michael.h.f.wilkinson

Here is the wide-field rig in action

That looks very nice indeed

O-III capture has started

I am currently running my ASI183MM-Pro with Sigma 50-100 mm F/1.8 zoom, with a filter wheel with Baader L, H-alpha, O-III, and S-II F/2 filters. Currently it is clicking away at the area around the Flaming Star Nebula. I am aiming for one hour each on H-alpha, O-III, and S-II, if the weather holds. Over 30 minutes on H-alpha are in the bag.

Absolutely lovely

I built one myself, details here:

I had a nagging feeling that the problems caused by APT telling the world the ASI183MM-Pro was a colour camera was throwing APP off, so I made new darks with APT set correctly, and edited the FITS headers of the lights and the master flat to remove the "RGGB" Bayer pattern entry (using FITSwork), and restacked the lot in APP. I definitely feel I have got a touch more out, and some annoying artefacts at the edges have gone. For some reason, one 60 s sub was rejected by APP, as it couldn't find stars in it, but here is the result of 4 hours 29 minutes of data, using an ASI183MM-Pro, with Astronomik 12 nm H-alpha filter, and Canon 200 mm F/2.8 L lens. I will first get data in other bands before processing this any further, I think

Magnificent

I am thinking of either O-III and S-II (I just saw a great SHO rendition of NGC 1499), but maybe I will just add RGB data. Much depends on getting a few more clear evenings

As I was using an EQ3-2 mount without guiding, I limited my subs to just 60 seconds, and cranked gain up to 300, just so I could see something on the subs. I think a lower gain would work adequately, but I tried this and it works

Managed to add some 2 hours of H-alpha data acquired yesterday evening with my ASI183MM-Pro, Astronomik 12 nm H-alpha filter, and Canon 200 mm F/2.8 L lens. Might want to re-stack the lot, as there are some artefacts on the edges, and I had issues with the camera being reported as an OSC camera with RGGB Bayer pattern.

The K designation stands for the Kelner design. These can be pretty decent. The AH I think is a Huygens or Huygens-like design, but I spotted some very positive comments on Cloudy Nights, listing as main drawback the rather narrow FOV

Sorted by help from the people at APP. If a Bayer pattern has been set erroneously, set the interpolation algorithm to "no interpolation", and it should work. Stacking with this setting now

I have noticed there is a bayer pattern "RGGB" item in the FITS header. The culprit here is APT, which defaulted the new camera to RGGB. I think I have sorted that out now. Having said that, I did at some stage manage to turn the previous batch of data into being interpreted as mono, so I am not sure what is different now

For some reason, while FITSwork and GIMP read the data as mono, APP insists on interpreting them as OSC colour images with RGGB. While I know OSC camera data which are accidentally seen as mono can be forced to the correct Bayer pattern, the reverse is not obvious. I did get one batch to process correctly, but the second set of images refuses to be treated as grey scale, so I cannot neatly merge the data. What is going wrong?

Quiting now, as clouds move in. Managed 2 hours of data. Not to be sneezed at

Contrary to the forecast, it is pretty clear outside (with the odd bit of haze), so I quickly set up the rig, and am imaging NGC 1499 again, with the ASI183MM-Pro, Astronomik 12 nm H-alpha filter, and Canon 200 mm F/2.8 L. I have already got 40 minutes worth of subs I was not expecting I hope to add all this to the 2.5 hours captured on Sunday.

I have a very different telescope, but with essentially the same specs in terms of aperture and focal length: a Meade 6" F/5 Schmidt-Newton, and I combine that with a camera with the same chip as yours (mine is the ASI183MC (non cooled)), so to give an idea of the kind of field of view you would have, here is an example of what I managed after four hours on M101, from Bortle 4-5 skies or 13 hours on M27 with L-eNhance filter

what telescope or lens, camera, and mount were used?

Regarding the choice between 8x42 or 10x50: that is very much a personal matter. I can hold 10x50 still really well, others struggle. I even use my 16x80s hand-held most of the time, without issues, but that may be the result of long practice. Regarding the cheap 15x70s: I have had two pairs, both of which got knocked out of collimation, but I collimated them again (not too hard on porro-prism bins). The EP bridge on one did break, so they are not terribly sturcy, but if treated with care can give many very enjoyable views for a long time. I stwitched to the much more expensive Helios Apollo 15x70s and never looked back, I must say. These are built like a tank. I only replaced them because I could get a good deal on a pair of Helios LightQuest 16x80, which are even better, and offer 30 % more light (at essentially the same magnification and weight). In conclusion: the Nikon 10x50 mentioned is a good choice, but there is indeed a dizzying array of choices available. I have a pair of Nikon bins for birding (Monarch 7 10x42mm) and can't fault them.

Very good indeed for such a short exposure

The M42 image on your Flickr page shows elongated stars, as you would get with guiding/tracking errors. That can throw DSS off

Very nice capture. I should try this one with my 6" F/5 Schmidt-Newton

I have been using the uncooled ASI183MC for DSO imaging for a while, and it does have an edge over my modded Canon EOS 550D in terms of sensitivity, but the set-point cooling of my new (second-hand) ASI183MM-Pro makes life a lot easier. I am not sure the fan cooling of the Altair adds anything useful.

I have no experience with Altair cameras, but I did notice some used fan cooling, rather than thermo-electric cooling (TEC). TEC is much better than fan cooling. I have an uncooled ZWO ASI183MC, which is very nice indeed, so I trust the pro version will be better still