susan-parker

Procyon and sounding stars. My First Light image with my updated SpaceCat telescope setup, with the QHY268M + QHYCFW3-M-US combo. 240 frames of 25 seconds each (6000s total), luminance filter only - stars discernable down to magnitude 16 in the original. Note Bortle8+ zone, no Light Pollution Filter, lots of atmospheric shimmer, and a full Moon but fortunately about 45degrees out of frame. This was a point at a bright star and find the focus point, check camera operates (first time powered up), is filter wheel recognized and operating, is balance okay for tracking, &c. Low gain, Sharpcap said 30 and 30 offset. No idea how this translated into real numbers, probably not at all optimal, but hey I go some stars SharpCap for image acquisition, stacked in Astro Pixel Processor, further processing in Photoshop including Astro Flat Pro tools. This version image is 25% scale from the original 4104x6231 pixel image; which was slightly cropped to remove stacking edge artefacts, but is effectively the full frame.

Yes, absolutely - especially for doing anything with a RASA type telescope. But the mono-sensor version cameras are getting correspondingly better too and the RGB Bayer matrix filters are not-optimal for DSO imaging. At some point maybe there will be something better, but for me the big difference is the Ha sensitivity and the pragmatic situation of being in a Bortle 8+ zone.

Particularly the Ha and SII in the red

... and

Mono and Filters are still considerably better than OSC, the RGB filters on an OSC chip are simple dye filters compared to the multi-layer interference filters... M17 comparisons...

The QHY268M mono should be here soon(ish) It will be a lot better than the Panasonic 4/3rd sensor cameras such as the ASI1600, and it should be ballpark for your stated budget price.

When I am acquiring a NB series I try to run off a quick LRGB set at the end of the main run. If there isn't time, then no matter.

Typically, as I am in a Bortle 8 zone, I am imaging at 2.5 seconds for L, 8 seconds for RGB, and 30 seconds for NB. At these shorter exposures download speeds become an issue. Also for focusing, although one might be able to define a smaller ROI if the camera supports it.

I am holding out for the mono camera - I want to look at Ha as there seems to be a lot more of that around than I first imagined and it specifically something that a mono camera and a suitable filter will perform significantly better at resolving than a OSC. Of course upgrading both Ha and SII from 7nm to 3.5nm will be another expense but for the moment I can cope with the 7nm filters I have.

Um, the amp-glow is an off-putter now we have sensors that don't have this issue; so still holding out until the QHY268M comes along!

Good news there, and thanks for the update. I am looking at the QHY268M as an upgrade to my Atik Horizon without having to replace my 36mm filters for my SpaceCat setup.

Mono APS-C format QHY268M camera coming soonish, maybe first part of 2021? ( Sony IMX571 sensor with native 16-bit A/D and 3.76um pixels )

I use the IDAS D1 filters... conveniently available in a range of lens sizes from FLO: https://www.firstlightoptics.com/idas-filters/idas-d1-light-pollution-suppression-filter.html ... been very pleased with the results, gives at least an extra magnitude in the DSO images in a Bortla 8+ zone. There are also CLIP filters now available, that fit in the body: https://www.astronomik.com/en/clip-filter/xl-clip-filter-nikon-vollformat-d800-d810-und-d850.html ... however I haven't tried these.

Example Cloud from last night to show the amount of local light pollution. Average RGB levels are at aproximalty 50% brightness. Nikkor 105mm f/2.5 @ f/2.8 , 2.0 seconds, ISO800. Scaled to 1200 pixels.

Um... mine isn't quite there yet: ... also I am using a 105mm lens, so I normally only get parts of constellations. I could try my Nikkor 60mm f/2.8 Micro which is probably my best lens optically but I don't have a Light Polution filter in that size (which may or may not be too aweful but I lose at least a stops worth of light differential).

Sorry, my window looks pretty much due South (I was staying up late to get the Orion shots).

Thanks ? The biggest stack I have done in one go was just over 200 frames. These are from a D800 so each frame is 7360x4912 pixels, about 200MB each as 16 bit TIFFs. It took over six hours on my i7-2600K CPU computer (which is a slow-coach at the best of times). Unfortunantly I don't have any of the comet: http://www.cometwatch.co.uk/comet-46p-wirtanen/ Most days I don't get visabilty as there are usually clouds.

The bottom half of Orion with the Belt and Sword, from a stack of six separate frame stacks with various ISOs from 100 to 3200 (which I roughly normalised before the final 6 image stack) from various evenings over the last month. Pics is a 1800 wide scale of the resultant frame. The detail of the M42/M43 nebulae is my best so far, with some structure showing. "The Running Man" and the Edge nebulae are both clearly visable. The Horsehead Nebula's position is just visable. There is some small misalignments in the top left and bottom right of the composite image from the lens geometric distortion as the various sets have come from different starting positions. There are also visable green background "swirls" which are from the intermixing of the lens' edge light dropoffs for the different sets. The emphasis for this stack is very much on the Nebulae detail. Stars in the original are down to magnitude 14 (according to Stellarium). Rigel is the very bright star at magnitude 0.15 in the bottom right hand corner. Static "hand-held" in the window frame: Nikon D800 with pre-Ai Nikkor 105mm f/2.5 at f/2.8; ISO at 100, 400 & 3200; stack of c.550 frames at 2.0 seconds each. IDAS LPS-D1 filter. Taken in West London, in a Bortle 8+ zone (for a visibility scale if I look very hard in "best" conditions I can just about see Cursa / Beta (67) Eridani, which is about magnitude 2.8).

