Stub Mandrel

Very nice 🙂

9 hours ago, vlaiv said:

Ok, still not sure what you are after, although I do understand what your work is about (just don't see relation to darks yet).

Dark subs are meant to correct for dark current but also other phenomena on sensor - like amp glow and hot/warm pixels. In principle it is Poisson type noise from thermal source, but there are other things with sensors that happen as well.

Now if you are after just Poisson type noise (or any other type of noise - Gaussian, uniform distribution, ....), then you can generate it quite easily with different parameters (something you might need). For example, here is small image 256x256 with Poisson noise and signal of "1" (let's say 1 photon/pixel/s and exposure 1s):

I'm not sure if you are doing "stills" or something like "video" in your research, but just for fun, here is "simulation", or rather animated gif made out of 16 such frames:

If above is something that you will find useful - just let me know and I'll explain here what software to get (ImageJ - it is free, java based and therefore OS agnostic) and what plugin for it to get (RandomJ) and how to generate such things.

This reminds me of a conversation I had with a friend many years ago.

We were sat in a room with a black and white TV that wasn't tuned properly. those of us of a certain age will remember the appearance of a screen of 'static', which is a pretty balanced random image as the automatic gain control averages it out to a mid grey.

We noted that it was possible to stare at the screen form much longer than, say, a plain painted wall or a blank sheet of paper. We surmised this was because the ever changing, but essentially information less image didn't 'bore' the retina or the brain as the nerve cells were receiving constantly changing input.

You can try this experiment with @vlaiv's two simulations. It's a pain to stare at the static one for more than a few seconds but the moving one has a wierd fascination. Obviously something with a longer cycle would be better as this short animation has some detectable repeating patterns.

I must say my fairly small apo scope (66mm f.6) which is probably helped by not being super fast, a which i use for AP and it doesn't really show any chromatic aberration.

On 14/12/2019 at 17:38, markse68 said:

Took a friend up onto the roof of our 3 floor work building this evening for a quick and my first look at Venus. Great view from up there! Venus was a bit boring to look at but I’m glad I’ve seen it now- scope didn’t have time to cool and I knocked the collimation out clonking the spider knobs carrying it up the fire escape 🤦‍♂️ so that combined with incoming cloud/atmospherics gave a nice disk but with colour fringes- yellow on one side and green blue on the other. We found Saturn too which looked fine for its elevation-  before the clouds rolled in

 

 

 

 

 

 

 

 

Not the best skies, but excellent pics!

(I'll never complain about light pollution again...)

I'll try the Ikea box first, I've ordered one along with some smelly candles for christmas presents...

Wow, some really good ideas - I like the way Carole's box closes up, but I've put an Ikea one in my 'bag (has anyone else noticed that all of a sudden shopping carts have become bags? Must be some 'nudge' psychology going on there...

On 10/12/2019 at 20:22, steppenwolf said:

Now even I recognize true beauty when I see it so using all the wrong gear, I captured 76 subframes of 0.5 seconds exposure through my 3nm Ha filter in my QSI 683 WSG camera and Esprit 150 ED.

That is rather nice!

Funnily one of my best moon images was through an Ha filter in the same circumstances probably because  red light is less scattered and  dispersed?

It's a bit close to full to show nice relief, but plenty of 'crater rays'.

Has   anyone made a good example of a 'laptop protector/box' for keeping the dew off etc. while allowing it to be used for  imaging. I imagine something that shields it a bit to stop dazzling and dew while enclosed to help keep it warm to max battery life.

I could do with some inspiration...

3 hours ago, JamesF said:

It looks a bit, err, y'know...

James

Like a thrusting, masculine Battlebus Logo?

This is far from perfect, virtually everything except the scope and mount was different to what I'm used to... ASI1600, EFW, EAF...

There wasn't much OIII about, conditions were poor with thin cloud passing through, guiding was off. Here's a comparison between the HOO and an L-enhance version on my DSLR on a better night.

Thanks Ivo.

1 hour ago, bottletopburly said:

Flat frames should be taken at same  iso setting as lights

And the same bit depth... I've just spent and age generating cooled flats and darks but in MONO8 so DSS hast just thrown them all back in my face 😞

6 hours ago, jimjam11 said:

I do the same, I dont have an lp filter and since switching to mono haven't seen a need. 

