Almost one year after my first try to build an amateur observatory in my  garden  this was unfortunately discarded due to poor location both in light pollution and water log coming form a nearby golf course grounds. The current location is situated in Istan Mountain around 270m from the sea level and away from light pollution. I am installing the observatory using a Pulsar 2.2M (https://www.pulsarastro.com/).


Description


The Pulsar Observatory Dome provides a high quality, secure and practical housing for your telescope. Providing excellent weather protection for you and your telescope, it allows you to have your instrument ready for use at all times. Whether imaging or visual, having the convenience of a permanent set up adds greatly to your enjoyment of exploring the night sky.



The Pulsar Observatories 2.2 metre full height dome benefits from the following advanced features:

Finest quality, weather proof GRP finish

High quality locking system

Simple design for self assembly

Motorised dome rotation available

Motorised dome shutters available

Accessory storage bays available

Available in white or sage green (other colours - please call)

Dimensions:

Total Height approx 2.47 metres

Dome Diameter approx 2.2 metres

Door Height approx 1.1 metres

Dome Aperture approx 0.6 metres

Ideal for up to 12" telescopes and a variety of installations.
​
www.pulsarastro.com/

Next Step - Internal Equipment Installation

Dome Drive
​
The mounts will follow the apparent movement of the stars in a smooth arc: ideal for imaging, but through the course of the imaging session, the telescope starts on the west side of the pier pointing east and ends up on the east side of the pier pointing west. 
This non-linear pointing has to be accounted for to ensure that the telescope points through the dome’s aperture at all times, requiring some complex mathematics.
It is the job of the dome control software to do this for you.
However, to do this correctly, the software must know exactly where the telescope is mounted in relation to the centre of the dome, so your first task is to make some careful measurements to obtain the dimensions required.
Using the spreadsheet available below will make it easier to get all the dimensions correct and ready for insertion into your software.
Install the ASCOM software and enter the offsets from your spreadsheet, ensuring the correct signs (positive or negative), into your choice of control software – we used MaxIm DL and POTH (Plain Old Telescope Handset) and my personal choose is Sequence Generator Pro.
Once the above is completed, your telescope and dome aperture will be in sync.
 An example below using my AstroPhysics 1100GTO mount, the dimension is obtained from the mount (see below)

​

​Settings in 10Micron

Keypad and virtual keypad settings
Sync Refines OFF → A 2s ENTER press with object data displayed will SYNC the model on the object coordinates.
Sync Refines ON → A 2s ENTER press with object data displayed will ADD A POINT to the current model, with the object coordinates matched against the encoder readouts.

10micron official ASCOM driver settings meaning
Enable Sync OFF(KeyPad-PC) → All synchronization commands through the driver are disabled, so the model cannot be altered. Basically cannot be used for modelling externally.
Enable Sync ON (Keypad), Use Sync as Refine OFF (in setup PC) → The ASCOM synchronization command will SYNC the model on the given target coordinates.

Enable Sync ON, Use Sync as Refine ON → The ASCOM synchronization command will ADD A POINT to the current model, with the given target coordinates matched against the encoder readouts. (basically will allow model points to the model already model)

Per Frejvall's ASCOM driver settings
Sync behaviour "Syncs append to refine model" → The ASCOM synchronization command will ADD A POINT to the current model, with the given target coordinates matched against the encoder readouts.
Sync behaviour "Syncs align model" → The ASCOM synchronization command will SYNC the model on the given target coordinates.


Which settings should I use?

When building a model with the keypad, you will use the 2-Stars or 3-Stars alignment and Refine Stars functions. These works the same whatever the settings are, so don't worry about them.
1.   Using the HandPad do a 3-Stars alignment
2.   Using the HP do a Polar Alignment.
3.   Using the HP/PC do a new 3-Stars Alignment (given that after the polar Alignment the previous 3-Stars alignment will disappear)
4.   Using the HP/PC do 15 to 20 Refine Stars Alignment.
5.   Using the HP/PC save this model.

