Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Martin Meredith

Members
  • Posts

    2,266
  • Joined

  • Last visited

Reputation

3,051 Excellent

6 Followers

Profile Information

  • Gender
    Male

Recent Profile Visitors

9,178 profile views
  1. Looks like a great session! When the moon is up I tend to favour open clusters as they're less affected, but in galaxy season the temptation can be strong... The Owl general comes out fuzzy for me so perhaps the nature of the beast for EAA timescales? I always enjoy seeing the blue central star. M51 is always a wow moment for me regardless of how often I've seen it. I see that in your first image you're getting a good representation of the 'horns' (as I call them) or trailers running to the right of NGC 5195, and evidence of the streamer heading off diagonally towards the lower left.
  2. Just to break the refractor trend 🙂 I'd keep my 10" Dob as it is manageable enough to come out on most clear nights yet large enough to keep me in celestial sights for many years.
  3. I've used Aladin a lot, but never for uploading/solving my own images. I simply put the relevant Aladin layer (DSS etc) side by side with my image and do a manual comparison. What you might find useful is the custom layers function (accessed via the stack icon at the top left). This allows you to choose any catalogue you wish to overlay, by clicking on 'add catalogue' and then typing in part of the name. For instance, "milliqu" will get you the million quasars catalogue. Then click on 'load cone', which provides labels within a specified radius of the current point. You'd be amazed how many quasars there are in each field.
  4. Very good going for a manual Dob. I'm just wondering if your debayer settings were correct, as that might explain the green-blue cast?
  5. Great results, especially considering the OSC->RGB approach isn't really optimised. I'm not sure why hot pixel removal isn't working for you but it might be to do with the 3-for-1 sub proliferation. Maybe try setting the successive subs value to 1 rather than 3?
  6. Actually, most of the Berkeley clusters are pretty small (nearly all are under 16 arcmin). They make fantastic EAA targets but they require decent total exposures. I started a thread some time ago about my EAA observations of these clusters. It would be great to see some further observations with different kit.
  7. No identification but it is definitely there on the DSS2 red plates on Aladin. Looks like a PN to me, maybe one that hasn't been spotted until now?!
  8. I believe the reverse-vignetting (overcorrection) will disappear if you use darks and flats together.
  9. Yeah, I forgot about monochrome but glad you found it and have it working!
  10. There's been a recent-ish change to the skimage package, one of Jocular's dependencies. They've done away with the 'multichannel' argument. If you're happy to edit the code you can just search for 'multichannel' in 'multispectral.py' and remove that argument. Or send me a PM and I'll send you the updated code.
  11. Well, what can I say. Just in from an hour's session before the clouds rolled in and everything worked perfectly! I set up in a location less afflicted by security lights so maybe that was it. Besides a spectacular first view of M42 in this scope, tonight's new highlights were the gorgeous NGC 2158 (the tight open cluster right next to M35) and the globular M79 (declination -24deg30' in Lepus). I'm at 55deg50' so was surprised to be able to get a decent view (or any view at all) of M79, not far above the southern horizon. Planetary nebula NGC 7662 (Blue Snowball) in Andromeda also showed some detail with a darker central zone, and I caught M33 and sigma orionis for the first time with this scope. I had time to revisit a bunch of objects en passant (something this tech makes all too tempting), including M82 which looked superb, M81, M95, M103, the Owl Cluster, M31, the double cluster, M52, M1, Jupiter and Uranus. Its true I'm still in 'filling my boots' mode with the new toy so didn't spent more than a few minutes on each. This scope and tech is a real game-changer for me. To be able to set up and be observing in 2 minutes flat with no tedious alignment is a marvel (the Synscan handset approach I've been using for EAA this last decade is so much dinosaur-tech in comparison). A few quick impressions of the scope and base (much has already been said above): the construction is really solid with no flex to speak of, and very fast settling time. The plastic handle to guide the top end is a real boon on cold nights, as are the carrying handles on the tube and base. Optically I'm enjoying really tight stars and very clear separations of the half dozen doubles I've looked at, and good colour as expected from a Newt. I'm not finding any objectionable coma. On a previous f4.5 scope I felt I needed to use a coma corrector but not here as yet though I'll try it out with the corrector at some point. The focuser is single speed but holds its position well so again no great rush to replace with a 2-speed. Cheers Martin
