Jump to content


Recommended Posts


I have a 130p ds and a newly acquired EQ5. I use am Olly e pl1 which takes great terrestrial pictures but when attached to a scope or Ep (via t adapter) I always get slight trailing. The amount of trail is the same between 1 and 15 seconds (anything after that I would presume comes from celestial movement. The amount of trail is also only marginally better than I had using the EQ2 which makes me think there's movement in the camera (I use a timer when I take the pics).

Do I need a new camera? A web cam isn't an option as I don't have the finds for a lap top. I don't want to spend my money on syncscan motors now if I'll still have this problem using this camera so what's the best used DSLR body I could buy. It would be used for Astro work only.


Link to post
Share on other sites

Forgive me if this is a stupid question, but you do have a motor drive for your EQ5?

Other than that, could you be seeing coma in the images? Stars trailing out towards the corners?

I don't think it can be anything to do with the camera unless you have a loose mounting and you are getting some shutter-shake. Does your camera have mirror lock up facility?

Failing any of that either a used 450D, 1000D or 1100D would be my preference. There is not much to choose from between them.

Link to post
Share on other sites

Thanks for the response.

Yes, I have a phone.

no I don't have a remote shutter I use timer

And no I don't have a motor drive. My camera is a micro four thirds so has no mirror. The trails all look to be through a shake rather than star movement and I wouldn't expect to see star trail at the short exposure time using the afocal method.

I'm in the market for a syncscan but want to make sure I don't need to use a different camera.

Thanks again.

Link to post
Share on other sites

A remote shutter release and built in introvolemetre would be a useful thing to have if your camera supports a remote shutter release cable. These are approx (£15) on Amazon.

Do the trails go right across the image or only in some parts of it?

My Nexus 7 running KitKat 4.4.4 with an OTG cable (£3) and an app called USBWebcameras (free) will run a compatible webcam. Which is why I asked. I bought a cheap (£3.49) webcam to try it out and it worked it will save video and take stills and has full gain and contrast support so next time the Moon comes round I am going to have a go.

Edited by happy-kat
Link to post
Share on other sites

Your camera has 4.3micron pixels, at 650mm with the camera body connected to the telescope at prime focus you are looking at 1.36 arcsec/pixel. Stars move at 15arces/sec so a 1sec exposure with out tracking motors a 1pixel star would be 11pixel long. To get your star within the seeing, assuming typical 3arc/sec seeing you would be looking at about 1/3sec exposure time. If you are connecting to an eyepiece or Barlow this will increase the effective focal length and reduce your exposure time even further.

A simpler way of looking at is is with the 500 rule. 500 / (focal length x crop factor) = max exposure time before visible trailing assuming you don't zoom in and further crop your image, nor look too closely at it.

500 / (650x2) = 0.38 sec exposure time.

For deep sky AP with a telescope you need a driven mount. You don't need Synscan but you do need a motor drive at minimum.

  • Like 3
Link to post
Share on other sites

rikm nailed it ... BUT you might try to go a little bit longer, say 0,5 sek, take 50 pics+50 flats and stack them in dss... that should give you a start to play around with until youve saved for a motorized mount ... i did sth similar

Link to post
Share on other sites

Thanks again for all your responses.

I do have pictures but won't be at my pc until Monday so can't show them till then.

Happy-kat: loving the cheap webcam idea, love to see how that pans out.

Rikm: thanks for the math. I think I'd heard that before but didn't want to believe it ;-).

Given a clear night next week, when I'm home, I'll try again and post the pics on this thread.

I did question buying motors first and then a syncscan but don't want to spend £90 now and then £300 in a few months time.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Paul779
      Hi all
      New to the astrophotography game. Looking to get into guiding now.
      Looking for an EQ3-2  with enhanced dual motor drives or synscan system would also consider barebones EQ3-2/EQ5 to upgrade, not minted right now can offer £150-200.
    • By Brownthunder93
      Anyone have any idea where I can get a replacement counterweight bar/shaft for my EQ5 mount? 
    • By Astrid
      My 200P just arrived and oh my God... I have been trying to wrap my head around the mount for 4 hours.
      The manual didn't really help so I decided to go on youtube, but again, I didn't find any good and detailed videos so I decided to ask here if there is any video or perhaps blog post that might help me set up the mount. 
      Thank you very much! 
      *by the way, is the EQ5 supposed to have slow motion cables? I only got 2 knobs (not cables) and I'm not sure if there is something missing or not... sorry, this is the first time I've used a serious equatorial mount or telescope. 
      Thank you very much!
    • By SteveBz
      Hi People,
      I have quite severe backlash, such that guiding assistant just gives up.  It seems to be about 11 secs in total, the one time GA came back with anything, but it's about 3-4 secs if I measure it by hand.  Here's some guiding.  Actually, it's worse when I'm dithering.

      So, I tried measuring the backlash with by counting and it's about 3-4 secs.  If I used PHD2 guiding assistant, mostly it fails, or it comes back with a very big number, like 11,350 msecs.
      I tried entering this:

      But then I got a see-saw mechanism, even when I dropped 8,000 to 3,000 it was the same.
      I've taken the motor off just now and looked at the grub/hex-screw mechanisms.  One hex-screw was loose, so I tightened it to hand tight and let the grub-screw off an eighth of a turn.  I'll look again this evening.
      I ran a three hour sequence of exposures on NGC6888 (with dither) and this is what I got on EVERY image.  Amazingly, they stacked nicely.

      So last night I ran without dither and it was mostly OK.  What I want is full dither, but to do that I need to deal with the backlash.
      Here's a photo of the motor and gears, most of the backlash seems to come from the top gear (ie the 12-tooth gear and its neighbour).  I guess the rest comes from the worm-gear:

      Does anyone have any suggestions? There doesn't seem to be a belt-mod for the EQ5 as far as I can see.  Maybe there are better Dec backlash compensation settings I could use.
    • By Rogr18
      Sorry if this has already been asked ( I think it would have been, there are posts similar but can't see the the answer I'm looking for) 
      I have a celestron C8-N scope that came with a Cg5 mount,  it's at least 10 years old and although it had a lot of use to start with it's been gathering dust the last few years. 
      So I would like to fit a motorised goto mount to it and was considering a synscan  pro3 for an Eq5 mount. 
      Can someone tell me are these 2 mounts the same and if so will the synscan be OK for my Cg5 mount. 
      If not are there any others I should look at? 
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.