Fegato

Due to lack of clear skies I've been waiting weeks to complete some tests to work out what's causing reflection artifacts in my images. I saw a brief opportunity a couple of nights back, and did manage to get about 30 mins of data in 4 hours of trying before the clouds made me give up. The whole session was chasing little bits of clear sky.

The funny part is that as I quickly spun my RASA into vertical using the handset, and started taking flats with an Aurora flat panel on top of the dew shield - my mount / NINA then decided to meridian flip! You should have seen me rush outside in a panic to rescue the panel before it fell off! 

Anyway, the moral and my take is - most of the problems I have in imaging sessions seem ultimately to be operator error.  And yes, they mostly happen all on one night, so I put this down to brain just not being in gear, or sometimes changes having been implemented incorrectly.  However, I take the point about USB - why isn't there anything better?  (well - I connect my CEM120 via direct LAN / ethernet connection, because I can, and this works a dream)

Well, like tomato above, I have plans to shoot Sharpless 2-240 and thought I might enter it for this challenge. However, reflection problems with my RASA setup and endless cloud have put paid to that. So as nothing more is probably going to get done this month, I thought I'd enter this one that I shot in early October.

Perhaps this is a bit cheeky as dark nebula Barnard 175 was the main target, but I also knew I had planetary nebula Dengel-Hartl 5 (PK 111 +11.1) in the frame, which came out nice and bright just above and to the right of centre. And as a bonus, the red filaments across the frame are part of the huge super nova remnant SNR 110.3+11.3.  

RASA 11, CEM120, ZWO ASI2400MC Pro.  126 x 30s with IDAS ODW (clear filter), 16 x 180s with IDAS NBZ dual narrowband filter. Processed in Pixinsight.

8 minutes ago, AstroGee said:

 

I presume stacking images will allow to discard or selectively keep the satellite/meteor trails

Yes, if you've got enough subs, they can all be removed with stacking and a good pixel rejection algorithm. Not sure how you'd selectively keep, but possible to add back in later if you really wanted to I guess!

I have to say that I never trash satellite trailed images when taking multiple stacked exposures. I use Pixinsight, and the pixel rejection routines work perfectly when integrating a stack of images - the satellite trails are just completely removed with no manual intervention required. You also get a nice rejection image at the end to see how bad it could have been - this is the busiest one I've managed to collect so far!

re: my comments above - the 10m USB3 cable I tried was an active repeater cable. It did promise to work, but I just had problems with connections or subsequent dropouts, so it never worked consistently. The hub at the scope I use is powered - you definitely need that.

This is essentially what I do. Laptop inside the house, and scope gets wheeled just outside onto a patio. The wires run through the middle of some bi-fold doors that I can still close. I run power and USB on 10m cables. I connect the 10m USB active repeater cable to a USB hub on the tray below the mount, and have "permanent" wiring  from there to the USB and iPolar on the mount (it's an iOptron CEM120, so is blessed with lots of through mount USB and power connections).

However, I think the problem you may have is USB 3.0.  I've never got USB 3 working properly over 10m cables, however I've tried. Certainly not to connect all the peripherals I need at once. And ZWO cameras seem to be more sensitive than other things. So my 10m cable is USB2. This forces everything "down" to USB 2, and it all works fine because what I'm shooting is DSOs, and even though I've got a fast set up, I'm not generally working below 20 second exposures.

On the odd occasion I want to shoot video for planets or moon, I'll go outside with the laptop and manually connect USB 3 direct to the camera, as really USB3 speed is essential for this.

Can you manage it with 5m?  That's more likely to work. Or just try it and see if you are lucky!  My problem was no doubt exacerbated by needing to connect 2 x cameras, focuser, power hub (for dew control) and iPolar all over the one cable.

I have occasionally got weird images like that in the day time when massively overexposed in Sharpcap, so certainly could be that

I've got hooked on astrophotography and can't call myself an astronomer. I've promised myself I will spend more time looking (with eyes and bins), and will try and start to properly recognise the constellations. The Plough bit of Ursa Major and Cassiopeia were the only ones I could easily identify, but I've got Cygnus now too, albeit it works for me as the Northern Cross.

I was likewise frustrated by cloud last night, having heaved everything outside.  I think it might have cleared in the early hours, but I took fright of a possible shower on the electrics and it at went back inside at by 11!

Just to add to my comments above, I have found the article linked below really useful. Although it's aimed at Pixinsight users, the first 5 sections are pretty generic, and give an excellent background to calibration. There is also some discussion on CMOS sensors and use of bias frames, and links to other material on this (the long Cloudynights post referenced in note 7 that points you at Jon Rista's comments is quite entertaining, come fraught / hilarious in places, if you've got time on your hands to look at it). Bias CAN be used with most CMOS cameras, and it certainly makes life easier.

https://pixinsight.com/forum/index.php?threads/for-beginners-guide-to-pis-imagecalibration.11547/

However, I suppose if you really don't need flats, then with these new CMOS sensors cooled to a suitable level, maybe you can get away with no calibration at all, particularly when dithering. As I have to use flats, I do the whole shebang -  bias and darks are a fixed set of masters that I don't need to shoot each time, so add next to no extra work for each image, just a bit of computing time.

NB  Yes that flat looks strange. How are you taking the flats?

Bias frames are a problem with some CMOS sensors. e.g. the IMX294 sensor in the ASI294MC Pro. I think this is due to particular (peculiar) characteristics at very low exposure times. For this reason, with this camera, I always shot flats and flat darks, no bias. Darks were necessary due to amp glow.