  12. Just reading the alignment tips here: https://astrobackyard.com/celestron-starsense-explorer-dob/ One suggestion is that there might be reflections off the back of a shiny phone case. I'd never thought about it before but checking now I see my phone case has quite a shiny back.... Something else to play around with next time.
  13. Thanks Paul for these tips and observations. I was pretty happy with getting the object into the FOV, and indeed I aligned by zooming right in each time. The mirror itself is clean, pristine almost. It might be that my phone camera lens wasn't... One thing I noticed during the initial setup was that when centering the camera over the mirror I always had a dark edge at top and bottom, while in their demo video I see a nice clear centred image. I also selected to have the advanced camera controls (exposure/gain/iso) on the menu but I'm not sure whether they're needed. It seems they're they're just available for the setup stage when centering the mirror since that's done in daylight I guess. I'm sure it will be a game changer for me too. I was really happy with the actual results, just surprised by how often it reported not being able to find itself.
  14. I recently took delivery of a Celestron 10" Dob -- great service from FLO as ever -- and immediately had a couple of clear-ish nights in between winter storms up here on the Isle of Bute to try it out. Don't tell anyone, but I didn't even have time to check collimation...🤫 I guess my home location is Bortle 4-5 -- but plagued with security lights (and intermittently the CalMac ferry -- surprisingly bright from some distance away). The NW of the island is around Bortle 3 and that's where I anticipate using the scope in the main when the weather is more settled. On the first night I set up in late twilight but found the app wasn't recognising the stellar pattern until the sky was somewhat darker, although I could see plenty of naked eye stars. After this, whether the app reported finding the sky position or not was rather hit and miss, with perhaps a 30% success rate depending on where the scope was pointing. The app reported trying out 4s and 8s exposures when it had initial platesolving difficulties -- does anyone else see this iterative process reported on the app? Even so, once it latched on to a location it was pretty easy to use the app to hop to other objects and find them in or close to the eyepiece field (I mainly used a 21mm EP, so around 1 degree FOV). In a 90 minute session I had excellent views of many open clusters (M35, 36, 37, 38, 44, 45, 52, 67, 103, Double Cluster, NGC 663, Hyades and several more I didn't record), several planetary nebulae (Catseye, Eskimo), galaxies (M31 and friends, M81, M92), as well as Jupiter and Uranus. The highlight was a superb Crab, and a surprisingly detailed Hubble's Variable Nebula. So in spite of platesolving issues, the tech worked sufficiently well for me to have a great session. I suspect there was a thin cloud layer that reduced platesolving success. Certainly I couldn't detect M101 or M51. On the second night I started to observe when it was completely dark in a sky with 30-40% thickish cloud cover most of the time, but localised to one part of the sky, the rest being pretty transparent. StarSense worked better on this occasion but still with a success rate of maybe 60% until everything dewed up, followed shortly afterwards by almost complete cloud cover. As well as some of the first night's targets, a bunch of gorgeous doubles and lots of NGC open clusters in Cassiopeia, I had very good views of M101 and the M51/NGC 5195 pair, a superb Owl Nebula, and clear views of some of the UMa galaxies, M106 and M108, in about an hour of observing. On this occasion I used my 13mm eyepiece throughout. I found that realigning on a bright star a couple of times in the session was enough to place the targets within the FOV. Realignment was also a useful check on the star patterns being seen by the camera/app, and I noted some mushiness towards the end no doubt due to dew. A few initial thoughts. Having spent much of the last few years doing camera-based observing and with only an 80mm refractor or 10x50s for visual, it was a great pleasure to see objects through a 10" scope, and I have high expectations for this Dob. It was also relaxing to have a completely silent scope experience without tedious mount alignment or motors whirring. With regard to StarSense, the app itself (as in the onscreen star chart and associated DSO information) is superb. I don't know whether the number of successful solves is par for the conditions, but more time and experience will tell. I intend to try StarHopper too to see which is the more accurate, though I imagine the charts and object info ought to give the edge to StarSense. Has anyone compared the two approaches? cheers Martin
  15. I too have a small sensor (this image was taken with a guide camera, apparent FOV about 0.35 degrees). However, I find that apart from many NGCs, most of the Berkeley open clusters fit well with plenty of space around. The other thing that really makes a difference is colour!
×
×
  • 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.