michael.h.f.wilkinson

The Equinox is a close match for my APM 80mm F/6 triplet, and the 22 Nagler is one of my favourite EPs for great wide-field views. Basically you have a 22x80mm with 3.76 deg FOV. I don't think I have ever had better views om M33 than with that combination, from a really dark site near Olly's place. The 31mm Nagler and Vixen LVW 42mm also give outstanding wide-angle views. Having said that, for lunar observations (which I normally do with the Celestron C8), when I travel, I carry a set of Vixen SLV EPs (5, 9 and 15 mm) which have much narrow FOV, but excelent quality. I also use a MaxVision 24mm 68 deg for wider views. Not a real replacement for the Nagler 22, but excllent views nonetheless. I also tested the cheap as chips 20mm Plössl (15 euro price tag), and found the views really nice as well, but not better than either the MaxVision or the Nagler. For the price, however, it is an excellent piece of kit. The main reason I got SLVs rather than the much cheaper Plössls is not so much optical quality, but eye relief.

It is narrower, and has rather smaller pixels.

I have the Helios LightQuest HR 16x80, and they are superb, a distinct step up from the venerable Helios Apollo 15x70 I had, not just in terms of aperture, but also in terms of image quality. I can only assume the 10x50 version will be very good indeed. The other bins I use regularly, but mainly for birding are my Nikon Monarch 7 10x42 bins. Absolutely great, and very comfortable. I got them because Olly had once done a comparison between his Leica Trinovid 8x42 and a pair of Nikon Monarch 7 8x42 bins a guest had brought. Three people compared the bins on astronomical targets, and the results were essentially a tie, with one favouring the Leica, one the Nikon, and one couldn't see a difference. As luck would have it, shortly after I read this review, a local camera store had a BNIB Nikon 10x42 second-hand. I tried it, and fell in love with it. Its colour rendition, detail, and viewing comfort is just great.

Flats don't correct accurately in areas where the signal is saturated. Flat correction assumes a linear response of the sensor to light (hence the need to capture at unity gamma), something that is clearly not the case in saturated areas.

Nice one

I myself amd considering the cooled, mono version of the ASI183MC I have, found here: https://astronomy-imaging-camera.com/product/asi183mm-pro-mono The colour version of that one is cheaper, so if you don't have a filter wheel it might be more suitable for you. My own, non-cooled colour version has given me a lot of joy on DSOs already. Three hours on M81 + M82 from Bortle 5 skies using a 6"F/5 Schmidt-Newton gave me this: and it works nicely on lunar and planetary with my C8 as well

I got myself a second-hand EQ3-2, and it works very nicely with camera+ 200mm telephoto ) or with an 80mm scope

For H-alpha on the sun I have only been able to get consistent results with AutoStitch

Adaptive sharpening is an idea I discussed with Filip (the author of ImPPG) some time back. I implemented an adaptive unsharp masking in C, which varies the strength of the unsharp masking as a function of local brightness, based on the idea that bright areas have better S/N, so can be tackled more aggressively, whereas darker areas need a gentler approach. The principle works, but it is difficult to set the parameters right, I find.

Welkom to SGL, from "way up north" in Groningen

I often use a Barlow or for preference a tele-centric lens like PowerMate with my CMOS cameras. I don't use a flattener combined with either. Typically, the order I use with a tele-centric is telescope, tele-centric, filter wheel , camera, but I could swap filter wheel and tele-centric around readily. A tele-centric lens has an almost constant magnification, irrespective of the distance between camera and lens. For a Barlow, the longer the distance between the Barlow and the image plane of the sensor, the larger the magnification. A typical Barlow might be designed for e.g. 2x magnification, but that just means that at the magnifcation the aberrations are minimal. In many cases (but not necessarily for "shorty" Barlows) the most likely order in which the optimum magnification is reached is probably telescope, filter wheel, Barlow, camera. I would simply try which configuration works best for you

You can take darks at the end of the session. No problem

Taking darks just means taking a series of exposures at the same settings as the "lights", but with the camera shut off from all light (simply put a cap on the scope). Darks can then be stacked into a master dark, which can then be subtracted from the lights, to correct for the signal the camera produces in the absence of light. Even though the temperature of the sensor is high, each exposure is very short, so little dark current may actually build up in that time.

