ollypenrice

One more for Baader film and remember to cover you finder! Olly

The last great eyepiece professional and the first great astrophotography professional were one and the same person, the incomparable E.E.Barnard. Olly

Six stars in the Trapezium? But yes, in terms of faint stuff, the camera is a hands down winner. Olly

We've used 14 inch, 8 inch, 5.5 inch, 4 inch, 3.5 inch and lenses of 200, 135 and 80mm here. They do what they do. We did find that a good 5.5 inch apo could resolve at the limit of the seeing, pretty much, and that more aperture did not really produce more resolution. If the aperture were used to produce more light grasp (at fast F ratios) then it would, in principle, be great - but you'd need to find optics as good as the TEC140 and, though possible, that would not be easy. Olly

Several answers: 1) Part of astrophotography is deciding what data to capture. What wavelengths, what field of view, what framing? If you just buy data you don't have much control of any of these important factors. 2) A metre class scope in Namibia is certainly going to out perform a metre class scope in the UK but it is not necessarily going to out-perform a 5 inch in the UK or anywhere else. With aperture comes focal length and a metre class telescope, even at F3 (which is optimistic) would have a 3 metre focal length. That will give a tiny field of view. Giant optics can do what they do very well. Tiny optics can also do what they do very well. In the real world, nobody is going to take the image below with a 3 metre focal length. It took 42 panels to shoot it with 135mm focal length. Much of the fun of making this image came in the form of 'Can we do it?' A hell of a lot of obstacles stand in its way. That said, I don't know whether or not I would do deep sky AP if I lived in the UK. Olly

The Vincent motorcycle was described as 'A solution looking for a problem.' I think we see that here... Olly

That really doesn't look like a camera lens image, does it. Excellent result. Olly

I wonder what problem they were trying to solve by offering a fine focus solution? Olly

I think it's more usual to mount a motor focus on the fast focus shaft. Could you do that? (The motor can move in tiny increments and reducing backlash is good.) Olly

I still do! lly

4000 euros is a lot for a casual casual user to pay and I don't really see this as being of much interest to someone seriously interested. It seems to be an 'enthusiast' price for a sub-enthusiast product. Olly

17mm is huge so you've probably cracked it. If using a filter, add 1/3 of the filter thickness to the backfocus. Filters are often 3mm thick so add 1mm. Olly

I take this view with all reducers! Olly

I live in a permanent state of semi-retirement, Harry. There's a lot to be said for it! Olly

Hello Harry! It's been a while. You need to come and see us... Olly

Yes, I think making 2 images is the only way. I would then co-register the larger FOV to the smaller in Registar and crop it to fit. As for how to combine them, I think you'd want to give each one a test stretch of its own to assess noise and resolution. I'd probably give each a basic stretch, not too hard, put one over the other in Photoshop layers, set the opacity to 50% at first and then move the opacity slider each way to see where I got the best result. I'd flatten and then stretch harder. There are lots of ways to kill this particular cat, depending on software. Olly

Do it-.More data beat less data. You may not really reach a true resolution of I.3"PP anyway, and 2.49 is perfectly respectable. There are some very fine little details in M78 but the bulk of the image is about faint stuff, so signal is the key. Olly Edit: when you co-register the data, register the lens to the scope - but I'm sure you would anyway.

I'm never comfortable with very green NB palettes and find that much more appealing. Olly

Well, in a way F2 systems are cloud guns... Oly

No, doing their publicity networking for them... Olly

Whatever it is, we are all doing just what they want us to do! lly

Agreed. Olly

https://www.teleskop-express.de/shop/product_info.php/info/p14967_TS-Optics-ToupTek-Color-Astro-Camera-2600CP-Sony-IMX571-Sensor-D-28-3-mm.html In the great tradition of SGL this is over budget but not excessively so. I use one of these and also the ZWO equivalent. I'm happy with it. We use it with a Samyang 135, viz I think it is all but certain that, if you buy a small chip, you will crave a bigger one and buy twice. Olly

What the RASA needs, based on two years and hundreds of hours use, are the following: - A system of collimation which leaves the camera in place. - A system of tilt adjustment which leaves the camera in place. If these could be managed remotely, or even automated into the system, the RASA would be perfect. - A built-in slide drawer. Olly

330mm focal length. Nice, assuming it can cover an APSc chip. Pity the F ratio is so slow, though. (More seriously, 2.2 squared is 4.84. The 2 squared of the RASA 8 is 4. The difference is not totally insignificant at these speeds. Still, not a big deal!) Olly