When building a model with a model building software such as Model Creator, Model Maker, Mount Wizzard,
6.   Normally you'll set "Enable Sync ON" and "Use Sync as Refine ON" on the 10micron ASCOM driver,

7.   or "Syncs append to refine model" on Per Frejvall's ASCOM driver.

In normal operation, usually you shouldn't resynchronize the model. If you connect to the mount with the 10micron ASCOM driver, you can prevent any synchronization through the driver by unchecking "Enable Sync" in the driver setting (note: this won't disable synchronization with the keypad, or with other software that connects to the mount with another driver).

If you have really to synchronize the model on a single star/object (please read above before deciding to do it), you can do it with the keypad (point at the object, centre it with the keypad, then, leaving the object data displayed, press ENTER for at least 2 seconds). In this case you must have "Sync Refines OFF" in the keypad.

If you want to synchronize the model on a single star/object (again - please read above before deciding to do it) with an external software via ASCOM, check "Enable Sync" and uncheck "Use Sync as Refine" in the 10micron driver, or set "Syncs align model" in Per Frejvall's driver.

Why synchronization fails?

Usually, the mount won't accept a synchronization or a refinement point if the coordinates that you are trying to synchronize are too far away from the coordinates the mount is believing it is pointing at. The exception is for QCI mounts before the alignment, which accept almost any synchronization except for positions near the meridian, where there is ambiguity on whether the telescope is west or east of the tripod - these positions can be pointed at with two different mechanical configurations. If you encounter such a situation, probably there is something wrong with your model - check that the right ascension axis is pointing at the celestial pole, that the clock is at correct (including timezone and daylight saving), that the site coordinates are correct, that the telescope is mounted in the correct position on the declination flange.
  

• First Step create two more copies of the image /2 new layers

​

With everything in place, I could finally take the mount out for the first time after a very long wait cause by moving house to a better viewing location. 
First, I wanted to try out the rough polar alignment with the green laser pointer on the scope, Although the laser light was weak, but I could see a beam weak but noticeable to align the beam to the North Star.

The 10Micron mount uses simple star alignments for polar alignment (3 stars for a rough alignment, a full model -20 at least for exact polar alignment), always using the hand control to select the stars , DO NOT use at this stage Model Makers or Model Creator.


One point, try to center the Polar Star with a view scope or Computer program like Maxim DL before you start any alignment, if not it will give you headaches. When the mount is not even nearly polar aligned it is difficult through a camera to center a star when it comes to the 3 or 2 star alignment, you will have to use your HC and view-scope to slew near the star.
Before polar alignment, I tried various of the 10Micron functions:

1. Balance check
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 0.00% off (everything below 0.04% is considered enough for good, stable imaging). For the DEC measurement, it was a bit of by 0.02, I measured the level with a bubble level and it was good, I then moved the weights lightly down measure it again and it was spot on.

2. Orthogonality (cone error)
From the various alignment points, the mount calculates the orthogonality error. In my case it was it was out by 12' 00", I realized that the mount bubble level was not dead center, I centered it by lefting of the tripot legs. Did another test and the Orthogonality error was reduced to 2' 45". Honestly I am not sure if this is within the parameters allowed.

3. The 3 Stars Alignment (prior Polar Alignment)
People say that the  polar alignment was fairly easy, NOT TRUE.

But before a polar alignment its recommended that you do first a 3 star alignment, you do this 3-star alignment from the mount Hand Control the 3 star alignment can be achieved relatively easy if you have certain things done prior.

• Balancing
• Orthogonality
• Rough but relatively pointing to the star
• Correct UTC /Computer time
• GPS or manually input the correct location.

If you have the above correctly input into the mount database then when slewing to the first star the mount position will be very near.

At this stage DO NOT GO TO Polar Alignment yet. The next step is to add more stars after you finish the 3 star alignment (10 is enough) to the pointing model of the mount  through the Hand Control.