Shot this just before dinner, stretched contrast and saturation a bit to bring out the circumzenithal arc section at the top. You don't see these that often

Actually, I am not sure this is just camera noise or photon noise. You need to look at darks to see if this is the case

Mine is still on the aluminium tripod. Luckily my garden is sheltered from the wind, so that doesn't cause issues (unless it's blowing a gale). As long as the mount is balanced, and the subs are short, this works fine. Short subs aren't a huge issue in terms of read-out noise with my CMOS cameras, although it does mean I spend FAR more time during stacking. I might give the EQ3-2 tripod the same hardwood makeover I did for the flimsy EQ-1 tripod

It is reported to be mag 13.5 at the moment and could be interesting. More info here: http://www.rochesterastronomy.org/supernova.html#2020hvf

Somehow missed this thread, I have been using my EQ3-2 mount quite a lot with either a telephoto on it or the APM 80mm F/6 triplet with reducer I am currently using the Vixen GP-DX, but I hope to get them running in tandem at some point, with the GP-DX carrying the Meade SN6 6" F/5 Schmidt Newton, and the EQ3-2 with the APM 80mm. That would leave the Vixen GP mount for the Celestron C8 for visual

That is very nice indeed. I was planning to make such a mosaic with my C8 yesterday, but the moon didn't rise above the trees, alas. I generally stack a higher percentage (depending on conditions), and usually manage 10% or even 25%. That allows you to push sharpening a bit more without exploding the noise too much. Might be worth a try

Saturn will always supply a WOW moment. I had my first view of Saturn through our school's 70mm F/10 achromat in the fall of 1978. It was special then, and remains special to this date. My best views have been with my Celestron C8, from my back garden, on a night of just magically stable seeing, using the Vixen 7mm LV EP I had at the time.

The speed of the scope is really important here. I have a MaxVision 24mm 68 deg EP in my travel set-up, and it works just fine in my APM 80 mm F/6. I did once put it in Olly's big F/4.1 Dobson and was rather horrified at the weird star shapes outside the centre of the FOV (granted, they are sold as "good down to F/5", which they are). My 22 mm Nagler was crisp right to the edge of the FOV, but then you pay for that performance.

Had a quick go at Venus before it ducked behind the neighbour's house. Combined this with an earlier shot I took on March 1 Not perfect, but given the turbulence over the neighbour's house, I am quite happy

I made 2 longer SER files of the Aristarchus and Copernicus region of the moon yesterday (2000 frames each) stacked, and stitched the stacked result (500 frames each) in MS-ICE. After sharpening the L-band in ImPPG, and playing with curves in GIMPI got the following shot: I then did a more selective manipulation of saturation, by boosting the B band only in LAB space in GIMP. This gives neat "silver and blue" appearance: Boosting the A band as well, gives a more "gold and blue" appearance: Stretching the A and B bands in LAB colour space can simply be done by applying curves to the appropriate layer after decomposing the RGB image into LAB layers. I do think I should have used my atmospheric dispersion corrector into the optical train, as a slight shift is visible. Will have a go in Registax to correct that later.

I had a bit of a struggle with the equipment yesterday, so I think that caused me to miss perfect focus here, (should have swung to Arcturus to get it right with the Bahtinov mask). Still, I got 19 usable panes of slightly varying quality with the ASI183MC behind the C8. Apart from the usual flip mirror and filterwheel (set to UV-IR block) I added a little extra extension tube to reach F/12, which is near optimal for the ASI183MC. I stacked the lot in AS!3, stitched the results in MS-ICE, and sharpened the L channel in ImPPG. Recombining L with the A and B channel in GIMP, and some tweaks with curves gave me this (warning 155 Mpixel image) Not as sharp as it could be, and I hope to get a rematch tonight

Amazing stuff. You are giving me aperture fever again. I have the ASI178MM, and it is a great little camera. Currently i do use the ASI183MC more, however.