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_dslr_mirrorlesss_winners.thumb.jpg.9deb4a8db27e7485a7bb99d98667c94e.jpg

sshenke

Members
  • Content Count

    57
  • Joined

  • Last visited

Community Reputation

8 Neutral

About sshenke

  • Rank
    Nebula
  1. Thanks, I will look at the rotation of the fw. Had very clear skies last night, but did not get any proper images at all. I can see the arc more clearly in the pictures of the pleiades and I can see the same sort of smudge in the picture of M33 ( that picture is a 120 sec exposure of M33!!!!). Looking through the objective port of the scope, I noticed that the secondary mirror is off centre, so I think collimation is definitely a problem. I can also see the bevelled edge of the secondary mirror being prominent and I wonder if there is light coming from the primary mirror that is being reflected off this bevelled edge on to the camera causing the arc.
  2. I am not sure if thats the case, because of 1. why would the dew always form on the same place- the optical window of the ccd camera looks clean to me 2. If it is because of dew, I would expect the images on the second round to be worse because of dew getting worse the longer the scope is outside. This is what I think, may be I am wrong, but thanks for looking into this issue. Really appreciate it
  3. Thanks Carole, yes this is what I have been targeting primarily, as it was an easy target to acquire, given the problems I have been facing. But I did try a few other things like veil nebula, but have not been able to do any substantial imaging with these targets because of the cloud cover. I am going to try again tonight with a differ ent target
  4. Hello all, I would appreciate your help on this problem please. I have been having a huge problem with capturing dso images since October last year, having previously managed to obtain good images of a few galaxies and nebulae ( I started doing this in July last year). For the last few months though I haven't captured even a single decent image and have been blaming the dew, refractor, filter etc. But finally I seem to have got to the bottom of it or so I think. As you can see in the attached images, there is a crescentic area of artefact near the centre of the image. Initially I thought it was the filter, but when I imaged without the filter, it is still there. I cannot see any obvious problem in the optical window of the CCD sensor, but still cleaned it properly with isopropyl alcohol and went onto test it last night and noticed this weird thing. I took 2 round of 1 frame each of lrgb images of m31. I didn't touch the scope or the capture software until the 2 rounds were completed and what I notice is that the smudge was there in round 1 images ( postfixed 1..red1, green etc), but not in round 2 images. I am not sure if it is due to drop in visibility as there was some cloud cover during round 2. Also I cannot see this artefact on images taken during daytime, such as of the sun. It moves independently of the image with the movement of the telescope, which is why I think it is on the CCD camera. This is ruining the images significantly and the unpredictability of it occurring is another frustrating thing. Would appreciate the help of the experienced and the wise please. The image with the title of andromeda 1 was taken about 2 months ago. I have also previously cleaned the primary and secondary mirrors thinking that that's where the problem was. Scope: sky watcher 130 pds Zwo asi 1600mm camera Thanks
  5. Thanks Vlaiv and Billy, I will switch to the 16 bit mode tonight and see if that makes a difference. What do you think about the histograms of the asi1600 and asi120, in the images posted above?. I never get a good histogram with the 1600. as for the dew heating, yes i have used a circular heating pad ( they use it for brewing!!!,) to the back of the primary and it stopped dew from forming, although now i am wondering if dew was present in the primary at all.
  6. Hello all, I have been struggling to obtain good images for some time now, which I have asked help with for , as in the following post: https://stargazerslounge.com/topic/342321-poor-image-quality-cause/ I thought that dew was the problem, hence I posted in this thread discussing about the merits of buying a refractor instead. Previously I was absolutely certain that there was dew on the primary mirror, but I am not sure now. In fact the dew that I noticed on the primary mirror was seen as soon as I had brought the telescope indoors, so it is very likely that the dew had condensed on the surface when it was brought indoors rather than while it was outdoors. Last night has been another disastrous (sorry for the pun!) session where I could hardly see the M31, this is really perplexing to me. Interestingly, the guidescope seems to produce better image than teh main camera as you can seen from the attached images: The ASI 120 mini is the camera attached to the guidescope and the ASI 1600MM pro is the main camera attached to the telescope- skywatcher 130PDS. For the same exposure time, or even less, the guidescope camera collects more light than the main camera. I am guessing that this shoudl not be the case? I wonder if anyone can shed light on this problem please. Thanks in advance
  7. i was thinking about cleaning the primary mirror as well, although it doesnt look too dirty.
  8. Thank you both. there are no water bodies nearby and i can't think of any local factors that might impact on dew formation.
  9. I am not sure if it is anything to do with location. I live in the Midlands ( milton keynes).
  10. Thanks. I left the rear end open, so as to use the fan with or without heating mode, in case the wrapping didn't work. Will close it off as well and see if it works. Thanks. B
  11. Thanks Ian, i am going to try the diy dew shield as well
  12. Thanks, well for what it's worth, I have wrapped the tube, even if it looks absolutely ridiculous!! I had checked the guidescope objective on last Monday and actually it did not have any dew on it.
  13. Yes, absolutely, i have attached a picture i took a few weeks ago looking down the ota
  14. i understand what you are saying. i wondered about that too, as i cannot see what's going on with the secondary mirror. however, it is absolutely clear that the main mirror dews up within a maximum of 1 to 2 hours. I have been using a fan with heating option to blow air from behind the main mirror, not directly down the tube from the front end
  15. Carole, this is really puzzling for me, i have draped the sw 130 pds in exercise mat when i took it out on Monday evening. i will post the picture later, might be hilarious. Temp on Monday evening was 1 to 2 degrees at 8 pm. mirror dewed up promptly within 1 hour. never got to see a single image of interest. Can I ask, if the sw 130 pds you used, worked well in winter too?
×
×
  • Create New...

Important Information

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