4. Polar Alignment
Now is a good time to polar-align.
Pick the Polar Align procedure from the keypad and pick a star from a list. I picked one near the meridian and fairly close to the equator. This time you must not use the hand-pad to center the star, but use the mount alt/az adjustment knobs to do the centering. Press enter when done. That’s very nearly it - but not quite as the pointing model is not that accurate as you moved the mount physically with the adjustments, but not far off. So next step is do another 3 stars alignment.

From the keypad select 2-Star Refine and pick a star from the list, the GM1000 will slew to it, halt and beep when ready and you center the star in the reticule eyepiece or the PC Screen (I use Maxim DL)  continue shooting frames (every second) and center the star.

Keep doing this in the 'Refine' to build up say a 12 to 20 star model from stars spaced widely over the sky - you can build a max of 100 stars into your model which is more practical to do (time wise) in a permanent setup. After each additional star you are told what the RMS pointing error is, is everything is working well the RMS will reduce a bit with each Refine star centered.

I experimented in three nights to learn how best to do it and how fast it could be done and how good the results are and if further model building and polar alignment iterations improved things. I performed

1. The optimum solution trading time for accuracy was to 3-star align, then add stars to build at least a 20 star model in the HC/ mount software.
2. Polar align.
3. Then repeat the 3 star align a second time and again go for at least 20 all-over-the-sky stars.
4. Polar align a second time.
5. Finally finish off with a third 3 star align and 12+ "star refine" to build a final model.

I tested the un-guiding without being totally accurate (with an 11 RMS) and unguided with a 900 sec image with prefect round stars. (see below)

5. 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!!!​

​After using Photoshop for some years I always had this urge to try Pixinsight, as I always say, you learn something new everyday, and who knows I might develop my processing and advance further, I am not sure where I am going or what I will achieve, but whatever I lean or not I will recorded each step on the way.

When I open SI and I see all the different processing tools under 'All Process' and those under 'Scrip' and the first impression is wow, where do I start??, while in Photoshop, the frames are coming over already  calibrated (from third party software like PhotoStack2), in SI you have the option to do the calibration as well, or used a third party software to carryout this task and just concentrate on the processing the frame in PI, so this addition of extra menus its a bit intimating.
.
First before I start this adventure I will start off by describing the meaning of 'Image Scale' followed by some useful points about PI , why?, because this awareness will come handy later.


1.    Image Scale 

arcsec/pix=(pix size/focal length)*206.3


Is the angular area of each pixel can see, this is referred as 1 bin, so if we combine 4 pixels into a single pixel the are will increase by 4x = 2bin.


First Setup


A camera / telescope combination. Telescope with 106mm aperture and 530 focal length, this means a F5 (530/106). The camera chip 2750 x 2200 with 4.54 pixel size. The image scale of the pixel is 1.76 arcsecond/pixel and the field of view is of 80.98 x 64.79 arcmin


 Second Setup


Telescope 356mm FL is 2563mm therefore F7.2 will result of an Image Scale of 0.72 arcsec/pixel and Field of View of 48 x 33 arcmin with an FOV in degrees of 0.8.


So the best resolution of both combo is the latter with a 0.72 arcsec/pixel


2.  Loading an Image


When loading an image in PI in 32 bits, the computer will display it in 8 bits, do not reduce from 32bits to 8bit the images. Instead use the STF (Screen Transfer Function) to stretch the images to see it better on the computer screen.


3.   PI is divided into two main sections for processing.


On one side we have the Process and on the other the Scrip. In Process you can find all the tools provided by PI, and in Scrip are third parties software within PI developed by PI users.


4.   On the top screen modules/menus


On the top selections we have : File-Edit-View-Preview-Mask-Process-Script-Workspace-Window-Resources and if you scroll down there are quite a bit of extra menus.


We will skip these menus for now.