The night before the full moon last month on the 26th June; a composite of a set of 17 frames for the stars plus one of the moon itself, plus an original single frame. Nikon D800 with Nikkor 105mm f/2.5, ISO 800; Stars at f/2.5 at 2 seconds, and moon at f/8.0 at 1/1000sec. Size reduced to 1600 pix wide.

Final shot taken on the night of the 7th July; this one is centered on Rasalhague, which is a bright magnitude 2.1 star at the top corner of the constellation Ophiuchus. Two pics; a 1800 pix wide scaled down from the full-frame, and an 1800x1800 pix 1to1 crop from the center. Stars are down to magnitude 14.8 (according to my star hunting with Stellarium) which shows that there is some benefit to increasing the number of frames for pulling out the background detail, however it is diminishing returns after about 30 frames (with this setup and using the in-camera sensor noise reduction). This sequence of frames was taken about 23:30 and was at the beginning of astronomical-dark. Notwithstanding this, there was still discernable sky glow from nearby vilages (Goult), towns, and city (Avignon), albeit a small fraction of what there is in West London. Looking carefully at the sky at day or night there always seemed to be a thin vapour layer high up in the stratosphere. Nikon D800 with Nikkor 105mm f/2.5 at f/2.5, ISO 250. IDAS D1 filter. Image is a stack of 32 exposures of 2.0 seconds each. Camera on fixed mini-tripod, plus IR remote.

Thire shot from the night of the 7th July; this one is the bottom leg of the constellation Hercules. Two pics; a 1800 pix wide scaled down from the full-frame, and an 1800x1800 pix 1to1 crop from the center (I have tweeked the brightest stars to reduce the red halos). Stars are down to magnitude 14(ish). Nikon D800 with Nikkor 105mm f/2.5 at f/2.5, ISO 250. IDAS D1 filter. Image is a stack of 17 exposures of 2.0 seconds each. Camera on fixed mini-tripod, plus IR remote.

Also taken on the night of the 7th July, the constellation Corona Borealis (for once I have a constellation that actually fits within the image frame!). Pics; two 1800 pix wide images scaled down from the full-frame, one the stack and the other a single frame "eye view"; a 1800x1800 pix 1to1 crop from the center, and the UniMap ID. Stars are down to magnitude 14. Nikon D800 with Nikkor 105mm f/2.5 at f/2.5, ISO 250. IDAS D1 filter. Image is a stack of 24 exposures of 2.0 seconds each. Camera on fixed mini-tripod, plus IR remote.

This time with a tripod Taken on the night of the 7th July, with Jupiter and it's four Galilean moons centered in the image (L2R = Ganymede, Europa, Io, and Callisto); situated to the right of the left hand side of the constellation Libra (Zubenelgenubi I & II is the pair of bright stars to the left of Jupiter). These two pics are a 1800 pix wide scaled down from the full-frame, and an 1800x1800 pix 1to1 crop from the center. Nikon D800 with Nikkor 105mm f/2.5 (pre-AI with scalloped focus ring - AI converted) at f/2.5, ISO 250. IDAS D1 filter. Image is a stack of 11 exposures of 2.0 seconds each. Stars are down to magnitude 13. Camera mounted on a fixed mini-tripod, and I used an IR remote plus the camera's 3 second delay after mirror-up before the shutter release. Taken near the village of Goult, Vaucluse, FR - where there was still some atro-dark around and after midnight although this sequence was in nautical-dark.

Taken Saturday night, top half of the constellation Libra. Stars are down to magnitude 12.0 (I found at least one). Image is a stack of 11 exposures of 2.0 seconds each. Hand held (really must sort out a proper mount). Nikon D800 with Nikkor 105mm f/2.5 at f/2.5, ISO 800. IDAS D1 filter. In the process of prodding around with Stellarium to check on magnitudes, &c. I found out that I had by happenchance caught the oldest known star with a determined (for variations thereof) age of circa 14.5 billion years in this image!!! A scaled image of the full FX frame, plus the DSS stacked starting point. A Unimap ID, and a couple of 1to1 pixel crops, one with the "Methuselah star" (otherwise known as HD140283 or SAO159456) in the centre of the image. More info here, with a bit more explanation as to why it has an apparent age greater than that of the Universe itself: https://www.nasa.gov/mission_p…/hubble/science/hd140283.html

Taken on the night of the 30th May, Jupiter (big blob in upper centre) which is sitting on the right hand edge of the constellation Libra. In this image Jupiter and the two moons Io,and Europa are just a blob, but Ganymede is out far enough to be seperate. The bright pair of stars below and to the right are Zubenelgenubi I and Zubenelgenubi II. Image is a stack of 10 exposures of 2.0 seconds each. Note that this is still only nautical twilight, we don't actually get any more propper astronomical dark untill after the summer. Nikon D800 with Nikkor 105mm f/2.5 at f/2.5, ISO 800. IDAS D1 filter. The Puzzle however is that in the full frame image the stars are down into the magnitude 10 range. However in a slightly further processed 1 to 1 pixel crop it would appear to have stars down to the magnitude 15/16 range. It could of course just be artifacts of stacking and sensor noise, however the distribution does look "star like" to my admitidly novice eye.