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Equipment
Overview
My current imaging setup consists of  an 8" F/5 Skywatcher Blackline Newton (BKP2001) mounted on an Skywatcher NEQ6 pro Syntrek. The mount is controlled from PC/Laptop using an EQdir-like interface cable and the freeware planetarium program Cartes du Ciel. The main imaging camera is a self-modified (Baader ACF) and peltier cooled Canon 350D using a Baader Multi Purpose Coma Corrector to battle the coma that accompanies fast Newtonians. Focusing is provided by an Arduino based DIY PC-controlled stepper motor in combination with a bahtinov mask. The setup is guided through an 9x50 finder guider coupled to an QHY5 guider camera. Images are aqcuired with Nebulosity 2 software, and autoguided using PHD software, both from Stark Labs. Focusing is performed with a bahtinov mask and the SGL stand alone focusing software, or with SGL ASCOM driver/Focus max software. Mount control and goto is provided by the EQASCOM/EQmod software and a planetarium program. Plate solving is caried out using AstroTortilla, to improve goto accuracy, and object framing on multiple imaging nights. Data reduction is performed by the excellent freeware program DeepSky Stacker 3. Post-processing is done using Photoshop Creative Suite 3, with several additional plug-ins, including Russell Croman's GradientXterminator, Hasta La Vista Green, Noel Carboni's Astronomy Tools, and Annie's Astro Actions, which greatly reduce some of the post-processing steps.


Imaging OTA: Skywatcher Black Line 8" F/5 Newtonian reflector/MPCC
The main imaging OTA is a Skywatcher Black Line 8" F/5  Newtonian Reflector, with the following specifications.
Manufacturer: SkyWatcher
Optical Design: Parabolic Newtonian Reflector
Primary Mirror Diameter: 200 mm
Focal Length: 1000 mm
Focal Ratio: F/5
Secondairy Mirror Diameter: 52 mm (Minor Axis)
Tube Dimensions: 240 mm Diameter, 920 mm Length
Tube Weight: 8.75 kg
Focuser: 2" ball-beared Crayford focuser
Limiting visual magnitude: 14m2
Resolution: 0.6 arc sec
Remarks: Mirror substrate similar to Pyrex
Thin spider vanes for more contrast
Diffraction-Limited System
To compensate the coma present in these types of fast Newtonian reflectors, a Baader Multi Purpose Coma Corrector Mk II is used.
Mount: Skywatcher NEQ6-pro Syntrek - EQdir/EQmod/CdC goto


The workhorse to support and move all the imaging equipment accros the sky, is probably the best reasonably priced mass-produced mount around, the Skywatcher NEQ6-pro (or Orion Atlas EQ-G). Details as specified on the Skywatcher site:

Mount Type: German Equatorial Mount
Tripod: 2” Diameter Stainless Steel Pipe
Tripod Height: 85 - 147 cm
Tripod Weight: 7.5 kg
Counterweight: 2 X 5.1 kg
Mount Weight: 16 kg (without counterweights)
Mount Height: 41 cm
Total Weight: 23.5 kg (counterweights not included)
Motor Type: Microstep driven 1.8 degree stepper motors
Motor Resolution: 0.144 arc sec (or 9.024,000 steps/rev.)
Gear Ratio: 705
Power Supply: 11 to 15 V DC 2A (Tip positive)
Max loading rate: approx. 40lbs (recommended)

