Stub Mandrel

3 hours ago, smr said:

And that would mean I am not straining my 80D (with long exposures)

I don't think long exposures cause any 'strain', its sheer number of mechanical actuations that matters. Longer exposures = fewer exposures.

11 hours ago, Dr_Ju_ju said:

…… leading on from the colour transmission system, the starting point of the signal, i.e. the television camera, especially in the early days, was based around a 3 monochrome camera system, i.e. RGB, where each camera being fed by the appropriate colour light, that had been split by a dichroic mirror, into its RGB components....  

now there's a thought for a full bandwidth 3 way system, an OCS with 3 mono cameras....

Not diffcult to arrange, the splitter prisms come up as surplus items regularly. With stacking you don't even need the precise alignment of all three sensors, as long as they are focused.

27 minutes ago, ollypenrice said:

Has anyone tried subtracting G and B from L and comparing it with B? I wouldn't be averse from trying it once the moon is gone.

Surely you already have LRGB data to play with? Can you use 'pixel math' in Pixinsight to do the work?

On 21/08/2019 at 08:15, ollypenrice said:

That is why the professionals invented the LRGB system. It saves time.

Please sir,

Why don't we image LRG and compute B as L-(R+G) ?

Or even LMY?

Then G =  L-M, B = L-Y and R= L -G +B   or  R = (M+Y)-L

Much quicker, but would need filters with sharp cutoffs... I'm sure someone will be along soon to say why it won't work!

5 minutes ago, iwols said:

think im getting there??

saturn2.tif 166.21 kB · 1 download

Much better, but I think you should be able to get a more natural colour balance.

Good idea to save as a PNG for upload to the website, saves having to download and then fire up a viewer.

Did a session in Ha a few days ago. The results were pretty poor, mostly because I had the scope pointing up and an intrusive dust bunny in a different place on each frame so flats wouldn't take it out. Also, very noisy - thin cloud? A shame as my guiding was rock solid at 0.65" for about three hours!

But... I made a point of focusing at the 2/3 point, I have always focused at the centre before. Result was round stars across the whole APSC frame, so that IS a good piece of advice to follow in the future.

Thanks Les,

I missed one this morning, but clouded out anyway.

I've got a few events on https://transit-finder.com/, but it doesn't say anywhere whether the times given are UTC or BST?

Trying to duplicate the events in Stellarium suggests BST, although I couldn't get it to duplicate an ISS transit exactly so I'm less than sure...

Does anyone know what times it uses

On 18/08/2019 at 16:43, Alan White said:

The post person also brought a bit of kit that I have no idea how to use, but something to learn with.
I am hoping to have ago at radio detection using Graves Radio on Meteors.
Have to make or buy an aerial, get some software and make this work.....what could go wrong!

I have a very similar one, it runs warm to the touch. I clamped a decent sized heatsink to it and it greatly reduced the noise.

I use Alibre Atom now, it's very easy to use and fast. It costs about £100.

I can send anyone dropping me a PM a link to a free 6 month licence to try it out.

'Double click or tap image for options' before you submit.

On 17/08/2019 at 21:48, Mr niall said:

Probably should have titled my post "Everyone has just got more expensive"

You can change the title by editing your first post.

5 hours ago, carastro said:

Then when I was at school I recall maybe a partial eclipse happening while we were in the school playground all getting arranged for a school photo and being told not to look at it (for safety reasons).  I had bought a folded up length of photo negative with me to look through it.  Well such was my ignorance about safety then, but I do recall having a few sneaky views of it.

We used silver coated sweet wrappers.

Grrr... my home network has lost my laptop again -(

So tomorrow I will switch off, stick all 2,500-ish captures on a128-gig SD card and  copy across the data files and see what I can do.

On 06/02/2018 at 12:27, vlaiv said:

Not sure how is that related to amp glow if we assume it is due to build up of heat on adjacent component and it is being fed into sensor via metallic circuitry. Sensor is kept at constant temperature because all excess heat is taken away by Peltier. If amp glow is rising faster than dark current - that means that part of chip is at higher temperature than the rest of the chip, and it is accumulating heat (if it were only at higher temperature but stable we would not be in trouble, since there is time linearity at different temperatures). Some of that heat will indeed be taken away by Peltier via sensor, but if it is rising, it will also be in dynamic with its surroundings - some of the heat will dissipate elsewhere because not all of it is being drawn away by Peltier. Otherwise amp glow temperature would also be stable. And if it is dissipating heat by other means than Peltier - speed of dissipation will depend on temperature gradient between that component and wherever that heat goes to.

