Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.



  • Content Count

  • Joined

  • Last visited

Community Reputation

386 Excellent

About Aramcheck

Profile Information

  • Location
  1. As you're using a laptop to control the EQ6 mount, I'd suggest using APT (Astro Photography Tool) to control the camera. I've found that much easier than using the Camera live view screen, and if you start using APT's platesolving features, you can use it to locate & centre objects without the need to do any star-alignment. I pick a bright star like Vega, which will be visible in APT's live view & a Bahtinov mask for focusing (along with APT's Bahtinov Aid tool). I platesolve the image, sync the mount in APT & then head to whatever target I want to photograph. https://www.astrophotography.app/index.php Cheers Ivor
  2. Just a reminder that the APPG consultation on Dark Skies & Light Pollution ends tomorrow, in case anyone still wants to give their 2p:- https://appgdarkskies.co.uk/dark-skies-consultation Cheers Ivor
  3. I suppose, in the ancient Greek sense it is! The word "planet" is derived from the Greek terms for "wanderer" and the original planets were considered to be the Moon, Mercury, Venus, Mars, Jupiter, Saturn & the Sun. https://en.wikipedia.org/wiki/Classical_planet Cheers Ivor
  4. May I ask what make of scope? I think there are some F8 114mm Newts which have a correcting lens fitted inside the focus tube, which seem to have a poor reputation. If it does have a lens fixed inside, I'm wondering if the variation in brightness could be caused by reflections from the lens surfaces? (I've not looked through such a scope, so could be completely wrong here!) Cheers Ivor
  5. Thanks @MarkAR - In the end I had to resort to Photoshop to stamp out the blown-out nebula & overlay it.... See here. Cheers Ivor
  6. 49 x 3min exposures (2hr 27min) with SW200dps + EQ6 + Cannon 600d (astromodified) & IDAS D2 light pollution filter. Bortle 6 skies. In order to bring out both the detail in M57 and retain as many of the faint fuzzies as I could, I had to apply a different stretch to the target nebula and background & then combine them at the end. I really didn't want to lose IC1296 (a small barred spiral galaxy which Simbad indicates is 243 million light years away), but in order to retain that 'low surface brightness' galaxy, the area surrounding M57 was very blown-out. Similarly, when stretching to maximise the detail in M57, the fainter stars / background was lost. Combining the images was a bit of a nightmare - in the end I had to resort to using the stamp tool in Photoshop to remove the blown out nebula from the background & overlay it with the separate M57 stretch. Cheers Ivor
  7. A black elasticated shower-cap is good for preventing light entering from the primary mirror end, if that is the source of the problem.
  8. I took 2hr27min of M57 last night with our SW200dps & Canon600d. I'm trying to process it, but M57 is very bright compared to the rest of the objects in the sky. If I stretch the image to bring out the nebula I lose the faint detail such as the barred spiral galaxy IC1296, but if I apply a 'normal' ScreenTransferFunction stretch, the nebula is completely washed out. What's the best way to proceed? Should I process both & recombine with PixelMath, or Mask M57 & apply different stretches to the nebula & background? I'm early on in the workflow, having just done background removal, BN & PCC (so no noise reduction yet). Screen Grab shows the 'normal' STF & a MaskedStretch applied to a preview. Any help much appreciated! Cheers Ivor
  9. From a couple of nights/early mornings in the back garden, about a week ago. SW200dps + EQ6, IDAS D2 light pollution filter & Canon 600d (astromodified). 9x50 finder/guidescope and Bortle 6 skies. Still having problems with random sporadic RA movement (40-75 arc mins!) - could it be gusts of wind? If so, why wouldn't DEC also be affected? M56 - 19x3min subs NGC6823 - 49x3min subs (the SH2-86 emission nebula is very faint). Intrigued to read that the central cluster has stars which are only 2 million years old & the dark dust pillar is caused by stellar wind eroding the dust. NGC6992 - 19x3min subs (Top) + 5x3min subs (Bottom). This was just an experiment to see what would come out in RGB & to attempt a mosaic. Camera battery died on the 2nd night after only 5 shots & barely had enough juice to take 13 flats. (& I couldn't find my spare batteries...) I've subsequently learnt how to generate a Mosaic plan using Cart du Ciel, which can be imported into APT as a Custom set of objects. Cheers Ivor