Only problem with this mount, is the easy bending altitude ajustment bolts, which aren't produced of stainless steel. On the top left side picture, as well as other shots of the mount on this page, they have been replaced by stainless steel threaded bars and 2 nuts. Problem with this, is that the stainless steel will start to eat its way into the softer aluminium and will tear up the threads in the pedestal. I have solved this by putten stainless steel end caps on the threaded bars and also installing an extra pivot the reduce strain on the altitude bolts.
Imaging Camera: Self-modified Peltier Cooled Canon 350Da
The main imaging camera is a self-modified Canon 350D. It has been modified by replacing the standard UV/IR cut-off filter by a Baader ACF filter, which allows about 5 times more H-alpha light to pass through to the sensor. In addition, a peltier based cooling system has been installed to reduce dark current. Although this cooling system can cool the CMOS to about 28C below uncooled working temperature, the daily practice is to cool to about 5-10C below the expected dew point for the night. This is mainly due to condensation forming inside the camera on the Baader ACF filter due to contact with warmer, moist air, despite having a dew heater mounted in front of the shutter to warm the air between the MPCC and the filter. Another problem I'm still having with this cooling system during freezing winter conditions, is that it distorts autoguiding when in operation. This is not such a big issue, as dark current on these winter nights is much lower anyway, so no cooling is required. I then do use the cooling system to take dark frames during the daytime, so no precious dark time is lost on taken long compensation frames. I've not attempted to create dark frame libraries, as in my opinion, the noise patterns changes to rapidly over time, and it is easier to take fresh darks for each imaging session, although I do recycle dark frames from consecutive nights.
Autoguiding: 9x50 Finder guider/QHY5

Shown to the left, is my autoguider setup, consisting of a standard Skywatcher 9x50 finder, mounted in a Baader Multipurpose Quick Release III finder bracket. This bracket has been slightly stripped and modified for direct mounting to the telescope rings of the 200 mm Newtonian. A QHY5 monochrome guider camera is mounted to the 9x50 finder by a special parfocal mounting ring that was originally supplied as a separate item or as part of the KWIQ guider package from KW-telescope in Canada, but can nowadays also be purchased from for instance Telescope-Service in Germany. The QHY5 guide camera has an Micron inch MT9M001 CMOS sensor , with a pixel size of 5.2um x 5.2um and 1280x1024 active pixels. The peak QE is 56% and has a USB 2.0 port. It supports both ST4 and ASCOM/EQmod based guiding protocols and from my own experience I have to say both work excellent.
Power supply: 2x 13.8V DC 6A (8A max surge)
Power is supplied  by 2 13.8 V DC PSU with 6A max output. One supply powers the NEQ6, Canon 350Da camera electronics, and the DIY EL panel when taking flats. The second PSU powers the Peltier Cooling System for the Canon 350Da, the Arduino Motor Focuser, and Dew heaters when needed. On the right side the Temperature Controller for the Peltier Cooling System on the Canon 350Da is shown with its 2 PWM adjuster knobs and the Canon 350Da dew heater channel below them. Left of the Temperature Controller, the Arduino Focuser Controller is shown.

The project box that is attached to the mount houses the 12V-8V DC power converter circuitry that powers the Canon 350Da.
Motor focuser: SGL developed Arduino-based Stepper Motor Focuser

To aid in perfect focus, the need for a precision motorized focuser is mandatory. However, commercial products can cost several hundreds of euros. I have therefore build my own stepper motor based focuser based on a superb design made by several English amature astronomers on the Stargazers Lounge (SGL) astronomy forum. Its strength is that it hardly requires any electronical knowledge, or programming skills for the PIC used to control the stepper motor. This is realized by using an Arduino Uno board controlling an easyDriver stepper driver board that in turn controls the stepper motor. The only connections that have to be made, are between the easyDriver and stepper motor (4 wires, 2 for coil A, and 2 for coil B), power to the easyDriver/stepper motor (2 wires, power and ground), and between the Arduino Uno and easyDriver (4 wires, Step, Direction, Ground, and Power down). The most work is the mechanical connection of the stepper motor to the focuser shaft, and mounting of the stepper motor to the telescope/focuser. I solved this by using a flexible shaft coupler and some spare copper plating I had lying around. Controlling the motor focuser by computer is really straight forward, as the people from SGL have made and excellent Arduino sketch combined with both a stand alone software solution, as well as an ASCOM driver. In the accompanying documentation, a clear step-by-step walk through is provided to install the Arduino sketch and how to configure the SGL software. It performs flawlessly, with only minor adaptations to be made to the Arduino sketch (direction) and SGL software (speed setting).
Flat fields: DIY Laptop backlight based EL-panel
Another item that is a necessity for quality astrophotographs is a flat field source. My first attempt at this was a light box using for warm white light LEDs, whose light was diffused by three layers of drafting vellum. However, with the moist conditions in The Netherlands, these diffusers got somewhat wrinkled and that distorted the flats, creating all sorts of optical problem when calibrating light frames and stacking. So my current device is based on the idea of the commercial Electro Luminescent (EL) panels, but made from an old laptop backlight. This idea was posted by another English amature astronomer on SGL, and basically consists of the backlight and a small electronical circuit to activate it. This is needed as to save power in the laptop, the backlight is only switched on in the presence of a VGA video signal. In fact the VGA signal sends a signal pulse of between 2-5V DC to the signal pin on the inverter board that powers the backlight. So the circuit supplies the inverter with both 13.8V DC power, and this signal, which in my case is 3.3V DC. The only problem which I still need to solve, is to reduce the brightness of the EL panel, as it is currently too bright leading to irreproducible flats, as I have to use very short exposures (0.003 sec). This will hopefully be solved by putting one or more layers of transparent white perspex plating in between the telescope and the EL panel.

