Gerry Casa Christiana

The way I resolved this issue on my Canon 550d (almost) is by removing the SD card out of the camera. Someone on here Carol if I remember correctly suggested I try. Since then I don’t keep a SD card in. I believe it’s a electronic signal being picked up in the frame. Give it a try

Gerry

On 03/09/2019 at 18:37, alacant said:

Hi

I'd tell PHD2 860 and make sure I recalibrated with the guide camera binned. Make a new profile.

Cheers

Hi Alacant 

Whats the benefit of the guide camera being binned?

Thanks 

Gerry

I think the issue is more the length of your exposures. 20 seconds is not enough to get the detail you need. The background in the first picture is too bright. In photoshop try to get the black levels to around 30 that will help to see more detail in the galaxy. 

Kind regards

Gerry

22 minutes ago, ollypenrice said:

I might add luminance or simply more RGB as a first step.

The colour to luminance ratio which I use depends very much on the target. If we are trying to capture faint dusty or other broadband signal it's the luminance which will find it so I'l shoot lots more luminance than colour, as in this example. https://www.astrobin.com/335042/?nc=user  The luminance found the difficult tidal tail. However, this makes the processing harder because you need various techniques to stop the luminance bleaching out all the colour. If keeping the star sizes down in a nebula shot is the priority then I might shoot no luminance at all and use the RGB as a vehicle to carry OIII and Ha and give naturally coloured small stars. There's no one answer but the great thing is that the mono camera gives you the flexibility to choose your approach.

The easiest processing comes from equal amounts of L and R and G and B.

Olly

I'm still on dslr and if price is no option God willing I would probably go mono there is still a temptation there to go one shot though. So even if you don't have a permanent setup you would say it's still faster? So using Ha on red and Oiii on blue and normal green for improving star colour and size? Learning a lot 

Thanks

6 hours ago, ollypenrice said:

I'm going to argue the other way but first let's get one thing sorted out: monochrome CCD with filters is faster than both one shot colour CCD and DSLR imaging. I did this image of the Heart nebula in only two hours and processed it quickly and simply. Each colour had 20 minutes and the H alpha had 1 hour.

This compares with the same equipment on the same target done 'properly' with well over 20 hours of data and complex processing:

I do not believe any one shot colour camera in an F5 system could match the first image in 2 hours.

In this case the speed in the first image came from the use of the Ha filter but it can also come from the luminance filter which is at least three times faster than a colour-filtered image whether that's from OSC or RGB filters. (OSC and RGB are pretty much equivalent.)

Personally I think that using the right tool for the job is always easier than using a multi-purpose tool or the wrong tool. I went straight into astrophotography with a mono CCD and almost no computing skills at all. It is often argued and assumed that you should go via DSLR into CCD but I don't agree with this. A number of people whom I've taught on my courses have said that they found DSLR to be a blind alley. Their words, not mine.

The big argument against CCD was cost, which is fair enough, but there are now dedicated and cooled CMOS cameras which are far cheaper than CCD and in my view they have introduced an exciting mid-cost alternative.

Olly

 

 

 

Love it when people go against the flow  I have to say it's quite convincing just a quick question if I may. With the first picture if you needed to improve on it would you increase time on rgb or spend more time on luminance or h Alpha? Is there a sound ratio to colour and luminance that you follow? 

Thanks

Gerry

Here is how to fit the rail in case you've made a mistake somewhere. It shouldnt slip regardless of how much weight on it. Might be worth checking if you have that problem. 

16 hours ago, Jose DmCardoso Moura said:

tighten by 2.5 mm allen screwdrivers?

Did you tighten them? If not you must but only to the point where the mount doesn't wobble side to side if you try and shake it while on the tripod. It should be solid. 

I can't say if it improved it but I can say it does not slip and polar alignment is fine on my setup as before. It's absolutely rock solid. The modification would in my opinion help to hold things firmer as your not holding the weight of the mount with the end of a bolt but it has a proper support. 

It's a great mod and I wouldn't be without it. I changed mine as the bolt started to bend and I couldn't turn it by hand anymore. When I dismantled it the bolts had started to damage the mount even though it's not that old. 3 years roughly. Hope that helps.

Kind regards 

3 hours ago, Jose DmCardoso Moura said:

Please, what was your polar alignment stability after the eq6 rail modification, does your mount keeps correct elevation in spite of being heavily loaded? Is it needed to have any other  modifications like substituting the three  lateral screws, tighten by 2.5 mm allen screwdrivers?

If anything I think the polar alignment stability is about the same. Not sure about when heavily loaded as im using a skywatcher 150pds on mine. The three lateral screws I tightened the so there was no wobble but beyond that I have had no issues. 

I'm pretty sure it won't work with a Newtonian  Unfortunately you will need one if you want to do imaging. 

I don’t think that you can use a SCT coma corrector on a Newtonian I doubt they would be compatible. Someone will give you the technical answer I’m sure. 

Kind regards

Gerry

From my understanding the CLS CCD is ok for galaxies as well as nebulas whereas the UHC is not. I use it for galaxies and although I'm no expert and my colours are not always right I always use the CLS CCD as I have full spectrum like you a modified Canon 550d. I don't think it will affect the galaxy too much it just removes a lot of yellow which can be adjusted afterwards. 

One of mine from earlier this year with the same filter. 

Gerry

Then the choice of camera? I was thinking about the 178mc but maybe 178mm would be good. It's to completely change the fov so I can get some smaller galaxies and maybe even some planetary nebulas. I noticed the 183 has the same sensor size of 2.4 does that mean if I crop I get the same image size? What about quality of image? 

On 04/05/2019 at 13:00, Adam J said:

This is one of the most common misconceptions in astro imaging, mono collects data faster than one shot color You will get a better image in three hours with the mono. In three hours you would do the following.

