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.

sgl_imaging_challenge_banner_comet_46p.thumb.jpg.9baae12eeb853c863abc6d2cf3df5968.jpg

SteveNickolls

Advanced Members
  • Content Count

    1,583
  • Joined

  • Last visited

  • Days Won

    1

SteveNickolls last won the day on December 11

SteveNickolls had the most liked content!

Community Reputation

1,052 Excellent

3 Followers

About SteveNickolls

  • Rank
    Sub Dwarf

Profile Information

  • Gender
    Male
  • Location
    Nottingham UK
  1. Thanks Neil for this, very helpful and informative. Best regards, Steve
  2. Thanks happy-kat. In the whole process it's the use of the LIFE Module on the comet head adjusting the 'Mask Fuzz' value to a very high level that removes the star streaks left in the background. Cheers, Steve
  3. Yes a valuable observation, the streaks wouldn't be there or be a lot shorter! Good luck if the sky is clear. Hey presto! That's using the technique in the video. Cheers, Steve
  4. Thanks happy-kat, let me know how you get on, I'll do likewise Cheers, steve
  5. Hi, I have come across this- If you go to YouTube and enter "Processing a comet using StarTolls Layers" you will find a host of videos. Not had chance to experiment with any ideas yet but good hunting! Cheers, Steve
  6. Thanks for this potential remedy. I will have another try in DSS and take extra effort where the centre of the comet is identified and see how that works out. Happy-kat I have restacked making sure sigma-kappa clipping is correctly used but the result was the same-streaks where the stars are. P.S. Added- I've just come across this piece of information in the DSS Technical help document relevant to the issue- Obviously the most demanding algorithm is the Comet and Stars stacking leading to the star freeze effect. Slow moving comets are leading to hard to detect large objects or big stars and in this case the comet extraction process may be less than perfect. In all cases, if you take a set of images from the same area without the comet (the day after or before) it will improve a lot the look of the final image. Best Regards, Steve
  7. Thanks happy-kat. I'm using the 64-bit version. I'd have to check but I'm sure I use kappa sigma clipping setting too. I was intrigued someone else was getting a similar effect on the final image. Time here is a little hard to come by at the moment but I might have chance this afternoon to recheck the DSS settings and try another run. Cheers, Steve
  8. Interesting thread. I took x33 light frames of the comet on Thursday (13th December) and for the first time used DSS employing it's comet staking options. The option "Comet and stars stacking: "star freeze effect" yields a similar final image to the OP's post with a static comet but ghost streaking to the stars. I did identify the centre of the comet in all the light frames- The images were taken with my Canon 600D DSLR, and Astronomik clip-in UHC filter, 75-300mm lens at 135mm and f/4.5 and ISO 1600. The 120 second images were stacked with x10 temperature matched dark frames and master flat and bias frames from x50 exposures each. The resulting master frame was processed in StarTools. Cheers, Steve
  9. SteveNickolls

    Animation of 46P/Wirtanen

    Thanks for posting this Neil. I managed to take 33 exposures of the comet last night and will be looking into what DSS can yield. Cheers, Steve
  10. SteveNickolls

    46P on 12 Dec

    Thanks for posting your image, lovely colours. I was fortunate last night to view and compare the comet through 10 x 50 binoculars and my 81mm Vixen binoculars at x48. I think I may have seen the comet more when it was between the two Mag 3 stars in the photo and I'm really pleased to see that the two brighter stars are a different hue, they certainly looked that way in the bino's! Hope the weather allows a another composition later this week. Thanks once again for posting, Steve
  11. SteveNickolls