5.   Inside PI (whole)

The software is divided into 4 sections - Preprocessing, Linear Post Preprocessing, Nonlinear Post-processing and Special Processing




Part 1

Pre-ProcessingThe processing of an image can be achieved by using the processing tools, if you click on the 'Process' and then <all process> you will open the screen below.






​

















​After a night of imaging you are exacting but also aware that not all the frames would be use for calibration for different reasons, previewing them can be achieved in PixInsight. Most processes can take quite a bit of trial and error to get the right settings and fine tune them for the optimal result. We run these processes on previews so that it is much faster see the effects compared to running it on the complete picture. Furthermore, we can use multiple copies of the same preview and apply the process with different settings so we can really compare the results of our fine tuning in great detail.


One of tools that unable preview your frames is 'Blink', it will preview a set of images. Open the images with the small folder in the Blink dialog window.

If your are setting the Star Detection and Fitting and these settings are inadequate, the console will report failure, leave the setting as default it works perfectly, but before hitting the  measure button, if you feel that you can enter a formula into Expressions/Approval to automate the grading process, do so, if not do not worry. Finally click measure, and the  Process Console   will appear as the script does its calculations.

Tables


The Table at the bottom , shows the finding calculation Note, you can change the field of interest, three of the main and basically used by many astrophotography are: the images’ signal to noise  ratios  , choose SNRWeight (noise), and in descending, if the SNR reading is higher-this is a good thing. 

If your choose on the Full Width at Half Maximum (FWHM) of the stars in the images, remember if the file at the top of the list would have the highest FWHM value—this is a bad thing. You might therefore switch to ascending order, placing the file with the smallest/best FWHM on top to make that category easier to read. 


FWHM measures star size/spread whereas eccentricity measures shape in terms of how out of round the star are.


Formula into Expressions/Approval 


Limits -Minimum and Maximum settings 


Eccentricity 
For eccentricity <=0.4 is considered 'round', if anything  from 0.4 to 0.49 will be acceptable,  if generally stack anything <0.55 and  above 0.55 and start to get picky and choose, it all depends how many frames you have to play with. For example if they're mostly 0.4 to 0.5 you can select with assurance and toss away any outliers that are above that, I would reject anything above 0.6.




FWHM
FWHM is a lot harder to be so absolute about, as it largely a factor of the seeing. On a really good night a seeing <3", but a 5" is considered poor. As such, for FWHM I tend to work in relative terms within the available frames I have for a target rather than absolutes. FWHMSigma is a good approval term to use for this and I'll typical approve frames that lie within 2 sigma, so an approval term of FWHMSigma < 2.

To sum up a typical approval expression I'll use for these factors in SubframeSelector will be:
Eccentricity < 0.5 && FWHMSigma < 2


[What I am saying here is I will only accept those frames with FWHS that lies with 2" and Eccentricity with a 0.5 value or below, any frame above any of these two parameters will be automatically rejected.]

• Smaller FWHM values are better.  I’ve also restricted the list by the Eccentricity and Noise metrics.  
• Noise is fairly straight forward, the higher the noise level the more difficult it is to discern your target, so again, lower values are better.  
• Eccentricity is a measure of how far from round a star is.  If a star is very elongated it will have a higher Eccentricity value, so it is also better to have lower values here.

The weighting is more complicated. Basically its means that you need to use one of the three weighting (SNR-FWHM or ECCEN). When applying the weighting to one of the three, first it will be based upon it own parameters--if you use FWHM as your most important factor to build the expression. If Eccentricity is more important to you than FWHM you can change the weightings in the formula.  

If we take the expression below (provided by....) and we take my reading below under FWHM its ranges from 3.05 to 3.6, so I  want to use a maximum value of 3.05 (<3.05) not further then this, so I put in the first part of the expression (3.6-3.05). For the Eccentricity range 0.534 to 0.511, and for the Noise its 0.736 to 0.707.


The numbers in front of each factor is based on 50 (50 frames), if you are interested in having a good FWHM (better resolution to rounded stars) you will have a higher value (30) in front of the equation. This is what the 30, 5 & 15 values are for.  If you were less concerned with resolution and wanted rounder stars with a better SNR then you might weight FWHM lower and Eccentricity and Noise higher.
  
