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.

oldannie

Members
  • Content Count

    221
  • Joined

  • Last visited

Everything posted by oldannie

  1. I recently imaged the Crescent Nebula in HaRGB as my first CCD image having recently moved from DSLR imaging. Not great but learnt a lot and it's still there for much needed practice on my processing. I would like to try a narrowband image next and would be grateful for some (well - lots) of advice! Is there any reason why I shouldn't try the Pacman nebula using Ha, O111 and S11 filters? My set up is Takahashi 106ed, Atik 460ex - mono, with EFW2 filter wheel and Baader filters. I image from a fairly dark site in mid Wales. Any other suggestions for a suitable target would be more than welcome - perhaps bi-color would be less complicated as a first attempt at narrowband? Are there any ground rules for determining the relative exposure times for each filter and what would be the minimum overall exposure time I should aim for? I've also read that narrowband can do strange things to stars and that one way round that is to produce a set of RGB stars - that being the case am I right in assuming I would only need to take short exposures of my target to produce R & G & B stars, ie 30 secs? This will all be quite a challenge for me but 'nothing ventured, nothing gained'! Annie
  2. ps - Olly when you mention making Ha subs longer do you mean each individual exposure or the overall exposure time?
  3. Thanks Olly that's very helpful info and I you're right about it providing an opportunity to learn a lot about processing irrespective. Dave - thanks for your last message. The reply afterwards related to the message before yours - if that makes sense!
  4. Here are two Ha subs - one looks ok , the other has stars trailing. Viewed via Avis Fits viewer the trails are obviously much more pronounced. Hope they post ok.
  5. No Dave my set up doesn't enable me to to view my guiding in real time so will def have to download the PC application for my MGEN so I can at least generate a guide graph. It's an interesting point about the stars being smaller with Ha subs - didn't appreciate that! Will try and post some subs as you suggest. Mant thanks Annie
  6. Still trying to sort out the reasons for the star trailing with Ha subs . On the first occasion I took 24x600 sec subs in Ha and around half suffered from star trailing. At the next imaging session I took some 600sec RGB subs with no signs of trailing. Next session I took 12x600 Ha subs (nothing else) and 8 out of 12 showed trailing stars. The first two subs were ok and the last two almost ok! Last night I took solely RGB subs and no trailing. Have checked for signs of anything obvious in my cabling/connections and will download the PC application for my guide camera so I can record a guide log next time but in the meantime is there anything else I need to consider - is it just coincidence that the trailing has only occurred when I take Ha. Star trailing is not something I have encountered until I moved from DSLR imaging to CCD imaging. Annie
  7. Thanks Tony - am hoping it is the most obvious cause - snagging cables. Annie
  8. yes Dave - I've had the guider for a number of years now and it's been great - I do wonder if it's something simple like cables pulling as I'm not used to lots of cables! I think recording a guide log on the mgen is easy it will be working out which driver to download and how to download it but am sure I'll get there. Carol - I don't think it was particularly windy that night but I do think cables pulling would be a logical reason. I was so busy checking my guide star was there that I forgot to check how the cables were doing!! Don't think there will be that much detail left when I eliminate all the bad subs. Learning a lot though. Thanks folks Annie
  9. Just seen your reply - I agree it's definitely a guiding problem - not one I've had before! Happy with the background - thanks for that. Annie
  10. Thanks to 'Oddsocks' for recommending Avis Fits viewer I've been able to look at all my Ha subs. The files are numbered sequentially ....595 to ....614. The first two are fine; 599 shows bad trailing and nos 601-606 show trailing also. Have not experienced this before with my guider though only recently started using it with a CCD . What might have caused this? I can record and download a guiding file from my guider but need to download the PC application first. Annie
  11. Thanks Dave - I didn't think they were right. I'll check my individual subs. I think the Lacerta guider does enable you to record the guiding and presumably produce a graph but in order to keep things simple I have avoided it. Something else to learn how to do next time - it seems pretty important to be able to look at the guiding. Lots of things have gone slightly wrong with my first attempt at CCD imaging but other bits have gone better than anticipated and have learnt a lot. I'm not very technically minded so it's all a big challenge but an enjoyable one - well most of the time ? Annie
