geoflewis

Hi Matt, For many imagers the C14 is the weapon of choice and it is a fantastic investment by the school's FPTA. It's a shame that is not getting more use, so I hope that you can persuade the powers that be to let you use it. What else did they spend the £25k on as a new C14 on a CGE mount would only cost about half of that? Is it in an observatory and what other equipment does the school have, e.g. eyepieces, cameras, filters etc.? Regards, Geof

There are lots of factors that contribute to poor seeing, a significant one of which is the location of the jetstream, which unfortunately frequently passes right over the UK. There are several websites that can provide jetstream forecasts, this is the one that I use. https://www.netweather.tv/charts-and-data/global-jetstream#2019/06/30/1200Z/jetstream/surface/level/overlay=jetstream/orthographic=-6.72,57.59,712 .... from which you can see that the jetstream is bang overhead today, however, if you play it forward you will see that it is forecast to move clear of the UK again by Tuesday/Wednesday (2nd/3rd July), so let's hope for clear skies then. Looking back to Friday's (28/06) better seeing, the MetCheck archive shows that much of the UK had the jetstream off to the west, but rapidly approaching, hence a likely contributor to last night's (29/06) less favourable conditions. http://www.metcheck.com/WEATHER/jetstream_archive.asp Please note, however, that it is not just the presence of an overhead jetstream that causes poor seeing, but the rate of airflow within in the stream. If there is a constant steady flow even at high speeds, then seeing may still be ok, as it is the boundary layers between different rates of airflow that churn up the atmosphere making planetary observing difficult. Hope this helps. Geof

What cable are you using between your laptop and the mount? You'll need one of these adaptors or similar... https://www.firstlightoptics.com/sky-watcher-mount-accessories/lynx-astro-ftdi-eqdir-usb-adapter-for-sky-watcher-eq5-pro-heq5-syntrek-pro-az-eq5-gt-az-eq6-gt-and-eq8-mounts.html https://www.ebay.co.uk/itm/HitecAstro-EQDIR-EQMOD-Skywatcher-EQ5-HEQ5-EQ3-EQ8-EQ6-ALTAZ-windows-10-/272062762570 I used the Hitec version with my NEQ6. Good luck, Geof

Nice prom, but OMG that was a seriously close call.....😲

I'm also packing up, clear sky but rubbish seeing......

Hi and welcome Greg. As John says, the main outer planets (Jupiter and Saturn) are difficult from the UK for the next few years with 2019 and 2020 being about as bad as it gets. The seeing tonight is certainly worse than last night, but it sounds like you made a good start. I can't get Jupiter's moons to settle tonight, they're just continuously going in and out of focus. Your Evostar 90 should yield some decent views in better seeing, but I think x180 magnification is probably going to be too much until the planets gain altitude in a few years time; try dropping down below x150. Good luck, Geof

Thanks, I think it will be a few years before I get close to that quality again, perhaps when Jupiter gains altitude in the mid 2020's, but then again it took me completely by suprise last year....

The seeing here in Norfolk is terrible compared with last night. Views at the eyepiece were poor, but once I put the camera in it was obvious that it's going to be a very short session....😞

Thanks Russ.

Hi Matt, thanks for looking. Yes, I got this one last year with the same rig, best image of Jupiter I ever captured, note the albedo markings on Ganymede. I have other images on my Asrobin page, if you want to peruse them. There's a mixture of planetary, lunar, solar and DSOs. https://www.astrobin.com/users/geoflewis/ Cheers, Geof

With Jupiter so low from the UK this year, I wasn't sure whether I do much more than take a glance at it, but as others have reported the seeing was pretty good last night, so after enjoying some visual observations I got the camera out and had a go at capturing some data. Since last year, I've had to replace my planetary imaging laptop which finally died this March, so I had to reinstal FireCapture and try to remember where all the settings are. I had some issues with drivers, but eventaully got everything working, so here is the result of 3 x R-G-B runs through the C14 with my ASI120MM-s, together with my ADC and x2 PM in train. Each capture was 2000 frames per filter, of which I processed 50%, so some 9000 frames in the final image. The end result is quite soft, despite me bullying the data somewhat in Registax and PS. It's certainly not going to win any prizes, but I'm quite pleased with it considering that Jupiter was below 15deg altitude throughout the session. I ran several other AVIs, which I'll process in due course, but as I reported on another thread, I discovered that running the OTA fans in humid conditions fogged both the corrector lens and primary mirror, so I suspect that the above is about as good as I'll get from the session. I hope to try again tonight, now that I've swept the planetary imaging cobwebs away and I've got my replacement laptop working. Cheers, Geof

Hi Stu, yes from my experience the ADC comes into its own at the higher magnifications possible with larger apatures. When I tried to push themagnification up I could still see blue/red fringing even with the ADC prism set to max. Without the ADC Jupiter loked like one of those 3D images without the 3D glasses. I just checked my C14 OTA and all is clear now, which is good. I've not experienced fogging on the inside of the scope previously and of course there's no easy way to clear that, unlike the outside of the corrector plate where a quick blast with a hairdryer generally does the job. I think the dew point was quite high last night as everything was wringing wet. Lesson learnt - I need to be a bit more judicious when using the fans in humid conditions - pity as they really do stabilse the image....😖. Cheers, Geof

