ollypenrice

You won't be able to capture detail at 0.86"PP because of the seeing, From what I remember of Derbyshire, I think you might need to double that figure, in which case your guiding is close to meeting your requirements, but I can understand that you'd like to improve it. I rather doubt that your guide trace is limited by the pixel scale of your guide setup: it's more likely to be limited by the mount's mechanical errors. You could certainly try an OAG but, from my fairly high site (900M) I've developed a liking for the ST80 as a guide scope. It gives a 400mm FL and has enough light to find stars everywhere. This may not be the case with with a Barlowed guidescope. Have you tried running the PEC on the mount as well as the guider? I've never tried it but several members have found that it worked for them. Olly

What is the pixel scale of your present guider and what is your imaging pixel scale? And, maybe, why do you ask? If you have a problem, what is it? Olly

What we see is wonderful. It's detailed, contrasty, colourful... bang on the money. I can't help wondering, though, if there might be faint stuff in your data which we are not seeing. Obviously, I can't know whether this is so or not. Olly

Indeed but, so far, all it has done is impede the OP's ability to take a picture. My point is simply that it isn't necessary at this stage. Olly

Too much software. Why don't you just use the handset, do a star alignment, GoTo your target and take a test sub? You will probably want to nudge the framing a bit so use the handset to nudge it, take another test shot, repeat and then start your autoguider. Because you are trying to use external software to find your target you haven't even got to the stage of running your autoguider. A PC mania has overtaken astrophotographers in the last few years. The only way to find your target is to plate solve... etc. This is nonsense. 95% of the images in my gallery were located and framed as I describe. https://ollypenrice.smugmug.com/Other Olly

You have the right information, here. Olly

It's the most likely cause. It can be difficult to get the green balance right because it can be too high in the low brightnesses and too low in the high. We know that green is critical, which is why we have SCNR Green, Hasta La Vista Green etc. The other end of the green axis is magenta, which also looks glaringly wrong on stars. Green-Magenta is, therefore very unforgiving. Have you tried one of the star removal routines possible these days? Starnet++ or StarXterminator. I'd highly recommend them. Once the stars are separated their stretch and colour can be adjusted independently of the rest of the image before they are replaced. Olly

There's also an argument, I think originally voiced by Sara Wager, for just having two mounts. Olly

Thanks Alan, I'll have another look at that. (Erm, I wouldn't drink Coca Cola if you gave me fifty quid but maybe a beer can would do instead?) lly

Same here! lly

Our system is all screw fit and the camera has no tilt plate. Basically the camera screws into a tube and the other end of the tube screws into the lens. The tube is telescopic, the male and female parts of it being threaded together. The camera doesn't have a face plate, just a female thread to take the telescopic adapter tube. I think we may be shim-proof! Personally I think we've been pretty lucky with a chip this size and a camera lens at F2. Maybe we just get on with it as is. Olly

Or you buy my Cassady T-GAD, now out of production, but that would be even more expensive! Since it will carry a 14 inch it might just be considered overkill for a Samyang. lly

Thanks, I think it will be tilt, as you say. I'm not sure it's worth struggling with it since disturbing this kind of setup is likely to cure one problem at the cost of provoking another. However, where would you put the shims? Olly

I don't do this kind of imaging but my very expert friend Tom O'Donoghue produces land and sky images at the top of the game using a Star Adventurer and Sequator software. I wouldn't push the focal length too far, though. 400mm is telescopic in its demands. Olly

Thanks for responding. We have an infinitely variable Baader extension in the system and, having tensioned the belt of the focus motor, we can still build a V curve at this distance, which plate solving says is slightly short of a FL of 135mm. Maybe we should stop there. I'm curious to know how good the corner stars can be on this chip, though. Olly

Would you experienced users care to comment on this, our worst corner on a 2600 chip wide open and shown here at 100%? The other corners meet the house standard. Our last tweak was a 0.2mm reduction in backfocus and was an improvement. Given that these aberrations are confined to a tight crop of one corner, we are inclined to try an image. Experience with the RASA suggests that a stack has better corners than an individual sub and Blur X might work on a stack. It didn't help the star shapes on this single sub. Seen at 50% we feel the corner looks fine and at 66% it seems acceptable. A two-minute cosmetic fix in Ps takes the corner to here: Are we in the zone? Olly

Negligible CA. I would never have given it a thought. However, on my monitor (which is calibrated) I see no green caste but I do see that your blues tend towards magenta, suggesting too little green weighting. Look at the bright star half way down on the right. I had a play with a screen grab in Photoshop and tried to lose the magenta dominance in blue. I also tried to bring out the blue in the Iris and open up the colour in the dust. Basically this meant a lift in the lower brightness reds. I felt that, above the fainter signal, you did have a green deficit. Olly

Yer doomed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! lly

Very tidy, bound and bundled cables are all very well till one of them packs up. Sod's law tells you that this will happen within minutes of your setting up the system. Sod's law has a point! (I host 6 robotic setups...) Products like the Pegasus offer a neat solution but they introduce another product to go wrong. One that I host found a short circuit in the mount and refused to power it up but, when the mount was connected directly to the mains via a 12V transformer, it worked fine. On the setup in which I'm personally involved, we have no USB or power hubs. We drive every item from its own 12 volt transformer and all our USBs go into a desktop PC with sufficient USB ports to make this possible. This is bliss. lly

Nobody on CN has thought of that... lly

According to some sources it is best to clean reflectors reasonably often because pollen can be chemically aggressive. Some insist that you shouldn't squirt the wonder fluid onto the lens but only put it on the cloth. I tend to think that dissolving is the gentlest of treatments so I do squirt the lens but I don't leave it for long and keep it pointing downwards -ish. A dabbing action with cotton wool means there is no need to move any grit relative to the surface. In the end, lens coatings are not like soft aluminium mirrors so I clean mine fairly often (2 or 3 times a year.) Olly

If you doubt the regularity of your panel, just rotate it during the shooting of flats. It doesn't matter if the panel moves during an exposure. Olly

I've found the dedicated ones from astro suppliers to be disgracefully unreliable. I had several failures with Aurora panels which use thin, essentially rigid cables which break at the joints. And I've just had a large (hundreds of euros) Geoptik panel peg out, just out of warranty. They do work, when they work, and make life easier but I've spent enough on them and am done. I'll make my own, as I did before they appeared on the scene. Olly

Before the diapers go into the laundry? Is this strictly essential? 😄lly

What bugs me about socks is that they are made in different colours. The stupidest thing is a pack of three pairs which are different from each other. This means you have to find and match them, which you never can, and so you have to go out armed with that old joke, 'There's nothing odd about these, I've got another pair the same at home.' Twice I have bought a large number of identical pairs and twice this has failed, after a time and for reasons unknowable, to solve the problem. The next time I do it, I'm going to buy one hundred identical pairs and burn all the ones I have in stock! If that doesn't work, and I have a morbid feeling that it won't, I will abandon all hope and surrender my soul (sole?) to the forces of darkness. Olly