Surely an LP filter will be useful for luminance under poorer condtions?

Hi @Yoddha/Ivo,

I've now got a setup worthy of APT... but I'll be honest I'm overwhelmed by the scale of what it offers.

Is there something like a 'checklist' for setting up a new install?

Well done!

Doiung my first Ha/OIII right now so...

Now share how you do it  🙂

2 hours ago, fireballxl5 said:

I purchased the OP's linked LED light panel and saw that the light intensity was heavily biased to one end. Together with the grid effect pattern I didn't like to look of it so returned it for a refund.

So I'm still on the lookout for an A4 sized LED panel that is evenly illuminated, ideally edge to edge😛

I use something very similar, if not identical.

I put a sheet of A4 paper over it which eliminates the 'grid', and I take 12 flats, rotating it about 30 degrees  between each one. This gives me excellent results.

I've just fitted the EAF to a 130P-DS which I think has a very similar focuser.

I had to mill 3mm off the end of the long part of the bracket and re-tap (they were already deep enough) the M2.5 holes for the screws that fix the angled bit on the end.

This allowed me to use the M5 screws through the bracket into the hole for the lock screw and the one opposite it which was closed by a set screw.

Without this the only option was to use long M3 screws centrally which would have meant the focuser was pivoting on the pad which sets the  focus rod tension which would not have been good (plus M3 screws don't really have large enough heads for the central slot in the bracket.

2 hours ago, alan potts said:

I prefer the first image and don't much like the starless version, it's a very large target this one, one which I hope the Borg can capture soon, if I get the spacing sorted.

Alan

I think I agree.

I need a way to add the stars back in better.

2 hours ago, Heizel said:

What guide scope will be better- 50/190 or 60/240? My camera is asi120mm mini (3.75 pixel size).

The smaller one will be fine, I use a 50/183 with a 120MC and guide to ~0.6" when the sky is nice and clear.

My first attempt at using StarNET to reduce stars. I felt the 'no stars at all' version was a bit 'posterised' so after doing some curves on the nebula I  blended the two. Not sure what I think... I'm aware the colour on all images is a blotchy (this was done with a triband filter so colour is challenging). This was just an experiment which would be better used as an L- layer over an RGB.

Before:

After:

Blended:

On 30/11/2019 at 12:03, BinocularSky said:

The latest - 8th Anniversary! - edition of the Binocular Sky Newsletter is ready. As well as the usual overview of DSOs, variable and double stars, this month we have:

* Our winter "friends" have returned
* X Oph near maximum
* Vesta, Uranus and Neptune

We're heading to wards winter solstice now, so we have lovely long evenings. I hope this helps you to fill them enjoyably with your binoculars or small telescopes.

To pick up your free copy, just head over to http://binocularsky.com and click on the Newsletter tab, where you can subscribe (also free, of course) to have it emailed each month, and get archived copies.

I thought that was a stereoscopic image and now I have a permanent squint...

2 hours ago, Laurin Dave said:

I think you'll find that the ZWO RGB filters have a strategic gap where light from Hg and Na street lights emit (just look on their or FLO's website to see.... Baader etc do the same) .  The luminance filter has no such gap so maybe just replace that with a LP filter..  as I understand it not much can be done about LED light pollution as it much broader band.

You're set up will be great for narrowband and if you wanted to add RGB stars you don't need much RGB exposure.. 10 mins total a channel would probably be enough a light stretch and no big worries about LP

Dave

+1

I've got an 8-splace wheel and I'm planning:

Baader UV/IR Cut (L) (1) ZWO LRGB (2-4) Baader HSO (5-7) Then a moon/skyglow (8) to sub for L if necessary (I have found these to be very effective here for OSC where most of my LP is LP sodium).

A dual/tri-band filter like the Optolong L-Enhance or similar?

That nebulosity is breathtaking.

55 minutes ago, Highburymark said:

Blimey that’s a big picture. Any advice on how to reduce the size?

Ideally reduce before uploading, otherwise, while editing double click after its uploaded and reduce the size in the dialogue appears.