            Most important                          Second most important                     lease important
(30*(1-(3.6-3.05)/(3.60-3.05)) + 5*(1-(0.534-0.511)/(0.534-0.511)) + 15*(1-(0.736-0.707)/(0.736-0.707)))

This expression will be reduced to:


(30x(1-(1))+5x(1-(1))+15x(1-(1)) = 30+5+15=50

​The mount is mechanically looks stable, the instrument payload capacity is 25 kg, my equipment will not surpass this weight, so I am confident that it will preform well.  The electronics is placed in an removable, independent control box, which is quite handy as it can be fixed if necessary without touching the mount. The GM1000 HPS can be controlled by using the hand pad without any connecting to an external PC, this is actually better them my other mount the AS1100gto,  also, the mount can be controlled by using common software by connecting it to a PC via RS-232 serial port, Ethernet or WiFi. I personally prefer the Ethernet connection.
The object data base contains a lot of different star catalogues and deep-sky-objects up to the 16th magnitude. It is possible to load orbital elements of comets, asteroids and artificial satellites. HPS stands for High Precision and Speed. With the help of ultra-high resolution absolute-encoders, directly mounted at the right ascension and declination axis, the 10micron GM1000 HPS allows a very accurate tracking.

For the standard alignment I have taken the following procedure before using an external pointing model like for example, Model Creator.
Quick setup and alignment checklist (GM1000HPS)

1. Disassemble the base adapter from the mount unscrewing the four knobs.
2. If you have a Baader AHT or 10Micron 30H100 by Geoptik tripod, assemble the tripod adapter on the tripod.
3. Mount the base adapter on the pier/tripod, paying attention that the protruding block is southward if you are in the northern hemisphere, northward if you are in the southern hemisphere.
4. Put and lock the mount on the base adapter.
5. Adjust the altitude of the R.A. Axis to match roughly the latitude of your observing site.
6. Mount the counterweights and the telescope OTA.
7. Turn on the mount.
8. Balance the telescope following the procedure detailed in the manual.
9. Check that the observing site coordinates and time are correct. You can use an optional GPS module to obtain these data.
10. Clear the previous alignment using the Alignment→Clear align function from the menu.
11. Choose from the MENU: Alignment→ 3-Stars.
12. Choose one star from the list and press ENTER.
13. Press ENTER to confirm the slew to the star; then centre the star with the maximum precision (a high-magnification eyepiece on your main scope, without diagonal mirrors, is preferable) and press ENTER again.
14. Repeat steps 12. and 13. for two other stars.
15. At this point, the mount will point correctly, but if you plan to do any photographic observation, you need to adjust the polar axis position. Choose from the menu:

            Alignment→Polar Align and select a star from the list.
16. The system will ask to slew to the star. Press ENTER to confirm. The scope will miss the star. At this point DO NOT centre the star with the keypad; use instead the altitude and azimuth mechanical adjustments until the star is centred. Then press ENTER.
17. Do another 3-Stars alignment by repeating steps 10. to 14..
18. If you like to have a better pointing and tracking precision, select from the menu: Alignment→Refine 2-stars to add stars to the pointing model (up to 25 stars in total can be used). Note: for the best result it's necessary to use more then 10 stars.
19. You can check the orthogonality error and polar axis alignment error by selecting from the menu Alignment→Align Info. Note that orthogonally error does not affect the pointing precision or tracking.


The above quick standard polar alignment is reached by aligning the mount to the north aligning on three stars. By adding more alignment stars the model is refined. An estimate of the expected pointing accuracy is shown on the hand controller after each additional calibration star is inserted.

The usage of a pointing model up to 100 stars allows the correction of the classical polar alignment and conic errors, also the most important flexure terms of the telescope. With the help of a good pointing model it is possible to obtain a pointing accuracy of 20 arcseconds RMS.