  10. So far, I haven't managed to get Deconvolution to produce decent results & on this image Starnet++ also didn't do a great job. I did tone down the stars to some extent using a star mask & Morphological Transformation in Pixinsight, but I think I need to spend more time playing with Deconvolution! Cheers Ivor
  11. I'd suggest getting a much longer total imaging time & to stick with one duration exposure, rather than a mix. If you can get away with 3 min subs then stick with that & get a total exposure of at least 1 hour (& preferably a lot longer). For Darks and Biases you can take more (about 50 bias + at least 25 darks), but you only have to do that once to generate Master Bias / Master Dark images, which you can then reuse. Flats, of course, have to be done each night, or each time the imaging train is changed. M31 is also a big image for the 130pds. I've only had one go at it & it took me 6 attempts at processing to bring out as much detail as I could in the outer edges, which are much fainter than the core. The red colour cast in the top image will be eliminated during the processing (colour calibration). Also worth looking at http://dslr-astrophotography.com/iso-values-canon-cameras/ which indicates that ISO 400 or 800 is optimum for the 450D. I'm also not sure how suited the Astronomik CLS CCD is suited for galaxies? Cheers Ivor
  12. From last night & early this morning... NGC6888 the Crescent nebula taken with the SW200dps & Canon 600d (astromodified), IDAS D2 light pollution filter & EQ6 mount + Bortle 6 sky. 44 x 3min subs. According to the inter-web, it's about 5000 light years away & is about 25 light years across. The bright star at it's centre is a Wolf-Rayet star which is shedding it's outer envelope in strong stellar wind (ejecting the equivalent of the Sun's mass every 10,000 years). The Stellar wind is colliding with material previously ejected from the star, when it was in its Red Giant phase, with two shock waves moving inward & outward. The inward bound shock wave is said to be heating the stellar wind to x-ray emitting temperatures (million kelvin to hundreds of millions kelvin?). Removing the light pollution gradient was a bit tricky due to the extent of the Ha in the region & I consequently lost some of it. Also had to drop 12 subs due to random movement in the RA, which I've yet to account for. I checked no cables were snagging & paused the image run to switched the initial guide star. Towards the end of the night I also had to change battery in the DLSR & tried running PHD2 calibration assistant (without success, though the RA seemed to better behaved afterwards). Attached guide log, in case anyone can suggest anything I can improve on the dithering time-outs & the odd RA pulses. Cheers, Ivor PHD2_GuideLog_2020-09-09_215940.txt
  13. It is an amazing feeling being able to capture these DSO images. Couldn't resist having a quick (and rather inebriated) play with your data. Looks like you have a bit of coma, but good stuff! Cheers Ivor (PS: I mangled the star colours somewhat - not sure what happened there!)
  14. It's caused by a combination of:- direct emission of light into the atmosphere, scattering of light by atoms & molecules in the air (Rayleigh scattering) + scattering of dust/water droplets (Mie scattering) reflection of light from the ground & other surfaces Scattering of light emitted at or close to the horizontal is a major factor in skyglow which is seen many miles from the source. The US Dept of Energy did some interesting modelling of skyglow from different light sources:- https://www.energy.gov/sites/prod/files/2017/05/f34/2017_led-impact-sky-glow.pdf https://www.energy.gov/eere/ssl/potential-impacts-led-street-lighting-sky-glow https://www.energy.gov/sites/prod/files/2017/08/f35/Sky-Glow-Webinar_7-27-17.pdf The only paper I've seen where measurements have been taken of a city before & after LED lighting was installed is in Tucson:- https://arxiv.org/abs/1802.03474 (If memory serves this showed approx 7% reduction, but isn't conclusive as they had equipment changes between the before & after measurements) Cheers Ivor
  15. @westmarch - That's good to hear - how did you phrase the request, i.e. was it because of light trespass into windows, or did you just say about light in the garden? Cheers Ivor
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.