M94 Croc's Eye Galaxy - LRGB stacks added to first post if anyone wants to try.

[Xiga]

Sorry i can't be of any help with the technical issues Adam. I have no doubt though the SGL community will get it sorted for you. 

But thanks to @wimvb i did go back and have another look at the core, and there was more signal in there that i had missed first time around. While there i also cleaned up the sky background noise a smidge too, using @ollypenrice 's excellent method of very slightly raising the level of only the darkest sky background pixels, rather than using traditional NR. 

[tooth_dr]

Thanks @Xiga amazing what can be done with the data. There is definitely more detail in this one, compared to the previous processing you done.

[tooth_dr]

@wimvb @Xplode @Laurin Dave

Last night I was heading to bed after watching a film, I looked out and it was partially clear, so I decided to take the opportunity to set up and test out the fan theory.  It was 00:39 when I started.  M51 was just past meridian and that part of the sky was clear, so I went for it.  As luck would have it, a bright satellite passed through my 3rd sub of 120s.

In this image, I only had the QHY9 on, and the ATIK and all associated gear were turned off.  The QHY9 is attached to the 250PX.

There doesn't appear to be any oscillations like before.  Guiding was similar to previous nights, perhaps slightly better.  It was also very calm last night.

I immediately turned on the Atik so that the fan was running, and sat for an hour waiting for another satellite.  Two very dim ones did pass, but I don't know how useful they are.   I then turned off the Atik and left just the QHY to run the rest of the night.  I got some good tight data on M51, tight compared to the first night I tried it anyway(!)

Any input again appreciated.

Guide log attached also, if any one can input on that also I would be grateful.  There was patchy cloud, but outside of that, it appeared to be guiding well, with periods of 0.4-0.6 RMS.

 

ATIK OFF:

ATIK ON:

ATIK ON:

 

 

Last nights stack of data 2 hours 44 minutes lum:

 

PHD2_GuideLog_2020-04-30_092644.txt

[wimvb]

I want guiding like that! At 0.4 " rms, you don't have much of a problem. Guiding rms is the same in dec and ra. It might have been wind previously, but that would probably have resulted in a less regular oscillation.

Btw, here's my go at your data. I had trouble with the colour. Maybe it's my processing, because I'm not used to combining data from several sources.

 

Now I must go back to my own M94 data.

Edited May 1, 2020 by wimvb

[tooth_dr]

3 hours ago, wimvb said:

I want guiding like that! At 0.4 " rms, you don't have much of a problem. Guiding rms is the same in dec and ra. It might have been wind previously, but that would probably have resulted in a less regular oscillation.

Btw, here's my go at your data. I had trouble with the colour. Maybe it's my processing, because I'm not used to combining data from several sources.

 

Now I must go back to my own M94 data.

Thank-you Wim.  That looks lovely, such warm colours and nice looking stars. I wonder is that yellow dust millions and millions of stars?

The guiding drops to 0.4 for periods, but typically sits at 0.6-0.7 so I wonder is that just the seeing that causing that?  Maybe that's as good as it gets.  

[wimvb]

1 hour ago, tooth_dr said:

Thank-you Wim.  That looks lovely, such warm colours and nice looking stars. I wonder is that yellow dust millions and millions of stars?

The guiding drops to 0.4 for periods, but typically sits at 0.6-0.7 so I wonder is that just the seeing that causing that?  Maybe that's as good as it gets.  

That "yellow dust" is a combination of stars and galaxies, with an odd quasar just to spice things up. At least, that's my experience since I started analyzing the background in my images. I use Simbad for this. http://simbad.u-strasbg.fr/simbad/sim-fid

Seeing can have a huge impact on guide rms, imo, even if you expose for 3 seconds. I also suspect camera noise to be an important parameter, especially when you use an oag like I do. 

[tooth_dr]

4 minutes ago, wimvb said:

That "yellow dust" is a combination of stars and galaxies, with an odd quasar just to spice things up. At least, that's my experience since I started analyzing the background in my images. I use Simbad for this. http://simbad.u-strasbg.fr/simbad/sim-fid

Seeing can have a huge impact on guide rms, imo, even if you expose for 3 seconds. I also suspect camera noise to be an important parameter, especially when you use an oag like I do. 

Thanks again.  I have sold off two astro items in the past two days, so on the look out for a used Lodestar X2.  I missed Rays, but hadnt the cash at the time.  My wife has rightly put a curtailment on any 'big' astro purchases, so I'm selling off some unused stuff instead. 

Edited May 1, 2020 by tooth_dr

[Xplode]

1 hour ago, tooth_dr said:

Thanks again.  I have sold off two astro items in the past two days, so on the look out for a used Lodestar X2.  I missed Rays, but hadnt the cash at the time.  My wife has rightly put a curtailment on any 'big' astro purchases, so I'm selling off some unused stuff instead. 