However, I think most CMOS sensors, and certainly the recent sensors, are absolutely fine. I have the ASI2400MC Pro (similar characteristics to ASI2600MC Pro) - and a single master bias frame works well with my flats, which saves me time, and avoids the problem of having to upset the image train on the RASA every time I take the flats, as stated above. I do use darks, but I suspect they are largely unnecessary. When cooled to -10, every master dark I have from 10s to 300s has pretty much identical stats, no amp glow, very few hot pixels.

As for flats - well, if you have dust motes, you will need them. And if you have vignetting (which I certainly do), you will also need them. If not, maybe not!

Yes that's right. AVX should avoid the rotation problem certainly. I think you will probably decide you want to guide though at some point.

My current setup with the 8 Edge is a ZWO ASI294MC Pro using the Celestron OAG (and another ZWO camera to guide).  Standard ZWO and Celestron adapters that come with the camera and OAG provide the correct back focus distance.

It's all a bit complicated when you get started - like you I started by sticking a DSLR (in my case Fuji) onto my 8 Edge HD.  You're correct though - take off the diagonal, attach the T adapter to the telescope, and the camera with correct T ring to the T adapter.

The space between scope and camera is critical to getting good focus across the whole of your camera frame / sensor. With the above, this should be correct (133.35mm for the 8 Edge at full FL). You'll notice that the T adapter comes in 2 pieces. By removing the shorter extension, you then get the correct distance for the 0.7x focal reducer (105mm). Easy as that! For long exposures (galaxies etc.) - the focal reducer gives you the advantage of halving exposure time (with a lower resolution bigger field - which might be advantage or not!).

Which mount have you got the 8 Edge on? You may find you're quickly frustrated, as without guiding, you will probably find that the mount tracking is not good enough to give you tight stars for more than 30-60 seconds. And if you have an Alt Az mount (e.g. Evo, like I had), you will get some rotation in the field beyond this sort of exposure (stars trailing in a sort of circular pattern around the field). 

Anyway, that's how I started...   but then I got a dedicated astro CMOS camera, an OAG for guiding, a Hyperstar lens for fast wide field shots, upgraded mount to a Eq mount, and then got a RASA 11 with an even bigger Eq mount etc etc. Addictive, expensive business, astrophotography! (but fun...)

I've been struggling all summer with this Veil Nebula 2 panel mosaic - it's been beset with various problems including failed meridian flips, operator error (failing to turn on camera cooler), and a general dissatisfaction with the stars (star problems are obviously even more of a problem with a mosaic). In the end I've gone with the nebulosity from subs using the NBZ dual narrowband filter  (41 and 35 x 240s) and the stars captured without filter (40 x 2 x 10s).

Anyway, I've done all I'm going to do with it, and am reasonably pleased with the result. As it fits this challenge, I thought I'd enter it!

RASA 11 v2, CEM120 mount, ZWO ASI2400MC pro camera.

I'm not surprised you had divided opinions - there's nothing in it between those three shots is there really? 

But thanks - I'm honoured!

Here's another (and final) attempt from me, NGC 7023, the Iris Nebula, a first go at this target. I thought this would be a good one for 30 second exposures - with no filter this is probably around optimum with the RASA in my Bortle 3 skies. But I also needed no moon, and just managed to grab this early last night (29th Aug). I had various issues with the calibration and some strange artifacts coming from somewhere in the image train, but fortunately the large frame available allowed me to crop most of these problems out!

RASA 11 v2, CEM120, ASI2400MC Pro, IDAS ODW (clear filter - optical distance worker),  99 x 30 seconds.

Robin

Here's another one from a couple of nights back. NGC7000, North America Nebula. 85x30s - same equipment as above, but processed (in Pixinsight) using pseudo Hubble palette to try and bring out detail, particularly the Cygnus Wall.

Robin

here's a first attempt from me - a widefield shot of M27, the Dumbbell Nebula, taken last night.

85 x 30s taken with ASI2400MC Pro and NBZ dual narrowband filter, on a RASA 11.

A nice bright target to go for when the moon is up, and although perhaps a bit small for this resolution, I like the way it looks a bit lonely and isolated amongst a wide star field! On the downside, the moon gave me some gradients which I haven't managed to totally remove, and my stars in the corners remain a work in progress!

Just came across this thread, thank-you...  

I'm a bit fed up endlessly fiddling with my Hyperstar in the freezing cold desperately trying to get "pinpoint star images" as promised. I didn't realise the RASA8 could take an ASI2600, the central obstruction is wider than I thought. I also hadn't twigged that the additional weight of the RASA over the 8 Edge HD was relatively small, so my CEM40 will carry it fine. 

Apart from the expenditure, I'll probably have to wait months too, but I'm sorely tempted. 

Hi - did you sort yourself out with this? I have the Edge 8HD, Hyperstar v4, and ASI294MC Pro too. I have spent ages trying to get the collimation right, including making sure the corrector plate is centred, and endless looking at defocused stars.  But despite very carefully getting the "doughnuts" as right as I can, I always have coma in all 4 corners facing in to the centre, implying collimation not right or spacing not right. I'm starting to worry that the spacing is the problem although that seems weird -  I assumed that having specified the right camera, I would just stick the camera with its standard nosepiece onto the Starizona adapter and all would be well, and  a very rough measurement suggests I'm about right for 39.8 from the start of the adapter to the sensor.

So - sorry, not providing any answers, just interested in your experience.

I have a CEM40, purchased fairly recently so still learning. I take in and out in a similar way to Paul, so in theory don't need to reset zero position. But any playing around while switched off does mean you need to do this.

The Search Zero Position function does allow the mount to find the zero position itself, so you don't need to do it by eye. I use this and it appears to work fine. Just make sure the mount is totally level first obviously.