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Found 14 results

  1. From the album: Deep Sky III

    A bi-colour image of the Cresent nebula with Ha mapped to Red and OIII mapped to Blue and Green. The OIII is very strong with this object to the point where it can overwhelm the Ha, reducing the redness, so I had to experiment with the relative contributions. I was quite impressed by the amount of detail revealed by the Esprit 150, in particular, I like the "bubble wrap" appearance made by the OIII contribution. About 8.5 hours total integration time. LIGHTS: 6 Ha, 11 OIII x 1800s, BIAS: 100, DARKS: 30, LIGHTS:40 all at -20C.
  2. From the album: A New Hope

    Image taken on the 10th October 2013 using Tak 85FSQ with unmodified Canon EOS 5D Mk2. (1hr 57 min of data - 39 x 3min subs @ ISO 1200 with same qty of darks, bias and flats). Captured with APT, stacked with DSS & Processed with Pixinsight / Photoshop.

    © AJG 2012

  3. Unexpected clear evening last night, and with the rich starfield of Cygnus overhead I decided to have a go at a previously untried nebula for me, NGC6888, the Crescent Nebula. Due to the considerable light pollution here in the heart of industrial Tyneside, I've gone for my usual Hydrogen Alpha filtration, in this case a Baader 2" 7nm filter fitted within the adaptive optics unit. Image is 10 stacked lights of 900 second duration giving 2.5 hours of total exposure, and calibrated with bias frames, flats (dark flats) and dark frames. Imaged with SX-VR H36 through a Pentax 75 SDHF scope which gives a 3 arcseconds per pixel resolution giving a massive field of view of 4.16 x 2.78 degrees. Optics mounted on an EQ8, guiding camera was a SX Lodestar activated through a SX-AO unit. Guiding and image collection software was Maxim DL 6, stacking was done usig DSS, image tweaking was through PS CS3 Thanks for looking, Steve
  4. I grabbed 3h40m of the Sadr region stretching from the crescent up to NGC6914 (not visible as it's a reflection neb!), in HA light - may add to this in HA, but also would be nice to bring LRGB into it at a later date. QHY163M, Canon 200mm 2.8L II (working at f3.85), Losmandy GM8 - taken 17th Sept 2018, West Oxfordshire. All in 5min subs, guided with a ASI120MM on a 50mm guider. Baader 7nm filter. Processed in PI. Thanks for looking. (ergh - jpg compression artifacts aren't great in this
  5. A bi-colour image of the Cresent nebula with Ha mapped to Red and OIII mapped to Blue and Green. The OIII is very strong with this object to the point where it can overwhelm the Ha, reducing the redness, so I had to experiment with the relative contributions. About 8.5 hours total integration time. The image consists of 30min unguided subs taken through an Esprit 150 on a GM1000HPS. Processed in CCDstack, Pixinsight and PS CC. Alan LIGHTS: 6 Ha, 11 OIII x 1800s, BIAS: 100, DARKS: 30, LIGHTS:40 all at -20C.
  6. Captured the data for this image on Saturday evening with an ~85% moon floating around, but pleased with the level of data I managed to get here. Taken using ST2000XM, Astrodon 5nm HA filter, through FLT110 at f5.6. This was first run after summer with a new adaptor between the drawtube of the FLT and the FLAT4 reducer - works brilliantly as it eliminates play found in the 2" nose/adaptor as before, and also reduces the vignetting as well. Exposures were 11 x 1200sec with APT; off-axis guiding with an ASI120MM and PHD2; reduction/processing in PI with final levels tweak in PS. So much background stuff here, I didn't bother with any DBE as couldn't really place the markers! Think the flats have worked nicely here though (tends to be less of an issue with backgrounds through HA anyhow). Thanks for looking!
  7. Typically, my first light image with my new 3nm Astrodon Ha filter took place under almost full Moon conditions but in some ways, this was quite a useful test in its own right as clear skies and full Moons seem to attract one another! There isn't much in the way of available nebulae around this time of the year so an early riser like the Crescent Nebula seemed as good a choice as any but I had to wait until 00:20 before I could get started. Nice to see the Soap Bubble Nebula in there as well. Mount: Mesu 200 Telescope: William Optics FLT98 CCD Camera: QSI 683 WSG-8 Guiding: OAG/LodeStar Filter: Astrodon 3nm Ha Exposure: 13 x 1200 sec Date: 09/05/17 + 10/05/17 Calibration: Bias, Darks & Flats I think I'm going to like this filter .....
  8. I´ve not posted for a while but everything appears to be working AND it was clear last week (I must have sold my soul without knowing) So I imaged a few of my favourites: NGC7635, bubble neb, is HA 20x600s NGC6888, crescent, is HA 18x600s Soon be winter and time to batten down the hatches ;-D
  9. The Crescent Nebula NGC 6888 The Crescent Nebula rides on the Swan’s neck in Cygnus in a dense swathe of Milky Way stars - an ideal target for my first bi-colour image with my new Astrodon 3nm Ha and OIII filters and Esprit 150 telescope. The nebula was discovered by William Herschel on 15th September, 1792 and he described it as ‘A double star of the 8th magnitude with a faint south preceding milky ray joining to it.8’ long by 1.5’ broad’. This double star is not the prominent star with an apparent companion close to the heart of the nebula, rather, it is ADS13515 at the 2 o’clock position on the nebula’s bright periphery. The bright star off-centre of the nebula is particularly significant as this is the star that is powering the emissions from the surrounding gas cloud. This magnitude +7.5 star, HD192163, is of the Wolf-Rayet type and is also designated WR-136. Charles Wolf and Georges Rayet first described wolf-Rayet stars in 1867 following detection of their broad emission lines. The Wolf-Rayet stage applies to stars with an original mass in excess of 30 times our own Sun’s mass. This stage comes late in the star's evolution when a rapidly expanding shell of hot gas is powered outwards by the stellar wind only to collide with the much slower-moving gas clouds that were ejected thousands of years previously when the star entered its Red Giant phase. These forceful collisions produce a shock wave that generates an enormous amount of energy including wavelengths within the light spectrum, allowing us to observe them. This complex process displays as an arc of bright nebulosity that we identify as the Crescent Nebula. Long exposure images fill in this arc producing a crab-shell shaped nebulous region rich in Hydrogen Alpha and doubly ionised Oxygen emissions. WR-136 is fated to go supernova at some time in the future – watch this space! Image Stats Mount: Mesu 200 Telescope: Sky-Watcher Esprit 150 ED Pro CCD Camera: QSI 683 WSG-8 Sampling: 1.04”/pixel Guiding: OAG/LodeStar Filters: Astrodon 3nm Ha and 3nm OIII Exposure: 30 x 1800 sec Ha, 15 x 1800 sec OIII Date: 11/06/17 + 19/06/17 – much of which was under Lunar illumination Calibration: Bias, Darks & Flats Object Stats RA: 20° 12’ 04.6” Dec: 38° 30’ 46.0” Magnitude: +10.0 Distance: 4700 light years The Crescent Nebula – NGC 6888 Comparison of Ha and OIII data We imagers (well me anyway!) tend to think that Ha is the all-powerful emission line in nebulous objects but it is interesting to compare the Ha and OIII data for this structure as there is an enormous amount of OIII emission present in The Crescent Nebula.
  10. I've seen a few posts with people asking about & comparing the ED80 & the ZS71 for AP. So I thought I'd post up my impressions & findings as I test these out to determine the direction for my next imaging setup. I'm hoping that the ZS71 will have better star control than my much loved ZS66, which tends to show star bloat in RGB. My last imaging session was nearly 4 months ago & whilst waiting for clear dark skies to return I've been collecting kit for next seasons rig. My plan is for a triple shooter and I've narrowed the affordable scopes down to 80ED's or ZS71's. Well, about 6 weeks ago I picked up a very clean, used ZS71 (2013), to compare with my 80ED and I just can't wait for dark skies any longer. So tonight I finally got back into the obsy and setup the 80ED & ZS71 side by side. Pier mounted NEQ6 Each is fitted with an .85x reducer/flattener. This takes the 80ED down to f6.37 and the ZS71 down to a nice f4.7 The CCD's are Atik 314L+'s and (because it's still not astronomically dark here yet) I've fitted a Baader 7nm Ha filter in the train for the first image test. I normally cool to -20c but it's warm tonight so settled for -10c Guiding is with a 50mm finder/guider (SX CoStar) & PHD Focused with Bahtinov masks NGC6888 The Crescent Nebula These are the first uncropped single 10 minute subs (taken at the same time under the same conditions) to roll out. No calibration, just an auto stretch in PixInsight. It gives you an idea of the field of view and the depth each scope allows for the same exposure time. I've probably got an hour or so's usable data with each one before the clouds have rolled in. I'll shoot some flats & bias later (I don't use darks with the 314's) & follow up with stacked versions. I think it might still be a few more weeks before I get to try RGB. 80ED ZS71
  11. From the album: Deep Sky II