If you want a really great guidecam get a ASI174MM-mini, it's much better than the Lodestar, lower noise, larger sensor, more sensitive, faster download. In my opinion it's the best guidecam for OAG right now.
The drawback is that it's quite costly.

[Xiga]

I agree, the 174MM-Mini is probably the best camera you can get for an OAG, but the 290MM-Mini would also work just as well and costs a fair bit less. And in fact, unless your OAG's prism is fairly large, then the larger sensor size of the 174 would just be wasted on it as it would have a serious amount of vignetting. How big is your prism Adam? If it's only in the region of say 9mm, then the 290 would be a great fit. 

Ps - I actually have an OAG with a 12mm prism I bought recently but is going unused. You're welcome to borrow it if you'd like. 

[tooth_dr]

2 hours ago, Xplode said:

If you want a really great guidecam get a ASI174MM-mini, it's much better than the Lodestar, lower noise, larger sensor, more sensitive, faster download. In my opinion it's the best guidecam for OAG right now.
The drawback is that it's quite costly.

Thanks for the advice.

I would need the camera for 1) imaging with my 1200mm fl scope via the OAG, and 2) using with a 9x50 finderscope and approx 500mm fl.

 

2 hours ago, Xiga said:

I agree, the 174MM-Mini is probably the best camera you can get for an OAG, but the 290MM-Mini would also work just as well and costs a fair bit less. And in fact, unless your OAG's prism is fairly large, then the larger sensor size of the 174 would just be wasted on it as it would have a serious amount of vignetting. How big is your prism Adam? If it's only in the region of say 9mm, then the 290 would be a great fit. 

Ps - I actually have an OAG with a 12mm prism I bought recently but is going unused. You're welcome to borrow it if you'd like. 

It's the ZWO OAG so I think small at 8mm x 8mm (although their blurb describes it as large!).  I've been reading up on the 290 and the 174, and I appreciate the differences.  So far the 120MM mostly finds stars, some times they are too dim and I have to move the target a little - say 1/4 of the FOV of the 120MM.    This has presented one issue where I was trying to do a mosaic, and I couldnt get a star in a new panel so SGPro went into recovery mode.

Is the 12mm OAG any thicker?  I was saying to you that I have probably max 1mm spare inward travel, so the OAG could not be any thicker than the ZWO OAG at 16.5mm.

Main reason for wanting a Lodestar is the reputation - there seem to be a large cohort of people who are very happy with it as a guide camera.  I'm not a massive fan of ZWO stuff in general, although I've owned 3 x ZWO cameras, and will probably buy another at some point.

 

I am now thinking, if I was to also use the guide camera for solar Ha imaging would that affect the choice?  I was quite happy with the FOV of the 120MM for solar imaging, but it has terrible NRs that would not go away with flats. 

 

Thanks for the advice

Adam

 

[Xiga]

25 minutes ago, tooth_dr said:

Thanks for the advice.

I would need the camera for 1) imaging with my 1200mm fl scope via the OAG, and 2) using with a 9x50 finderscope and approx 500mm fl.

 

It's the ZWO OAG so I think small at 8mm x 8mm (although their blurb describes it as large!).  I've been reading up on the 290 and the 174, and I appreciate the differences.  So far the 120MM mostly finds stars, some times they are too dim and I have to move the target a little - say 1/4 of the FOV of the 120MM.    This has presented one issue where I was trying to do a mosaic, and I couldnt get a star in a new panel so SGPro went into recovery mode.

Is the 12mm OAG any thicker?  I was saying to you that I have probably max 1mm spare inward travel, so the OAG could not be any thicker than the ZWO OAG at 16.5mm.

Main reason for wanting a Lodestar is the reputation - there seem to be a large cohort of people who are very happy with it as a guide camera.  I'm not a massive fan of ZWO stuff in general, although I've owned 3 x ZWO cameras, and will probably buy another at some point.

 

I am now thinking, if I was to also use the guide camera for solar Ha imaging would that affect the choice?  I was quite happy with the FOV of the 120MM for solar imaging, but it has terrible NRs that would not go away with flats. 

 

Thanks for the advice

Adam

 

Ah yes, you're out of back focus, i forgot about that. The OAG i have is around the 22mm mark, so would be too wide. Sorry! 

If you want to use the new cam for guiding on both scopes, then perhaps the smaller pixels of the 290 would be the safer bet. That way, at x1 bin you could get the benefit of a higher pixel scale on the finder-guider, and on the OAG with the big 1200 FL scope you could bin it x2 to get something close to the pixel size of your 8300 camera. The smaller pixels are more versatile this way. It's true that the Lodestars do have a good reputation, but i think a lot of that is close to being outdated now. From what i've read, most of the larger-sized SCT folk have moved on from their Lodestars to the 174 as their OAG guidecam these days, as they say it is way more sensitive. But i think a fair few of them are using the Celstron OAG, which has a large 12mm prism, so they actually get the benefit of the larger sensor. I have definitely read of people just buying the 174 without considering their OAG prism size, and then they are disappointed with the 'porthole-effect' they end up with due to the prism being too small (most seem to be in the 9mm range). 

