Clarkey

I have done the binning in software for each channel as you suggest, but not using PIPP. (I have downloaded it for trying planetry imaging at some point in the future but not used it yet). If it has a 'summing' function I might try it out. Affinity uses a number of algorithms but I could not see a huge reduction in noise. Thanks.

FWIW I have tried binning my ASI1600MM both in the camera and in software afterwards and I struggled to see any significant difference. Similarly using un-binned made very little difference to the image quality. Obviously, as the ZWO CMOS cameras average the 4 pixels when binning 2x2 there is no real advantage in 'speed'. It is a shame that they do not 'sum' the pixels in the camera - that would give a significant increase in data capture rate. Given the very low read noise of a CMOS sensor I have never really understood why this is not done? Perhaps someone more knowledgeable than me could explain....

Hello and Welcome to SGL. As masjstovel has said, there is not really a correct answer. Personally I would by the CC first and then modify the camera for two reasons. Firstly there are quite a few targets that will not need to pick up the extra Ha data and secondly, the coma will be evident in all your pictures unless very heavily cropped. You can still image DSO's without the modification, you might just need a little longer. Also, you can always add more data to your images later - you won't be able to do this if you buy the CC second as the star shapes will not match. With regards to the mount, what has been said is also true. However, if you have an EQ5 this is what you will need to use. You might need to keep your subs slightly shorter than ideal, but this should not be a major show-stopper. I just hope you don't live anywhere too windy!

I really like it. The dust gives it a great feel.

For the limited integration time that is a good result. Well done! I can't really help with the processing as I use Affinity. The only thing I would say is you can use layers to stretch the nebulosity more than the stars or use a star mask.

Thanks. Appreciated.

The APT dithering can be set to adjust the mount only for widefield imaging (I just randomly moves the mount slightly). This avoids the need for a program like PHD2. From the APT manual: "APT Dithering is special feature made to provide dithering when there is no guiding because your mount is high-end (ASA, 10Micron and etc.) or when you are using short focal length lens or telescope. APT Dithering uses a mount connection to make the needed random position changes between the exposures" If you go to the APT website you can download the manual and have a look at the functionality.

I think I saw some of the advice from Olly and Alicante - for some reason I thought this was for the SW Quattro. I think in a while I will be really looking at one of these when finance and financial manager (wife) approves. I quite like the idea of the Mn190 but the weight puts me off as I have to set up each night. This would be slightly easier to cart around.

How do you find collimating the F4? I have an F5 newt which is relatively easy, but I am lead to believe the F4's are much more tricky to get right? Having said that, I need to collimate my 8" RC which I am dreading😬

That is really impressive for 90 minutes of data. 👍

Just to add to my earlier comment. To manually dither you can just use the hand controller to move the image in the camera a fraction at a time every few frames. This will get rid of the walking noise. If you have dozens of frames you only need to do it every few minutes. Alternately I would suggest a laptop with some basic control software which can dither for you even without a guider. It will also help with things like focusing and framing.

I'm not sure how you find Gimp, personally I did not really get on with it. I purchased Affinity Photo which I find excellent. At the moment it is 50% off at 24 pounds which is a months rental of PS. Also, the developers seem to be getting on the AP bandwagon and are starting to add useful tools. There are also some macros available from James Ritson which can help.

Slightly better version - slightly better processing (I think).

Thanks for the comment. This was taken using the ASI1600 mono.

Despite my head saying 'forget it', with 3 nights of clear skies forecast I felt I had to image something. Narrowband would have been a better option, but due to available targets from my garden I decided to have a crack at M51. In total I managed 17.5 hours integration, unfortunately a large proportion of this was in the blue channel as I put the wrong filter in my sequence. In addition, on the first night I got my gain setting wrong on the calibration frames and the following night the mirrors were covered in dew by the morning. I ended up having to use one set of calibration frames for all 3 nights. I guess the usual frustrations of AP🤬. Anyway, given all the challenges I am quite pleased with the result. (I know the collimation is out on the RC8 but as yet I have not been brave enough to try an re-align in). Any feedback welcome - especially with regards to the processing as I still have a lot to learn. Thanks for looking. 68 x 3min Lum 59 x 3min R and G 117 x 3min B 30 x 5min Ha Processed in APP and Affinity

Maybe the Iris nebula is like the place in the sea where all the rubbish collects! It's unbelievable the amount of space junk.

You best option will be dithering the images. Even if you don't guide, some software allows dithering (APT and NINA I think do this). If you are just using an intervalometer and saving in the camera, just shift the image by a few pixels every few frames.

I had some similar issues with my flats last night. The previous day with exactly the same set up they were completely fine (I ended up using the previous days flats as nothing had moved and I ran the same image plan for two nights). I have put it down to condensation on the mirrors or camera. It looked similar to this except the centre of my flat was dark. Could this be something similar?

Really nice image. Great colour. Whenever I see this I still struggle to see the monkey though! Definitely one for my 'things to do list'

Looks like dust in the image train on a reducer, flattened or filter. It will be tricky to pick up on calibration frames but it should be removed by flats. You will only notice them on stacked images because they are so faint on a single sub.

You need to move to Penrith for the clear skies and sunshine😉 The delights of F4 imaging. That detail would take me a few hours......

I have a similar issue with my new RC8, although it is not as bad as this. I believe it is due to tilt on the focuser - this effect is exaggerated by using a reducer inserted in the focuser tube. Although the collimation is pretty good, the focuser alignment is definitely wrong on mine. (You can see the offset reflection on a very bright star shown by the mirror reflection being out of line). I put a simple laser collimator in the focuser and this shows the reflective plane of the secondary does not line up with the focuser. Rotating the collimator shows the offset is consistent. I am hoping to get an M90 tilt adjuster to compensate. Unfortunately this is down to focuser being attached to the primary mirror - but very slightly out of alignment. I would wait for some 'expert' opinion on this though. I am new to the RC8 so I might be wrong!

It might be - I got two of a faulty batch of FF / Reducers from SW in the summer so it does happen. However, as the stars seem to be pointing out to the edge of the frame it could be the distance from the FF to the sensor that is slightly out. Difficult to tell in the top right as there are no big stars to look at in detail. Maybe try altering the spacing slightly and see if it improves. Ian

Regarding the cooling question - cool to the same temperature regardless of the external temperature. I normally cool to -20 but in theory it would be possible to go lower. I have my Darks library at -20 so it make sense to keep at this temperature. Below this temperature you will not see much improvement in the amount of noise from the sensor. Having said that, you could try it and see. The only possible benefit of not cooling so much is if you were running a mobile unit from a battery. If it was warm you might want to save power by reducing the cooling current. Not really a problem in Cumbria!

As has already been mentioned, longer subs and much more integration time will really help. But a good start none-the-less. WRT the vignetting, this should be removed by the flats. I assume the stacking has been set up correctlty? I'm not sure of the size of the 533 sensor, but I can use a 1.25 connection on my 1600mm without issue (although this is right at the end of the image train).