Foton Pharming from FRO





FROG ROCK OBSERVATORY - GSTAR-EX DEEP-SKY VIDEO CAMERA

On our property was an old wheat silo which I converted into an astronomical observatory. It became operational in 1984. In 1996 a nasty storm ripped the old roof off. In 1999 I rebuilt a new flat-top 'dome' and installed it with help from a couple of mates, Pete Hartnett and Steve Pocock.

FRO, Earth shadow and 13 day old Moon


The observatory is 5 metres high and 4.2 metres in diameter with 2 stories.
Down stairs was used for storage but is now a library and display area.
In August 2013 I built a new set of custom stairs to match the curve around the wall and an extra tread to make the climb a bit easier.

The name of the observatory comes from a nearby landmark, a split rock boulder in the shape of a crouching frog.

My sister-in-law Sue, created the emblem for me.

The sign was made for me by overseas visitor Oded Averham and friend, Trish from WA.


I've bought and built several telescopes over the years up to a 31cm reflector for deep-sky imaging and a 45cm for visual observations (listed below). Over a period of 10 years, I took several hundred astro-photos on various hi-speed 135 mm colour print films through a 25 cm f/5.8 reflector on a Samson mount (left) and later a 31 cm f/4.5 reflector on a (very heavy) Parks mount (right). In 2006 I started using a GSTAR-EX Deep-sky video camera for imaging and other observations, including asteroid occultation timing, asteroid and supernova coordinate measurements (astrometry).

After 21 years service, I retired the Parks mount and purchased a Skywatcher EQ 8 from my mate Steve Massey at AstroShop in December 2013. I adapted the old pier so the new one could be clamped inside it and still use the new adjustment functions of the EQ 8. It can be easily taken out if required and used elsewhere on its own heavy duty tripod. I still have the same 2 telescopes as above (31cm f5 and 20 cm f4) but only have one mounted at a time. Swapping over is pretty easy with the dovetail bracket.

The tracking was very good straight out of the box and even though it has PEC, I have not needed it when using the GSTAR video camera system.
I haven't used a goto system before but have found the EQ 8 synscan controller to be quite intuitive to operate. It is a real pleasure being able to drive the scope around or just enter objects into the hand controller and have them appear on the video monitor. After a couple of years use, I am very happy with this new equatorial mount.


 

GSTAR-EX DEEP-SKY VIDEO CAMERA

What an amazing tool for astronomy.


This camera is capable of delivering live views of deep-sky objects on a PC or TV monitor in real time, fainter than the eye can see through the same telescope. It can produce images of everything from lunar and planetary to deep-sky objects without the need for fine guiding. It gives instant feedback for focusing and can do event timing observations with millisecond accuracy. After using this camera for well over five years, it continues to astound me. It is simple to use, plug it in, turn it on and start observing. This camera shows an image live on the screen that reveals much fainter stars than can be seen even with good dark adaptation through the same scope. The camera achieves this by having a very sensitive CCD chip and summing up to 128 video frames internally before updating the screen output every 2.56 seconds (max integration). It also has a wider spectral sensitivity then the eye, ranging from 350 - 1100 nanometres. When using this camera for imaging, I can now see immediately how the targets are focused, framed and how the subject looks live on the PC monitor. I use GSTAR-Capture software (see below) to record video files direct to a PC via a USB capture device. Accurate guiding is no longer needed as video frame stacking software like Registax can easily compensate for a small amount of image drift when stacking the video file later.

The examples below show screen grabs of the live view of Messier 42/43 and NGC 1977 nebula through a 20 cm f/4 reflector.The GSTAR camera is set to full integration of X128 sense-up and maximum gain. Because the camera is not actively cooled, on hot nights a few hot pixels can be seen. The hot pixels are easily be removed when creating images by subtracting dark frames in the stacking process. The camera can reveal faint objects even when the Moon is bright in the sky, or from light polluted city skies because of its sensitivity to a broad spectral range. In particular the red end of the spectrum, extending to 1100 nanometres (1.1 micron) which is way beyond our visual range of 700 nanometres.

See here for my latest mosaic of Messier 42/43 and NGC 1977.

These screen grabs on the right show the Horse Head Nebula, a very difficult target visually, but it is easily seen in the live view using a 20 cm f/4 reflector.
See here for my latest mosaic of the Horse Head.


Want to know more about video imaging the Deep-Sky?
Have a look at this book, co-authored by Steve Massey and myself, on this very subject.

Deep-Sky Video Astronomy


Cropped section of a live screen grab of Messier 57 through my 31.5 cm f/4.5 reflector. Arrowed star is 16.1 magnitude.
Typically, stars down to nearly 17th magnitude can be seen live on screen, depending on the sky conditions and seeing.
A stack of 100 x 2.56 second frames, with dark frames removed, reduces the noise and makes the stars and detail much clearer.
More frames and further processing will reveal even more detail.


Looking at the Crab Nebula (Messier 1), the 16th magnitude neutron star/pulsar can be picked out in this screen grab of the live image from the computer monitor, it's the fainter of the close pair near the centre of the nebula.