Lum = 1.5 hours

Red = 0.5 hour

Green = 0.5 hour

Blue = 0.5 hour

Total = 3 hours

So if you assume that each RGB pixel collects 1/3rd of the signal of the Luminance filter then you get the following.

The formula for light gathered per channel is:

(Filter transmission as a percentage of Lum) x  (number of active pixels) x (integration time in hours) = relative signal strength.

**Remember that One Shot Colour uses a filter matrix and so for red only one in 4 pixels are active for green two in four pixels are active and for blue one in 4 pixels are active. For mono all pixels are always active.

First For One Shot Colour:

Red = 1/3 x 1 x 3 = 1

Green = 1/3 x 2 x 3 = 2

Blue = 1/3 x 1 x 3 = 1

Total = 4

Now for Mono:

Lum = 1 x 4 x 1.5 = 6

Red = 1/3 x 4 x 0.5 = 0.66

Green = 1/3 x 4 x 0.5 = 0.66

Blue = 1/3 x 4 x 0.5 =0.66

Total = 8

 

So using LRGB on mono you collect twice the number of photons as one shot colour in the same amount of time. So relatively your 3hours is now 6hours of equivalent data. Hence if you are short on time can you afford not to go mono?

So long as you have a filter wheel you only need focus on Lum then just rotate for each filter.

Adam

 

Well that convinced me I think. So now I just have to save more money for filters and filter wheel. Now you say it I've heard this before and it does make perfect sense. I'll be saving for a mono now if it means saving time. Thanks for taking the time to explain that. 

15 hours ago, tomato said:

No, it is the mono version with a filter wheel. 

Now it makes sense why it was so good. I would love to do mono but it's a question of time but seems like a lot more time needed? I seem to have a couple of sessions when it's clear maybe 3 hours and then call it session done  anyway very nice well done. 

On 27/04/2019 at 15:29, tomato said:

I am using an ASI 178 on an Esprit 150 to capture small galaxy targets. This is M51, 2.92 hrs integration time. The camera has been fitted with a Peltier cooler bringing the sensor temp down to 0-5 deg C. I am having some fun trying to get the colour balance right, this is a version modified by @Han Solo using PS. The camera is very sensitive and the small pixels can capture fine detail under the right conditions, but the FOV is limited with this scope.

That is really nice. So you have the colour version. I've been thinking about this camera too especially for galaxies like the one above. 

2 minutes ago, andrew s said:

Yes I study star spectra with a home built echelle spectrograph. I have a guide head on a telescope which feeds the starlight into a fibre optic which guides the light to the spectrograph. This allows the spectrograph to be stable as it does not move as the telescope tracks the star.

Regards Andrew 

Wow fascinating. Love to see what kind of results you get. Anyway for another thread. 

2 minutes ago, andrew s said:

The reflective version should be ok with any camera. A prism adds aberrations when off axis.

I use  mine as the input to a spectrograph. 

Regards Andrew 

A spectrograph. It's a area I know nothing about. Could I ask what you use it for?  Related to spectral analysis of stars etc?

Regards

Gerry

19 hours ago, andrew s said:

The second coloured diagram is not correct. The blue prism is the wrong way round. No  known material could deviate the light at a right angle in this configuration.

Regards Andrew 

So that's where all the confusion is. Types of prism  looks like one is reflective another transparent. As you say we live and learn. Wonder what works best in practice. Good to know actually because later if like for me I decide to get a cmos then i might need a different oag. 

All the best

Gerry

Ah yes it is quite different. Looking at the picture looks like a clear prism? No matter as long as it works. With mine which I also bought from there but made for dslr you cannot adjust the mirror like yours but it works fine for me  let us know when all is working. 

19 hours ago, andrew s said:

I think the first was correct. The light undergoes total internal reflection at the 45 deg face. The light path in the coloured diagram is impossible. 

Regards Andrew 

Actually looking a little closer probably both are correct  it's just the angle of the prism that threw me.  Regardless of the pictures. Thanks google! The idea is light comes down the telescope to both the camera and the guide camera in the same direction one small part gets refectled up by the prism towards the guide camera. That's the principle which is clearer than pictures obviously in this example. Apologies for any confusion. 

Let us know when it's all working otherwise one of us will pop over to fix the mess I've created  

Actually the picture above is incorrect the angle of the prism will be going towards the focuser not the camera  

Kind regards

Gerry

Yes I think it's a bit pricey too but now I've installed it I'm really glad I spent the money. Mine was chewed up like that too so I was glad to avoid any further damage. I wouldn't hesitate to get one if you have problems moving the bolt. Also I still have my original bolt which was bent and I straightened and I reinstalled it. Works great! Gerry

6 hours ago, LightBucket said:

You do realise that the bolt does not tighten in that nut...it tightens in the mount base itself, which is threaded...that nut is supposed to be fitted afterwards as a lock nut, as when moving the mount up and down the main bolt can work loose without that nut in place...

it would be impossible to tighten that bolt in the base as well as get that nut back on and tight, as you have said... and there is no way you could do this without removing the decal on that side..

No I managed to fix it into the nut by laying it on its side so the bolt is threaded into the nut but maybe it's not on at all! But its working good but I can always take it off but so far it's solid  let me know what you think of the mod. Clear skies 

Gerry 

49 minutes ago, LightBucket said:

Did you still have some play in the mount after tightening up the bolt, (about 1mm side to side) and then take that out with the three grub screws....as that’s what I did..but not sure if correct...

Yes I think I was lucky with the nut  I managed to get the bolt back into it and tightened it up. Yes I'm sure yours will be fine. The best way is to put your gear on it before the final assembly try to move it side to side then adjust until you have no play then put the sides back on. That's what I did. 

Gerry