Astrophotography – equipment

Scale for focussing tube

Hi, it’s useful to know the focussing position especially when imaging and using different combinations of filters/ lenses with the camera, although my sky watcher 120 Evostar has a graduated Crayford focuser, the newly acquired ST102 doesn’t, so rather than replace the rack & pinion focuser with a calibrated Crayford I managed to source some transparent adhesive scale tape, which I have attached to barrel, after cleaning the area with some isopropyl alcohol, its still on but have yet to put it to use. The tape was relatively cheap, and I do have an excess of repeating 40cm lengths, so if any one fancies adding a scale to their focussing tube get in contact.

 

Pete Hill

Solar – Mikrokular with or without barlow?

One of the reasons I like the Mikrokular is that it is full HD. It should therefore stand more magnification before being limited by pixels (the PD and Toucam are 640X480). So as an experiment, I took the last solar image I posted, cropped out the “no barlow” part including the prominences, desaturated it, re-sized it by 200%, “unsharp masked” it slightly, and set it alongside the X2 barlow version for comparison.

Although I think the barlow version is better, there is not much in it! (Just look at the prominences detail, not the disc)

Sun in a new Light – Cak

Using recently acquired skywatcher ST102 refractor, see above with collapsible dark box and shroud.  Along with a Baader CaK double stacked filter 390 – 398 nm covering both CaK 393.7 nm and CaH 396.85 nm I managed to image the sun in Ca k.

The filter was attached to a DMK41 mono CCD camera with a x0.5 focal reducer to enable whole disc imaging.

 

The CaK filter needs an energy rejection system to be used on scope, it comes packaged with 3.8 OD Baader film, but a Herschel wedge can also be used.

Other CaK systems like those available from Lunt contain both Cak filter and energy rejection system, hence the cost.

I missed the early morning activity recorded by Nick and Roger and by this afternoon there was little prominence activity according to Gong, so I just concentrated on Sunspot AR2670, imaging using CaK filter and the Baader 590nm Contiuum filter.

Whole disk in White light, continuum filter.

Whole disk in CaK, showing Plages

Colourised CaK whole disk.

 

Left white light image without x0.5 focal reducer.

Centre CaK without focal reducer.

 

 

Below colorised Cak

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

With x2 Barlow (below), smaller image white light. Trying to dodge between clouds meant that the sun was getting lower during the session and subsequently I was imaging over my neighbours roof and the garage roof, started to get lots of atmospheric wobble. However I was reasonably pleased that different detail could be imaged with the CaK filter, couldn’t take H alpha (656.78nm) at same time as I’d used the vixen rail I normally attach it to, to mount the ST102 on the HEQ5. Compare the rese CaK images with Rogers H alpha.

The white light image shows what is happening on surface of suns photosphere, the observeable surface at 5500k, H alpha shows what  is happening in the chromosphere, the layer above the photosphere where the temperature rises to 50000K at its upper level. CaK images show what is occurring between the upper photosphere and lower chromosphere.

At 393.37 nm CaK is not visible to eye , in fact there is a lot of UV being passed, not good for the eyes, so this filter is for imaging purposes only.

Future activity will compare Herschel wedge / Baader film combinations with CaK filter and comparison with H alpha images from Coronado PST.

Pete H


Nice All Sky Camera timelapse

Hi Folks,

Here’s a nice little timelapse from a few days ago, edited using a free bit of software for windows called Shotcut (https://www.shotcut.org/). It’s a bit like Windows Media player and VLC player but it allows you to export a speeded up video, which is very handy

This one is effectively running at 60fps and was a timelapse recorded on my All Sky Camera with iSpy recording at 1 frame per minute over about 6 hours, although, I’ve cropped this much shorter as it was getting light

It’s quite nice as you can see the Plough moving down the screen, and the after about 20 seconds you’ll see Cassiopeia coming in at the top right near the tree . You can also faintly see the Milky Way moving down the screen after that.

I think for a cheap DIY camera it’s not bad

Ed Mann

07802 350187

ed.mann@btinternet.com

A Challenge to the Quarkers out there – – –

To quote Holmes: “When you have eliminated the impossible, whatever remains, however improbable, must be the truth”

I have been musing over my recent post concerning the apparent lack of fine detail on my solar images (https://roslistonastronomy.uk/h-alpha-question-puzzle). While they are comparable with other LS35 images I have seen, and with GONG images, they do lack the fine detail you sometimes see in other published images. I am not 100% convinced it isn’t a stacking artifact, but setting this aside what else could it be?

Daytime observing suffers from atmospheric turbulence big-time, and you need a fast shutter speed to reduce this. I wonder if I simply have not got the sensitivity to employ an appropriately fast speed.

Simple optics would inform me that a Quark with an 80mm scope has the potential of being at least 2 stops faster than my LS35, everything else being equal.

So, the challenge to the Quarkers – I know that there are at least 3 of you out there, and one of them at least (mentioning no names, Andy), has a Mikrokular, the same as I use:

Can you get finer detail than I get using a fast shutter speed? Simple stacking is likely not to help, as the images you stack will be slightly displaced due to the turbulence, thus blurring the final stack.

 

 

NASA salute A.S.B.O successful installation with flypast!

NEWS FLASH – Wednesday 24th May 2017

NASA scientists can be seen here celebrating the success of their latest endeavour…

It was all systems ‘GO’ at A.S.B.O Headquarters last night as final checks took place for this historic event:

The site was deemed clear for operations around 9pm

Due to cables on-site, all Perimeters were secured from any invading – ‘Andrews!’ > CHECK!

Comms > CHECK!

Visuals > CHECK!

Data storage > CHECK!

At 00.58am BST, A.S.B.O picked up the link and the NASA ‘flypast’ commenced……. the ISS (plus some stray plane getting in on the action – possibly the RAG Chair flying back from ESA) !

Pass took over two minutes, the movie is speeded up x4

The ISS passed through Bootes (Arcturus to the left) and headed through Hercules and just north of Vega in Lyra before comms cut-off.

With thanks to Heavens-Above, below !

Damian ( a pyjama clad ‘Operations Director’ at A.S.B.O)

All Sky Camera Workshop

A massive thanks to Ed Mann for his RAG ‘All Sky Camera Workshop’ run on Saturday 13th May.

The amount of work he’d put into this event was incredible – what started as a load of bits at 10am turned into a working unit by the time we finished….. around 3pm – still in Saturday!

We left with a set of printed instructions, tips and tricks, and now need to explore just what can be achieved with the software and unit…

Damian

 

I wonder what happens when I do… this!

 

Bags… of Bits!

 

Ed’s view of the proceedings – his ‘class’ 😉

 

The build in progress…

 

Unit complete!

 

It’s…. ‘ALIVE’!