ollypenrice

It's very good, no question. But it is also, by a mile, the brightest DSO in the sky. When I last imaged M42 I used 11 second subs for this, the Trapezium region, and 15 minute subs for the outer nebulosity. That gives an idea of just how bright the Trapezium is. Olly

Yours is the first of the two scenarios. This is actually good news because the other source of elongation, besides tracking, is tilt - and that's a pain to sort out. Yours is the nicer kind of problem to have! lly

General points... Since planets can usually be seen from home, and since small apertures cannot reveal small, faint extended objects anyway, my thinking has always been that compact travel scopes should be able to do what small scopes do best - and that's widefield. I wouldn't make higher powers a priority. I'd also be reluctant to use a light-consuming complex EP in small apertures. Olly

Another way to think of it is to remember what 'magnify' means. It means 'to make larger.' When you look at the moon with naked eye the moon's image on your retina is a certain size. When you use optical aid, the size of the image on your retina will be made larger than it was before, and by a definable amount, 10x, 50x, 100x etc. This is all nice and easy: we have an image on a retina and that is what we magnify. Now point an imaging telescope at the moon. It collects and focuses light and projects an image onto the chip. Is this image 'magnified?' Magnified over what? There is no definitive baseline size equivalent to the image on the retina so we have nothing to 'magnify.' We certainly don't magnify the moon since our image is a fraction of the moon's size. The only magnification to be found in photography is in the macro world. Some macro lenses can project an object's image onto the chip, an image which is larger than the object itself, and this is, quite reasonably, known as magnification in macro photography. In fact, all telescopes compress the moon's image to a tiny fraction of the moon's real size. This is really negative magnification! Olly

93x3 minutes this time. Paul does this bit so I always have to look it up. Your wish is my command! Some of the cosmetic processing was done after the crop so I've made no real effort with the bright stars. I think the crop has the best of it. Olly

I do like this region not to totally swamped by Ha signal, leaving the details, like the trunk, picked out in silhouette as they are here. Olly

This is indeed a loss. I had the pleasure of Steve's company as a guest here, a few years ago, and endorse everything said. Olly

This may come as a surprise, but I have never dithered. Caveats: I've only ever used cooled cameras. I've never bust a gut to finesse polar alignment, though, in the CCD days, it needed to support 30 minute subs. Now it only needs to support 3 minute subs. Given the short exposures needed by CMOS, and their tiny pixels and low read noise, won't a small polar alignment error provide any dither that your system actually needs? If it really needs any at all? I would forget the clamour of the orthodoxy and received wisdom and just try not dithering and getting more good subs. Olly

ELP is right, but you white point is also clipped. Here's your image with its histogram in Photoshop. A healthy histogram looks like this. (I'll use my own Heart Nebula here.) On the left to right axis the histogram goes from dark pixels to bright. On the vertical axis it shows the pixel count at a given brightness. What we see in your histo is no thin line on the left. That's because you have 'black clipped' your data, cutting out pixels with slightly more light than the background sky. This leaves you with a jet black background sky and your faintest signal discarded. On the right hand side we see, also, that the line exiting the graph is not dead flat either. Your brightest pixels and your slightly less-then-brightest have been cut off before they can be distinguished from each other. This is, without doubt, the most common beginner error and is easily fixed, but only by stretching from scratch. When it's clipped, it's clipped. It is very tempting to try to fix sky gradients by clipping them out. My advice is never to do this. Gradients must be fixed by gradient removal tools which are now many and various - and very good. Olly

My favourable (and very short) review of the ST80 as a guidescope goes like this: Running an old school, low sensitivity CCD Lodestar in an ST80, I imaged commercially for around ten years, and about 250 nights per year, without dropping a single sub to guiding error. The mount was a Mesu 200. Olly

I like this object, the third in our recent run of four. Capture and pre-processing by Paul Kummer, my post-processing. RASA 8/NEQ6/ASI2600MC Pro. This is cropped to about 25% of the full frame. Olly