  12. Thanks Dave. Some of the stars look as though they have a 'pimple' on the end but perhaps what I'm seeing is just smaller less bright stars very close to brighter ones - if that makes sense! In other words I'm seeing stars! Annie
  13. Thanks for your reply Richard. My broadband speed is low (2/3mps) so I have difficulty posting anything other than jpegs and have tried using Dropbox but again the low broadband speed makes that difficult. I did check all my calibration files and couldn't see anything obvious so sent a jpeg copy of my stacked Ha to Carol (a regular in SGL) and much to my embarrassment it has turned out to be lack of skill in processing that has been the problem!!! Still I've learnt a lot in the process of finding that out! In the past I've tended to ask before I've allowed myself sufficient time to think through the issue but I take your point about advice being readily forthcoming and have already experienced that. Here is a copy of the stacked and processed Ha data - 25x600 secs using Takahashi 106ed: Atik 460es mono: stand alone mgen Lacerta guider on neq6. Hope the 8bit jpeg image appears ok - just under 500kb! Do you think the stars look a bit odd or am I being pedantic? Thanks again Richard Annie
  14. What a lovely shot. It's very easy to overdo the color but yours is just right - love it. Annie
  15. Couldn't wait til tomorrow to check Avis - works fine!
  16. Have downloaded and installed Avis ok and will have a proper look at it tomorrow. The link above to 'Fits Liberator' was the one I have been using and I still had no joy with it. It appeared in my C drive and the manual opened ok but when I tried to open the application it took me to something entirely unrelated in my D drive - very strange! Many thanks for the replies - much appreciated. Annie
  17. At the moment I use DSS to stack and photoshop cc to process. My mono CCD produces fits files which won't open in ps. Though I can stack and convert to tifs in DSS if I want to look at individual fits files I have no way of doing that so have been trying to download 'fits liberator' to my windows 10 laptop but having difficulties and not sure why? Annie
  18. Yes you're right. Am def going to check my calibration files. The Ha flats were taken at around 24000 adu's so that part should be ok but I do take your point about stray light and think I might need to be a bit more careful about that aspect. Thanks Annie
  19. I think that's very good advice and in fact I thought maybe I'd posted a little prematurely (ie. before I'd thought it through properly!!) I have already tried it without any calibration files and it's quite a bit better so am going to go through my calibration files as you suggest and also my light subs. Much appreciated. Annie
  20. Am trying to image the Crescent Nebula as my first image with a CCD camera having just moved from DSLR imaging and realise I am quite ignorant about some of the basics. Having collected some RGB subs, stacked and aligned in DSS using a red channel sub as reference image I have managed to generate a color image in photoshop. Last night I took some Ha - 25x600sec using Atik capture software, Artemis. When I lightened the first sub in Artemis it looked great with lots of detail - a wow moment! This morning I stacked and aligned in DSS using the same red channel sub as reference image together with darks, flats and bias frames and as is often the case the result was a quite dark image. Opened it in photoshop expecting to reproduce the same detail I saw on my computor screen last night but it still showed very little detail and soon showed signs of over - processing when I tried to use levels. As is oft the case with this hobby have gone from euphoria to disappointment in the space of 12 hours!! Have I missed something obvious - it wouldn't be the first time!! Using Takahashi 106ed, Atik 460ex on neq6 with lacerta mgen stand alone guider. Annie
  21. That would seem to be a sensible compromise Carole - Cheers! Annie
  22. I did wonder about the efficacy of darks Olly and no I would rather not go to all that trouble. - does that mean you just use flats and bias. I would expect to take around 20 flats and loads of bias? Annie
  23. And I can run it for say seven hours non-stop?
  24. I want to collect some 600sec and 300sec darks, maybe 20/30 of each over as short a period as possible, using Atik 460ex, mono. I have my cooling set to -15 deg C (max for the 460 is -25) and the weather forecast is telling me it's going to be about 8 deg C overnight though as we're quite high and rural it may well be lower. Using the sequencer on Artemis capture can I safely let everything run for 6/7hours (in my pulsar) or would I be better acquiring darks over shorter periods? Have only just moved from DSLR to CCD and not overly technically minded so full of naive questions! Annie
×
×
  • Create New...

Important Information

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