10 Micron GM 1000 HPS take three stars and have an ability to do a high quality polar alignment. It normally takes about 15-18 stars on the GM 1000 HPS to generated a polar alignment of 30 or so arc seconds accuracy. After an observing session, the entire electronics box (motor electronics with Linux computer) and HC can be easily detached and protected from premature aging and moisture damage, especially in winter weather.

A virtual key-pad on PC is available for remote control.

Model Creator Program

​Ideal to creat a map of your sky and pass the information to the mount

Dark, Bias & Flat images looks,

The first step in calibration is to prepare a bias frame. A bias frame is basically an image taken with the shutter disabled. The image will consist only of read-out noise and noise caused by interference of the computer.

What a bias frame does is set the zero point of the CCD output and the pixel scales to the same value. This makes the final image more accurate since the zero points are equal and no
nonlinear pixel values exist.

A bias frame will also take into account thermal current that collects while the frame is being
downloaded to your computer.

Note: If one uses darks that are the same duration as the light frames, bias calibration is
unnecessary because it is included in the dark data. Bias frames are only required If one
intends to scale their darks.

Taking Bias Frames

Not all CCDs can take pure bias frames. Some CCDs just are not designed to take an exposure
without using the shutter. In those cases you can simply skip the bias frame and go straight to
the dark frame (which will include some of the same data as the bias frames) or you can make a
psuedo-bias by taking an exposure with the shutter at the shortest possible exposure length and
your system completely blocked of any light.

If your camera can take a bias frame, it is likely already setup in your software. A bias frame is a
0 second exposure, at the same temperature.

 Dark Frames

A dark frame measures the thermal readout of your CCD, a.k.a. its
temperature. A dark frame is an exposure where the shutter is
opened but no light is allowed to hit it so it only measures the
energy from the CCD itself (dark current). This is normally done by
placing a dust cap on the telescope and then covering it with a
blanket, cloth, or something opaque to light. Darks also compensate
for hot pixels, which are defects in the CCD chip that makes pixels
look like they are permanently "on" or "lit". Darks are very easy to
take and are the most important calibration step so there is no reason not to take darks.


Taking Darks
The Handbook of Astronomical Image Processing recommends the "Image-Times-Five" rule. Page 142

The more dark frames you take, the more accurate the frame and the lower the noise
.
For a sample of 100 electrons, the uncertainty is 10%, for 10,000 it is 1%. , so at lease 10 Darks Frames

A good rule of thumb is to make sure the total exposure time of all your dark frames equals five times that of the image you are calibrating.

So if you are taking a 2 minute image of expose time.
 you can do 5 x 2 minute darks or 10 x 1-minute darks.


Example: 120 sec x 10 frames = 1200 sec  or 20 mins ,

The Dark would be   20mins x 5 = 100mins of dark!!!

                                                                                    Total : 120mins
        

If the numbers of frames is 10 mins x 100mins = 1,000 mins = 16 hours
                                 5 x  100mins =   500  mins = 8 hours

A night observation = 20 mins L + 20 Mins R + 20mins G + 20mins B = 80mins + 100min Dark
Total 180Min or 3 hours

I am using only one filter time exposure to calculate the dark frames , in this case L20 mins (20 x 5=100), and the total of the 4 filters


Inspect each frame to make sure that cosmic ray events do not contaminate them. They will appear as a bright spot
on your dark frame. It depends on altitude, physical size of the CCD chip, and exposure time but in general expect
about 1 cosmic ray event every few minutes of exposure time. When you have a bunch of darks, average them together to create a master dark. (You can skip the cosmic ray inspection by median combining at least 3 frames instead of averaging them; but then your final dark will have slightly more noise.)

Tip: It is possible to create a library of dark frames for different temperatures and operating environments.

However, these dark frames will never be as good as ones you take during the observing session.
Experiment with your own system and see how a library of darks affects your final error and then decide
whether the savings in hassle is worth it for your current project.