No guidescopes have alignment rings. What they have, if they have rings, are misalignment rings which were used in the days of insensitive autoguiders which needed to be pointed this way or that, relative to the imaging scope, to find a workable guide star. Those days are long gone but manufacturers insist on still providing them, leading to the modern myth that guidescopes need to be aligned. Actually I think they are just there because these scopes are based on findersscopes which do need to be aligned. A rigid mounting is much to be preferred. By the way, I've started using one of these mini finder guiders a couple of years ago and consider it a darned nuisance. It de-focuses itself a couple or three times a year. When I was using locked-up-solid ST80s for guiding I never touched them in ten years, scraping out the worst of the spider webs every three years or so. The worked perfectly. I'd be delighted to see the back of the pretty little anodized pest which replaced them! Olly

The lighter has more information, the darker has more mood... or so it seems to me. Keep 'em both! Olly Edit: I should have added that both are flawless.

As usual, Paul Kummer drove the scope (based here) from the UK, did the pre-processing, and the post-processing is mine. RASA8/EQ6/ASI2600MC Pro. The nebula is just the bright spot below the centre but the dusty nebulosity is rather shapely as well. This is a considerable crop with full resolution (of this field) here: https://ollypenrice.smugmug.com/Other/DUSTY-DARK-AND-MILKY-WAY-TARGETS/i-6k82XXG/A

Exactly what I did, with the same consequences! Olly

The first from a breathless run of four images captured by Paul Kummer and post-processed by me. This is a two panel, RASA 8/NEQ6/ASI2600MC Pro. It isn't often imaged and is very faint. The red was hardly present at first glance but, after seeing a rendition from the Atacama in which it showed strongly, I went after it big time. (There is a long standing rivalry between the Atacama and Les Granges. ) Whether this red is Ha or ERE (Extended Red Emission) I don't know. I don't think the person who called it the Wolf was as familiar with this fine animal as we are around here, so it's also LBN917 Olly LBN917 RASA 8 2 Panel CropHi blue downV2.tif

Nice result with good control of the bright and the faint, which are a long way apart in this target. Olly

Nice! Olly

Last night I went outside again had exactly the same experience, with the same star. This has set me pondering about whether the effect might not be directly caused by the cloud, but by some process going on in the brain. I don't get the effect when I go out into a clear sky but perhaps something needs to settle in the brain when it observes a single star isolated by cloud. Something to do with orientation? I will try to find out whether I still get the effect if I'm dark adapted before looking up. Olly

A few nights ago I went outside to find a semi-cloudy sky and noticed a bright light in a hazy patch, west of south. I saw it very clearly move directly downwards at a jerky, variable speed so I wondered what it was. As the sky cleared it stopped moving and turned into a perfectly normal, stationary star - which is what it was all along, of course. I don't recall seeing this illusion before but it told me a lot about why people think they see moving objects. I suppose the clouds create the illusion but can't be sure. It was very striking and I'd have sworn I saw a downward trajectory. Olly

This could be a small desk-top tripod if there's a suitably placed desk. I don't suppose windows on 30th floors open up all that widely? 👹 Olly

I love the first one, especially in its rendition of the dust (and I agree with tooth_dr about the refreshingly different framing. In the second one I feel the colour has gone out of kilter, especially the Flame which has lost its unusual orange-yellow. Olly

Seems very odd to me. Are you sure? You really do need to exclude all light when taking darks. I compared darks done on the scope with the lens cap on with darks done with the camera off the scope and its metal scew-fit cover in place. The ones done off the scope were different and had slightly lower ADU values. I can imagine an opaque filter plus a lens cap being useful but some scopes, notably Newts, often leak light from beneath the mirror. Off axis guiders can also let light in. Olly

I don't think the stars are over-controlled except in terms of their colour. Of course, most star colour is found around the fainter edges so, when these are reduced, so is the colour. If you could get a bit more colour into them I think you'd be spot on. It's a tricky target to process and I think this is very decent indeed. Olly

Long integration always shows its class. Olly