Deep Space
20250318 - Haig Mount Time
The Haig mount was designed by a gentleman named George Haig and the original design was published in Sky and Telescope back in 1975.. It broadly consists of a hinged flap (or 'barn door') that opens at Sidereal rate (15 degrees per hour). A Camera on a ball mount is mounted on the opening door and this can then be used for imaging large scale items such as constellations. This Wikepedia article explains the principle.
I built my Haig mount about 17 or 18 years ago, I don't use it very often, I don't know why not as it keeps me occupied while my other telescopes are doing more serious work.
We had what appeared to be a clear night on 2025-13-18, in reality, it was actually pretty awful with high level cloud limiting naked eye magnitude to about Mag 2.5 or 3. Polaris was just visible and M45 was an averted vision fuzzy patch.
So while my 200mm F5 newton telescope was trying and failing to capture the nubulosity surrounding M45, I thought I would have play with my Haig mount.
I used my Sony A65 DSLR - not the best choice as the 'live view' viewfinder is very limiting on framing the image in the dark. and selected 3 targets
- Orion and M42 as it was setting in the west
- Cancer with M44 - I love M44 - my favourite open cluster
- Leo - hoping to capture some of the galaxies (M65/M66).
Orion & M42
This made quite a good movie as the hedge slowly rose up. The mount tracked the constellation really well. Quite a few frames had to be discarded due to aircraft trails and some brighter satellite trails.
Cancer & M44
Quite a nice shot although there is some evidence of flaring on some of the brighter stars. I think I need to check that the lens is clean - it hasn't been used for years.
Leo
I didn't capture either M65 or M66 - it took me a while to navigate around the image. It didn't help that Denebola had been cropped off the left hand side. I have marked out the Greek letter star notations. Still quite a pleasing shot considering the conditions.
20250205 - M42 in Hα
This is my first attempt using a Hα Deep Sky Filter. I managed to pick up a second hand Baader 1.25" Hα filter for less than half the price of a new price. Orion is due South of me early evening so M42 (the Great Orion Nebula) is an obvious candidate for a first attempt at deep space astrophotography with a narrow band Hα filter.
A Hα filter (Hydrogen Alpha) only passes light emitted by the Hydrogen Alpha Balmer line and blocks most visible light. It increases the contrast of Ha emission nebula and other sources that emit light that is rich in Hα. H-alpha (Hα) is a specific deep-red visible spectral line in the Balmer series with a wavelength of 656.28 nm; it occurs when a hydrogen electron falls from its third to second lowest energy level.
There is nothing extraordinary about the equipment setup, the telescope is a 20 year old SkyWatcher 200mm F5 Newtonian reflector supported by an elderly Orion EQ-G Pro equatorial mount.. My camera is another near relic, a Starlight Xpress SXVR-H694 mono CCD which is probably somewhere between 10 and 15 years old. Nothing modern here!
I carefully polar aligned the mount and performed a 3 star alignment which identified an as yet unresolved problem in either the RA or Dec drives. However, this did not prevent me from performing a fairly accurate track of M42 for almost an hour. I originally intended to use a guide scope and PHD2 tracking but ran into another problem with the old guide scope camera. So my capture was unguided. There was noticeable periodic error when comparing individual frames from the sequence.
100 frames of 30 seconds exposure (2x2 binning, 50 minute total exposure time) seemed like a reasonable first attempt. Dark frame subtraction but no bias or flat frames. A comfortable 75% of the frames were usable for the stack..
There are a couple of problems with the image that I can see:
The most obvious fault is the dark halos around the brighter stars which is especially notable where the stars are in front of the nebula.
I am quite pleased that I have managed to capture detail in the core of M42 that would normally be burnt out when captured in visible light. However, I am unsure about the sharpness of the detail in the core area of the Nebula. Conversely, I was a bit disappointed that there was not more detail visible in the 'bat wings' of the nebula. I guess that I will need a much longer exposure than 50 minutes.
The Camera settings from SharpCap4 were as follows:
[H694]FrameType=LightCapture Area=2750x2200Binning=2x2Pan=0Tilt=0Frame Rate Limit=MaximumExposure=30.000sTarget Temperature=0Cooler=OnTemperature=-10.300000190734863Digital Gain=4.056833039356836Notes=TimeStamp=2025-02-05T20:37:39.3647135ZDuration=3298.046sFrameCount=100
M42 - The Great Orion Nebula
The fuzzy patch just below the belt of Orion. Probably the most photographed object after the Sun and Moon. A hot star forming region fuelled by 4 young stars known as the trapezium that invariable burn out the centre of the image. It is located approximately 1300 Light Years Away and is 24 Light Years across. It is an Emission Nebula.
This is an old image, taken back in 2008. It comprised of 10 exposures, stacked and processed using Registax 4. AT the time, I was absolutely delighted with this photo, nice and sharp and clearly recognisable. Although it can't compete with the works of art produced by top astro-photographers, there is still something special about using a DSLR for Astronomy.
Camera was a Konica Minolta 7D DSLR Camera at 1600 ASA, the exposure time was 30 seconds per frame.
Telescope is my old, trusty Skywatcher 200mm F5 with the camera at Prime Focus..
Mount is a EQ5 Equatorial, Polar Aligned and driven in Right Ascension. Still going strong, now about 18 years old.
NGC2024 - The Flame Nebula
This nebula sits just to the east of the left hand star in Orion's Belt, Alnitak. It is an Emission Nebula about 1350 light years away.
North (up) is to the Right
Equipment
Telescope: SVBony ED80mm F7
Mount: EQ5, Polar Aligned with RA Drive
Camera: Starlight Xpress H694
Camera Settings (SharpCap 4)
Capture Area=1600x1200
Binning=2x2
Colour Space=MONO16
Exposure=30.000s
Cooler=On
Temperature=-10.3000001907349
Black Level=0
Digital Gain=17.3686507275937
TimeStamp=2024-03-06T20:17:02.8275920Z
Duration=1037.299s
FrameCount=32