michael.h.f.wilkinson

Managed to get 2.5 hours of H-alpha data on NGC 1499 last night, using my (second-hand) ASI183MM-Pro, an Astronomik 12 nm H-alpha filter, and Canon 200 mm F/2.8 L lens. I stacked the result with darks, dark flats, and flats with Astro Pixel Processor, and gave some last tweaks in GIMP. There is a halo around Menkib, but otherwise I am pretty chuffed with the image. Next time I might actually turn to a wider lens, like a Carl Zeiss Sonnar 135 mm F/2.8 (Contax mount) I have lying around, or the Sigma 50-100 mm F/1.8 zoom, to capture more of the context of the nebula. For the latter I might need a different H-alfa filter, as it is too fast for the Astronomik.

Calling it a day. Got 2.5 hours of data on the California Nebula, now creating flats and dark flats, and will leave APP to stack the lot

Got everything up and running. First tried the Flaming Star Nebula, but it was too close to the moon, so switched to the California Nebula.

Or just use a telephoto lens. I will be testing my ASI183MM-Pro with a 200 mm tonight

The ASI183MM has a nice FOV and resolution for a small wide-field rig, like my APM 80 mm F/6 with 0.8x reducer

I do wear glasses when observing.

Just had a look at a list of likely targets, and the 200 mm F/2.8 L has the nicer framing of them, and isn't too fast for the Astronomik 12 nm H-alpha filter, so this will be the imaging combo this evening.

Things get worse if you don't have a permanent set-up, and you have to tangle/untangle the cables every time

I also wonder how well it will perform in such a fast lens. I might go for the Carl Zeiss Sonnar 135 mm F/2.8. I might want to ge the Baader F/2 rated ones. Regarding the camera, it is also the first higher resolution monochrome CMOS camera I will be using on deep sky. I have an 8 position filter wheel (also ZWO), so I should be able to catch some nice sequences automatically. I like the way the camera has a built-in USB hub, which does cut down the cables.

I have a Baader 35 nm, but also a narrower Astronomik 12 nm, which I will use tonight.

I got a second-hand, but good as new ASI183MM-Pro last Friday, and am looking forward to first light this evening. It is my first cooled camera, and it feels like a real luxury to be grabbing dark frames at a set temperature during daytime, rather than wasting precious clear skies on that chore. I have slotted an H-alpha filter in between the camera and the Sigma 50-100 mm F/1.8 zoom and will go for a target like the Flaming Star Nebula, or California Nebula. I hope the filter will cut out enough moonlight. The darks show a little amp glow when stretched, but that was to be expected. This is just a single dark, stretched.

I haven't had any issues with the flat cables (yet), but I do have a collection of higher pedigree cables I tend to favour. I keep an eye out for issues, and bin them at the first sight of trouble.

I have the ES 12 mm 92 deg EP, and it is brilliant. I also have a 14 mm Delos, which is a lot lighter, just as sharp, and perhaps a shade more comfortable, but I find the ES 12 mm 92 deg absolutely superb. It definitely beats the Tele-Vue Nagler 12 mm Type 4 for viewing comfort (and FOV), and even has a slight edge in terms of image quality. It is rather a beast in terms of sheer size: For reference: that is an 80 mm F/6 refractor

I have had no issues using 80x with my C8 on the sun, especially when observing fairly early, when seeing is usually best

Another configuration would be with the Sigma 50-100 mm F/1.8 zoom That lens worked beautifully at full aperture when imaging NEOWISE on a bigger sensor, so certainly worth a shot.

I have been using a copy of the Revised Shapley-Ames Catalogue of Bright Galaxies to select targets

Might use it in this configuration for the Spaghetti Nebula, with a Carl Zeiss 85 mm F/1.4 and H-alpha filter.

I don't extend the exposure time for my subs. If my tracking orguiding was better, I suppose I could extend them a lot.

More like a 4.5" F/4.3 Newtonian. I have one that works happily with a 20 mm Plössl, or a 24 mm 68° Maxvision, but not so much with a 4mm planetary EP.

Sometimes these fast Newtonians with spherical mirrors are intended as "rich-field" telescope. Thus, they are intended for low magnification, wide-field views, where the coma of a parabolic mirror might actually be more troublesome than the spherical aberration of a spherical one.

I have the un-cooled, colour version, and that doesn't show much in the way of amp glow, if darks are used, so I guess this should work well enough.

An ASI183MM-Pro came up for sale for a song here in the north of the Netherlands, so naturally, I caved in. Can't wait to try it out

JAY!! Brilliant stuff!

Alas, yes. They wouldn't suit me, however, with just 7 mm ER. I will stick to my amazingly good Helios LightQuest 16x80s. Absolutely superb and about the same weight as the Helios Apollo 15x70s I had before.

If you are willing to pay a lot of money, there is the Nikon WX 10x50, with 76.4° field of view at 15.4mm eye relief. https://www.nikon.co.uk/en_GB/product/sport-optics/binoculars/wx/wx-10x50-if A snip at £6,199.00 The Vixen Ascot 10x50 ZCF Super Wide sport an even more impressive 8.5° true FOV or 85° AFOV, but with just 7 mm eye relief. https://global.vixen.co.jp/en/product/1552_00/