Well done Stu, I also had my first session this year on Jupiter tonight using my C14. I set up to try some video captures, but started and finished with some visual. The GRS was on its way to exiting when I started, but I had some lovely views of it using a 40mm eyepiece with the x2 TV Powermate and ADC also in train (approx x200 magnification) - the later makes a huge difference with Jupiter at such a low altitude from my location, removing the red/blue fringes. Io was right on Jupiter’s limb just before being occulted - really a very enjoyable view. I tried a 25mm eyepiece, but x400 was too much for the conditions. I then swapped the eyepieces for my ASI120MM-s camera and ran a bunch of R-G-B and IR AVIs. I did a few test processing with AS3! & Registax and as expected, nothing much to write home about, but I’ll work through them the next few days to see what I can extract. Towards the end of the session I noticed that the images were getting dim and inspection of the corrector plate revealed that it was dewing over. More concerning I could see that the primary was also mirror fogged. I had been running the fans to stabilise air currents in the OTA and am wondering if they had sucked in moist air which settled on the mirror. Anyway, nothing to be done tonight, so I packed up, set the dehumidifier running in the Obs and will check everything out tomorrow. It was fun while it lasted.... Geof

Very good images coming from a DSLR, well done. Geof

Excellent image Rodd, but isn't that M110, not M32? Geof

Superb image Stuart. I have no idea what it is, but you got me checking my Rosette from Jan 2018 and it's there as a faint smudge, best seen in the Ha stack.... Cheers, Geof

Hi Gav, thanks for the detailed explanation, which is what I feared, but I'll give it a try. I find myself sitting there watching the AF hoping and praying for a decent V curve, often to see it fail and have to rerun it, so I may as well cut to the chase and focus away from the cluster... Cheers, Geof

Hi Gav, thanks for posting that link and that's an excellent M2. I'm going to play with the Focus Target module in SGP, but one question I have is does SGP automatically run plate solve to ensure accurate centering of the imaged target after each Focus Target AF run? Did that make sense - basically how do you guarantee the accurate return to and centering of your image target after focus is done? Is that automated or another manual process? Cheers, Geof

Thanks @Demonperformer, that's a good question and I guess the answer is 'yes and no'. Yes, the star colours come from the raw data, but the arcsinH stretch that I used tends to lose star colour, so I used a selective colour mask, with a threshold mask to select just the brighter yellow stars, to given them a colour/saturation boost, so that perhaps means No the colours are not completely genuine. I ran a similar process for the brighter blue stars. I'm reluctant to mess too much with the star colours, but pehaps did a bit more than usual with the golden stars in this image. I hope that clarifies and thanks for asking. Geof

Thanks @MarsG76 and yes, I agree that focus may have been slightly off. I don't have a B-mask for the C14, though I've used them previously on my former 10" Meade LX200 and WO ZS71 APO. I agree that they work very well, but it's not really a solution for the C14 as I'm using SGP autofocus on change of filter, but as discussed elsewhere that routine has issues with globs - see @PhotoGav's thread where we discussed this problem..... Automating AF with SGP for globs remains very much 'work in progress' and ultimately I may have to resort to manual intervention for these targets. Cheers, Geof

Hi John, my filters are Astronomics, which are rated parfocal and appear to be so, but as I don't have anything to monitor temperatutre changes, I do generally opt to check focus on filter change and sometimes at timed intervals, e.g. every hour, just as a precaution. Ok to PM me and perhaps we could also have a brief telcon. Geof

Thanks John, SGP has a module called Focus Target, which allows you to set an alternative target for focussing which is different from the imaging target, so that you can slew back and forth between them as required for focussing and image capture, but it is a manual process that does not run in tandem with auto focus, so I have not used it - yet..!! It's on my list to try this summer, but really I want a fully automated solution that will cycle through filters without my manual intervention to refocus on filter change. Cheers, Geof

@Jkulin thanks for sharing the video tutorial by @RayD . I wish I seen that previously as my first few attempts at setting up SGP AF were mostly fumbling in the dark (literally as well as metaphorically). However, that's not my (nor I think @PhotoGav's) main problem, which is that SGP often (too often in my experience) interprets the cluster core stars as one or more large stars completely throwing off the HFR stats resulting in incorrect (sometimes wildly so) focus positions. As others have mentioned Maxim (which I have used) and ImagesPlus which I also have, use single stars with subframes to calculate HFD, which always worked well for me, but I prefer the other sequence automation features of SGP to both of those other AP solutions. I now always monitor the SGP AF routine to be confident that it runs ok, before letting the sequence continue. That's a very nice M13 BTW, which I'd previously seen, but looking at yours again got me reviewing my processing workflow to brighten the core stars, which looked rather dull and grey in my original version. FYI the revised version is up on Astrobin at https://www.astrobin.com/full/407729/B/ Cheers, Geof

I've also considered using either Maxim, or ImagesPlus Camera Control focus routines for these globs as both allow me to select a star and use subframes and give good results.....

Thanks Gav, yes, globs are definitely targets that fair pretty well when imaging in bright skies. Cheers Geof