    Star Adventurer

    Hi and thanks for posting, You have just bought a great piece of kit which used within its limits will do you proud. As Davey-T notes depending on the light pollution where you live will place a glass ceiling on how long you can expect to expose for. You might want to try this out at your imaging site to know how good or bad the light pollution is and its affects on your imaging, at least for OSC-http://www.pbase.com/samirkharusi/image/37608572 There's a lot been said about which ISO to use but if you are in the situation where light pollution is a pain I would advise you to experiment on the ISO used and see what you prefer to use-there's no golden rule especially where light pollution rules. A higher ISO won't capture anymore detail in your images but it will make them brighter albeit at the cost of dynamic range. I've experimented with 1600, 800, 400, and 200; the benefit from using a lower ISO is you will be able to expose for longer. The ability to take longer exposures with the Star Adventurer (SA) depends on a few factors such as your own experience and ability to polar align the mount and not subsequently knock it when later adding, adjusting, moving and tightening and loosening the optics to the mount (all done at night and possibly in the numbing cold). Individual mounts vary and the design of the SA places a limit to the weight and length of optics you can realistically use. The longer the focal length of your lenses the shorter the individual exposure you can expect to take without star trailing. My own experience, for what it is worth has shown that 180 seconds are achievable with a 300mm lens, and 900 seconds and more with a 135mm lens. I routinely expose for 300 seconds at ISO 400 and f/2 using a Samyang 135mm lens which is a great lens to buy sometime. If you can download the SkyWatcher Mini App you can use the polar clock utility to get accurate polar alignments. You can get a distinct advantage by ending the polar alignment routine when Polaris is on a main division (10, 20, 30 etc minutes) or at the midway point (5, 15, 25 etc minutes). If you can get or make something like this-https://www.darkframeoptics.com/product/polarite-right-angled-polar scope it will help take the pain out of polar aligning. It has a x2 magnification to allow really accurate judgments when polar aligning. I think practically there is a sensible limit to how long you want to take on each exposure. I have reduced my exposure times from 900 to 300 seconds after following the advice gleaned from tests which you can find in articles here-http://www.stark-labs.com/craig/articles/articles.html now a plane or cloud passing overhead only spoils a 5 minute exposure and not a 15 minute one. If you take really long light frames you will have to endure taking equally long dark frames, not ideal at the end of a long session with work possibly the following morning. As for how many exposures to take, that really depends on the object but if you can achieve 2 hours of total exposures your image ought to be fine but some faint objects will need much more exposure. This is a lot to absorb I know and the best I can say is- you have a great mount in the SA, go experiment with the lenses you have and enjoy the time learning. Don't forget to post your images though. Best Regards, Steve
  12. SteveNickolls

    Next Attempts at DSO's

    I have been imaging using my SkyWatcher Startravel 102mm refractor on a Go-To Synscan alt-az mount and Canon 600D DSLR since just before Christmas 2015. Having since read, "Astrophotography on the Go" by Joseph Ashley I have been inspired to use longer exposures, typically 30 seconds at ISO 1600 and to take more images per object (up to 200 light frames) weather permitting. I use Deep Sky Stacker to collate frames and subsequently process the master image using StarTools. I hope this album of images shows improvement upon my earlier attempts. Since April 2017 I have been using a SkyWatcher Star Adventurer (SA) mount on an old Celestron heavy duty tripod to image DSO's with my Canon DSLR. At Christmas 2017 I received a modified Canon 700D DSLR and an Astronomik clip-in Ha 12nm filter to complement my UHC filter. I am continually impressed by the accuracy of the little SA mount. In January of 2018 I began using my old CG-5 Go-To mount to take images and later swapped the original Celestron polar scope for an modern SkyWatcher type which has made polar alignment faster and more accurate.
  13. Well done Nige! Cheers, Steve
  14. Hi and thanks for posting. Rather than getting a copy of the United Federation of Planets Gunnery book as I refer to it I'd advise along with Mr naill to order a copy of this book instead-https://www.firstlightoptics.com/books/astrophotography-on-the-go-book.html it is available from our sponsors and deals much much more with 'things Alt-Az' and which will therefore be of immediate use to you. Beware, you can image with an alt-Az mount and the link to the No EQ Challenge amplifies that point despite what tradition says. Do enjoy imaging and don't forget to post! Cheers, Steve
  15. SteveNickolls

    What to watch on TV when it's cloudy

    Is it definitely off the air now for always? I know Prof. Cox took the format to Australia this year but haven't been able to watch any of the programmes as they are not accessible from the UK which is a great pity. Haven't recently checked if some kind soul might have placed them on YouTube. With Stargazing Live I always wanted to see more of the practical side of astronomy which I know is affected by the weather. They could do so much more to promote awareness of light pollution but the will doesn't seem to be there. I did write to Dara about this topic this autumn after seeing him live in Nottingham but wasn't surprised not to get a reply. Cheers, Steve
×

Important Information

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