My computer monitor is a 19" LCD, so the borderless, full screen, live view image is much bigger than what you see here and it is this view that continues to amaze me every time I use the GSTAR-EX camera.

Turning up the contrast and brightness in the capture software, faint stars and nebula can be seen more easily in the live view but the noise is also exaggerated too.

The pulsar is quite obvious now. I use this mode when searching for faint objects
and I can identify almost any target on screen.

After stacking 400 x 2.56 second video frames, virtually all the noise is eliminated and then boosting the brightness and contrast levels, much detail is revealed.

By adding exposures taken through Red, Green and Blue filters to the Luminance exposure, you can produce a colour image.

The Crab in motion.

At the suggestion of Steve Massey, I imaged the Crab on Jan 16th 2018 and compared it to my image from 2006.

To my amazement it did show some changes in the nebula and filaments.

The images also shows a magnitude 8.3 star with high proper motion in the upper right - HIP 26240 aka G 100 - 20, moving about 0.25"/yr.


GSTAR-EX Capture V4

A great piece of free software for image capture with the GSTAR-EX camera has been developed by Steve Massey and Chris Wakeman.

 Features include:
Most importantly... the ability to capture at the correct frame rate with no repeat frames, progressive mode de-interlacing for a smooth output and live image, borderless full screen view, guide cross hairs, point and zoom for focusing, countdown timer, snapshot grabber, object database and many other tools.

This software continues to be enhanced, so visit the GSTAR-EX page at AstroShop for the latest version.

For many other fine examples of lunar, planetary and deep-sky imaging done with this camera see Steve Massey's personal website.

Also, see what other users are doing with this camera, GSTAR-EX users image gallery.

 * A review of the GSTAR-EX appeared in the
July/Aug 2007 issue of Australian Sky&Telescope magazine.


My telescope history:

Diameter - FocalRatio - Type - Mount - Brand - Bought/Made - Comments

60 mm - f/11 - Refractor - Alt-Az - Amasco AT-7 - Aug 1982 - My first. Later used as guide scope on 150 mm. Give away

150 mm - f/5.5 - Reflector - Vixen Mk II Equatorial - AO OTA - Oct 1982 - Going photographic. OTA now disused

250 mm - f/5.8 - Reflector - Dobsonian - AO mirrors in home built mount - Feb 1983 - Got aperture fever. Later used in FRO, then in Dob and sold.

75 mm - f/15 - Refractor - Lens in cell Home made into guide scope - Oct 1983 - Used with 250 mm in FRO

New Equatorial AO Samson heavy duty mount - May 1984 - For FRO

150 mm - f/9.3 - Reflector - Mirror kit Ground, polished and figured - Oct 1988 - In home-made Dobsonian mount (sold in 1991)

200 mm - f/5.1 - Reflector - Mirror kit Ground, polished and figured - May 1990 - Made for a friend. Bought back in 2009 put in Dob mount (sold in 2011)

315 mm - f/4.5 - Reflector - Mirror kit Ground, polished and figured - Jun 1991 - Replaced 250 mm in FRO. Later used in Dob mount

315 mm - f/5 - Reflector - Parks mirror on heavy duty Parks EQ mount - Nov 1992 - Bought from friend. Used in FRO

200 mm - f/4.8 - Reflector Mirror kit Ground, polished and figured - Feb 1993 - Imaging system with 75 mm guide scope (sold in 2000)

200 mm - f/6 - Reflector - Alt-Az - AO mirror put in home built mount - Feb 1994 - Light weight ''stick'' scope for wife, Janet

GSTAR-EX Video Camera After a long spell, got back into astro-imaging - Apr 2006 - Used with several optical systems

80 mm - f/5 - Refractor - Tasco Starguide from damaged Tasco stock clean up - Mar 2007 - Used in FRO

200 mm - f/4 - Reflector - Optex from damaged Tasco stock clean up - Mar 2007 - Used in FRO

200 mm (2) - f/5 - Reflectors - Dobsonian Binocular telescope. Mirrors and other parts from damaged Tasco stock clean up - Oct 2007 - Why not :-). Now in Hervey Bay

250 mm - f/6 - Reflector - Mirror kit from Joe Halloran Ground, polished and figured - Sep 2010 - Built for Hervey Bay Astro Group

200 mm - f/6 - Reflector - Dobsonian - Not sure where this mirror come from. Had it for ages - Mar 2011 - Put in Dob mount and sold. Now stored here

455 mm - f/4.5 - Reflector - Dobsonian - Complete re-built of OTA and Dobsonian mount - Mar 2011 - 2nd hand mirror re-aluminized

New Equatorial Skywatcher EQ 8 goto mount - Dec 2013 - For FRO

Alt-Az - Altutude-Azimuth mount
AO - Astro Optics Sydney
FRO - Frog Rock Observatory
OTA - Optical Tube Assembly
Parks Telescope manufacturer in USA