Storage and Transportation: DIY Flight cases

To store my gear during the many cloud filled days in The Netherlands, I build these flight cases to safely store, and move my gear up and down the stair case for each imaging session. As a convenience, I can also take my gear on the road without any problems. The inside of the casings is covered with foam, to keep all the gear save, and in place. The large case holds the 8" Newton, PSUs, Canon 350Da, peltier/camera dew heater controller, 9x50/QHY5 finder guider, cables, game controller, Arduino focuser controller, dew heater controller, and bahtinov mask. The smaller case holds the NEQ6-pro head, counter weights, tools, and anti-vibration pads. The tripod is stored separately. Besides the advantages, the only disadvantage is the weight of both cases, 42 kg (large case), and 36 kg (small case), which is just manageable by me.  When the flight cases are not in use for storage, they double in use as PC and PSU tables. This works great and saves me the trouble of having to bring extra tables for this. Also in the field, as I power the PSUs with 230V AC,  provides an extra meassure to ensure the PSUs to come into direct contact with the moist ground/grass, which is usually the case in The Netherlands.

Weather protection between imaging sessions
For protection of my gear in between imaging sessions, or during star parties, I use this cover from GEOPTIK. Although it is not intended for year round protection like a Telegizmos 365 cover, it does provide good protection for unexpected rain fall if I leave my gear setup for another night of imaging. The mylar like reflective material on the outside also keeps the heat of the sun out during sunny days.

For the future, I'm planning on realizing an observatory on our second floor balcony. This will truly be a very small structure that will only cover the mount and scope/camera. The control PC will be located indoors, and will likely be remote operated from elsewhere inside our home. Plans and construction will follow elsewhere on the is site when preparation/building will commence.






Software

Nebulosity is a nicely priced piece of software that is suitable for camera control, image calibration, and some image post-processing. Although it is currently in its 3rd major release, I still use version 2, as up to now I have not used the pre-processing routines that much.
PHD guiding is a relatively easy autoguiding application that has a very straight forward user interface, that lets you start guiding in 5 mouse clicks, although several guiding parameters have to be fine tuned off course.
DeepSky Stacker is a very powerfull piece of freeware for image calibration and some minor post-processing. It has a user friendly interface and provides excellent results.
Photoshop CS3 is a well known and powerfull package for post-processing, although it comes at a price. Luckely, I can obtain a full license at only a fraction of the normal retail price,due to my daytime job at a university medical center.
Russell Croman's GradientXterminator is a very powerfull add-on for Photoshop, that is an absolute need in the light polluted Netherlands. Without it, it would be a nightmare to manually remove the gradients from my home taken images.
Hasta La Vista Green is a plug-in written by Rogelio Bernal Andreo (www.DeepSkyColors.com) that removes incorrect green hues from astronomical images that is based on the SCNR Average Neutral algorithm in PixInsight.
Noel Carboni has written a lot of usefull actions for Photoshop that shorten a lot of manual Photoshop work specifically for astronomical image processing.
Annie's Astro Tools is another excellent action set for processing astronomical images, for both beginner, and advanced astrophotographers.

All content on astrovirus.nl 2010-2013 by T. Schuurman