    I decided to attempt to improve the star field of the image by mainly making the stars more circular at the edges of the frame (mainly top right and bottom left). This was done by two methods: 1. Radial blur on individual stars; 2.Creating a duplicate of the image which is then shifted by a one or two pixels in the horizontal and vertical directions pixels via the offset filter and then applying the Darken blending mode. I also used masks to limit the impacted area and the degree of the effect.
  12. I'd thought I would attempt to improve my processing ability of NB images with another go at the Cresent, this time with my Esprit 150. This is a bi-colour image with Ha mapped to RED and OIII mapped to Green and Blue and represents about 8.5 hours integration time. I liked the starfield so much that I decided not to replace it with RGB stars, which I normally do on NB images. Comments and criticisms welcome. Alan LIGHTS: 6 Ha, 11 OIII x 1800s, BIAS: 100, DARKS: 30, LIGHTS:40 all at -20C.
  13. This is 63 x 300s with a 7nm Ha Altair filter, so a total of 5 hours and 15 minutes. It needs much more and perhaps some longer subs too before I start collecting the O3 data to go with it.
  14. I am relatively new to narrow band imaging, the processes, techniques etc - so the Crescent nebula I set as a goal as it was something I had VERY faintly seen through an eyepiece a few years back and wanted to really "see" it in detail via camera. Shot over the past several days, I managed to get enough data to produce a hopefully reasonably presentable image. 24x600s Ha exposures (4 hours) 19x1200s OIII exposures (6.3 hours) All binned 1x1 using an ATIK414ex, Baader filters, and my Meade LX90 8" SCT, reduced to f/6.3 So whilst this is the longest project I have yet undertaken and managed two channels of data, I know that more data is always better, so I started shooting more OIII last night to add to the image. I checked focus and found that I was off, so refocused and started shooting, dragged the first FIT in to DSS's file list and registered, it scored WAAAAY more than the previous nights data, so much more, that I am now replacing the previous nights data and not adding to it, so the following image has less OIII (7x1200s), but the stars, well they're sharper. Typically clouds are now due, so adding data back to bring it to atleast 24x1200 is frustratingly on hold, and ...yeah the halos will be removed, turns out my optics are great at smearing blue data. Comments and critique welcome. On a personal note really glad I went and got on OAG a few months ago, my total error last night was down to 0.65" - image didn't translate all night, so have a spare Orion ST-80 now!
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