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_30_second_exp_2.thumb.jpg.7719b6f2fbecda044d407d8aba503777.jpg

SteveNickolls

Members
  • Content Count

    1,642
  • Joined

  • Last visited

  • Days Won

    1

SteveNickolls last won the day on December 11 2018

SteveNickolls had the most liked content!

Community Reputation

1,104 Excellent

3 Followers

About SteveNickolls

  • Rank
    Sub Dwarf

Profile Information

  • Gender
    Male
  • Location
    Nottingham UK
  1. 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.
  2. Good luck deciding. Nothing wrong with the 700D, it has a touch sensitive screen which is articulated. At the back of my mind I recall concern over the 650D model. Cheers, Steve
  3. Thanks for the heads up, will have a look at the product. Cheers, Steve
  4. Not sure on your particular model but there are 4 lens reviews here for Samyang 14mm lenses which might shed light on the design-https://www.lenstip.com/lenses_reviews.html Cheers, Steve
  5. That's brilliant So pleased for you. May I enquire what model DSLR you have and what functionality you have with the camera, that is are all the DSLR capabilities able to be used (e.g. 'Live View'). Good luck with your future imaging and don't forget to post your images. Best Regards, Steve
  6. Hi, some people on CN have reported partial success of sorts with some models but my understanding is more work is needed before all Canon DSLR's work fully functionally with the ASCOM driver, but you might be fortunate with your camera though the odds are probably against it right now. Cheers, Steve
  7. Be nice if that works out for you. This was raised on the BYEOS forum-https://www.otelescope.com/forums/topic/2821-bye-3rd-party-api-used-as-basis-for-ascomdslr-driver/ I do hope better progress can be made but Guylain's comment may be telling. Cheers, Steve
  8. I certainly would, you may find it needs no change from the factory. Enjoy the mount. Cheers, Steve
  9. I really wish that Sharpcap will be able to extend its functionality to DSLR's but am haunted by the knowing comment, "let's see how far it gets" here-https://www.otelescope.com/forums/topic/2821-bye-3rd-party-api-used-as-basis-for-ascomdslr-driver/ Cheers, Steve
  10. Hmm, they have averaged the readings that my son and I made on the same evening, 8 for me and 16 for him and an average of 13. Age and acuity are very important to consider. Cheers, Steve
  11. Sorry to hear this if I'd known performance could vary so much I'm not sure I'd have committed to getting one. I'm aware there are a number of different maker alternatives out there on the market for this caliber of mount. Best Regards, Steve
  12. Hi Fabio, Sorry to hear your experience with the SA has not been so good. I have only just recently been working to bring my old CG-5 Go-To mount back into use and learning how to use PHD2 and decipher its graph to check how the mount is performing. I've not thought it necessary to use it on the SA so no idea what its PE etc are like. Are you using a PoleMaster accessory to obtain your alignment on the SA mount? I have been very pleased with how the SA tracks finding the supplied polar scope so much better than the old Celestron types. It didn't need any adjustment from the factory when checking the polar scope was aligned in the mount. As I mentioned in an earlier post I did find the SA wedge quite poor so it's very likely that quality varies with each part of the assembly, luckily I replaced the wedge for an old Celestron Alt-Az mount/tripod I had lying around which is so much smoother to operate for polar alignment and probably more sturdy than a photographic tripod. I didn't mention before but a house brick (about 3kg) is placed on the eyepiece tray to keep everything steady. Regarding subs at 135mm yes my standard exposure length is 300 seconds and unguided the only time I had an issue was when I had not balanced the set up properly to image at a high elevation and found a few slipped frames. Most of my imaging is relatively wide field with the Samyang 135mm lens at around 6 x 10 degrees but good for making mosaics. Here's a 4-pane mosaic of part of Cygnus from last October each pane was made from between 18-24 300 second light frames with matching dark frames from my library and master bias and flat frames, I've used StarTools to turn it into an inverted image so you can see the stars better, the Samyang gives good star shapes- As I've been busy on the few decent nights this season making mosaics I've not used my 75-300 mm lens much to follow consistently up on the 150 and 180 second exposures performance but may next season give this lens more of a try. After imaging at f/2 using the stock zoom at around f/6 is so ponderous. Again I'm sorry to hear you have had less fortune with your SA mount. Just a thought, is it still under warranty to return it to the retailer? Best regards, Steve