From ZWO's website:

Quote

 

When it comes to CMOS cameras, “amp glow” is usually not from an amplifier. CMOS sensors are usually “fully integrated” which means that, unlike a CCD, readout electronics are included on the sensor die along with all the pixels themselves. Each sensor has at least one, often many, ADC (analog to digital conversion) and CDS (noise reduction) units on it. There are also other support circuits on the sensor die itself these days…clock generators and power supply regulators and such. These support circuits can generate heat or may even emit NIR light, both of which can cause glows. Additionally, many modern CMOS sensors include high performance image processing as part of the sensor package, either in the form of on-die processing or a secondary processor that is directly integrated into the sensor by attaching it (often to the reverse side of the sensor.) This processing circuitry can often generate heat that may produce glows.

Heat can increase the dark current accumulated in pixels. Pixels that exhibit roundish glows, usually soft without any obvious structure, are caused by heat sources. NIR, or Near Infra-Red, may also be emitted by some sensor circuitry. NIR glows can exhibit anywhere on a sensor, may often exhibit distinct structure, and are often radiated from specific locations around the periphery of the sensor. Not all pixels in a sensor will be affected, nor will those affected be affected uniformly. Glows may not “grow” with time the same way dark current itself does, and may accelerate over time becoming brighter faster than dark current itself as exposures become longer.

 

https://astronomy-imaging-camera.com/tutorials/what-is-amp-glow.html

1 minute ago, ScouseSpaceCadet said:

Go for it Stub. That one you linked looks jazzy! Although opening a parcel from Staffs isn't as exciting as Moscow. (Unless you're in Moscow getting a parcel from Staffordshire... )

 

It's probably the same one!  You know you need your own 3D printer now. Mine is already warming up...

23 minutes ago, ScouseSpaceCadet said:

A 3D printed dual finder bracket courtesy of Ebay. £8 + £4.90 postage. It took 6 days to arrive from Russia.

 

Hmm, this could supplement my income...

https://www.thingiverse.com/thing:2496996

Superb!

Number 2, the first one lacks contrast.

1 hour ago, Lockie said:

They use them to zoom over large lakes or the sea to try and prove the Earth is flat. 

😭

I would be lost without the P520, it's my most useful work tool as I use photos a lot in my work. I can use it for things where a DSLR would be completely impractical and I have never had any problems with image quality shooting on high quality all the time.  Compared to a DSLR the image quality can drop off in the corners with wide angle shots, but this has never been an issue in practice.

See what you can get from the moon.

I can only do 1-second exposures at higher ISOs - my phone is better for stars!

The new Nikon P1000 looks amazing, I tried the P900 out the other day (x83 zoom!) and it was pretty fantastic and costs the same as my P520 did!

The so-called 'Sturgeon Moon' in glorious technicolour. 10 jpeg frames with Nikon P520 bridge camera, PIPP, AS!3, then RGB layer in Photoshop for saturation and colour balance, luminance layer vis Astra Image for deconvolution.

For when subtle really won't do.

The point of this image is to prove you don't need any special astronomy equipment to image planets, just a camera, any camera, with a long lens.

20 frames on Jupiter and 30 frames on Saturn with my Nikon P520 bridge camera, 1000mm equivalent focal length, 400 iso, 1/60 second, hand held with support and image stabilisation.

Cropped in PIPP, stacked with 3x drizzle in AS!3, slight gamma tweak and combine the two images.

This is a single frame from my Nikon P520 bridge camera, 1000mm equivalent focal length, 400 iso, 1/60 second, hand held with support from car roof and image stabilisation.

No processing at all, just cropped.

Went out with my bridge camera and a bat detector, managed to get some iffy video of bats, but great 'snaps' of the 'sturgeon moon', jupiter and saturn.

Feel guilty for not setting up for planetary as the conditions are great, probably the high wind is sorting the seeing. But my lappy is recording meteors and my camera has a wide angle adaptor on it and is lying on its back on a bit of foam on top of the shed roof taking dodgy pics in the hopes of getting a late meteor.