cfpendock

I think that this is a very good image, although I'm not sure from where you found the time with clear skies. I like the OIII very much - certainly well worth the 11 hours! Chris

Very nicely done, Martin. I think you've got the blue absolutely right, and I like the star colour. Personally, I think I would dial the red back a bit, but really this is an excellent image. Chris

Nicely done for a difficult target. I like the processing, and you've managed to reduce the stars very well. What scope was this? Chris

Keep going and eventually you will get there! I frequently image at 2800mm focal length and although it is true that SCTs do produce rather larger "wooly" stars, this can be overcome with careful setting up and processing. I have found the following helps: Use of an off axis guider - almost essential for long FL work, and you should be able to guide at around 0.25 secs. But in order to achieve this, attention to balance is critical - I usually balance slightly off so the mount is always pushing slightly - I find this helps with overcoming backlash. With my C11, any significant wind ruins everything. As has been pointed out, round stars are no indication of good guiding. When focussing the SCT, I always make sure that I am focussing so that the for the final adjustment the mirror is being pushed upwards ( I do use an auto-focus system), but I find focussing at F10 anyway is not too difficult compared to short focal lengths. To keep the stars from bloating, I always re-layer a less stretched version into the final image as Olly suggests above. It seems to me that your subs are quite short. Do you have a lot of light pollution? I normally have average rural light pollution, but I do use subs of around 5 minutes. For your information, my sampling rate is just over 1"/px using my Atik 4000 and binning 2x2. I stack in DSS and process in Photoshop. My version taken at 2800mm FL is in my album: https://stargazerslounge.com/gallery/image/33396-ngc-891png/. Hope this helps. Chris. (No, seriously!)

Thank you very much, Martin. Your comments always very encouraging! Chris

Thank you very much Hallingskies. Yes, the tracking from my EM200 is pretty good - around 0.3 arcsec, but I take care under-balance slightly so that the mount is always pushing. Yes, I think you are right - the noise reduction is excessive, but because of the light pollution, the image was otherwise horribly blotchy.... But I did cheat on the core by using some selective sharpening which absolutely did not work on the outer areas....I shall try again when I have a moment. It is exactly these kind of comments which I find extremely useful - I get blinded by looking too much at the same thing! So once again, thanks. Chris

M74 is a rather faint galaxy around 30 million ly distant. It measures around 10' across, so a perfect size for my C11 at 2800mm focal length and Atik 4000 camera which gives around 20' field of view. I managed to get 16 x 5 minute subs each of RGB to add to my previous 24 x 5minute subs of luminance. I decided that this was enough for now due to banks of LED lights on nearby roadworks (which will continue until April), but I have managed nevertheless to squeeze out a bit of colour. Any comments / criticisms welcomed. Chris

Thank you very much Martin. Yes, I was a bit surprised to get much detail with the light pollution. Unfortunately the bank of lights will stay until April, so although I will try colour, I suspect it may be rather "washed out". The EM200 does indeed work well - I would say almost faultlessly, especially with around 16kg of kit on it. And guiding to well less than 0.4 arcsec.... Chris

Thank you very much Dave. I think for using as a luminance I suspect that I may need a tad more contrast as I have experimented with as below, although I have to say that as a stand alone image I prefer the first. Chris

This was my first go at imaging since February so everything was a bit rusty. However, all the kit still worked, together with my trusted Windows XP, and I managed to get two hours worth on this galaxy. Surprisingly difficult to find (it is rather faint), especially as I have serious problems with light pollution from nearby 24/24 roadworks which use amazingly bright banks of LED lights to illuminate the surrounding countryside. However, it was the first clear night for ages so I just had to give it a go. I managed two hours of luminance before the fog/mist rolled in, so hopefully I might be able to augment it with some RGB soon. So, definitely “work in progress”, but despite the light pollution problems, I am quite pleased with the result so far. It is rather blotchy, but perhaps some more time will help to sort that out, or even better, if someone on this forum can point me in the right direction? Processing was Photoshop CS5. Imaged with my C11 at 2800mm focal length and Atik 4000, all on an EM200 mount. 24 subs at 5 minutes each. All comments and criticisms very much appreciated. Chris

So would I. What is the existing roof - not asbestos I hope as this is a pain to get rid of. Chris

Very nice and detailed, especially considering it's apparent size of only around 5 minutes. And excellent star size and colour (as can be expected from this source). And that TEC certainly works! I must give this one a go with my C11- if our skies ever clear...... Chris

I am not an expert - I use a 23mm Luminos. But they can be expensive....around £150. Chris

A lot. I have one. Stars, clusters and planets are very good. Of course, it depends on the eyepiece - you should have a good one to see the best. I don't have very good skies, and galaxies and nebulae are not outstanding, although that is normal for any visual observation. I also use this scope for astrophotography where I find the long focal length very good for small galaxies. If you look on my DSO albums on my profile, the wizard, NGC660, NGC891, Stephans Quintet, and NGC 3718 among others shows what this scope is capable of. Chris

I like the 3D effect your processing has given this. Very nice. Chris