the Baby-Q. The location is still my garden though so I didn’t manage to find darker skies.
In part 1 we looked at getting a Pulsar dome to follow movements of the telescope when slewing from within Cartes Du Ciel. This time we’ll build on this foundation and add Maxim DL to the mix.
Recall from part 1 that both EQAscom and Shelyak dome driver have only POTH connected to them. POTH intercepts mount movements and calculates dome movements to match. This is required as the planetarium does not have the ability to connect to a dome.
Maxim DL does have the ability to directly control a dome so by connecting it’s dome output to POTH we can control the dome either via Maxim or the planetarium. POTH acts as a hub enabling us to connect more than one program to a single device. The telescope device EQAscom also acts as a hub and multiple programs can be connected to it so we’ll select EQAscom directly as the telescope device in Maxim. The main reason behind this is that we can’t use pulse guiding if Maxim is connected to POTH; it must be connected directly to EQAscom. In addition, as we’re sending dome commands from Maxim we don’t need POTH to intercept mount movements.
All of the dome slaving measurements that we made previously have to be entered in Maxim as well from the Options button on the dome tab of the observatory window. The setup screen specifies inches as the unit of measurement but this is not important provided the same unit is used for all values within this screen. Don’t forget that the dome size is specified here as the radius and not diameter.
The telescope type should be set manually as German Equatorial and the pier side as ASCOM Normal. These setting are available from the observatory setup tab’s Options button.
The dome home azimuth can be set but leave the sync option unticked as the driver will do this for us.
And that’s it! Additional programs can be connected provided you follow the same rules as we’ve adopted here for Cartes Du Ciel and Maxim. If you’ve entered all of the measurements and the home azimuth position accurately then the dome should follow the telescope as it slews and tracks around the sky driven from both Maxim and your planetarium program.
Having recently worked through the issues of slaving a Pulsar dome to a telescope and helping someone else through the same process I thought it would be useful to document the setup here. I have an Avalon Linear Fast Reverse mount but from a software point of view this is identical to an EQ6 and I use Maxim DL for image capture, CCD Commander for automation and Cartes Du Ciel as a planetarium. With a few peculiarities, the setup is applicable to other programs that you may be using.
The first step is to run the Shelyak Test_DomeTracker.exe program. This is supplied on the CD and you’ll need to run ‘Do Calibration’ several times. What you’re looking for is that the number of steps per rotation remains very similar from run to run. Any large differences here means that mechanical problems are causing you to lose steps. This must be rectified before continuing. Make a note of the number of steps per rev and acc/decc steps obtained.
Next up we need to run POTH which is available in Scope-Dome hubs under the Ascom Platform 6 program group. We need POTH because we can only connect one program to the Shelyak ASCOM driver. With POTH, we connect it to the dome driver and then connect our other programs to POTH. There’s a fair amount of information to add to the dome setup screen and it will require some careful measurements of your mount and pier and it’s position within your dome. Within POTH, click Setup. If dome data isn’t displayed then press Dome>> to expand the screen.
Click ‘Choose Dome’, select the Shelyak ASCOM dome driver and click Properties.
Enter your COM serial number, then look at the Dome Azimuth settings. Enter the values you obtained from your calibration runs, your best guess for the home azimuth position and the dome diameter (in metres). Now we need some measurements from your dome and mount so a tape measure will be required.
All measurements are made from an imaginary point at the intersection of RA and DEC axis on your mount. This will be inside the body but make an estimate of it’s position. From this point make the following measurements:
- Any East-West offset referenced to the dome. Usually this is zero but check to make sure
- Any North-South offset, again referenced to the dome. If there’s any offset, it will usually be to the south so this will be entered as a negative number
- The height of the intersection above or below the base of the dome hemisphere
All these measurements are made in metres and are entered in the relevant dialog boxes under ‘Telescope position wrt dome’.
You’ll need one more measurement; the distance between the intersection and the optical axis of your telescope. Don’t forget that a top mounted guide scope will significantly increase this distance. This is entered as the German mount offset and you’ll also have to set the mount management here as per the illustration above. Click the OK button
Once all this information is entered you’re most of the way there. Now we check the home position azimuth that you entered.
Start the test_ASCOM_DomeTracker.exe program from the CD, check the Setup dialog to ensure the information you entered is all correct and then Connect.
Park the mount so it’s pointing due north and using the Actions buttons in the program ‘Find Home’. The dome should move to it’s home position with the silver tape in front of the sensor. Next Slew to AZ 0 degrees and the dome slit should end up directly in front of the telescope. Failure at this point indicates that either your tick count or home position is incorrect. As you’ve carefully made multiple calibration runs earlier we’ll assume it’s the home position. Using the setup dialog, make an adjustment to the home azimuth setting and re-home the dome. Slew to AZ zero again and compare the dome position to the previous position. Repeat this process until the dome slit stops reliably in front of the telescope when slewed.
It’s worth stressing here that you must get the previous stage setup and working reliably before moving on. The dome must reliably move from the Home position to North otherwise what follows will be an exercise in frustration.
With all this done the dome should be set and it’s time to bring the mount into play. Once again, like the dome, we will connect POTH to the ASCOM mount driver and then connect other programs to POTH. The reason for this is that POTH will intercept mount moves for us and command the dome to move as well to follow the telescope pointing. Using the POTH setup screen choose the EQ6 driver, setup and then connect. The screen should look similar to this:
Note that you need to enter your mount/dome measurements again in the Geometry section. Pay attention here as this time the dome radius is required in metres and all other measurements are in millimetres.
In your planetarium program (for this example we’ll be using Cartes Du Ciel) open the telescope dialog and select the POTH.Telescope driver.
In Part 2 I’ll look at connecting Maxim.