  13. Hi, and thanks for posting. I’ve had my Star Adventurer (SA) mount since April 2017 and found it a lovely piece of equipment for taking wide field images. Used within its operational capabilities it works extremely well, the tendency is to push too long a FL optic or payload weight onto it. You will need to factor in a suitable, rigid tripod to hold the SA and your experience with the SA’s wedge will vary. Mine was very stiff to use and coarse so I did away with it and used an old Celestron heavy duty Alt-Az mount which is way smoother when polar aligning. Your experience will of course vary. The large clutch on the SA can get over tightened but Sky Watcher produced this video to help rectify the matter- You soon get to judge what tightness is needed on the clutch and how to do things in the dark! When polar aligning the SA’s polar scope is very decent and if you employ the SkyWatcher Star Adventurer Mini App you can use the polar clock capability to accurately set Polaris. My advice would be to finish polar alignment when Polaris is at either a major division (eg 0, 10, 20, 30 ,40 ,50 minutes) or at the half way point (5, 15 etc.). This accuracy can make the difference when using longer FL lenses. I was able to increase the exposure time at 300 mm FL from 150 to 180 seconds using this technique. The polar illuminator that comes with the SA is annoying and has a tendency to drop off until you use some tape to secure it. Using the SA you come to the point wondering what sub-exposure length to adopt as with short FL lenses you find you can track for ages. There’s a law of diminishing returns as far as exposure time goes, especially if your location is controlled by local light pollution. With shorter FL lenses such as 135 mm I’ve been quite able to obtain exposures of 15 minutes but depending on the light pollution where you image a much shorter exposure time may suffice. Here the speed of your optics will come into play. I generally use a 135 mm Samyang f/2 lens with a clip-in Astronomik 12nm Ha filter and find 300 seconds an optimum exposure time, I have done longer but 300 second sub-exposures do the job and now a spoilt frame due to cloud only loses 5 minutes of the session. The 300 seconds sub-exposure time came partly out of extensive imaging and using the histogram in BYEOS to best judge what I considered was an optimum exposure time, it comes out pretty close to what is explained and calculated in the presentation below. You might find this sky fog calculator useful- http://tools.sharpcap.co.uk/ with it you can determine the amount of light pollution at your imaging site and employ the value to provide a value for your optimum sub-exposure duration depending on your optics, local light pollution level, type of camera (colour/monochrome) and any filter you are using. This presentation is very rewarding on the matter of what sub-exposure lengths to try and well worth watching all the way through- You could skip the very interesting presentation and go to 49.12 in the video where the formula for calculating your Optimum sub-exposure time is given. Provided you know the read noise of your DSLR, how much sky glow you have and how much extra noise you can tolerate in the image you can quickly work out your sub-exposure length. For my set up the sub-exposure time calculates to 312 seconds if I accept a 3% added noise so close to my 'suck it and see 300 seconds actually used. I hope this all helps, I’m sure you will really enjoy the SA mount and look forward to seeing your posts on SGL in the future. Best Regards, Steve
  14. Hi, and thanks for posting. My experience with longer FL lenses (Canon) with the SA mount is that at 300mm FL expect up to 3 minutes sub-exposures if you get polar alignment and payload balance right. That was with a fairly light 75-300 mm zoom lens and which together with a Canon 600D weighed in at 1,164g (2.57lbs). The lens was simply connected to the camera with no additional support. Mostly however I use shorter, faster FL optics on my SA to provide long enough exposures for my imaging conditions in a Mag 5.0 sky. Good luck coming up with your decision and don't forget to post your successes on SGL. Best Regards, Steve.
×
×
  • Create New...

Important Information

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