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

28 Excellent


About Imd

  • Rank
    Star Forming

Profile Information

  • Gender
  • Location
  1. I agree i would be uncomfortable on my own in the dark with expensive equipment unless im in the back garden. Im in solihull. A few of us meet up occasionally for some social observing/imaging. We are members of knowle asteononomical society. We were in the cotwolds at the weekend. We are not going to get many dark hours at this time of year and so observing sessions will be quiet for a while. Ian
  2. I gave it another go last night after I spent some time with the PA. PA was out a bit out but I expect would normally get away with that level of error when using my 200p. I tried using sharpcap to get a really good PA but that might have to be another thread because the laptop seem to have a significant delay in reflecting changes made after the bolt adjustments. However PS is now much better. I also think I had better look with focusing and the results to me appear to be rounder stars reaching more into the corners than shown previously. I'm inclined to agree with Blinky that the SCT is probably more sensitive to field rotation field when using a DLSR. Ill also speak to FLO about the 105mm Back focus However I'm much more pleased with this image. I think I'll add a focus mask to my shopping list too. I just want to thank all those who have helped me by discussing this subject. I'm always amazed by the members willingness to support each other and the collective expertise available. Here is last nights image another M27 to help compare with the previous image - single 5 min exposure using a modified Canon 1100D, CLS filter, guided with a finder guider, moon not quite risen. Hope you like it, I did
  3. Thanks Michael, I raise this with FLO to see what they say about this.
  4. I enjoyed your book Steve, its nice to hear from you. I think the BF is 104-105mm
  5. Thanks Alex, You are of course correct, too much tweaking. Ill give it another go sometime. The T-adapter-sc is 50mm long so in total I would have a bf of 104mm-105mm. I will definitely try the focus again as you describe.
  6. Just wanted to say thanks already to all those who have taken the time to respond so far
  7. This is a an interesting article although some of it goes above my head and to me using those graphs it looks like the optimum for a a 9.25 with a reducer would have a BF of less that 100 to achieve optimum aperture but I have heard previously 105mm is the magic number. I have measure the distance from the collar at then back of the SCT to the front of the camera and its about 95mm and then the sensor is probably 10mm or 15mm inside the camera so it looks about right. There is not actual extension tube but do use a celestron T-adapter to attach to the reducer. The back focus seems about right, I think. What do you say?
  8. Thank you, I hope there is room for improvement without great expense I only managed 4 subs and 2 darks for processing later, no flats collected yet, here was the result after stacking in DSS a bit of PS tuning and a lot of cropping
  9. Please could you expand on what is meant by field curvature, is this something I can correct?
  10. I doubt it would be flexture as its a tight grip use a baader double screw shoe but I admit the focal length differences are quite significant. But if it was guiding I would have expected the whole image to be affected.
  11. I agree it could look like field rotation. I suppose that as the central stars are nice and round that the guiding was ok, I need better polar alignment. I think I may have been a bit hasty about popping it back on the pier after a star party. This is really good news, Ill check polar alignment the next chance I get. I'm please with the finder guider results, I suppose if I have a camera with a smaller chip the guiding may be more sensitive. Thanks both for being so helpful. Ian
  12. Hi all budding astrophotographers, I recently acquired a C9.25 and after a few days I had my first clear night (moon rising). I bought a Celestron f6.3 reducer which I connected after removing the 2" back, then connected my Canon 1100d DLSR camera via a T-tring. Many of the central stars seem sufficiently round in shape but I was surprised to find so many stretched stars in the corners even after the installation of the x0.63 reducer, I thought it also acted as a coma corrector. The dew shield was not perfectly sitting on the scope but I don't imagine this could be the cause. Is this coma on the corners or something else? Do you think I'm being unrealistic of my expectations when using the reducer to also flatten the image? Is it because of the unrealistic field of view from a DLSR camera on the C9.25 or perhaps I have possibly a dodgy reducer or could collimation be the source of my problem? FYI, the image is a single 5 min exposure without any processing, guided using a finder guider and using a CLS filter, EQ6 on a pier. Im pleased with the image apart from the corners due to the stretched stars. Many thanks for looking, your advice is always appreciated.
  13. Hi, Im looking for a Skyshed pod bay in white. Perhaps some shelves too if I'm not pushing my luck. thanks for looking Ian
  14. After one year of having my pier in my garage I finally decided to get it installed. It was ordered online and when it arrived it was about a foot taller then the eq6 tripod. Presumably the greater height was by design as most surround their pier with decking. I decided not to use decking and to dig a hole 3 foot deep and 2 foot square-ish (shape of the flags are hexadecimal. This would mean 2 foot deep with concrete and 1 foot space between the concrete and ground level. This would allow me to change the height later if required. I bought a pack 6 threaded rods from screwfix to set into the concrete and created 2 templates to match the whole on the base of the pier. One template would be used to ensure the bolts would enter the concrete correctly and the other template to ensure the bolts were plumb. My helpers and I used metal plates also from plumb centre to help anchor the bolts in the concrete and some metal wire to also help keep the bars plumb The last foot of digging was hard due to limited space so I had to get some help from some little experts. It took 19 bags of concrete ballast and 2 bags of cement. I waited a week to dry and voila. The pier now rests on 6 bolts and washers. It took a little while to get the load spread evenly over the bolts. The pier base holes needed a little filing to ensure the pier when down over the bolts too. It then took another 5 hours sawing wood to fill in the remaining 1 foot cavity so that I wouldn't slip down there when walking around the scope in the dark. Ill remember to by an electric saw next time. The pier feels very solid and although it will vibrate if knocked the vibration settles down very quickly. Thanks to the following for your help Dad who can still dig and saw better then me 3 kids Kristian, Lucas and Sophia who dug a hole like happy Victorians when it became too deep for adults Karl who helped shovel some concrete, file holes and provide general expert advice. I hope others find this post useful Regards Ian
  15. Hi Steve et al, Two of us expect to join you from Thursday to Sunday from knowle Astro soc. Its our first time at Astrofest. We look forward to meeting you all. Ian ps if anyone fancies a game of tennis whilst we are waiting for crystal clear, cloudless, dark nights. Please bring racket and ping me.
  • Create New...

Important Information

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