No idea on the Solar side of things i'm afraid. Although i do know the 174 has a Global shutter, which is unusual in the ZWO range, and is apparently an important feature for Lunar imaging. Not sure if that extends to Solar imaging too, might be worth checking in the Solar forum on that one. 

[Xplode]

1 hour ago, tooth_dr said:

I would need the camera for 1) imaging with my 1200mm fl scope via the OAG, and 2) using with a 9x50 finderscope and approx 500mm fl.

If you want to use the guidecam on a guiderfinder the ASI174mm isn't a good fit, the pixels are too large, so are the Lodestars pixels.
In that case the ASI290mm mini is your best choice.

[wimvb]

I was also looking at the lodestar x2 for a guide camera. I have the cooled ASI174MM for imaging, and a zwo oag + ASI120mm-s for guiding. I can usually find guide stars, but snr is low, resulting in poor performance. I may go for the ASI290 and use it binned 2x2 to get the pixel scale up. 

[tooth_dr]

7 minutes ago, wimvb said:

I was also looking at the lodestar x2 for a guide camera. I have the cooled ASI174MM for imaging, and a zwo oag + ASI120mm-s for guiding. I can usually find guide stars, but snr is low, resulting in poor performance. I may go for the ASI290 and use it binned 2x2 to get the pixel scale up. 

Sounds like we have the same problem! Will the guidecam bin ok being a CMOS? The brief time I tried my 178 binned I’m not sure it worked as intended with PHD2

[wimvb]

I binned the asi120 and am under the impression that I got lower noise. With a fl of 1000 mm, I might test binning the ASI290 3x3.  That would be the equivalent of 7.2 um pixels, vs 5.86 for my imaging camera. Still somewhat smaller than the Lodestar's 8.2/8.4 um, which are oblong, btw. 

[tooth_dr]

Would I be safer getting the USB3.0 290MM if I want it to double up as a solar camera?

Are there any disadvantages to the round one other that costing more? 

[wimvb]

2 hours ago, tooth_dr said:

Would I be safer getting the USB3.0 290MM if I want it to double up as a solar camera?

Are there any disadvantages to the round one other that costing more? 

The mini fits easier as an oag guide cam. Other than that, they're the same, afaIk. 

[tooth_dr]

26 minutes ago, wimvb said:

The mini fits easier as an oag guide cam. Other than that, they're the same, afaIk. 

Thanks. I can see how it would fit in easier around the body of the camera.  I guess the 290 USB3 would be easier for me just to drop into my current setups as it all been designed around 12.5mm back focus of the ZWO sensors.   I’d need a new spacers with the 8.5mm spacing on the mini.  Or maybe there is enough travel in the finder guider lens to compensate, and the OAG comes with 1.25” barrel and attachments (but I prefer a screw connection for rigidity)
 

Edited May 2, 2020 by tooth_dr

[wimvb]

Yes, I forgot that the wider model has usb3, and the mini only usb2. For solar and planetary imaging, usb3 is faster and better.

I too prefer screw on connections, but they can end up at awkward positions sometimes. Usually, zwo items have everything included to fit with other zwo products. With my zwo filter wheel, and oag, everything was included and matched re distances. You just need to put everything in the right order. Very much like that Swedish furniture store.

[happy-kat]

I was going to have a play with the data but it downloads bad files unfortunately for me, fitsliberator can't even open them.

[tooth_dr]

1 hour ago, happy-kat said:

I was going to have a play with the data but it downloads bad files unfortunately for me, fitsliberator can't even open them.

That's odd, sorry about that, TIFFs attached below.

 

St-avg-9000.0s-Red-NoSt-SGL.tiff St-avg-5400.0s-Green-NoSt-SGL.tiff St-avg-4800.0s-Blue-NoSt-SGL.tiff St-avg-13500.0s-Luminance-NoSt-SGL.tiff

[happy-kat]

I am going to have to pass, all files except one download incomplete, I must be losing packets

[tooth_dr]

2 hours ago, happy-kat said:

I am going to have to pass, all files except one download incomplete, I must be losing packets

I’m not sure what that means! They download ok here.  No worries 👍🏼

[RayD]

They all downloaded fine for me.

[happy-kat]

If you needed to move 100 kilos it would be easier to throw it in small bags of 1 kilo and get the 100 kilos moved except if one of those little packets had a hole you wouldn't get the starting 100 kilo amount. Data streams in packets, if the steam breaks or is not constant you might lose packets or bits of a packet, so your concatenated received data is incomplete.